CA1101539A - Solid state color camera - Google Patents
Solid state color cameraInfo
- Publication number
- CA1101539A CA1101539A CA279,340A CA279340A CA1101539A CA 1101539 A CA1101539 A CA 1101539A CA 279340 A CA279340 A CA 279340A CA 1101539 A CA1101539 A CA 1101539A
- Authority
- CA
- Canada
- Prior art keywords
- solid state
- color
- signal
- image sensing
- circuit
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
- H04N25/40—Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled
- H04N25/44—Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled by partially reading an SSIS array
- H04N25/447—Extracting pixel data from image sensors by controlling scanning circuits, e.g. by modifying the number of pixels sampled or to be sampled by partially reading an SSIS array by preserving the colour pattern with or without loss of information
Abstract
ABSTRACT OF THE DISCLOSURE
A solid state color camera of a type in which a composite color video signal of the NTSC system is obtained without using a specific color encoder. The solid state color camera has a solid state image sensing device having a plurality of image sensing cells or elements aligned in both vertical and horizontal directions for converting a light information of an object into an electric signal information in association with said image sensing elements, a color filter disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information, a read-out register adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing device and to supply an output video signal in a serial form, a separating circuit for separating a luminance signal component and chrorminance signal component out of said output video signal from said read out register means, an adding circuit for adding said separated luminance signal components and chrominance signal components, a circuit for deriving at a system output a composite color video signal acceptable in the NTSC color system, a supplying circuit for supplying vertical and horizontal scanning signals to said solid state image sensing device, a circuit for supplying read out pulses to said read out register, a frequency of said read out pulses being selected to ? x fS, where N and M are both integers and fS is a frequency of subcarrier of the NTSC color system. and an adjusting circuit for adjusting phase condi-tions of said luminance signal components at said system output as they become equal to said alignment states of said image sensing elements of said solid state image sensing device.
A solid state color camera of a type in which a composite color video signal of the NTSC system is obtained without using a specific color encoder. The solid state color camera has a solid state image sensing device having a plurality of image sensing cells or elements aligned in both vertical and horizontal directions for converting a light information of an object into an electric signal information in association with said image sensing elements, a color filter disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information, a read-out register adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing device and to supply an output video signal in a serial form, a separating circuit for separating a luminance signal component and chrorminance signal component out of said output video signal from said read out register means, an adding circuit for adding said separated luminance signal components and chrominance signal components, a circuit for deriving at a system output a composite color video signal acceptable in the NTSC color system, a supplying circuit for supplying vertical and horizontal scanning signals to said solid state image sensing device, a circuit for supplying read out pulses to said read out register, a frequency of said read out pulses being selected to ? x fS, where N and M are both integers and fS is a frequency of subcarrier of the NTSC color system. and an adjusting circuit for adjusting phase condi-tions of said luminance signal components at said system output as they become equal to said alignment states of said image sensing elements of said solid state image sensing device.
Description
IL~39 I'ielcl Or the Invenlion This invention relates generally to a solid state color camera using a solid state image sensor such as a charge coupled device. and is directed more particularly to a solid state color carnera using a solid state image sensor from which a color video signal satisfying a color video (picked up) signal of the quasi-NTSC system is obtained, The following description is to be taken in conjunction with the accompanying drawings in which like re~erence numerals designate like elements . :
BRIEF DESCRIPTION OF TI~E DRAWING~i -Fig.l is a schematic diagram showing one example of a solid state image sensor used for explaining the presènt invention;
Fig.2 is a part of Fig.1, in enlarged scale. showing an arranging pattern of imaging sensing cells Or the sensor shown in Fig. 1 Fig.3 is a schematic diagram showing a part of another example Or a solid state image sensor;
Fig.~ is a part o~ Fig.3 . in enlarged scale. showing an arranging pattern of image sensing cells Or the sensor shown in ~;
Fig . 3 ;
Fig.5 Is a frequency spectrum diagram Or an output signal from the image sensor;
; Fig.6 is a schematic diagram showing a spatial arranging relation of plural solid state image sensors;
Fig.7 is a phasor diagram showing the phase relation of side band components; .
Fig.8 is a systematic diagram showing an example of a prior art solid state camera system;
Figs.9A . 9B and 9C are diagrams used for explaining the operation of the cell shirting mechanism of the solid state camera shown in Fig.8;
~' ~
' ,. ' 53~
~igs.10A, 10B, 10C and 10D are diagrams used for explaining the operation of this invention;
Fig.11 is a systematic block diagram showing one example of the invention;
Figs.12 and 13 are diagrams used for explaining the operation Or the invention shown in Fig.11;
Figs 14, 16, 18 and 20 are systematic block diagrams showing other examples of the invention, respectively;
Figs.15, 17 and 19 are diagrams showing arranging patterns of spacial and reproduced cells and used for expalining the operations of the examples shown in Figs.14, 16, 18 and 20, respectively .
Description of the Prior Art In the art, when a charge coupled device (which will be referred hereinarter to simply as CCD) is used as a solid state image sensor, the CCD is usually constructed as shown in Fig.1 . `~
The solid state image sensor 10 showrl in the rigure is of the type of a frame (or field) transfer system. In Fig,1 t 1A designates an image sensing array on which an image of an object to be picked - 20 up is projected and which consists of a plurality of image sensing cells 2 (serving as picture elements) arranged in the row and column directions, 1B designates a temporary storage array which is sub-stantially same as the image sensing array 1A in construction except ~ ~;
that it is shielded optically and stores carriers corresponding to the light image of the object and transferred from the sensing array 1A at the positions corresponding to those, of the array 1A, 1 C
designates a horizontal shift register which reads out the information carriers Or one H (where H represents one horizontal scanning period) from the array 1 B, and 3 designates an output terminal led out from the horizontal shift register 1 C- respectively. Further, 4 indicates 1 ~ 4 --'` '' ;'' cl~anl1el stoppers which are formed to be extended to the carrier tr~nsrer direction.
Fig.2 is a schematic diagram which conceptionally illustrated the image sensing cells 2 Or the image sensing array 1A in view of the center of image sensing cells. As shown in Fig.2, plural image sensing cells 2 are arranged in the horizontal and vertical scanning directions parallel with one another In Fig.2 ~ ~H
indicates the arranging pitch of the cells 2 in the horizontal direc-tion. Further, the arrangement of the cells 2 in Fig.2 is the io case of an interlaced image taking system. The image sensing c,ells 2 shown by solid lines in Fig.2 are used in odd fields, while the cells 2 shown by dotted lines in the figure are used in even fields .
The CCD 10 ~vith the arrangement of cells 2 as shown in Fig.2 is conventioIlally called as a parallel-aligned CCD. A
CCD whose arrangement of image sensing cells is . for example, checker-board pattern can be also used as the solid state image sensor of this system.
Fig.3 shows a part of one e~;ample of the checker-pattern CCDs, in which areas o~ each-image sensing cell 2 are optically shield by 2 pitch ( 2 ~H) as shown by the hatched portions in Fig.3, and the optically shielded areas are arranged alternately to make the output signals of adjacent lines in opposite phase condition.
Fig.4 shows a part of Fig.3, which illustrates the image `~
sensing cell portion in enlarged scale, conceptionally.
Before describing a solid state camera using the above CCD, a problem caused by using the above CCD as a solid state ; camera will be now described.
Since the input light informations corresponding to the image of an object are converted to electric signals under such a state that they are sampled at every image sensing cell, a picked ^ - _ 5 _ up signal SO includes a side band component (AC cornponent) SM
iJ) acidition to a base band componen~ or modulated component (DC
component) S~C ~ hich will become a luminance signal, as shown in Fig.5. In this case, a part Or the side band component SM is overlapped on a high band por~ion of tlle modulated component SDc to causean aliasing noise SDH . Thus, the quality Or a reproduced picture is deteriorated.
It is, however, possible to eliminate the aliasing nolse by suitably selecting the band width of the modulated component SDc and the fundamental transfer frequency (samp]ing frequency) fc ( = 1/ ~H ), but this generally means that the band width of the modu-lated component SDC must be selected narrow. If the band width of r .
modulated component SDc is selected, for example, about 3.5 MH
as in the ordinary case, the number NH of image sensing cells in the horizontal scanning direction must be increased because the transfer frequency fC is selected high as the band wid~h of modulated component SDc is ~indelled. Thus, the above mel;hods are not practical.
Accordingly, a solid state camera free from the above problem will be now described. In such an exampl~ as sho~Yn in Fig.6 ~
three CCDs 10A ~ 10B and 10C are used. In this caSe, three CCDs 1 OA, 10B and 1 OC are relatively displaced by--~H with one another in view of projected images. Thus, if the side band components de-rived from the CCDs 10A, 1 0B and 1 0C are taken as Sma, Smb and Smc, respectively ~ and the read-out timing or time relation upon reading out signals from the CCDs 1 OA, 1 OB and 10C is selected to satisfy the phase difference of 120 , the phase difference between the adjacent side band components Sma Smb and SmC becomes 120 as shown in Fig.7. Thus, as shown in F\ig.8, ir picked up output signals Soa Sob and SOc from the CCDs 10A, 1 OB and 1 OC which satisfy the above time relation are supplied to an adding circuit 5, the adding circuit 5 produces a picked-up signal ST in which the side band components Srna Smb and Smc are cancelled and hence there is no aliasing error. The solid state camera system shown in l;`ig.8 is .53~
disclos~tl in ~ho US Patent No.3,975,760 , so that its detailed description will be ormitted. But, in Fig.8, 6 denotes an object to be picked up, 7 an optical system, and 8 a spectroscopic system ~hich includes, for exarmple, half mirrors 8a, 8b and mirrors 8c, 8d. Furtl1er, lZR, 12G and 12E~designate color optical îilters located at the front of the CCDs 10A, 10B and 10C, 9 a matrix (decoder) circuit which is supplied with the picked-up signal ST
from the adding circuit 5, and 11 an encoder which is supplied the output signal from the matrix circuit 9 and produces a color picked-up (video) signal satisfying the NTSC system to be delivered to an output terminal 1 1 a .
If the camera is constructed as shown in Fig.8, the aliasing noise can be eliminated and hence the detcrioration of picture quality caused by the aliasing noise can be avoided.
By using plural CCDs, the number N~ of image sensing cells of each CCD can be decreased.
In order to obtain a desired color picked-up signal of the NTSC system at the output terminal 1 la of the camera sho\vn in Fig 8, it is conventional to supply the composite picl~ed-up si~nal ST
from the adding circuit 5 to the decoder 9 and to carry out the con-version processing of the signal.
In order to satisfy the picked-up signal ST itself as a color picked-up (video) signal SNTSc of tlle NTSC system (this system will be hereinafter called as a direct NTSC system). the following -conditions (I) and (Il) must be at least carried out.
(I) SNTSC = Sy + SC ............................... (1 ) '~ S~r = 0.30 ER + 0.59 Ec; + \0.1 1 EB .. ~ ... (2) SC = --cos 2~ fS t + 2 03 sin2~ fS t .... (3) '~A
:, :
(n) rs = ~55 fl-~ ................... (4) f~' 2 fV --................. (5) where ER ~ EG and EB: R (red); G (green) and B (blue) color signals fs frequency of color sub-carrier fH : horizontal scanning frequency fV : vertical scanning frequency The condition (l) can be satisfied by suitably selecting, for example, the spectroscopic sy,tem and demodulating system, and ~- -the condition (11) can be satisfied by selecting, for example, the frequency of the transfer signal Sc ~ which ~ill be fed to the hori-~ontal shift register 1C of the CCD 10, equal to the frequency fS
t= 3.5795't5 MHz) of the color sub-car:rier of NTSC standard.
