CA1322043C - Apparatus for detecting edge position of elongated article - Google Patents
Apparatus for detecting edge position of elongated articleInfo
- Publication number
- CA1322043C CA1322043C CA000607477A CA607477A CA1322043C CA 1322043 C CA1322043 C CA 1322043C CA 000607477 A CA000607477 A CA 000607477A CA 607477 A CA607477 A CA 607477A CA 1322043 C CA1322043 C CA 1322043C
- Authority
- CA
- Canada
- Prior art keywords
- article
- television camera
- edge portion
- edge
- edge position
- 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.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/028—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring lateral position of a boundary of the object
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
Abstract
63-194,568 APPARATUS FOR DETECTING
EDGE POSITION OF ELONGATED ARTICLE
Abstract of the Disclosure An apparatus for detecting an edge position of an elongated article in which an image of the edge portion of the object is picked up by a two-dimensional television camera arranged above the article such that the scanning line of the television camera is made substantially parallel with the edge portion of the article, an image signal of the image of the edge portion is converted into a bivalent signal representing black and white pixels, the number of the black pixels in every scanning line is counted to obtain an histogram, a scanning line number at which the number of the black pixels is abruptly increased in the histogram is detected as the edge position of the article.
EDGE POSITION OF ELONGATED ARTICLE
Abstract of the Disclosure An apparatus for detecting an edge position of an elongated article in which an image of the edge portion of the object is picked up by a two-dimensional television camera arranged above the article such that the scanning line of the television camera is made substantially parallel with the edge portion of the article, an image signal of the image of the edge portion is converted into a bivalent signal representing black and white pixels, the number of the black pixels in every scanning line is counted to obtain an histogram, a scanning line number at which the number of the black pixels is abruptly increased in the histogram is detected as the edge position of the article.
Description
13~2~3 The present invention relates to an appara-tus for detecting an edge position of an article, particularly an apparatus for detecting a substantial-ly linear edge position of an elongated article without bringing the apparatus into contact with the article.
Hitherto, it has been widely practiced to detect the edge position of the elongated article without bringing the apparatus into contact with the article. In a typical prior art apparatus, an edge ; portion of an article is illuminated by a light source, and an image of the edge portion is picked up by a television camera having a one-dimensional linear array sensor. In the linear array sensor there are provided a plurallty of light receiving elements which are linearly arranged in a direction perpendicular to an extending direction of the edge portion of the article. The edge position can be obtained by compar-ing an output signal level of the linear array sensor with an appropriate threshold level.
In the conventional apparatus, the light receiving elements of the linear array sensor are arranged substantially perpendicular to the extending direction of the edge portion of the article, a single point on the edge portion at which the linear image sensor and the edge portion intersect with each other , .
:~:
~ ~ - 2 -132~43 is detected and the thus detected point is regarded as the edge position of the article. Thus, when the length of the article is measured on the basis of the thus obtained position of the edge portion, if a defect is formed in the edge portion of the article and the image sensor intersects with the edge portion at the defect, the length of the article could not be measured correctly. Thus, the conventional apparatus has a drawback that the detecting result is apt to be largely affected by a defect, dust or an obstacle formed in or adhered to the edge portion of the article to be measured.
A tread rubber for use in manufacturing tires is liable to have such a defect or dust in the edge portion thereof due to the transportation or handling after cutting the tread rubber. Further, the : edge portion of the tread rubber is usually cut obliquely in order to joint tread rubbers to each other by putting over the obliquely cut edge portions : ~ 20 successively. Therefore, when the article to be measured is the tread rubber, the measured length .~ thereof might be varied depending upon :
- ..
. - 3 -A
, . . .
. ' .
r 132~
the point at which the linear array sensor intersects with the edge portion of the tread rubber. In order to reduce the affect caused by the defect or dust formed in or adhered on the edge portion of the tread rubber, it o~i would be suggested to detect the edge position at two or more points and to derive a mean value of the detected results. However, if there is a defect or a dust at one of these points, it is not possible to measure the length of the tread rubber accurately and the reliability of the measurement becomes low because any error caused by the defect or the dust in the edge portion of the article will be still appeared in the measurement results.
The present invention has for its object to 1~ provide a novel and useful apparatuq for detecting an edge position of an article, by means of which the edge position can be accurately detected with a high reliability even if a defect or a dust is formed or adhered in the edge portion of the article to be measured.
The apparatus according to the present invention comprises:
a light ~ource mean~ for pro~ecting an illumination light at least to the edge portion of the article;
Hitherto, it has been widely practiced to detect the edge position of the elongated article without bringing the apparatus into contact with the article. In a typical prior art apparatus, an edge ; portion of an article is illuminated by a light source, and an image of the edge portion is picked up by a television camera having a one-dimensional linear array sensor. In the linear array sensor there are provided a plurallty of light receiving elements which are linearly arranged in a direction perpendicular to an extending direction of the edge portion of the article. The edge position can be obtained by compar-ing an output signal level of the linear array sensor with an appropriate threshold level.
In the conventional apparatus, the light receiving elements of the linear array sensor are arranged substantially perpendicular to the extending direction of the edge portion of the article, a single point on the edge portion at which the linear image sensor and the edge portion intersect with each other , .
:~:
~ ~ - 2 -132~43 is detected and the thus detected point is regarded as the edge position of the article. Thus, when the length of the article is measured on the basis of the thus obtained position of the edge portion, if a defect is formed in the edge portion of the article and the image sensor intersects with the edge portion at the defect, the length of the article could not be measured correctly. Thus, the conventional apparatus has a drawback that the detecting result is apt to be largely affected by a defect, dust or an obstacle formed in or adhered to the edge portion of the article to be measured.
A tread rubber for use in manufacturing tires is liable to have such a defect or dust in the edge portion thereof due to the transportation or handling after cutting the tread rubber. Further, the : edge portion of the tread rubber is usually cut obliquely in order to joint tread rubbers to each other by putting over the obliquely cut edge portions : ~ 20 successively. Therefore, when the article to be measured is the tread rubber, the measured length .~ thereof might be varied depending upon :
- ..
. - 3 -A
, . . .
. ' .
r 132~
the point at which the linear array sensor intersects with the edge portion of the tread rubber. In order to reduce the affect caused by the defect or dust formed in or adhered on the edge portion of the tread rubber, it o~i would be suggested to detect the edge position at two or more points and to derive a mean value of the detected results. However, if there is a defect or a dust at one of these points, it is not possible to measure the length of the tread rubber accurately and the reliability of the measurement becomes low because any error caused by the defect or the dust in the edge portion of the article will be still appeared in the measurement results.
The present invention has for its object to 1~ provide a novel and useful apparatuq for detecting an edge position of an article, by means of which the edge position can be accurately detected with a high reliability even if a defect or a dust is formed or adhered in the edge portion of the article to be measured.
The apparatus according to the present invention comprises:
a light ~ource mean~ for pro~ecting an illumination light at least to the edge portion of the article;
2~ a television camera means for picking up an image of . ths edge portion of the article to produce an image 1322~43 signal, said television camera means being arranged such that scanning lines of the television camera means are substantially parallel with a width direction of the edge of the article;
06 means for converting said image signal into a bivalent signal representing white and black pixels;
mean~ for counting the number of the white or black pixels of the bivalent siqnal in every scanning line to make a histogram of the white or black pixels; and edge detecting means for receiving the histogram and detecting the edge position of the article in accordance with a change in the number of the white or black pixels in the histogram.
In the apparatus according to the invention, an 1~ image of the edge portion of the article is picked up by a two-dimensional television camera which is arranged above the article auch that the scanning lines of the television camera are made aubstantially parallel with : the extending direction of the edge portion, the number of white or black pixels on every scanning line of the thus obtained image signal is counted to make a histogram therefor, and a scanning line from which the number of white or black pixels is largely changed is detected as the edge po~ltion of the article.
2~ ~herefore, it ia poasible to detect the edge position accurately with high reliability but without being ~: :
,. ~
affected by the defect or dust existed in the edge portion of the article to be detected.
Fig. 1 is a schematic view showing the conventional apparatus for detecting the edge position of the article;
Fig. 2 is a schematic view depicting the relative position of the linear image sensor of the conventional apparatus and the edge portion of the article;
10Fig. 3 is a schematic view illustra*ing the baslc constitution of the apparatus for detecting the ; edge position of the article according to the inven-tion;
Figs. 4A to 4C are schematic views for explaining the operation of the apparatus according to the invention;
Fig. 5 is a schematic view representing an embodiment of the apparatus according to the invention by means of which a length of a tread rubber for manufacturing a tire is measured;
, Fig. 6 is a plan view showing the relation between the edge portion of the tread rubber and the field of view of the television camera installed in ~ ~the apparatus according to the present invention; and '' ~,: ~
~' - 6 -: , `',. , , , ~
' 1322~4~
Fig. 7 is a schematic view explaining a calculating method for calculating the length of the tread rubber.
Fig. 1 is a schematic view showing a conven-tional apparatus therefor. As is clear from Fig. 1, an edge portion 51a of an article 51 is illuminated by a light source 52, and an image of the edge portion 51a is picked up by a television camera 54 having a one-dimensional linear array sensor 53. In the linear array sensor 53 there are provided a plurality of light receiving elements which are linearly arranged in a direction perpendicular to an extending direction of the edge portion 51a of the article 51. The edge position 51a can be obtained by comparing an output signal level of the linear array sensor 53 with an appropriate threshold level.
In the conventional apparatus, since, as shown in Fig. 2, the light receiving elements of the linear array sensor 53 are arranged substantially perpendicular to the extending direction of the edge portion 51a of the article 51, a single point on the edge portion at which the linear image sensor 53 and the edge portion 51a intersect with each other is detected and the thus detected point is regarded as the edge position of the article. Thus, when the length of the article is measured on the basis of the ., .
- 6a -.
" ' ' :
.
1322~
thus obtained position of the edge portion, if a defect 55 is formed in the edge portion of the article and the image sensor 53 intersects with the edge portion at the defect as shown in Fig. 2, the length of the article could not be measured correctly.
,, ~
~ 6b -t ~A
' , .
1 , , i .
- . ~ .
,, .
.
1322~3 Fig. 3 is a block diagram showing the basic constitution of the apparatus for detecting the edge position of the article according to the present invention. Above an article l is arranged a light o~ source 2 to uniformly illuminate the edge portion la of the article. A two-dimensional television camera 3 is also arranged above the article l to pick up the image of the edge portion la of the article l which is illuminated by the light source 2. In the present invention, the television camera 3 is of the raster ~canning type and is arranged such that the scanning line~ of the television camera 3 are made parallel with the extending direction of the edge portion la of the article l. An image signal of the edge portion la 16 picked up by the television camera 3 is supplied to a bivalent circuit 4 in which the image signal is converted into a bivalent image signal composed of white and black level signals by comparing the image signal with a predetermined reference level. In this case, the white level signal represents the article and the black level signal denotes the background. The bivalent signal i~ supplied to a histogram circuit 5 in which the number of white or black level pixels in every scanning line is counted and a histogram of the white or black 2~ level pixels is formed as illustrated in Figs. 4A to 4C.