That is, since the input light inSormations corresponding to Lhe image of the object are converted to the electric signals under such a state that they are sampled at every image sensing cell. the chrominance component in the picked-up output signal ST from the CCDs 10A, 10B and 10C is obtained as a carrier chrominànce slgnal. `
Further, if the ~ransfer frequency fC is selected as the color sub- ~`
carrier frequerlcy fs ~ the carrier frequency of the carrier chromi- `
nance signal becomes the transfer frequency or color sub-carrier ` ` frequency to satisfy the above conditions (I) and (Il). As a result,even if the encoder 11 is not used, the color video signal of the ~;
NTSC system can be obtalned finally. ~;
;` By the way, if the camera is constructed to satisfy the ; condition (1~), the spatial arrangement of image sensing cells differs from the arrangement of image sensing points in the reproduced :
;
.rr . . . ~
'. ` ~
s~ c~ and ill ~llc arl-all~clllcnt Or rcproduced image sensing points the arrangelllent becomes different at every field and every frame.
As a result, a flicker appears in a reproduced picture.
The above flic]cer phenomenon will be described in a case Or the parallel-aligned CCD. Fig.9A shows the spatial arrange- -ment of image sensing cells 2 at the picking up portion of a CCD, and Figs.9B and 9C sho~ the arrangements of reproduced image sensing cells, respectively.
The number NH of image sensing cells in the horizontal scanning direction in one horizontal scanning period T~l is ex- ~`
pressed as follows.
NH = fS TH ............................................ (6) Therefore, tlle displacement of the arrangement of the reproduced cells or points from the spacial arrangement of the cells on a CCD can be obtained by the equations (6) and (4).
That is, the cell arrangement at a certain field is sufficient to consider the arrangement of tl-e final cell of previous line.
If an odd field at an odd frame is taken as a reference Or first consideration, tlle number oï final image sensing cells in N
lines is given as follows, N NH = N rs TH ....... (7) Since Lhe follo~dng eguation (8) is established fH = T ................................ , (8) tlle equation (7) can be expressed as follows.
N . NH = 2 fH TH N
455 M ..................... ..(9) Thus~ if the number N is an odd number or since the first -~A ~
.. , ~ :;
i39 ]i"c o~ tl~is fiekl is N - l, the cclunLion (9) can be rewritten as rOI10~
1 x NH = 455 wl1ere Q is an integer.
In general, if the reading out order which corresp~nds to a television scanning is taken into consideration, the final image ~-sensing cell N Nll and the first cell (N N~ + l ) in the following (N -~ 1 ) line are arranged apart from each other by ~H in view of space similar to the other cell arrangements. Therefore, the fraction-- in the equation (10) means that the first cell in the next (second) line is displaced from the reference time of the horizontal scanning period Tl~ by--~H . That is, the reproduced positions of the cells beLween the N and (N ~ 1 ) lines are relatively displaced by 2 ~H-Accordingly, at the odd field in the odd frame, a movement or disp]acement of 1 ~ of reproduced cells appears between the N line (odd line) and N ~1 line (even line) as shown in Fig.9B
by the solid llne.
20 ~ Next, an even field in an odd frame is now considered. In this case, since 264th line becomes the first line, Lhe number Or image sensing cells between the lines 263 and 264 can be calculated similar to the equatic,n (9), as follows.
263 NH = 263 x 2 . fH . T~
x 263 x 455 ~:
m ~ 1 \ .. . ...... (11 ) ~here m is an integer. Thus, the reproduced ima6e sensing cells move b~ 2 ~H
..
. ~ . :
Accol~lingly in the cAse of the even rield different lrom the ocld fie~d the reproduced image sensing cells Or only the odd line move hich is s} own in Fig.9B by dotted lines.
In the case of an even frame. the reproduced image sensing cells opposite to the those of the odd frame move on the respective fields. ~hich is shown in Fig.9C.
That is. in the even frame~ the reproduced cells on the odd lines of the odd field move. while the reproduced cells on the even lines of the even field move.
As may be apparent from the comparison Or Figs 9B and 9C. the movement of the reproduced cells occur between the odd and even frames and there is a period of every two frame.
~ \hen the arrangement of the reproduced cells is moved at every field and every frame as described above there are caused flickers and jitters and hence a reproduced picture becomes discom-fortable for a viewer.
\~hen a chec]~ered-pattern of a CCD is used as the CCD of the solid state camera the similar phenomenon will be caused. In this case. however. the movement Or thè reproduced image sensing cells appears in only one ~ield in either of the odd and even frames.
OBJECTS AND SU~IMARY OF THE INVENTION
Accordingly. it is an object of the present invention to provide a solid state color camera free from the defects of the prior art caused by the movement of reproduced image sensing cells in the direct NTSC system.
It is another object Or the invention to provide a solid state color camera vhich is simple in construction but free from the defect inherent to the prior art.
It is a further object of the invention to provide a solid state : ' `'' ~
~ ~-,-- - .~ -, ' ' '~
color camera ~hich produces a color video signal of tl-e quasi-N l'SC system withollt USillg an ellcoder and ~ur~her without separatin~r the luminance and chrominance components.
According to an aspect of the present invention there is provided a solid state color camera ~vhich comprises a solid state irnage sensing device having a plurality of image sensing cells or elements aligned in both vertical and horizontal directions for converting a llght information of an object into an electric signal information in association with said image sensing elements, a color filter disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information, a read-out register adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing device and to supply an output video signal in a serial form, a circuit for separating aluminance signal component and chrominance signal component out of saicl output video signal from said read out register~ an adding circuit for adding said separated lurllinallce signal components and chromirlance signal components, a deriving circuit l`or deriving at a system output a composite color video signal acceptable in the NTSC color system, a supplying circuit for supplying vertical and horizontal scanning signals to said solid state image sensing device, a circuit for supplying read out pulses to said read out register. a frequency of said read out `~ pulses being selected to M x fS J ~here N and M are both integers and fS is a frequency of subcarrier of the NTSC color system, and an adjusting circuit for ndjusting phase conditions of said luminance `~ signal componen~s at said system output as they become equal to said alignment states of said image sensing elements of said solid state image sensin~ device.
, ~ , . .
Lt339 I)ESCRIPTION OF THE PREFERRED EMBODIMENTS `
The present invention ~vill be hereinafter described.
In the invention7 the frequency fC of transfer signal Sc is selected to a multiple of that fs of color sub-carrier by n ( m and n are integers). The arranging pattern of reproduced image sensing cells by the transfer signal Sc is selected or adjusted to be same as the spacial arranging pattern of image sensing cells of the solid state camera, and further a signal adjusting means is provided in the chrominance signal processing circuit such that the phase of color sub-carrier in the chrominance signal of the picked-up output becomes same as that of the color sub-carrier fS in the NTSC s~rstem.
Embodimen~s of the present invention can be classified in accordance witll the number of CCDs used therein as follows:
I In case of three CCDs being used;
A: CCDs of the parallel-aligned type are used and the transfer frequency fC is selected as fs ( . - m = n ), which is referred to first example.
I-B: CCDs of the checkered-pattern type are used and fC = fS ~ which is referred to second example.
I-C: Checkered pattern CCDs are used and fC =--fS
(~ n =2m), which is referred to third example.
. .
A :~
1~ In case Or one~ CCD being used;
II-A: A parallel-aligned CCD is used ancl fC = 3rS ' ( . . 3n = m ), which is referred to fourth example . ~;
~-B: A checkered-pattern CCD is used and fC = 3fS ' which is referred to fifth example.
Il-C: A checkered-pattern CCD is used and fC = 2 fS ' which is referred to sixth example.
A typical one among the above examples of the invention will be described.
In the invention, there are provided a means for correcting undesirable shifts or displacements of reproduced image sensing cells wherein the transfer frequency fC is selected to the color sub-carrier frequency fS of NTSC system and a means for adjusting the phase oî color sub-carrier of chrominance signal same as that of the color sub-carrier of NTSC system, respectively.
As described previously, in the relation between the spacial ~ .
cell arranging pattern and reproduced cell arranging pattern, if the carriers corresponding to the image of an object are read out with the phase of transfer frequency fC (that is, the phase of calor sub-carrier fS 3 as a reference, the spacial cell arrange1nent pattern shown in Fig.9A is reproduced by the patterns as shown in Figs;9B and 9C, in which the cells on only certain lines are displaced by ~ respec-tively. That is, in Figs9B and 9C the reproduced cells with hatches are displaced by 2 ~H ~ respectively.
The patterns of reproduced cells shown in Figs.9B and 9C
are those based upon the luminance signal and also those based upon the color signal. In other words, when the cells are read out with --; the phase of transfer frequency fC as\reference, the pilase betweenthe adjacent horizontal scanning periods become opposite, so that the patterns of reproduced cells based upon the color signal are displaced as shown in the figures.
"' ' `
53~ -1 irstly, the manner to correct tl-e reproduced pnttern oS
luminance signal will be described now. In an odd f~ me~ if Lhe signals on lines where no displacement of reproduced cells is caused (an odd line in an odd field and an even line in n even fie~d) are delayed by a time corresponding to 21 ~H as shown in Fig.
1 OB, the reproduced pattern Or cells becomes same as the spaci~l arranging pattern of cells on a CCD (shown in Fig.1 OA). In view of time, the former pattern is displaced from the latter by just 12 ~H
In an even frame, if the signals on an even line of an odd îield and those an odd line of an even field are delayed, respectively, contrary to the odd frame, the arranging pattern of reproduced cells just same as that shown in Fi~.10B can be obtained.
As described above, if the signal of certain lines are delayed by desired amount, the arranging pattern of reproduced cells of luminance signal can be made coincident with the spacial arranging pattern of cells.
The reproduced pattern of chrominance signal will be now described. The phase of carrier frequency Ss (same as transfer frequency fc) of chrominance signal in the picked-up output must be same as that of color sub-carrier frequency fs of NTSC system in case of direct NTSC system. While, the reproduced pattern of color signal has the phase relation to color sub-carrier of NTSC
system, so that as to the color signal it is suf~icient to correct its delay error relative to the luminance signal whose arrangement is made same as the spacial cell arrangement.
The cell arrangement pattern of luminance signal after it is :,, - corrected is as shown in Fig.1 OB, while the reproduced pattern of ~ ~;
color signal is as shown in Fig.9B in even frame but as shown in Fig.
:. ' \
-, 9C in odd frame. Since the cell displacement amount of color signal is 12 rH l in order to make the displacement amount of repro-~ :
-clnced cells color sigl1al Lrelative to the reproduced cells of luminance signal minin1un1, it is sufficient to delay the color signal by 4 As a result? the relative relation bctween the reproduced cells of color and luminance signals becomes as shown in Figs.lOB, 10C and 1 OD . respectively.
Fig.10C shows the arxanging pattern of reproduced cells in odd frame, and Figs.10D shows that in even frame, respectively with regard to the chrominance signal, in which only the cases of N line are shown. Under such a relation, the time difference between the luminance and chrominance is oniy 1 If the arranging patterns of reproduced cells in the luminance and color signals are desirably corrected respectively as described above. all the defects inherent to the prior art direct-NTSC system can be avoided.
The condition necessary for achieving the direct-NTSC
system, i.e. the above condition (I) will be briefly described [n thespectroscoplcsystemJthe following conditions (a) and (b) are satisfied.
(a) The level ratio; among the signals R, C; and B, which form the luminance signal in the NTSC system, satisfy the equa-tion (2).
(b) The side band components are cancelled so E3S to ellminate aliasing error In order to meet the above conditions (a) and ~b~, it is neces-sary that the output levels of the respective CCDs 1 0A, 1 0B and 1 0C
are equal, so that the spectroscopic characteristics of color filters 1 2R, 1 2G and 1 2B must be selected to satisfy the above conditions .
If color filters 1 2R, 1 2G and 1 2B, e~ch being a single color light transmission type as shown in Fig.8, are used, neither of the above conditions can be satisfied. Thus, color filters having the following .
:`~
;i39 c~troscol):ic clla.:ractc!ristics cl~re p:referably reqll.ired, \t ~irst. tllc relation betweell tl~e outputs Soa ~ Sob and Soc Or the CCDs l OA, 1 0B and I OC and the signals R. G and B `
is expressed by the following equation (l2).
~ Soa l - r1 g1 bl I R ~ ;
ob ~ = r2 g2 b2 x ~ G ~ ............. (12) Soc r3 g3 b3 B
Although the detailed description for the above equation (12) to satisfy the conclitions (a) and (b) will be omitted, if the respecti~e constants are selected in accordance with the ïollowing equation (13).
the conditions (a) and (b) are satisfied.
r1 gl b1 l ~f 0,2028 0,1305 0.0000 l r2 g2 b2 ~ = l 0.0423 0.2911 o-OOOO ~ (13) ] 3 g3 b3 ~ O.0549 0.1 68~ 0.11 00 From the equation (l3). the respective output le~rels ER~ EG
and EB of the signals R, G and B become as follows, Er~ = (rl -~ r2 -1- r3 ) R = 0,3000 EG ~ (g1 ~ g2 ~ g3 ) G = 0,59 ,.,.,,,, (1 EB = (b1 ~ b2 -1- b3 ) B = 0,1100 Thereby, the condition (a) is satisfied, Further. since the - respective outputs Soa Sob ancl SOc from the CCDs 10A . 10B and - 10C are expressed by the following equation (15) Soa = r1 R + gl G = 0,3333 - - Sob = r2R ~ g2G = 0.333~ ~ ....... , (15) Soc = r3 R ~ g3G ~ b3B 0,33 where R = G = B = 1 . the condition (b) is also satisîied, Accordingly.
the color ïilters 12R. 12G and 12B, w,hich have filter characteristics to satisfy the equation (13). are located at the front of the CGDs -I OA, 1 OB and l OC, respecti~ely~
.
.
.. . ' 53~
~n c~aml)le o~ thc soLid state color camera according to the present invention, which satisfies the above conditions (I) and (11) wilL be explained with reference to Fig.11 In Fig.11 which is a systematic diagram of the example of the invention, 20 generally designates the solid state color camera wherein three CCDs 10~, 1 OB and 1 OC are supplied at their hori-zontal shift registers ~vith the transfer signal Sc obtained from a synchroni~ing board 21~ respectively. In this case, it will be apparent that transfer signals Sc2 and Sc3 supplied to the CCDs 10B and 10C are shifted in phase from the transfer signal Sc ( or Scl ~ supplied to the CCD 1 OA by 3 ~ and 3~ 7~, respectively (Refer to Figs.12A, 12B and 12C). To this end, phase shifters 22 and 23 are provided to receive the transfer signal Sc from the synchro~ ing board 21 and to produce the phase-shirted transfer signals Sc2 and Sc3 ~ respectively.
As described above, with the invention read-out signals Soa ~ Sob and Soc are obtained from the :respective CCDs 1 OA
l OB and 1 OC aLternately and successiveLy in delayed state in view of time and then composed. In this case, however, in the respec-tive signal transmission paths for luminance signal from the CCDs 1 OA ~ 1 OB and 1 OC to an adder 25, there are provided correcting circults 26A, 26B and 26C which serve as adjusting means to adjust the displacement of reproduced image sensing cells of luminance signal .
Since all the correcting circuits 26A, 26B and 26C are same in construction, one of them~ for example~ the correcting circuit 26A
; will be now described. The correcting circult 26A is formed of a delay circuit or delay line 27A and a s,witching circuit 2~A which is supplied with the delayed output signal from the delay line 27A and non-delayed signal~ respectively~ and switched at every 1H. In this -!.g.-~ ~ ' casc, the clelay time Or c-lelay ]ine 27A is selected to be the time correspon~ing to the correctil1g amount 1 ~H of the pitch shown in Fig.10. ~Vhen three CCDs 10A, 10B and 10C are used.
--~H is about 140 n sec. (Nano second) so that this time is the delay time of delay line 27A. As set forth just above, the other correcting circuits 26B and 26C are formed of delay lines 27B, 27C, whose delay time is same as that of delay line 27A, and switching circuits 28B, 28C, respectively.
The switching circuits 2~A, 28B and 28C are supplied O with a switching pulse SH, which is obtained from the synchro-nizing board 21 and synchronized with the horizontal pulse . so that from the switching circuits 28A, 28B and 28C there are derived the delayed and non-delayed output signals alternately at every 1H in a certain field. As described above, the delay line for delaying the picl;ed-up outputs Soa ~ Sob and Soc is the N line in the case of an odd field in an odd frame but the ( N + 1) line in the case of an even field in the odd frame. ~Vhile, in an even frame~ the delay line is the (N + 1) line in an odd field and the N line in an even field. Therefore. in order to carry out the - above mentioned switching operation, on the transmission path of ~ -- the s~vitching pulse signal SH there is provided a phase-inverting control circuit 29 which is formed of a phase inverter circuit 29a and a switch 29b which is switched at every field.
If the picked-uP outputs Soa J Sob and SOc J which are obtained by the above switching operation, are composed . the luminance signal . whose reproduced cell pattern is shown in Fig.10B, can be obtained.
In Fig.11 . 32A . 32B and 32C are sampling hold circuits connected be~ween the CCDs 1 OA, 1 OB, 1 OC and the delay circuits 0 27A, 27B, 27C, respectively.
_ 1 9 _ ~. , .
/~s to the chrominance ~signal~ since whole signal is clelayed by the time corresponding to ~ , only a sirnple signal proces-sing different from the luminance signal is necessary. That is, the picked-up outputs Soa, S;~b and SOc at the prior stage of the correcting eircuits 26A, 26B and 26C are suppliecl to an adder 33 to be composed, and then fed to a band pass filter 3~ which passes therethrough the chrominance signal Sc . The chrominance signal SC is fed to a delay circuit or line 35, which ~orms a eorreeting means whose delay time eo:rresponds to--~l (70 ,u see. in this l O example ). The arranging pattern of reproduced cells based upon the output from the delay line 35 becomes as shown in Figs.10C and 1 OD .
The output or composite output signal ST from the adder 25 is supplied to a low pass filter 36 to be rest-ricted to a desired band (about ~.5 Ivll-Iz) and then to a proeessing eireuit 37, whieh is also supplied with the various synehroniz;ing signals to produee the well-l~nown eomposite eolor video signal ~SNT$c . That is, the blanlcing pulse BL[C, synehronizing signals VD, ~ID, burst signal BWRST, whieh are obtained from the synchronizing board 21. and so on are supplied to the processing cireuit 37. As shown in Fig.11 J vertical ~;
and horizontal synchronizing signals of the NTSC system are also sup-plied to respective CCDs 10A . 10B and 10C from the synchronizing board 21 in well-known manner.
In this caseJ the phase of the burst signal is selected as follows. When the ehrominaneé signal is demodulated in a television reeeiver, its demodulating axes are R-Y axis and B~Y axis~ In this ease, the demodulated eolor signal with the above demodulating axes must be satisfy the eondition of the NI~SC system, namely, the equa-tion (3). To this end, the axes R-Y and B-Y are seleeted as shown in Fig.1 3. The angle ~ shown in Fig.1 3 ean be determined, for example, as follows.
... .
,
BRIEF DESCRIPTION OF TI~E DRAWING~i -Fig.l is a schematic diagram showing one example of a solid state image sensor used for explaining the presènt invention;
Fig.2 is a part of Fig.1, in enlarged scale. showing an arranging pattern of imaging sensing cells Or the sensor shown in Fig. 1 Fig.3 is a schematic diagram showing a part of another example Or a solid state image sensor;
Fig.~ is a part o~ Fig.3 . in enlarged scale. showing an arranging pattern of image sensing cells Or the sensor shown in ~;
Fig . 3 ;
Fig.5 Is a frequency spectrum diagram Or an output signal from the image sensor;
; Fig.6 is a schematic diagram showing a spatial arranging relation of plural solid state image sensors;
Fig.7 is a phasor diagram showing the phase relation of side band components; .
Fig.8 is a systematic diagram showing an example of a prior art solid state camera system;
Figs.9A . 9B and 9C are diagrams used for explaining the operation of the cell shirting mechanism of the solid state camera shown in Fig.8;
~' ~
' ,. ' 53~
~igs.10A, 10B, 10C and 10D are diagrams used for explaining the operation of this invention;
Fig.11 is a systematic block diagram showing one example of the invention;
Figs.12 and 13 are diagrams used for explaining the operation Or the invention shown in Fig.11;
Figs 14, 16, 18 and 20 are systematic block diagrams showing other examples of the invention, respectively;
Figs.15, 17 and 19 are diagrams showing arranging patterns of spacial and reproduced cells and used for expalining the operations of the examples shown in Figs.14, 16, 18 and 20, respectively .
Description of the Prior Art In the art, when a charge coupled device (which will be referred hereinarter to simply as CCD) is used as a solid state image sensor, the CCD is usually constructed as shown in Fig.1 . `~
The solid state image sensor 10 showrl in the rigure is of the type of a frame (or field) transfer system. In Fig,1 t 1A designates an image sensing array on which an image of an object to be picked - 20 up is projected and which consists of a plurality of image sensing cells 2 (serving as picture elements) arranged in the row and column directions, 1B designates a temporary storage array which is sub-stantially same as the image sensing array 1A in construction except ~ ~;
that it is shielded optically and stores carriers corresponding to the light image of the object and transferred from the sensing array 1A at the positions corresponding to those, of the array 1A, 1 C
designates a horizontal shift register which reads out the information carriers Or one H (where H represents one horizontal scanning period) from the array 1 B, and 3 designates an output terminal led out from the horizontal shift register 1 C- respectively. Further, 4 indicates 1 ~ 4 --'` '' ;'' cl~anl1el stoppers which are formed to be extended to the carrier tr~nsrer direction.
Fig.2 is a schematic diagram which conceptionally illustrated the image sensing cells 2 Or the image sensing array 1A in view of the center of image sensing cells. As shown in Fig.2, plural image sensing cells 2 are arranged in the horizontal and vertical scanning directions parallel with one another In Fig.2 ~ ~H
indicates the arranging pitch of the cells 2 in the horizontal direc-tion. Further, the arrangement of the cells 2 in Fig.2 is the io case of an interlaced image taking system. The image sensing c,ells 2 shown by solid lines in Fig.2 are used in odd fields, while the cells 2 shown by dotted lines in the figure are used in even fields .
The CCD 10 ~vith the arrangement of cells 2 as shown in Fig.2 is conventioIlally called as a parallel-aligned CCD. A
CCD whose arrangement of image sensing cells is . for example, checker-board pattern can be also used as the solid state image sensor of this system.
Fig.3 shows a part of one e~;ample of the checker-pattern CCDs, in which areas o~ each-image sensing cell 2 are optically shield by 2 pitch ( 2 ~H) as shown by the hatched portions in Fig.3, and the optically shielded areas are arranged alternately to make the output signals of adjacent lines in opposite phase condition.
Fig.4 shows a part of Fig.3, which illustrates the image `~
sensing cell portion in enlarged scale, conceptionally.
Before describing a solid state camera using the above CCD, a problem caused by using the above CCD as a solid state ; camera will be now described.
Since the input light informations corresponding to the image of an object are converted to electric signals under such a state that they are sampled at every image sensing cell, a picked ^ - _ 5 _ up signal SO includes a side band component (AC cornponent) SM
iJ) acidition to a base band componen~ or modulated component (DC
component) S~C ~ hich will become a luminance signal, as shown in Fig.5. In this case, a part Or the side band component SM is overlapped on a high band por~ion of tlle modulated component SDc to causean aliasing noise SDH . Thus, the quality Or a reproduced picture is deteriorated.
It is, however, possible to eliminate the aliasing nolse by suitably selecting the band width of the modulated component SDc and the fundamental transfer frequency (samp]ing frequency) fc ( = 1/ ~H ), but this generally means that the band width of the modu-lated component SDC must be selected narrow. If the band width of r .
modulated component SDc is selected, for example, about 3.5 MH
as in the ordinary case, the number NH of image sensing cells in the horizontal scanning direction must be increased because the transfer frequency fC is selected high as the band wid~h of modulated component SDc is ~indelled. Thus, the above mel;hods are not practical.