In Figs. 4A to 4C, images of the edge portions of three ; - 7-.
'. , ~
~ 322043 kinds o~ articles picked up by the television camera 3 are schematically illustrated in the right-side view, and the histograms thereof are shown in left-side graphs, respectively. In the graphs, the ordinates o~j represent the scanning line number of the raster of the television camera 3, and the abscissa the number of the black level pixels. The condition of the edge portion of the article illustrated in Fig. 4A is almost perfect, i.e. no defect or dust is in the edge portion, and therefore the number of the black level pixels is abruptly increased up to the maximum just at the Nth scanning line. In Fig. 4B, the image of the article having a concave defect at the edge portion is picked up and in the histogram, there is acknowledged a slight 16 increase in the number of the black level pixels in some scanning lines before the Nth line. But the increased number of pixels before the Nth line is not so large and at the Nth scanning line the number of black level pixel~ i8 suddenly increased. Contrary to this, the article illustra~ed in Fig. 4C has a convex defect at the edge portion. In the histogram therefor, the number ; of the black level pixels i8 suddenly increased at the Nth scanning line, but does not reach the maximum value.
At a scanning line N' which situates after the Nth l~ne 2~ by several ~canning lines, the number of black level pixels becomes maximum. Anyway, it i9 possible to 13220~3 detect the scanning line at which the number of the black level pixels firstly exceed~ a predetermined threshold level, so that the edge position of the article can be detected accurately without being 05 affected by the defect or dust.
The scanning line at which the number of black level pixels is abruptly increased is found in the above explained manner, and a signal denoting the relevant scanning line is supplied to an edge position calculating circuit 6. In the calculating circuit 6, a position of the relevant scanning line is calculated on the basis of the center of the field of view of the television camera 3. In this manner, the position of the edge portion la of the article l can be detected.
Fig. 5 shows an embodiment of the apparatus according to the present invention. In the present embodiment, the apparatus is used for measuring a length of a tread rubber for use in manufacturing tires.
As shown in Fig. 5, the tread rubber ll has a parallelogram shape viewed from the side. Generally, the length of the tread rubber is determined by measuring the longitudinal distance of the tread rubber between one edge portion lla having an obtuse angle viewed from the side (first edge portion) and the other 2~ edge portion llb having an acute angle (second edge portion).
1322~3 In the embodiment, the fi~st edge portion lla is detected by the apparatus according to the present invention, and the second edge portion llb is detected by a light projector 12 and a photo electric switch 13.
05 The tread rubber 11 is conveyed in a direction shown by an arrow A by means of a belt conveyor 14. Above the traveling path of the tread rubber 11 are arranged a light source 15 and a two-dimensional television camera 16. It should be noted that an optical axis of the light projector 12 and photoelectric switch 13 is arranged to be separated from the television camera 16 by a standard length of tread rubber for tires, In order to illuminate the edge portion lla uniformly, the light source 15 has a ring like shape and is arranged so as to surround the television camera 16.
The two-dimensional television camera 16 comprises a solid state image sen~ing device by means of which the image of the first edge portion lla of the tread rubber 11 is scanned two-dimensionally. In the television camera 16 solid state image pick-up elements are arranged in two hundreds and fifty six (256) rows each having two hundreds and fifty six (256) elements.
The two-dimenaional television camera 16 has its field of view F of 20x20 mm and i9 arranged such that the 2~ center portion of the first edge portion lla of the tread rubber 11 i9 included in the field of view as illustrated in Fig. 6. The scanning lines of the television camera 16 are arranged to be made parallel with the extending direction of the edge portion lla of the tread rubber 11. The output image signal of the 06 two-dimensional television camera 16 is supplied to an image signal memory 17 and is stored therein. That is to say, a signal which is produced at the timing when the second edge portion llb of the tread rubber 11 is detected by the photoelectric switch 13 is supplied to the image memory 17 as a freeze timing signal, and the image signal read out of the television camera 16 at that timing is memorized in the memory 17 in a moment.
It should be noted that, the belt conveyor 14 is driven continuously. The image signal of one frame is stored 16 in the memory 17 in this manner, when the edge portion lla of the tread rubber 11 comes within the field of view of the television camera 16.
Next, the image signal is read out of the memory 17 and is supplied to a bivalent circuit 18. In the zO bivalent circuit the analog image signal is compared with a thre~hold level and is converted into a bivalent signal representing the black and white level pixels.
The bivalent signal i~ supplied to a black level pixel number counting circuit 19 in which the number of the 2~ black level pixels of the bivalent signal is counted at every scanning line.~ The signal representing the thus 1322~43 obtained number of the black level pixels at every scanning line is supplied to a histogram circuit 20 in which a histogram for the number of black level pixels at every scanning line is made. The thus obtained 05 histogram signal is supplied to an edge position judging circuit 21. In the judging circuit 21, the black pixel number signal is compared with a threshold level such a~
100 pixels and a scanning line at which the number of the black level pixels firstly exceeds the threshold lo level of lO0 pixels is detected as the position of the edge portion. It is possible to determine the threshold value in accordance with the kind of the objec~ to be measured, so that the best threshold value for the kind of the object can be obtained experimentally.