Accordingly, a solid state camera free from the above problem will be now described. In such an exampl~ as sho~Yn in Fig.6 ~
three CCDs 10A ~ 10B and 10C are used. In this caSe, three CCDs 1 OA, 10B and 1 OC are relatively displaced by--~H with one another in view of projected images. Thus, if the side band components de-rived from the CCDs 10A, 1 0B and 1 0C are taken as Sma, Smb and Smc, respectively ~ and the read-out timing or time relation upon reading out signals from the CCDs 1 OA, 1 OB and 10C is selected to satisfy the phase difference of 120 , the phase difference between the adjacent side band components Sma Smb and SmC becomes 120 as shown in Fig.7. Thus, as shown in F\ig.8, ir picked up output signals Soa Sob and SOc from the CCDs 10A, 1 OB and 1 OC which satisfy the above time relation are supplied to an adding circuit 5, the adding circuit 5 produces a picked-up signal ST in which the side band components Srna Smb and Smc are cancelled and hence there is no aliasing error. The solid state camera system shown in l;`ig.8 is .53~
disclos~tl in ~ho US Patent No.3,975,760 , so that its detailed description will be ormitted. But, in Fig.8, 6 denotes an object to be picked up, 7 an optical system, and 8 a spectroscopic system ~hich includes, for exarmple, half mirrors 8a, 8b and mirrors 8c, 8d. Furtl1er, lZR, 12G and 12E~designate color optical îilters located at the front of the CCDs 10A, 10B and 10C, 9 a matrix (decoder) circuit which is supplied with the picked-up signal ST
from the adding circuit 5, and 11 an encoder which is supplied the output signal from the matrix circuit 9 and produces a color picked-up (video) signal satisfying the NTSC system to be delivered to an output terminal 1 1 a .
If the camera is constructed as shown in Fig.8, the aliasing noise can be eliminated and hence the detcrioration of picture quality caused by the aliasing noise can be avoided.
By using plural CCDs, the number N~ of image sensing cells of each CCD can be decreased.
In order to obtain a desired color picked-up signal of the NTSC system at the output terminal 1 la of the camera sho\vn in Fig 8, it is conventional to supply the composite picl~ed-up si~nal ST
from the adding circuit 5 to the decoder 9 and to carry out the con-version processing of the signal.
In order to satisfy the picked-up signal ST itself as a color picked-up (video) signal SNTSc of tlle NTSC system (this system will be hereinafter called as a direct NTSC system). the following -conditions (I) and (Il) must be at least carried out.
(I) SNTSC = Sy + SC ............................... (1 ) '~ S~r = 0.30 ER + 0.59 Ec; + \0.1 1 EB .. ~ ... (2) SC = --cos 2~ fS t + 2 03 sin2~ fS t .... (3) '~A
:, :
(n) rs = ~55 fl-~ ................... (4) f~' 2 fV --................. (5) where ER ~ EG and EB: R (red); G (green) and B (blue) color signals fs frequency of color sub-carrier fH : horizontal scanning frequency fV : vertical scanning frequency The condition (l) can be satisfied by suitably selecting, for example, the spectroscopic sy,tem and demodulating system, and ~- -the condition (11) can be satisfied by selecting, for example, the frequency of the transfer signal Sc ~ which ~ill be fed to the hori-~ontal shift register 1C of the CCD 10, equal to the frequency fS
t= 3.5795't5 MHz) of the color sub-car:rier of NTSC standard.
That is, since the input light inSormations corresponding to Lhe image of the object are converted to the electric signals under such a state that they are sampled at every image sensing cell. the chrominance component in the picked-up output signal ST from the CCDs 10A, 10B and 10C is obtained as a carrier chrominànce slgnal. `
Further, if the ~ransfer frequency fC is selected as the color sub- ~`
carrier frequerlcy fs ~ the carrier frequency of the carrier chromi- `
nance signal becomes the transfer frequency or color sub-carrier ` ` frequency to satisfy the above conditions (I) and (Il). As a result,even if the encoder 11 is not used, the color video signal of the ~;
NTSC system can be obtalned finally. ~;
;` By the way, if the camera is constructed to satisfy the ; condition (1~), the spatial arrangement of image sensing cells differs from the arrangement of image sensing points in the reproduced :
;
.rr . . . ~
'. ` ~
s~ c~ and ill ~llc arl-all~clllcnt Or rcproduced image sensing points the arrangelllent becomes different at every field and every frame.
As a result, a flicker appears in a reproduced picture.
The above flic]cer phenomenon will be described in a case Or the parallel-aligned CCD. Fig.9A shows the spatial arrange- -ment of image sensing cells 2 at the picking up portion of a CCD, and Figs.9B and 9C sho~ the arrangements of reproduced image sensing cells, respectively.
The number NH of image sensing cells in the horizontal scanning direction in one horizontal scanning period T~l is ex- ~`
pressed as follows.
NH = fS TH ............................................ (6) Therefore, tlle displacement of the arrangement of the reproduced cells or points from the spacial arrangement of the cells on a CCD can be obtained by the equations (6) and (4).
That is, the cell arrangement at a certain field is sufficient to consider the arrangement of tl-e final cell of previous line.
If an odd field at an odd frame is taken as a reference Or first consideration, tlle number oï final image sensing cells in N
lines is given as follows, N NH = N rs TH ....... (7) Since Lhe follo~dng eguation (8) is established fH = T ................................ , (8) tlle equation (7) can be expressed as follows.
N . NH = 2 fH TH N
455 M ..................... ..(9) Thus~ if the number N is an odd number or since the first -~A ~
.. , ~ :;
i39 ]i"c o~ tl~is fiekl is N - l, the cclunLion (9) can be rewritten as rOI10~
1 x NH = 455 wl1ere Q is an integer.
In general, if the reading out order which corresp~nds to a television scanning is taken into consideration, the final image ~-sensing cell N Nll and the first cell (N N~ + l ) in the following (N -~ 1 ) line are arranged apart from each other by ~H in view of space similar to the other cell arrangements. Therefore, the fraction-- in the equation (10) means that the first cell in the next (second) line is displaced from the reference time of the horizontal scanning period Tl~ by--~H . That is, the reproduced positions of the cells beLween the N and (N ~ 1 ) lines are relatively displaced by 2 ~H-Accordingly, at the odd field in the odd frame, a movement or disp]acement of 1 ~ of reproduced cells appears between the N line (odd line) and N ~1 line (even line) as shown in Fig.9B
by the solid llne.
20 ~ Next, an even field in an odd frame is now considered. In this case, since 264th line becomes the first line, Lhe number Or image sensing cells between the lines 263 and 264 can be calculated similar to the equatic,n (9), as follows.
263 NH = 263 x 2 . fH . T~
x 263 x 455 ~:
m ~ 1 \ .. . ...... (11 ) ~here m is an integer. Thus, the reproduced ima6e sensing cells move b~ 2 ~H
..
. ~ . :
Accol~lingly in the cAse of the even rield different lrom the ocld fie~d the reproduced image sensing cells Or only the odd line move hich is s} own in Fig.9B by dotted lines.
In the case of an even frame. the reproduced image sensing cells opposite to the those of the odd frame move on the respective fields. ~hich is shown in Fig.9C.
That is. in the even frame~ the reproduced cells on the odd lines of the odd field move. while the reproduced cells on the even lines of the even field move.
As may be apparent from the comparison Or Figs 9B and 9C. the movement of the reproduced cells occur between the odd and even frames and there is a period of every two frame.
~ \hen the arrangement of the reproduced cells is moved at every field and every frame as described above there are caused flickers and jitters and hence a reproduced picture becomes discom-fortable for a viewer.
\~hen a chec]~ered-pattern of a CCD is used as the CCD of the solid state camera the similar phenomenon will be caused. In this case. however. the movement Or thè reproduced image sensing cells appears in only one ~ield in either of the odd and even frames.
OBJECTS AND SU~IMARY OF THE INVENTION
Accordingly. it is an object of the present invention to provide a solid state color camera free from the defects of the prior art caused by the movement of reproduced image sensing cells in the direct NTSC system.
It is another object Or the invention to provide a solid state color camera vhich is simple in construction but free from the defect inherent to the prior art.
It is a further object of the invention to provide a solid state : ' `'' ~
~ ~-,-- - .~ -, ' ' '~
color camera ~hich produces a color video signal of tl-e quasi-N l'SC system withollt USillg an ellcoder and ~ur~her without separatin~r the luminance and chrominance components.
According to an aspect of the present invention there is provided a solid state color camera ~vhich comprises a solid state irnage sensing device having a plurality of image sensing cells or elements aligned in both vertical and horizontal directions for converting a llght information of an object into an electric signal information in association with said image sensing elements, a color filter disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information, a read-out register adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing device and to supply an output video signal in a serial form, a circuit for separating aluminance signal component and chrominance signal component out of saicl output video signal from said read out register~ an adding circuit for adding said separated lurllinallce signal components and chromirlance signal components, a deriving circuit l`or deriving at a system output a composite color video signal acceptable in the NTSC color system, a supplying circuit for supplying vertical and horizontal scanning signals to said solid state image sensing device, a circuit for supplying read out pulses to said read out register. a frequency of said read out `~ pulses being selected to M x fS J ~here N and M are both integers and fS is a frequency of subcarrier of the NTSC color system, and an adjusting circuit for ndjusting phase conditions of said luminance `~ signal componen~s at said system output as they become equal to said alignment states of said image sensing elements of said solid state image sensin~ device.
, ~ , . .
Lt339 I)ESCRIPTION OF THE PREFERRED EMBODIMENTS `
The present invention ~vill be hereinafter described.
In the invention7 the frequency fC of transfer signal Sc is selected to a multiple of that fs of color sub-carrier by n ( m and n are integers). The arranging pattern of reproduced image sensing cells by the transfer signal Sc is selected or adjusted to be same as the spacial arranging pattern of image sensing cells of the solid state camera, and further a signal adjusting means is provided in the chrominance signal processing circuit such that the phase of color sub-carrier in the chrominance signal of the picked-up output becomes same as that of the color sub-carrier fS in the NTSC s~rstem.
Embodimen~s of the present invention can be classified in accordance witll the number of CCDs used therein as follows:
I In case of three CCDs being used;
A: CCDs of the parallel-aligned type are used and the transfer frequency fC is selected as fs ( . - m = n ), which is referred to first example.
I-B: CCDs of the checkered-pattern type are used and fC = fS ~ which is referred to second example.
I-C: Checkered pattern CCDs are used and fC =--fS
(~ n =2m), which is referred to third example.
. .
A :~
1~ In case Or one~ CCD being used;
II-A: A parallel-aligned CCD is used ancl fC = 3rS ' ( . . 3n = m ), which is referred to fourth example . ~;
~-B: A checkered-pattern CCD is used and fC = 3fS ' which is referred to fifth example.
Il-C: A checkered-pattern CCD is used and fC = 2 fS ' which is referred to sixth example.
A typical one among the above examples of the invention will be described.
In the invention, there are provided a means for correcting undesirable shifts or displacements of reproduced image sensing cells wherein the transfer frequency fC is selected to the color sub-carrier frequency fS of NTSC system and a means for adjusting the phase oî color sub-carrier of chrominance signal same as that of the color sub-carrier of NTSC system, respectively.
As described previously, in the relation between the spacial ~ .
cell arranging pattern and reproduced cell arranging pattern, if the carriers corresponding to the image of an object are read out with the phase of transfer frequency fC (that is, the phase of calor sub-carrier fS 3 as a reference, the spacial cell arrange1nent pattern shown in Fig.9A is reproduced by the patterns as shown in Figs;9B and 9C, in which the cells on only certain lines are displaced by ~ respec-tively. That is, in Figs9B and 9C the reproduced cells with hatches are displaced by 2 ~H ~ respectively.
The patterns of reproduced cells shown in Figs.9B and 9C
are those based upon the luminance signal and also those based upon the color signal. In other words, when the cells are read out with --; the phase of transfer frequency fC as\reference, the pilase betweenthe adjacent horizontal scanning periods become opposite, so that the patterns of reproduced cells based upon the color signal are displaced as shown in the figures.
"' ' `
53~ -1 irstly, the manner to correct tl-e reproduced pnttern oS
luminance signal will be described now. In an odd f~ me~ if Lhe signals on lines where no displacement of reproduced cells is caused (an odd line in an odd field and an even line in n even fie~d) are delayed by a time corresponding to 21 ~H as shown in Fig.
1 OB, the reproduced pattern Or cells becomes same as the spaci~l arranging pattern of cells on a CCD (shown in Fig.1 OA). In view of time, the former pattern is displaced from the latter by just 12 ~H
In an even frame, if the signals on an even line of an odd îield and those an odd line of an even field are delayed, respectively, contrary to the odd frame, the arranging pattern of reproduced cells just same as that shown in Fi~.10B can be obtained.
As described above, if the signal of certain lines are delayed by desired amount, the arranging pattern of reproduced cells of luminance signal can be made coincident with the spacial arranging pattern of cells.
The reproduced pattern of chrominance signal will be now described. The phase of carrier frequency Ss (same as transfer frequency fc) of chrominance signal in the picked-up output must be same as that of color sub-carrier frequency fs of NTSC system in case of direct NTSC system. While, the reproduced pattern of color signal has the phase relation to color sub-carrier of NTSC
system, so that as to the color signal it is suf~icient to correct its delay error relative to the luminance signal whose arrangement is made same as the spacial cell arrangement.
The cell arrangement pattern of luminance signal after it is :,, - corrected is as shown in Fig.1 OB, while the reproduced pattern of ~ ~;
color signal is as shown in Fig.9B in even frame but as shown in Fig.
:. ' \
-, 9C in odd frame. Since the cell displacement amount of color signal is 12 rH l in order to make the displacement amount of repro-~ :
-clnced cells color sigl1al Lrelative to the reproduced cells of luminance signal minin1un1, it is sufficient to delay the color signal by 4 As a result? the relative relation bctween the reproduced cells of color and luminance signals becomes as shown in Figs.lOB, 10C and 1 OD . respectively.
Fig.10C shows the arxanging pattern of reproduced cells in odd frame, and Figs.10D shows that in even frame, respectively with regard to the chrominance signal, in which only the cases of N line are shown. Under such a relation, the time difference between the luminance and chrominance is oniy 1 If the arranging patterns of reproduced cells in the luminance and color signals are desirably corrected respectively as described above. all the defects inherent to the prior art direct-NTSC system can be avoided.
The condition necessary for achieving the direct-NTSC
system, i.e. the above condition (I) will be briefly described [n thespectroscoplcsystemJthe following conditions (a) and (b) are satisfied.
(a) The level ratio; among the signals R, C; and B, which form the luminance signal in the NTSC system, satisfy the equa-tion (2).
(b) The side band components are cancelled so E3S to ellminate aliasing error In order to meet the above conditions (a) and ~b~, it is neces-sary that the output levels of the respective CCDs 1 0A, 1 0B and 1 0C
are equal, so that the spectroscopic characteristics of color filters 1 2R, 1 2G and 1 2B must be selected to satisfy the above conditions .
If color filters 1 2R, 1 2G and 1 2B, e~ch being a single color light transmission type as shown in Fig.8, are used, neither of the above conditions can be satisfied. Thus, color filters having the following .
:`~
;i39 c~troscol):ic clla.:ractc!ristics cl~re p:referably reqll.ired, \t ~irst. tllc relation betweell tl~e outputs Soa ~ Sob and Soc Or the CCDs l OA, 1 0B and I OC and the signals R. G and B `
is expressed by the following equation (l2).
~ Soa l - r1 g1 bl I R ~ ;
ob ~ = r2 g2 b2 x ~ G ~ ............. (12) Soc r3 g3 b3 B
Although the detailed description for the above equation (12) to satisfy the conclitions (a) and (b) will be omitted, if the respecti~e constants are selected in accordance with the ïollowing equation (13).
the conditions (a) and (b) are satisfied.
r1 gl b1 l ~f 0,2028 0,1305 0.0000 l r2 g2 b2 ~ = l 0.0423 0.2911 o-OOOO ~ (13) ] 3 g3 b3 ~ O.0549 0.1 68~ 0.11 00 From the equation (l3). the respective output le~rels ER~ EG
and EB of the signals R, G and B become as follows, Er~ = (rl -~ r2 -1- r3 ) R = 0,3000 EG ~ (g1 ~ g2 ~ g3 ) G = 0,59 ,.,.,,,, (1 EB = (b1 ~ b2 -1- b3 ) B = 0,1100 Thereby, the condition (a) is satisfied, Further. since the - respective outputs Soa Sob ancl SOc from the CCDs 10A . 10B and - 10C are expressed by the following equation (15) Soa = r1 R + gl G = 0,3333 - - Sob = r2R ~ g2G = 0.333~ ~ ....... , (15) Soc = r3 R ~ g3G ~ b3B 0,33 where R = G = B = 1 . the condition (b) is also satisîied, Accordingly.
the color ïilters 12R. 12G and 12B, w,hich have filter characteristics to satisfy the equation (13). are located at the front of the CGDs -I OA, 1 OB and l OC, respecti~ely~
.
.
.. . ' 53~
~n c~aml)le o~ thc soLid state color camera according to the present invention, which satisfies the above conditions (I) and (11) wilL be explained with reference to Fig.11 In Fig.11 which is a systematic diagram of the example of the invention, 20 generally designates the solid state color camera wherein three CCDs 10~, 1 OB and 1 OC are supplied at their hori-zontal shift registers ~vith the transfer signal Sc obtained from a synchroni~ing board 21~ respectively. In this case, it will be apparent that transfer signals Sc2 and Sc3 supplied to the CCDs 10B and 10C are shifted in phase from the transfer signal Sc ( or Scl ~ supplied to the CCD 1 OA by 3 ~ and 3~ 7~, respectively (Refer to Figs.12A, 12B and 12C). To this end, phase shifters 22 and 23 are provided to receive the transfer signal Sc from the synchro~ ing board 21 and to produce the phase-shirted transfer signals Sc2 and Sc3 ~ respectively.
As described above, with the invention read-out signals Soa ~ Sob and Soc are obtained from the :respective CCDs 1 OA
l OB and 1 OC aLternately and successiveLy in delayed state in view of time and then composed. In this case, however, in the respec-tive signal transmission paths for luminance signal from the CCDs 1 OA ~ 1 OB and 1 OC to an adder 25, there are provided correcting circults 26A, 26B and 26C which serve as adjusting means to adjust the displacement of reproduced image sensing cells of luminance signal .
Since all the correcting circuits 26A, 26B and 26C are same in construction, one of them~ for example~ the correcting circuit 26A
; will be now described. The correcting circult 26A is formed of a delay circuit or delay line 27A and a s,witching circuit 2~A which is supplied with the delayed output signal from the delay line 27A and non-delayed signal~ respectively~ and switched at every 1H. In this -!.g.-~ ~ ' casc, the clelay time Or c-lelay ]ine 27A is selected to be the time correspon~ing to the correctil1g amount 1 ~H of the pitch shown in Fig.10. ~Vhen three CCDs 10A, 10B and 10C are used.
--~H is about 140 n sec. (Nano second) so that this time is the delay time of delay line 27A. As set forth just above, the other correcting circuits 26B and 26C are formed of delay lines 27B, 27C, whose delay time is same as that of delay line 27A, and switching circuits 28B, 28C, respectively.
The switching circuits 2~A, 28B and 28C are supplied O with a switching pulse SH, which is obtained from the synchro-nizing board 21 and synchronized with the horizontal pulse . so that from the switching circuits 28A, 28B and 28C there are derived the delayed and non-delayed output signals alternately at every 1H in a certain field. As described above, the delay line for delaying the picl;ed-up outputs Soa ~ Sob and Soc is the N line in the case of an odd field in an odd frame but the ( N + 1) line in the case of an even field in the odd frame. ~Vhile, in an even frame~ the delay line is the (N + 1) line in an odd field and the N line in an even field. Therefore. in order to carry out the - above mentioned switching operation, on the transmission path of ~ -- the s~vitching pulse signal SH there is provided a phase-inverting control circuit 29 which is formed of a phase inverter circuit 29a and a switch 29b which is switched at every field.
If the picked-uP outputs Soa J Sob and SOc J which are obtained by the above switching operation, are composed . the luminance signal . whose reproduced cell pattern is shown in Fig.10B, can be obtained.
In Fig.11 . 32A . 32B and 32C are sampling hold circuits connected be~ween the CCDs 1 OA, 1 OB, 1 OC and the delay circuits 0 27A, 27B, 27C, respectively.
_ 1 9 _ ~. , .
/~s to the chrominance ~signal~ since whole signal is clelayed by the time corresponding to ~ , only a sirnple signal proces-sing different from the luminance signal is necessary. That is, the picked-up outputs Soa, S;~b and SOc at the prior stage of the correcting eircuits 26A, 26B and 26C are suppliecl to an adder 33 to be composed, and then fed to a band pass filter 3~ which passes therethrough the chrominance signal Sc . The chrominance signal SC is fed to a delay circuit or line 35, which ~orms a eorreeting means whose delay time eo:rresponds to--~l (70 ,u see. in this l O example ). The arranging pattern of reproduced cells based upon the output from the delay line 35 becomes as shown in Figs.10C and 1 OD .
The output or composite output signal ST from the adder 25 is supplied to a low pass filter 36 to be rest-ricted to a desired band (about ~.5 Ivll-Iz) and then to a proeessing eireuit 37, whieh is also supplied with the various synehroniz;ing signals to produee the well-l~nown eomposite eolor video signal ~SNT$c . That is, the blanlcing pulse BL[C, synehronizing signals VD, ~ID, burst signal BWRST, whieh are obtained from the synchronizing board 21. and so on are supplied to the processing cireuit 37. As shown in Fig.11 J vertical ~;
and horizontal synchronizing signals of the NTSC system are also sup-plied to respective CCDs 10A . 10B and 10C from the synchronizing board 21 in well-known manner.
In this caseJ the phase of the burst signal is selected as follows. When the ehrominaneé signal is demodulated in a television reeeiver, its demodulating axes are R-Y axis and B~Y axis~ In this ease, the demodulated eolor signal with the above demodulating axes must be satisfy the eondition of the NI~SC system, namely, the equa-tion (3). To this end, the axes R-Y and B-Y are seleeted as shown in Fig.1 3. The angle ~ shown in Fig.1 3 ean be determined, for example, as follows.
... .
,
- 2 0 -::
5~9 9 = 12.~1 ................................. (16) A demodulated output signal (chrominance signal) Sc~ in the case of equation (16)is e~cpressed by the following equation (17) Sa = 0.2~5A~ - cos2~-fs t + 2 03 sin2~ fS t ~ - (17) where A represents the output gain ratio between the side band component S~,l and the modulated component SD . Thus, the demodu-lated output signal Sa cliffers from that of NTSC system ;n only the factor 0.2~5A, but the factors or levels can be coincident with each other by utilizing the operation of an automatic color level control circuit in the television receiver.
If the phase of burst signal is selected as shown in Fig.13 which sat;sf;es the equation (16), color difference signals can be correctly demodulated. In F;g. l 1 . 39 designates a phase adjusting circuit and ~0 designates a level adjusting circuit which are inserted into the transmission path of burst signal BURST for the above purpose.