16 The signal representing the scanning line at the edge portion lla of the tread rubber ll i5 then supplied to a length calculating circuit 22.
As shown in Fig. 7, the distance L between a position of the second edge portion llb of the tread rubber detected by the light projector 12 and photoelectric switch 13 and the center of the television camera 16 has been previously determined and also the distance corresponding to one pitch of the scanning lines of the televis~on camera 16 has been known.
a6 In the length calculating circuit 22, a distance ex between the position corresponding to the center of the television camera 16 and the position corresponding to the relevant line, i.e. the position of the first edge portion lla, is calculated. This distance ex can be easily obtained by multiplying the number of the 05 scanning lines existing between the center of the television camera 16 and the relevant scanning line by the distance corresponding to the scanning line pitch.
Thereafter, the length e of the tread rubber ll is calculated by an e~uation of e=L+ex~
lo As explained in the above, according to the apparatus of the present invention, the position of the edge portion of the object can be detected accurately with a high reliability but without being affected by a defect or a dust formed in or adhered on the edge portion of the object, 2~
06 means for converting said image signal into a bivalent signal representing white and black pixels;
mean~ for counting the number of the white or black pixels of the bivalent siqnal in every scanning line to make a histogram of the white or black pixels; and edge detecting means for receiving the histogram and detecting the edge position of the article in accordance with a change in the number of the white or black pixels in the histogram.
In the apparatus according to the invention, an 1~ image of the edge portion of the article is picked up by a two-dimensional television camera which is arranged above the article auch that the scanning lines of the television camera are made aubstantially parallel with : the extending direction of the edge portion, the number of white or black pixels on every scanning line of the thus obtained image signal is counted to make a histogram therefor, and a scanning line from which the number of white or black pixels is largely changed is detected as the edge po~ltion of the article.
2~ ~herefore, it ia poasible to detect the edge position accurately with high reliability but without being ~: :
,. ~
affected by the defect or dust existed in the edge portion of the article to be detected.
Fig. 1 is a schematic view showing the conventional apparatus for detecting the edge position of the article;
Fig. 2 is a schematic view depicting the relative position of the linear image sensor of the conventional apparatus and the edge portion of the article;
10Fig. 3 is a schematic view illustra*ing the baslc constitution of the apparatus for detecting the ; edge position of the article according to the inven-tion;
Figs. 4A to 4C are schematic views for explaining the operation of the apparatus according to the invention;
Fig. 5 is a schematic view representing an embodiment of the apparatus according to the invention by means of which a length of a tread rubber for manufacturing a tire is measured;
, Fig. 6 is a plan view showing the relation between the edge portion of the tread rubber and the field of view of the television camera installed in ~ ~the apparatus according to the present invention; and '' ~,: ~
~' - 6 -: , `',. , , , ~
' 1322~4~
Fig. 7 is a schematic view explaining a calculating method for calculating the length of the tread rubber.
Fig. 1 is a schematic view showing a conven-tional apparatus therefor. As is clear from Fig. 1, an edge portion 51a of an article 51 is illuminated by a light source 52, and an image of the edge portion 51a is picked up by a television camera 54 having a one-dimensional linear array sensor 53. In the linear array sensor 53 there are provided a plurality of light receiving elements which are linearly arranged in a direction perpendicular to an extending direction of the edge portion 51a of the article 51. The edge position 51a can be obtained by comparing an output signal level of the linear array sensor 53 with an appropriate threshold level.
In the conventional apparatus, since, as shown in Fig. 2, the light receiving elements of the linear array sensor 53 are arranged substantially perpendicular to the extending direction of the edge portion 51a of the article 51, a single point on the edge portion at which the linear image sensor 53 and the edge portion 51a intersect with each other is detected and the thus detected point is regarded as the edge position of the article. Thus, when the length of the article is measured on the basis of the ., .
- 6a -.
" ' ' :
.
1322~
thus obtained position of the edge portion, if a defect 55 is formed in the edge portion of the article and the image sensor 53 intersects with the edge portion at the defect as shown in Fig. 2, the length of the article could not be measured correctly.
,, ~
~ 6b -t ~A
' , .
1 , , i .
- . ~ .
,, .
.
1322~3 Fig. 3 is a block diagram showing the basic constitution of the apparatus for detecting the edge position of the article according to the present invention. Above an article l is arranged a light o~ source 2 to uniformly illuminate the edge portion la of the article. A two-dimensional television camera 3 is also arranged above the article l to pick up the image of the edge portion la of the article l which is illuminated by the light source 2. In the present invention, the television camera 3 is of the raster ~canning type and is arranged such that the scanning line~ of the television camera 3 are made parallel with the extending direction of the edge portion la of the article l. An image signal of the edge portion la 16 picked up by the television camera 3 is supplied to a bivalent circuit 4 in which the image signal is converted into a bivalent image signal composed of white and black level signals by comparing the image signal with a predetermined reference level. In this case, the white level signal represents the article and the black level signal denotes the background. The bivalent signal i~ supplied to a histogram circuit 5 in which the number of white or black level pixels in every scanning line is counted and a histogram of the white or black 2~ level pixels is formed as illustrated in Figs. 4A to 4C.
In Figs. 4A to 4C, images of the edge portions of three ; - 7-.