If the optical characteristias aro selectecl and the signal ~; processing circuit are ~ormed as described above, a camerà of the direct-NTSC s~rstem can be formed and eliminate flickers in a reproduced picture, -The above description is given on a first example of the present invention, in which the reading out is carried out under - the phase of fs being reference and the arranging pattern of repro- -:
duced cells becomes as shown in Figs.9B and 9G. It is, however, possible that the reading out can be achieved for the pattern oî
reproduced cell to become the spacial arranging pattern of cells .
To this end, it is sufficient to use the\ transfer signal Sc which is inversed in phase at every I H .
Fig.1~ is a block diagram showing the above example of the ' :.
. : . :.~: : :
~1539 invention. In this e~:ample, the transrer signal Sc from the synchroni~ing board 21 is fed to a control circuit 43 which is formed Or a switch 41 which is switched at every 1 H and a phase inverter circuit 42. ThusJ the control circuit 43 produces a desired transfer signal Sc ( or Sc1, Sc2 and SC3 )- In ;this case, the switch timing of switch 41 is selected so that the signal on the N line is phase-inverted. As a result, the pattern of reproduced cells becomes same as the spacial arranging pattern of cells and hence no correcting means for the luminance signal is required.
In this case, on the other hand, the phase of carrier fl equency Ss f chrominance signal is shifted, it becomes neces-sary to correct it. If the phase on only the line, on which the transfer signal Sc is inversed, is inversed, it becomes the original phase Or fs . ThereforeJ a correcting means 35 provided on the signal tranSmission path for chrominance signal can be formed by an amplirier 35A for phase-inversion and a switch 35B which is switched at every 11-l. The swilched state in the figure is on the N line. In this case, it is Or course possible to use a delay circuit whose delay time is selected as 140 n sec. (which corre-sponds to 2 ~H) in place of amplifier 35A.
As described above, in the invention the spectroscopic system is selected suitably and the frequency fC of transfer signal Sc supplied to the CCDs is selected to the frequency of the color sub-carrier frequency fS of NTSC system, a color video - signal of the NTSC system can be obtained directly from the CCDs.
Therefore, the encoder 11 can be omitted and hence the circuit can be simplified. In other words, a sol\id state camera of direct-NTSC system can be formed.
Further,since in the invention the adjusting means is _ ~ ~ _ 153~
pl ovidctl in the s;gnal processillg circuit for the picl;ed-up signal so a s to make that the arrallging pattern of read-out signals formiIlg the lumillance signal becomes the spacial arranging pattern ;~
Or cells and also that the phase Or color sub-carrier in the carrier chrominance signal Or picl~ed-up signals becomes same as that of co~or sub-carrier in the NTSC system. the bad influence on a re-produced picture, when the direct-NTSC system is employed, can be effectively elirninated. Thus, with the invention a good picture can be always reprocluced.
l 0 Other examples of the invention will be now described. When the CCD 10 of checkered-board pattern shown in Fig.4 is used in a second example of the invention, although the detailed explanation will be omitted, the arranging pattern Or reproduced cells on an odd rrame becomes same as the spacial arranging pattern Or cells on CCDs but is relatively displaced by--~H as sho~,vn in Fig~.1 5B
in only an even rrame.
Accordingly, as in the second example of the invention shown in Fig 16 in bloclc, ir the phase inversion control circuit 43 is provicled on the transmission path Or transrer signal Sc to ~- inverse the phase of transfer signal Sc only in the even frame, the arranging pattern of reproduced cells for the luminance signal can be made coincident with the spacial arranging pattern of cells on CCDs.
In this case, the phase of carrier frequency Ss becomes different from that of fS due to the presence Or phase inversion control circuit 43. Thus. the arranging pattern Or reproduced - cells for the chrominance signal, which should be as shown in Fig.
1 5A in an odd frame and as shown in ~Fig.1 5B in an even frame, -~ becomes as shown in Fig.15A in either of the frames.
Therefore, in the exampleJ the color signal is delayed, as ' ,~ .
.
, ' . ~ :~
::
a ~vl1ole, by 1 ~ in the ot1d frame to displace the arranging pattern Or rcprodllced cellsfrorn the spacial arrangil1g pattern of cells as sho~vn in Figs 17A and 17B, and is subjected to delay process in the even frame described later. That is, if such a signal processing that an N line in odd field and (N ~ 1 ) line in even field are delayed by-- cH 9 respectively, is carried out, for the pattern sllown in Fig.17A, there is obtained the repro-duced pattern shown in Fig~17C, which is same as that shown in Fig.1 5B.
Therefore, it ~vill be understood that the relation between the patterns shown in Figs.17B and 17C is similar to the re-lation în wllicll the signal is read out by selecting the phase of transfer signal Sc same as that Or fs and hence the phase shift can be corrected. In this case, however, the luminance signal is displaced from the chrominance signal by 2 ~H ~ so that if the signal processing to shift the luminance signal by 1 ~H as shown in Fig.17D, the time difference bet~een the luminance and chro-minance signals can be made zero.
T~lrning back to Fig.16, an example of the circuit, which achieves the above signal processing, will be now described. A
delay circuit 50 is provided at the next stage of low pass filter 36 for delaying the luminance signal by the time corresponding to 2 -~H ( 140 n sec. ) which is determined in view of various factors such as transmission delays by the low pass filter 36, color signal -processing and so on as described later.
On the color signal processing, there are provided first and second correcting circuits 52 and 53. The first correcting ` circuit 52 is used for the correction of odd frame so that it is - formed of a first switch 52A, which is supplied with the output of adder 25 and the vertical s~nchronizing signal Sv from the board : :
2~
: ::
'; :
:
L53~ ' :
21 ~ arld a firs~ delay circuit 52B connected to switch 52A. The rirst switch 52A is switched at every frame and rests on the position shown in Fig.16 in odd frame. The delay time of first delay circuit 52B is selected to the value corresponding to--~H
or 140 n sec The second correcting circuit 53 is used for the correction of even fl;ame and hence is formed of a second switch 53A, which is connected to switch 52A and is switched at every 1 H and a second delay circuit 53B,which is connected to the switch 53A and whose delay time is selected to the value corresponding ~ ;
to ~H or 280 n sec.
In Fig.16~ 54 designates a control circuit which is pro~
vided to receive the horizontal synchronizing signal SH from the board 2l and to supply its output to the second switch 53A for inversing the phase at every field, and 55 designates an adding circuit which is supplied with the outputs from first and second delay circuits 52B, 53B and second switch 53A.
Each of the examples of the invention descrlbed above is given on the case where the transfer signal Sc itself is selected as the color sub-carrier signal. However, it is possible that the transfer frequency fC is selected as one-half of color sub- ~-carrier Irequency fs ( 12 fs ) and the frequency fs itself is used as the carrier frequency of carrier chrominance signal. Such a case is the third example of the invention. In this case. the phase of color sub-carrier frequency fS is a reference for that of transfer frequency fc. If the signal is read out under the above phase relation, though not illustrated, the spacial arranging pattern - ~:
cells is a checkered-pattern, but that Or reproduced cells becomes -` same as the spacial arranging pattern of cells of parallel type CCD.
': \ : '~
Thus, in the third example it becomes necessary to correct both the ;~
~`; 30 luminance and chrominance signals.
~, . . , . ~
I`ig. I 8 is a b1Ock c1iagram showing the third e~cample of tl1e invention~ in which both (n -~ -I ) and (263 -~ N) lines are delayed by ~I-I ïor the luminance signal, although its detailed description will be omitted. In Fig.18, 80 indicates a cor-recting circuit for that purpose which is formed of a delay circuit 80A whose delay time is selected as ~H and a control switch 80B switched at every 1 H
Furthe:r, in Fig.18 56 indicates a correcting circuit .`-for the chrominallce signal which is formed of a delay circuit 56A connected to the adder 25 and a control switch 56B con-nected to the d61ay circuit 56A and adder 25. In this case, since the line, on which the signal is delayed by 2 ~H at every frame, is dirferent, it is necessary to provide, on the transmis-sion path of the switchlng pulse Sll fed to the control switch 56B, a phase inverting control circuit 57 same in construction as tbat of above describecl on so as to pha~se-invert the pulse SH . 57A
indicates a phase inverter. Further, a delay circuit 58 of 2 Il-I is provided on the chrominanc:e signal transmission path to correct the time error of the chrominance signal with respect to~
the luminance signal.
When the transfer frequency fC is selected as 2 f ` color sub-carrier frequency fS ~ side band components whose fundamental frequency is 1 fS are present and the side band components fall within the band of the luminance signal. There-fore, it is necessary to remove the side band components. To this end, the vertical correlation can be utilized For example, an elimination or removing circuit 60 is provided as shown in ; Fig.18. That is, the luminance si~nal is supplied to a low pass filter 61, from which low band components of 1 to 2 MHz are derived and the low band components are led to a subtracter circuit ~ ' ~
,, .
,' . ~' : , :
r ~ ~
' lS39 62 whicll :is also suppliecl ~ the luminance s.ignal wl1ich is not rest-ricted in bal1d. Thus, tho subtl-.lcl.er G2 p:roduces higl1 ballcl compol1e~ s. Tl1e 1:~easol1 why the :low balltl componellts a.re :I.`t`lllOVCCI .iS lo avo:i.tl tht3 :resoLIll:.ioll in the ve:l:~tica`l direction In lhis cnso, a cleL.a~y C.i:l`CU:it. 63 ;s providecl bet~een switch 55l3 and snl~tracte:L 62 to compellsale îor tlle t.ime clolay caused by tlle existellce of low pass filter 61.
The hi.gll band components f:rom subtracte:r 62 is fed to a clelay circuit 6~1 Or 1 l-l ancl thereafte:r to adder circuit 65 which is also supplied with the non-delayed high band components from subtracter 62 directly so as to carry out the vertical correlation process. That is, since the phases the side band eomponents eontained in the high band eomponents a:re reverse between adja-eent hori.~ontal scanning lines, the sicle band eomponents ean be erfeeti~rely :removed by the provision Or clelay ei:reuit 6~l. Arter the luminanee signa.l is subjected to the vertical correlation pro-cessing, it is added with the above low band component at an adder 67 and supplied to the composite circuit 37 as the final luminance : signal.
In the above examples, three CCDs are used to form solid ~:
state color cameras, but it is possible to form a solid state color camera of this kind by using only one CCD. One typical example of this case will be described.
When one CCD is used, the transfer frequ~ncy fC is selected as 3fS ( fC = 3fS ) and the pitch corresponding to three image sensing cells becomes a unit of the arranging pitch (refer to Fig.1 9A) In this case, for example, if the signal is read out with the phase of, for example . 3f~ as a reference, the pattern of reproduced cells is displaced by 16 ~H as shown in Figs.1 9B
- and 1 9C. Accordingly, the luminance and chrominance signals have to be corrected, respeetiYely.
~L1~1539 Since tl1e line on whicll cells move is different dependent upon frames, if cells on N and {263 -~ (N~ lines in an odd frame and (N -~1 ) and (263 -~ N) lines in an even frame are moved by ~H 1 respeclively, as to the luminance signal, the original cell arrangement can be obtained Thus, it is sufficient that a correcting circuit 70 consisting of a delay circuit 70A with the delay time of 6 ~H and a control switch 70B inversed at every 1H as shown in Fig.20.
On the other hand, a correcting circuit 71 is also provided for the chrominance signal. The correcting circuit 71 is formed of a delay circuit 71A with the delay time of 1 ~H ~ which is supplied with the output from the sampling hold circuit 32, and a control switch 7lB which is supplied with the output delay circuit 71A and also the output of sampling hold circuit 32 and is switched l 5 at every 1 H to delay lines different from the afore-said lines. Thus~
the phases can be made coincident. In this case~ however, there is caused a time delay between the luminance and chrominance sig- -nals ~ so that it becomes necessary to clelay the luminance signal .
To this end, a delay circuit 72 is provided between low pass ~ilter 36 and processing circuit 37. In Fig.20, 73 designates a phase ` - inversion control cirouit which consists of a switch 73B for receiving signal SH from synchronizing board 21 and a phase inversion circuit 73A supplied with signal SH through switch 73B. The output of clrcuit 73 is fed to control switches 70B and 71 B, respectively, The fifth and sixth examples previously mentioned could be easily understood from the above description on the first to fourth examples, so that an description thereon will be omitted.
It may be apparent that many\modifications and variations could be effected by one skilled in the art without departing f:rom ~ .
the spirits or scope Or the novel concepts of the invention, so that .:` . ~.
.
2 c~
. , : ' ' :
~' the scope of the ;n~rention sh~ ld be dete:rmined by the ~ppellded cl~ims. ::
', ` . ' ` , -:
'-' ' ~ . ' ' .
' ' :
,'~ ' '', _ ,~ '! -
5~9 9 = 12.~1 ................................. (16) A demodulated output signal (chrominance signal) Sc~ in the case of equation (16)is e~cpressed by the following equation (17) Sa = 0.2~5A~ - cos2~-fs t + 2 03 sin2~ fS t ~ - (17) where A represents the output gain ratio between the side band component S~,l and the modulated component SD . Thus, the demodu-lated output signal Sa cliffers from that of NTSC system ;n only the factor 0.2~5A, but the factors or levels can be coincident with each other by utilizing the operation of an automatic color level control circuit in the television receiver.
If the phase of burst signal is selected as shown in Fig.13 which sat;sf;es the equation (16), color difference signals can be correctly demodulated. In F;g. l 1 . 39 designates a phase adjusting circuit and ~0 designates a level adjusting circuit which are inserted into the transmission path of burst signal BURST for the above purpose.
If the optical characteristias aro selectecl and the signal ~; processing circuit are ~ormed as described above, a camerà of the direct-NTSC s~rstem can be formed and eliminate flickers in a reproduced picture, -The above description is given on a first example of the present invention, in which the reading out is carried out under - the phase of fs being reference and the arranging pattern of repro- -:
duced cells becomes as shown in Figs.9B and 9G. It is, however, possible that the reading out can be achieved for the pattern oî
reproduced cell to become the spacial arranging pattern of cells .
To this end, it is sufficient to use the\ transfer signal Sc which is inversed in phase at every I H .
Fig.1~ is a block diagram showing the above example of the ' :.
. : . :.~: : :
~1539 invention. In this e~:ample, the transrer signal Sc from the synchroni~ing board 21 is fed to a control circuit 43 which is formed Or a switch 41 which is switched at every 1 H and a phase inverter circuit 42. ThusJ the control circuit 43 produces a desired transfer signal Sc ( or Sc1, Sc2 and SC3 )- In ;this case, the switch timing of switch 41 is selected so that the signal on the N line is phase-inverted. As a result, the pattern of reproduced cells becomes same as the spacial arranging pattern of cells and hence no correcting means for the luminance signal is required.
In this case, on the other hand, the phase of carrier fl equency Ss f chrominance signal is shifted, it becomes neces-sary to correct it. If the phase on only the line, on which the transfer signal Sc is inversed, is inversed, it becomes the original phase Or fs . ThereforeJ a correcting means 35 provided on the signal tranSmission path for chrominance signal can be formed by an amplirier 35A for phase-inversion and a switch 35B which is switched at every 11-l. The swilched state in the figure is on the N line. In this case, it is Or course possible to use a delay circuit whose delay time is selected as 140 n sec. (which corre-sponds to 2 ~H) in place of amplifier 35A.
As described above, in the invention the spectroscopic system is selected suitably and the frequency fC of transfer signal Sc supplied to the CCDs is selected to the frequency of the color sub-carrier frequency fS of NTSC system, a color video - signal of the NTSC system can be obtained directly from the CCDs.
Therefore, the encoder 11 can be omitted and hence the circuit can be simplified. In other words, a sol\id state camera of direct-NTSC system can be formed.
Further,since in the invention the adjusting means is _ ~ ~ _ 153~
pl ovidctl in the s;gnal processillg circuit for the picl;ed-up signal so a s to make that the arrallging pattern of read-out signals formiIlg the lumillance signal becomes the spacial arranging pattern ;~
Or cells and also that the phase Or color sub-carrier in the carrier chrominance signal Or picl~ed-up signals becomes same as that of co~or sub-carrier in the NTSC system. the bad influence on a re-produced picture, when the direct-NTSC system is employed, can be effectively elirninated. Thus, with the invention a good picture can be always reprocluced.
l 0 Other examples of the invention will be now described. When the CCD 10 of checkered-board pattern shown in Fig.4 is used in a second example of the invention, although the detailed explanation will be omitted, the arranging pattern Or reproduced cells on an odd rrame becomes same as the spacial arranging pattern Or cells on CCDs but is relatively displaced by--~H as sho~,vn in Fig~.1 5B
in only an even rrame.
Accordingly, as in the second example of the invention shown in Fig 16 in bloclc, ir the phase inversion control circuit 43 is provicled on the transmission path Or transrer signal Sc to ~- inverse the phase of transfer signal Sc only in the even frame, the arranging pattern of reproduced cells for the luminance signal can be made coincident with the spacial arranging pattern of cells on CCDs.
In this case, the phase of carrier frequency Ss becomes different from that of fS due to the presence Or phase inversion control circuit 43. Thus. the arranging pattern Or reproduced - cells for the chrominance signal, which should be as shown in Fig.
1 5A in an odd frame and as shown in ~Fig.1 5B in an even frame, -~ becomes as shown in Fig.15A in either of the frames.
Therefore, in the exampleJ the color signal is delayed, as ' ,~ .
.
, ' . ~ :~
::
a ~vl1ole, by 1 ~ in the ot1d frame to displace the arranging pattern Or rcprodllced cellsfrorn the spacial arrangil1g pattern of cells as sho~vn in Figs 17A and 17B, and is subjected to delay process in the even frame described later. That is, if such a signal processing that an N line in odd field and (N ~ 1 ) line in even field are delayed by-- cH 9 respectively, is carried out, for the pattern sllown in Fig.17A, there is obtained the repro-duced pattern shown in Fig~17C, which is same as that shown in Fig.1 5B.
Therefore, it ~vill be understood that the relation between the patterns shown in Figs.17B and 17C is similar to the re-lation în wllicll the signal is read out by selecting the phase of transfer signal Sc same as that Or fs and hence the phase shift can be corrected. In this case, however, the luminance signal is displaced from the chrominance signal by 2 ~H ~ so that if the signal processing to shift the luminance signal by 1 ~H as shown in Fig.17D, the time difference bet~een the luminance and chro-minance signals can be made zero.
T~lrning back to Fig.16, an example of the circuit, which achieves the above signal processing, will be now described. A
delay circuit 50 is provided at the next stage of low pass filter 36 for delaying the luminance signal by the time corresponding to 2 -~H ( 140 n sec. ) which is determined in view of various factors such as transmission delays by the low pass filter 36, color signal -processing and so on as described later.
On the color signal processing, there are provided first and second correcting circuits 52 and 53. The first correcting ` circuit 52 is used for the correction of odd frame so that it is - formed of a first switch 52A, which is supplied with the output of adder 25 and the vertical s~nchronizing signal Sv from the board : :
2~
: ::
'; :
:
L53~ ' :
21 ~ arld a firs~ delay circuit 52B connected to switch 52A. The rirst switch 52A is switched at every frame and rests on the position shown in Fig.16 in odd frame. The delay time of first delay circuit 52B is selected to the value corresponding to--~H
or 140 n sec The second correcting circuit 53 is used for the correction of even fl;ame and hence is formed of a second switch 53A, which is connected to switch 52A and is switched at every 1 H and a second delay circuit 53B,which is connected to the switch 53A and whose delay time is selected to the value corresponding ~ ;
to ~H or 280 n sec.
In Fig.16~ 54 designates a control circuit which is pro~
vided to receive the horizontal synchronizing signal SH from the board 2l and to supply its output to the second switch 53A for inversing the phase at every field, and 55 designates an adding circuit which is supplied with the outputs from first and second delay circuits 52B, 53B and second switch 53A.
Each of the examples of the invention descrlbed above is given on the case where the transfer signal Sc itself is selected as the color sub-carrier signal. However, it is possible that the transfer frequency fC is selected as one-half of color sub- ~-carrier Irequency fs ( 12 fs ) and the frequency fs itself is used as the carrier frequency of carrier chrominance signal. Such a case is the third example of the invention. In this case. the phase of color sub-carrier frequency fS is a reference for that of transfer frequency fc. If the signal is read out under the above phase relation, though not illustrated, the spacial arranging pattern - ~:
cells is a checkered-pattern, but that Or reproduced cells becomes -` same as the spacial arranging pattern of cells of parallel type CCD.
': \ : '~
Thus, in the third example it becomes necessary to correct both the ;~
~`; 30 luminance and chrominance signals.
~, . . , . ~
I`ig. I 8 is a b1Ock c1iagram showing the third e~cample of tl1e invention~ in which both (n -~ -I ) and (263 -~ N) lines are delayed by ~I-I ïor the luminance signal, although its detailed description will be omitted. In Fig.18, 80 indicates a cor-recting circuit for that purpose which is formed of a delay circuit 80A whose delay time is selected as ~H and a control switch 80B switched at every 1 H
Furthe:r, in Fig.18 56 indicates a correcting circuit .`-for the chrominallce signal which is formed of a delay circuit 56A connected to the adder 25 and a control switch 56B con-nected to the d61ay circuit 56A and adder 25. In this case, since the line, on which the signal is delayed by 2 ~H at every frame, is dirferent, it is necessary to provide, on the transmis-sion path of the switchlng pulse Sll fed to the control switch 56B, a phase inverting control circuit 57 same in construction as tbat of above describecl on so as to pha~se-invert the pulse SH . 57A
indicates a phase inverter. Further, a delay circuit 58 of 2 Il-I is provided on the chrominanc:e signal transmission path to correct the time error of the chrominance signal with respect to~
the luminance signal.
When the transfer frequency fC is selected as 2 f ` color sub-carrier frequency fS ~ side band components whose fundamental frequency is 1 fS are present and the side band components fall within the band of the luminance signal. There-fore, it is necessary to remove the side band components. To this end, the vertical correlation can be utilized For example, an elimination or removing circuit 60 is provided as shown in ; Fig.18. That is, the luminance si~nal is supplied to a low pass filter 61, from which low band components of 1 to 2 MHz are derived and the low band components are led to a subtracter circuit ~ ' ~
,, .
,' . ~' : , :
r ~ ~
' lS39 62 whicll :is also suppliecl ~ the luminance s.ignal wl1ich is not rest-ricted in bal1d. Thus, tho subtl-.lcl.er G2 p:roduces higl1 ballcl compol1e~ s. Tl1e 1:~easol1 why the :low balltl componellts a.re :I.`t`lllOVCCI .iS lo avo:i.tl tht3 :resoLIll:.ioll in the ve:l:~tica`l direction In lhis cnso, a cleL.a~y C.i:l`CU:it. 63 ;s providecl bet~een switch 55l3 and snl~tracte:L 62 to compellsale îor tlle t.ime clolay caused by tlle existellce of low pass filter 61.
The hi.gll band components f:rom subtracte:r 62 is fed to a clelay circuit 6~1 Or 1 l-l ancl thereafte:r to adder circuit 65 which is also supplied with the non-delayed high band components from subtracter 62 directly so as to carry out the vertical correlation process. That is, since the phases the side band eomponents eontained in the high band eomponents a:re reverse between adja-eent hori.~ontal scanning lines, the sicle band eomponents ean be erfeeti~rely :removed by the provision Or clelay ei:reuit 6~l. Arter the luminanee signa.l is subjected to the vertical correlation pro-cessing, it is added with the above low band component at an adder 67 and supplied to the composite circuit 37 as the final luminance : signal.
In the above examples, three CCDs are used to form solid ~:
state color cameras, but it is possible to form a solid state color camera of this kind by using only one CCD. One typical example of this case will be described.