'. , ~
~ 322043 kinds o~ articles picked up by the television camera 3 are schematically illustrated in the right-side view, and the histograms thereof are shown in left-side graphs, respectively. In the graphs, the ordinates o~j represent the scanning line number of the raster of the television camera 3, and the abscissa the number of the black level pixels. The condition of the edge portion of the article illustrated in Fig. 4A is almost perfect, i.e. no defect or dust is in the edge portion, and therefore the number of the black level pixels is abruptly increased up to the maximum just at the Nth scanning line. In Fig. 4B, the image of the article having a concave defect at the edge portion is picked up and in the histogram, there is acknowledged a slight 16 increase in the number of the black level pixels in some scanning lines before the Nth line. But the increased number of pixels before the Nth line is not so large and at the Nth scanning line the number of black level pixel~ i8 suddenly increased. Contrary to this, the article illustra~ed in Fig. 4C has a convex defect at the edge portion. In the histogram therefor, the number ; of the black level pixels i8 suddenly increased at the Nth scanning line, but does not reach the maximum value.
At a scanning line N' which situates after the Nth l~ne 2~ by several ~canning lines, the number of black level pixels becomes maximum. Anyway, it i9 possible to 13220~3 detect the scanning line at which the number of the black level pixels firstly exceed~ a predetermined threshold level, so that the edge position of the article can be detected accurately without being 05 affected by the defect or dust.
The scanning line at which the number of black level pixels is abruptly increased is found in the above explained manner, and a signal denoting the relevant scanning line is supplied to an edge position calculating circuit 6. In the calculating circuit 6, a position of the relevant scanning line is calculated on the basis of the center of the field of view of the television camera 3. In this manner, the position of the edge portion la of the article l can be detected.
Fig. 5 shows an embodiment of the apparatus according to the present invention. In the present embodiment, the apparatus is used for measuring a length of a tread rubber for use in manufacturing tires.
As shown in Fig. 5, the tread rubber ll has a parallelogram shape viewed from the side. Generally, the length of the tread rubber is determined by measuring the longitudinal distance of the tread rubber between one edge portion lla having an obtuse angle viewed from the side (first edge portion) and the other 2~ edge portion llb having an acute angle (second edge portion).
1322~3 In the embodiment, the fi~st edge portion lla is detected by the apparatus according to the present invention, and the second edge portion llb is detected by a light projector 12 and a photo electric switch 13.
05 The tread rubber 11 is conveyed in a direction shown by an arrow A by means of a belt conveyor 14. Above the traveling path of the tread rubber 11 are arranged a light source 15 and a two-dimensional television camera 16. It should be noted that an optical axis of the light projector 12 and photoelectric switch 13 is arranged to be separated from the television camera 16 by a standard length of tread rubber for tires, In order to illuminate the edge portion lla uniformly, the light source 15 has a ring like shape and is arranged so as to surround the television camera 16.
The two-dimensional television camera 16 comprises a solid state image sen~ing device by means of which the image of the first edge portion lla of the tread rubber 11 is scanned two-dimensionally. In the television camera 16 solid state image pick-up elements are arranged in two hundreds and fifty six (256) rows each having two hundreds and fifty six (256) elements.
The two-dimenaional television camera 16 has its field of view F of 20x20 mm and i9 arranged such that the 2~ center portion of the first edge portion lla of the tread rubber 11 i9 included in the field of view as illustrated in Fig. 6. The scanning lines of the television camera 16 are arranged to be made parallel with the extending direction of the edge portion lla of the tread rubber 11. The output image signal of the 06 two-dimensional television camera 16 is supplied to an image signal memory 17 and is stored therein. That is to say, a signal which is produced at the timing when the second edge portion llb of the tread rubber 11 is detected by the photoelectric switch 13 is supplied to the image memory 17 as a freeze timing signal, and the image signal read out of the television camera 16 at that timing is memorized in the memory 17 in a moment.
It should be noted that, the belt conveyor 14 is driven continuously. The image signal of one frame is stored 16 in the memory 17 in this manner, when the edge portion lla of the tread rubber 11 comes within the field of view of the television camera 16.
Next, the image signal is read out of the memory 17 and is supplied to a bivalent circuit 18. In the zO bivalent circuit the analog image signal is compared with a thre~hold level and is converted into a bivalent signal representing the black and white level pixels.
The bivalent signal i~ supplied to a black level pixel number counting circuit 19 in which the number of the 2~ black level pixels of the bivalent signal is counted at every scanning line.~ The signal representing the thus 1322~43 obtained number of the black level pixels at every scanning line is supplied to a histogram circuit 20 in which a histogram for the number of black level pixels at every scanning line is made. The thus obtained 05 histogram signal is supplied to an edge position judging circuit 21. In the judging circuit 21, the black pixel number signal is compared with a threshold level such a~
100 pixels and a scanning line at which the number of the black level pixels firstly exceeds the threshold lo level of lO0 pixels is detected as the position of the edge portion. It is possible to determine the threshold value in accordance with the kind of the objec~ to be measured, so that the best threshold value for the kind of the object can be obtained experimentally.
16 The signal representing the scanning line at the edge portion lla of the tread rubber ll i5 then supplied to a length calculating circuit 22.
As shown in Fig. 7, the distance L between a position of the second edge portion llb of the tread rubber detected by the light projector 12 and photoelectric switch 13 and the center of the television camera 16 has been previously determined and also the distance corresponding to one pitch of the scanning lines of the televis~on camera 16 has been known.
a6 In the length calculating circuit 22, a distance ex between the position corresponding to the center of the television camera 16 and the position corresponding to the relevant line, i.e. the position of the first edge portion lla, is calculated. This distance ex can be easily obtained by multiplying the number of the 05 scanning lines existing between the center of the television camera 16 and the relevant scanning line by the distance corresponding to the scanning line pitch.
Thereafter, the length e of the tread rubber ll is calculated by an e~uation of e=L+ex~
lo As explained in the above, according to the apparatus of the present invention, the position of the edge portion of the object can be detected accurately with a high reliability but without being affected by a defect or a dust formed in or adhered on the edge portion of the object, 2~
Claims (10)
1. An apparatus for detecting an edge position of an article comprising:
a light source means for projecting an illumination light at least to the edge portion of the article;
a television camera means for picking up an image of the edge portion of the article to produce an image signal, said television camera means being arranged such that scanning lines of the television camera means are substantially parallel with a width direction of the edge of the article;
means for converting said image signal into a bivalent signal representing white and black pixels;
means for counting the number of the white or black pixels of the bivalent signal in every scanning line to make a histogram of the white or black pixels; and edge detecting means for receiving the histogram and detecting the edge position of the article in accordance with a change in the number of the white or black pixels in the histogram.
a light source means for projecting an illumination light at least to the edge portion of the article;
a television camera means for picking up an image of the edge portion of the article to produce an image signal, said television camera means being arranged such that scanning lines of the television camera means are substantially parallel with a width direction of the edge of the article;
means for converting said image signal into a bivalent signal representing white and black pixels;
means for counting the number of the white or black pixels of the bivalent signal in every scanning line to make a histogram of the white or black pixels; and edge detecting means for receiving the histogram and detecting the edge position of the article in accordance with a change in the number of the white or black pixels in the histogram.
2. An apparatus according to claim 1, wherein said television camera means comprises a two-dimensional television camera.
3. An apparatus for detecting an edge position of an elongated article having a first and second edge portions according to claim 2 further comprising:
means for conveying the elongated article in a longitudinal direction of the article:
timing detecting means for detecting a timing at which the first edge portion of the article comes-within a field of view of the television camera and producing a detection signal thereof; and means for freezing the image signal of the first edge portion of the article picked up by the television camera in response to said detection signal.
means for conveying the elongated article in a longitudinal direction of the article:
timing detecting means for detecting a timing at which the first edge portion of the article comes-within a field of view of the television camera and producing a detection signal thereof; and means for freezing the image signal of the first edge portion of the article picked up by the television camera in response to said detection signal.
4. An apparatus according to claim 3, wherein:
said timing detecting means is arranged to be separated from the television camera by a standard length of the article and comprises a light source and photoelectric switch arranged on respective sides of the article, said detection signal being generated when the second edge portion of the article is detected by said photoelectric switch.
said timing detecting means is arranged to be separated from the television camera by a standard length of the article and comprises a light source and photoelectric switch arranged on respective sides of the article, said detection signal being generated when the second edge portion of the article is detected by said photoelectric switch.
5. An apparatus according to claim 4, wherein:
said image signal freezing means comprises a memory for storing the image signal of the first edge portion of the article supplied from the television camera in response to the detection signal.
said image signal freezing means comprises a memory for storing the image signal of the first edge portion of the article supplied from the television camera in response to the detection signal.
6. An apparatus according to claim 2, wherein:
said counting means comprises a circuit for counting the number of black level pixels in every scanning line and a circuit for making a histogram in accordance with the number of the black pixels.
said counting means comprises a circuit for counting the number of black level pixels in every scanning line and a circuit for making a histogram in accordance with the number of the black pixels.
7. An apparatus according to claim 6, wherein;
said edge position detecting means detects as the edge position a scanning line at which the number of the black level pixels firstly exceeds a predetermined threshold number.
said edge position detecting means detects as the edge position a scanning line at which the number of the black level pixels firstly exceeds a predetermined threshold number.
8. An apparatus according to claim 7, wherein:
said television camera has two hundreds and fifty six (256) scanning lines each having two hundreds and fifty six (256) pixels and said predetermined threshold number is set to about one hundred (100).
said television camera has two hundreds and fifty six (256) scanning lines each having two hundreds and fifty six (256) pixels and said predetermined threshold number is set to about one hundred (100).
9. An apparatus according to claim 5, further comprising:
means for calculating a length (?) of the article from a distance (L) between a center of the field of view of the television camera and the timing detecting means, and a distance (?x) between the center of the field of view of the television camera and the scanning line at the edge position.
means for calculating a length (?) of the article from a distance (L) between a center of the field of view of the television camera and the timing detecting means, and a distance (?x) between the center of the field of view of the television camera and the scanning line at the edge position.
10. An apparatus according to claim 9, wherein:
said elongated article is a tread rubber for use in manufacturing tires, and a length of the tread rubber is measured by detecting an edge position having an acute angle viewed from a side by means of the photoelectric switch of the timing detecting means and an edge position having an obtuse angle viewed from a side by means of the television camera.