When one CCD is used, the transfer frequ~ncy fC is selected as 3fS ( fC = 3fS ) and the pitch corresponding to three image sensing cells becomes a unit of the arranging pitch (refer to Fig.1 9A) In this case, for example, if the signal is read out with the phase of, for example . 3f~ as a reference, the pattern of reproduced cells is displaced by 16 ~H as shown in Figs.1 9B
- and 1 9C. Accordingly, the luminance and chrominance signals have to be corrected, respeetiYely.
~L1~1539 Since tl1e line on whicll cells move is different dependent upon frames, if cells on N and {263 -~ (N~ lines in an odd frame and (N -~1 ) and (263 -~ N) lines in an even frame are moved by ~H 1 respeclively, as to the luminance signal, the original cell arrangement can be obtained Thus, it is sufficient that a correcting circuit 70 consisting of a delay circuit 70A with the delay time of 6 ~H and a control switch 70B inversed at every 1H as shown in Fig.20.
On the other hand, a correcting circuit 71 is also provided for the chrominance signal. The correcting circuit 71 is formed of a delay circuit 71A with the delay time of 1 ~H ~ which is supplied with the output from the sampling hold circuit 32, and a control switch 7lB which is supplied with the output delay circuit 71A and also the output of sampling hold circuit 32 and is switched l 5 at every 1 H to delay lines different from the afore-said lines. Thus~
the phases can be made coincident. In this case~ however, there is caused a time delay between the luminance and chrominance sig- -nals ~ so that it becomes necessary to clelay the luminance signal .
To this end, a delay circuit 72 is provided between low pass ~ilter 36 and processing circuit 37. In Fig.20, 73 designates a phase ` - inversion control cirouit which consists of a switch 73B for receiving signal SH from synchronizing board 21 and a phase inversion circuit 73A supplied with signal SH through switch 73B. The output of clrcuit 73 is fed to control switches 70B and 71 B, respectively, The fifth and sixth examples previously mentioned could be easily understood from the above description on the first to fourth examples, so that an description thereon will be omitted.
It may be apparent that many\modifications and variations could be effected by one skilled in the art without departing f:rom ~ .
the spirits or scope Or the novel concepts of the invention, so that .:` . ~.
.
2 c~
. , : ' ' :
~' the scope of the ;n~rention sh~ ld be dete:rmined by the ~ppellded cl~ims. ::
', ` . ' ` , -:
'-' ' ~ . ' ' .
' ' :
,'~ ' '', _ ,~ '! -
Claims (10)
1. A solid state color camera of a type in which a composite color video signal of the NTSC System is obtained without using a specific color encoder, comprising :
A) solid state image sensing means having a plurality of image sensing cells aligned in both vertical and horizontal directions for converting a light information of an object into an electric signal information in association with said image sensing cells ;
B) color filter means disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information ;
C) read out register means adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing means and to supply an output video signal in a serial form ;
D) means for separating a luminance signal component and chrominance signal component out of said output video signal from said read-out register means, E) means for adding said separated luminance signal compo-nents and chrominance signal components ;
F) means for deriving at a system output a composite color video signal acceptable in the NTSC color system ;
G) means for supplying vertical and horizontal scanning signals to said solid state image sensing means, H) means for supplying read-out pulses to said read-out register means a frequency of said read out pulses being selected to ? x fS , where N and M are both integers and fS is a frequency of subcarrier of the NTSC color system ;
and I) means for adjusting phase conditions of said luminance signal components at said system output as they becomes equal to said alignment states of said image sensing cells of said solid state image sensing means.
A) solid state image sensing means having a plurality of image sensing cells aligned in both vertical and horizontal directions for converting a light information of an object into an electric signal information in association with said image sensing cells ;
B) color filter means disposed in a light path of said light information of the object for modifying said electric signal information inaccordance with color components included in said light information ;
C) read out register means adapted to receive said electric signal information of one horizontal scanning period line by line from said solid state image sensing means and to supply an output video signal in a serial form ;
D) means for separating a luminance signal component and chrominance signal component out of said output video signal from said read-out register means, E) means for adding said separated luminance signal compo-nents and chrominance signal components ;
F) means for deriving at a system output a composite color video signal acceptable in the NTSC color system ;
G) means for supplying vertical and horizontal scanning signals to said solid state image sensing means, H) means for supplying read-out pulses to said read-out register means a frequency of said read out pulses being selected to ? x fS , where N and M are both integers and fS is a frequency of subcarrier of the NTSC color system ;
and I) means for adjusting phase conditions of said luminance signal components at said system output as they becomes equal to said alignment states of said image sensing cells of said solid state image sensing means.
2. A solid state color camera as claimed in claim 1, wherein said solid state image sensing means includes three chips of two dimensional solid state imaging devices, and each chip has a color filter relative to one of three primary colors, respectively.
3. A solid state color camera as claimed in claim 1, wherein said solid state image sensing means is a single chip of a two dimen-sional solid state imaging device, and color filter triads of three primary colors are aligned in said horizontal direction so that each of said image sensing elements corresponds to one Or said three primary colors.
4. A solid state color camera as claimed in claim 3, wherein a value of said ratio ? is selected to be three.
5. A solid state color camera as claimed in claim 4, wherein said phase adjusting means for said luminance signal is disposed in a luminance path for said separated luminance signal components to be supplied to said adding means.
6. A solid state color camera according to claim 5 further comprising means for adjusting phase conditions of said chrominance signal components at said system output to be a phase condition of a NTSC color subcarrier signal between successive line intervals.
said chrominance phase adjusting means being disposed in a chromi-nance path for said separated chrominance signal components to be supplied to said adding means.
said chrominance phase adjusting means being disposed in a chromi-nance path for said separated chrominance signal components to be supplied to said adding means.
7. A solid state color camera as claimed in claim 2, wherein a value of said ratio N is selected to be 1, and said phase adjusting means is disposed in a luminance path for said separated luminance signal components to be supplied to said adding means.
8. A solid state color camera as claimed in claim 2, wherein said phase adjusting means is disposed in a read out pulse path of said read-out pulse supplying means,
9. A solid state color camera according to claim 8 further com-prising chrominance phase adjusting means disposed in a chrominance path for said separated chrominance signal components so as to yield a phase reversal at line by line so as to accord with a phase condition of a NTSC color sub-carrier signal.
10. A solid state color camera as claimed in claim 2, wherein a value of said ratio ? is selected to be ? , and said phase adjust-ing means is disposed in a luminance path for said luminance signal components to be supplied to said adding means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62081/76 | 1976-05-28 | ||
| JP51062081A JPS60838B2 (en) | 1976-05-28 | 1976-05-28 | Color solid-state imaging device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1101539A true CA1101539A (en) | 1981-05-19 |
Family
ID=13189748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA279,340A Expired CA1101539A (en) | 1976-05-28 | 1977-05-27 | Solid state color camera |
Country Status (8)
| Country | Link |
|---|---|
| US (1) | US4106056A (en) |
| JP (1) | JPS60838B2 (en) |
| AT (1) | AT360097B (en) |
| CA (1) | CA1101539A (en) |
| DE (1) | DE2724170A1 (en) |
| FR (1) | FR2353191A1 (en) |
| GB (1) | GB1555158A (en) |
| NL (1) | NL7705968A (en) |
Families Citing this family (24)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS546424A (en) * | 1977-06-16 | 1979-01-18 | Sony Corp | Signal processing method of solid pickup unit |
| JPS5535536A (en) * | 1978-09-06 | 1980-03-12 | Hitachi Ltd | Solid color image pickup device |
| US4264921A (en) * | 1979-06-29 | 1981-04-28 | International Business Machines Corporation | Apparatus for color or panchromatic imaging |
| US4288812A (en) * | 1979-11-19 | 1981-09-08 | Rca Corporation | Color filter |
| JPS581391A (en) * | 1981-06-26 | 1983-01-06 | Sony Corp | Color image pickup device |
| US4591899A (en) * | 1982-03-25 | 1986-05-27 | Canon Kabushiki Kaisha | Color image pickup device |
| JPS5997291A (en) * | 1982-11-26 | 1984-06-05 | Canon Inc | Image pickup device |
| GB2133257B (en) * | 1982-12-22 | 1987-07-29 | Ricoh Kk | T v game system |
| US4644390A (en) * | 1984-11-19 | 1987-02-17 | Fuji Photo Film Co. Ltd. | Photoelectric sensor array support package |
| FR2577669B1 (en) * | 1985-02-21 | 1992-05-15 | Fuji Photo Film Co Ltd | IMAGE READING METHOD AND APPARATUS |
| US4814861A (en) * | 1985-07-10 | 1989-03-21 | Canon Kabushiki Kaisha | Signal processing apparatus with independent gain control for chrominance and color signals |
| JP2773324B2 (en) * | 1989-11-27 | 1998-07-09 | ソニー株式会社 | Imaging device |
| JP2919110B2 (en) * | 1990-08-28 | 1999-07-12 | 池上通信機株式会社 | Output signal processing circuit of solid-state imaging device |
| DE69127950T2 (en) * | 1990-10-31 | 1998-05-28 | Hitachi Ltd | Digital color signal processing with clock signal control for a video camera |
| KR940004433B1 (en) * | 1991-02-26 | 1994-05-25 | 삼성전자 주식회사 | Method and apparatus for moving picture element by using sample and holding method |
| JPH0851635A (en) * | 1994-08-05 | 1996-02-20 | Sony Corp | Image pickup device |
| US5766006A (en) * | 1995-06-26 | 1998-06-16 | Murljacic; Maryann Lehmann | Tooth shade analyzer system and methods |
| US6134631A (en) * | 1996-08-19 | 2000-10-17 | Hyundai Electronics America, Inc. | Non-volatile memory with embedded programmable controller |
| US8790118B2 (en) * | 1998-11-03 | 2014-07-29 | Shade Analyzing Technologies, Inc. | Interactive dental restorative network |
| JP4230113B2 (en) | 1998-11-03 | 2009-02-25 | シェード アナライジング テクノロジーズ インコーポレイテッド | Interactive dental treatment network |
| US7118374B2 (en) | 2003-06-09 | 2006-10-10 | Ivoclar Vivadent Ag | Enhanced tooth shade guide |
| US7341450B2 (en) * | 2003-10-03 | 2008-03-11 | Shade Analyzing Technologies, Inc. | Tooth shade scan system and method |
| JP4548390B2 (en) * | 2006-06-16 | 2010-09-22 | ソニー株式会社 | Imaging apparatus and signal processing method |
| JP2008054292A (en) * | 2006-07-28 | 2008-03-06 | Matsushita Electric Ind Co Ltd | Device and method for phase adjustment |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1501016A (en) * | 1974-03-29 | 1978-02-15 | Sony Corp | Television cameras |
| JPS5654115B2 (en) * | 1974-03-29 | 1981-12-23 |
-
1976
- 1976-05-28 JP JP51062081A patent/JPS60838B2/en not_active Expired
-
1977
- 1977-05-24 US US05/800,013 patent/US4106056A/en not_active Expired - Lifetime
- 1977-05-24 GB GB21879/77A patent/GB1555158A/en not_active Expired
- 1977-05-27 CA CA279,340A patent/CA1101539A/en not_active Expired
- 1977-05-27 AT AT381377A patent/AT360097B/en not_active IP Right Cessation
- 1977-05-27 DE DE19772724170 patent/DE2724170A1/en not_active Withdrawn
- 1977-05-31 FR FR7716620A patent/FR2353191A1/en active Granted
- 1977-05-31 NL NL7705968A patent/NL7705968A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| NL7705968A (en) | 1977-11-30 |
| JPS52146117A (en) | 1977-12-05 |
| US4106056A (en) | 1978-08-08 |
| AT360097B (en) | 1980-12-29 |
| FR2353191A1 (en) | 1977-12-23 |
| DE2724170A1 (en) | 1977-12-08 |
| FR2353191B1 (en) | 1980-02-08 |
| GB1555158A (en) | 1979-11-07 |
| JPS60838B2 (en) | 1985-01-10 |
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