said elongated article is a tread rubber for use in manufacturing tires, and a length of the tread rubber is measured by detecting an edge position having an acute angle viewed from a side by means of the photoelectric switch of the timing detecting means and an edge position having an obtuse angle viewed from a side by means of the television camera.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63194568A JPH0244202A (en) | 1988-08-05 | 1988-08-05 | Apparatus for detecting end position of object |
| JP63-194,568 | 1988-08-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1322043C true CA1322043C (en) | 1993-09-07 |
Family
ID=16326696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000607477A Expired - Fee Related CA1322043C (en) | 1988-08-05 | 1989-08-03 | Apparatus for detecting edge position of elongated article |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US4974077A (en) |
| EP (1) | EP0358331B1 (en) |
| JP (1) | JPH0244202A (en) |
| KR (1) | KR900003642A (en) |
| CA (1) | CA1322043C (en) |
| DE (1) | DE68901598D1 (en) |
| ES (1) | ES2033098T3 (en) |
Families Citing this family (33)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5160643A (en) * | 1990-01-16 | 1992-11-03 | Bj Services Company | Method for delaying the gellation of borated galactomannans with a delay additive such as glyoxal |
| US5272649A (en) * | 1990-04-11 | 1993-12-21 | Campbell Gregory A | Video method and apparatus for measuring and controlling dimensional stability |
| US5119436A (en) * | 1990-09-24 | 1992-06-02 | Kulicke And Soffa Industries, Inc | Method of centering bond positions |
| US5132791A (en) * | 1990-09-25 | 1992-07-21 | Ball Corporation | Optical sheet inspection system |
| JP3134009B2 (en) * | 1990-11-21 | 2001-02-13 | アーチ・デベロップメント・コーポレーション | Image processing method and apparatus |
| US5265173A (en) * | 1991-03-20 | 1993-11-23 | Hughes Aircraft Company | Rectilinear object image matcher |
| US5212656A (en) * | 1991-04-26 | 1993-05-18 | Prime Technology, Inc. | Box inspection device and method |
| GB2262339B (en) * | 1991-12-13 | 1995-09-06 | Honda Motor Co Ltd | Method of inspecting the surface of a workpiece |
| US5206720A (en) * | 1991-12-16 | 1993-04-27 | Bridgestone Corporation | Apparatus and technique for monitoring component position during tire building |
| US5394183A (en) * | 1992-05-05 | 1995-02-28 | Milliken Research Corporation | Method and apparatus for entering coordinates into a computer |
| KR0141445B1 (en) * | 1993-06-10 | 1998-07-01 | 모리시타 요이찌 | Method and equipment for measuring displacement |
| US5566244A (en) * | 1993-11-22 | 1996-10-15 | Honda Giken Kogyo Kabushiki Kaisha | Method of inspecting a workpiece surface including a picturing system with a shortened focal plane |
| US5581632A (en) * | 1994-05-02 | 1996-12-03 | Cognex Corporation | Method and apparatus for ball bond inspection system |
| JP3193240B2 (en) * | 1994-09-08 | 2001-07-30 | 株式会社東芝 | Image processing device |
| DE4438014C2 (en) * | 1994-10-25 | 1997-07-31 | Bodenseewerk Geraetetech | Device for measuring the length of moving parts |
| JP2730665B2 (en) * | 1994-12-15 | 1998-03-25 | 北陸先端科学技術大学院大学長 | Character recognition apparatus and method |
| DE19510753A1 (en) * | 1995-03-24 | 1996-09-26 | Will E C H Gmbh & Co | Device for measuring sheets of paper |
| US6521905B1 (en) | 1999-09-22 | 2003-02-18 | Nexpress Solutions Llc | Method and device for detecting the position of a transparent moving conveyor belt |
| DE10063528B4 (en) * | 2000-12-20 | 2011-05-19 | Goss International Montataire S.A. | Method for determining the accuracy of a folded position |
| DE10127746B4 (en) * | 2001-06-08 | 2006-03-30 | A-Z Formen- Und Maschinenbau Gmbh | Cutting device for treads |
| US20030087739A1 (en) * | 2001-11-08 | 2003-05-08 | Hagemann John R | Methods and systems for constructing multiwall corrugated container blanks having body portions and flap portions with different wall thicknesses |
| US7456379B2 (en) * | 2003-02-03 | 2008-11-25 | Kodak Graphic Communications Canada Company | Printing plate registration and optical alignment device including locating at least a part of a reference edge in at least one digital camera image |
| DE10346467A1 (en) * | 2003-10-02 | 2005-05-19 | E.C.H. Will Gmbh | Measuring device and method for checking the cut quality of a sheet |
| DE102005009132B4 (en) * | 2005-03-01 | 2019-03-14 | Manroland Goss Web Systems Gmbh | Method for controlling a folding apparatus of a printing machine |
| JP4881584B2 (en) * | 2005-06-28 | 2012-02-22 | 株式会社ブリヂストン | How to create master data for inspection of uneven figures |
| JP4837538B2 (en) * | 2006-12-04 | 2011-12-14 | 昭和電工株式会社 | End position measuring method and dimension measuring method |
| JP4837541B2 (en) * | 2006-12-18 | 2011-12-14 | 昭和電工株式会社 | End face shape inspection method and apparatus |
| US7856798B2 (en) * | 2008-11-03 | 2010-12-28 | Delkor Systems, Inc. | Method and apparatus for flap adjustment of a carton |
| JP5952005B2 (en) * | 2012-01-25 | 2016-07-13 | 株式会社ブリヂストン | Tread length measuring method and tread length measuring device |
| MX2016007367A (en) * | 2013-12-13 | 2016-08-03 | Pirelli | Method and apparatus for applying a band-like elastomeric element for tyres on a forming support. |
| US9750646B2 (en) * | 2014-06-26 | 2017-09-05 | The Procter & Gamble Company | Systems and methods for monitoring and controlling an absorbent article converting line |
| US20170128274A1 (en) * | 2015-11-11 | 2017-05-11 | The Procter & Gamble Company | Methods and Apparatuses for Registering Substrates in Absorbent Article Converting Lines |
| CN107860319A (en) * | 2017-11-28 | 2018-03-30 | 杭州朝阳橡胶有限公司 | A kind of tyre surface measuring motion and method applied to feed frame |
Family Cites Families (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1574263A (en) * | 1977-07-27 | 1980-09-03 | Measurex Corp | Measurement of tread length |
| FR2437610A1 (en) * | 1978-09-29 | 1980-04-25 | Usinor | Length and speed meter esp. for steel industry - uses video camera and opto-electronic gating in pulse counting technique |
| JPS5547573A (en) * | 1978-09-29 | 1980-04-04 | Mitsubishi Electric Corp | Pattern extracting device |
| JPS55116208A (en) * | 1979-02-28 | 1980-09-06 | Yokohama Rubber Co Ltd:The | Measuring length of black rubber object |
| JPS5729438A (en) * | 1980-07-31 | 1982-02-17 | Toyoda Gosei Co Ltd | Method and apparatus for measuring outer diameter of extrudate |
| US4441125A (en) * | 1981-11-03 | 1984-04-03 | Micron Technology, Inc. | Image sensor using dynamic random access memory |
| JPS58173409A (en) * | 1982-04-06 | 1983-10-12 | Toyo Tire & Rubber Co Ltd | Measuring method of length for belt-like object |
| JPS58191908A (en) * | 1982-05-04 | 1983-11-09 | Toyo Tire & Rubber Co Ltd | Length measuring device of band-shaped material to be carried |
| JPS5975106A (en) * | 1982-10-22 | 1984-04-27 | Toyo Tire & Rubber Co Ltd | Length measuring device for beltlike body |
| FR2560472B1 (en) * | 1984-02-23 | 1987-08-21 | Proge | FAST PROFILE TAKING DEVICE |
| JPS60207980A (en) * | 1984-03-31 | 1985-10-19 | Tokinaa Kogaku Kk | Method and device for fetching picture |
| JPS60210644A (en) * | 1984-04-05 | 1985-10-23 | Bridgestone Corp | Material for conveyor belt |
| JPS60228906A (en) * | 1984-04-27 | 1985-11-14 | Bridgestone Corp | Length measuring method and apparatus thereof |
| JPS6114507A (en) * | 1984-06-30 | 1986-01-22 | Yokohama Rubber Co Ltd:The | Measuring method of tire tread length |
| JPS62249005A (en) * | 1986-04-22 | 1987-10-30 | Bridgestone Corp | Inspecting deice for abnormality of shape of object |
| JPH0621766B2 (en) * | 1986-10-25 | 1994-03-23 | 住友ゴム工業株式会社 | Method and apparatus for measuring cross-sectional shape |
-
1988
- 1988-08-05 JP JP63194568A patent/JPH0244202A/en active Pending
-
1989
- 1989-07-31 US US07/387,041 patent/US4974077A/en not_active Expired - Fee Related
- 1989-08-03 KR KR1019890011109A patent/KR900003642A/en not_active Application Discontinuation
- 1989-08-03 CA CA000607477A patent/CA1322043C/en not_active Expired - Fee Related
- 1989-08-04 EP EP89307992A patent/EP0358331B1/en not_active Expired - Lifetime
- 1989-08-04 ES ES198989307992T patent/ES2033098T3/en not_active Expired - Lifetime
- 1989-08-04 DE DE8989307992T patent/DE68901598D1/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| EP0358331A3 (en) | 1990-10-17 |
| US4974077A (en) | 1990-11-27 |
| ES2033098T3 (en) | 1993-03-01 |
| JPH0244202A (en) | 1990-02-14 |
| EP0358331A2 (en) | 1990-03-14 |
| DE68901598D1 (en) | 1992-06-25 |
| KR900003642A (en) | 1990-03-26 |
| EP0358331B1 (en) | 1992-05-20 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA1322043C (en) | Apparatus for detecting edge position of elongated article | |
| EP0917649B1 (en) | Apparatus and method for detecting surface defects | |
| US5216481A (en) | Method of and apparatus for inspecting transparent object for defect | |
| JP3041090B2 (en) | Appearance inspection device | |
| US5235649A (en) | Cigarette inspection method | |
| GB2036301A (en) | Foreign matter detecting device | |
| EP0744862A1 (en) | A method of and apparatus for correcting the output signals of a plurality of photodetecting elements | |
| JPH02114106A (en) | Apparatus for measuring length of sheet material | |
| EP0871008B1 (en) | Device for measuring the dimensions of an object that is very extensive longitudinally and whose cross section has a curved contour | |
| JPH06103170B2 (en) | Appearance inspection method and device | |
| JP2946765B2 (en) | Fruit sorting equipment | |
| JPH1173948A (en) | Inspection device for electrode plate group of storage battery | |
| JPH0545127A (en) | Method and apparatus for measuring position and shape of strip-shaped member | |
| GR3003820T3 (en) | ||
| CA2237640C (en) | Apparatus and method for detecting surface defects | |
| JPH09222399A (en) | Acceptable defective quality discrimination method for synthetic resin corrugated sheet | |
| JPH0534125A (en) | Method and apparatus for measuring shape of strip-like member | |
| JPH0650873A (en) | Inspection method for density unevenness of sheetlike object | |
| JP3337640B2 (en) | Automatic shell sorting equipment | |
| JP2532513B2 (en) | Object presence inspection method | |
| JPS6322521B2 (en) | ||
| JPH0857432A (en) | Bottle sorting apparatus | |
| EP0507638A2 (en) | Method and apparatus for detecting angle and pitch of cord in belt-shaped members | |
| EP0099229A3 (en) | Image measuring system | |
| JP2646333B2 (en) | Incorrect page detection method and apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |