DE3134210A1 - Dimension monitoring device - Google Patents

Abstract

A dimension monitoring device for monitoring at least the width of an object, consisting of a radiation source for illuminating the object while the object is moved along a prescribed linear section of a path; a video camera having a linear arrangement of radiation-sensitive scanning elements, which are arranged diagonally in a transverse fashion over this path at an angle of 30 to 60 DEG relative to the direction of movement of the object and during successive scannings are active thereon to generate electric signals as a function of the occurrence of radiation reflected by successive strips of the object. In this case, the number of the elements receiving the radiation is a function at each instant of the length of the strip from which the reflected radiation is received at the specific instant, as a result of which the signal generated by each scanning represents the length of the corresponding strip. The device also comprises signal processing devices which respond to the electric signals in order to generate a signal representing the width of the object by making calculations using data derived for specific selected scannings.

Description

The invention relates to a dimensional monitoring unit

direction for monitoring at least the width of moving objects, like, for example, biscuits that are conveyed out of an oven.

As used in this description, the word "width" means the dimension which runs and should run transversely to the direction of movement of the object also include the diameter of a circular object.

In the production of biscuits you can monitor various Parameters of the biscuits such as thickness, length, width and color as well as their control Achieve significant commercial benefits. The uniformity in the first three of these parameters is essential if the automatic generation is more uniform Biscuit wraps is to be achieved. Deviations in any of these three parameters can lead to biscuit packs that are either overweight or underweight or are misshapen. In the most extreme case, such deviations can lead to serious Cause malfunctions in the packaging machines.

Monitoring the color is desirable so that biscuits use constant browning can be generated. You influence the browning of the biscuits good appearance that appeals to the customer, as well as the aroma, and it is therefore desirable that the browning is maintained at a level known to be most desirable Product produces.

To be able to exercise control over the production of the biscuits it is necessary to monitor at least sample groups of the biscuits to be produced, and this monitoring is preferably done while the biscuits are on move at normal production speed on conventional conveyors.

The object of the invention is to provide a device for monitoring monitor at least the width of objects such as biscuits, while the objects move along a predetermined path.

According to the invention includes a dimensional monitoring device for monitoring at least the width (as defined above) of an object, one Radiation source to illuminate the object while it is on a given moving along a linear section of a path, a video camera with a scanned linear arrangement of radiation-sensitive elements diagonally across the Path arranged at an angle of 300 to 600 to the direction of movement of the object and operate during successive scans to be in Depending on the impact of one of successive strips of the object reflected radiation thereon generate electrical signals whereby the number of Elements that receive the radiation at any moment depends on the Length of the strip from which the reflected radiation at that moment is received, which makes the signal produced by each sample the length of the appropriate Strip represents, and Signalververarbeitungein directions on electrical Respond to signals by calculating from for certain selected ones of the samples derived data to generate a signal representing the width of the object.

The device preferably also operates to monitor the length of the object (i.e. the dimension in the longitudinal direction of the path). It is also advantageous, especially when the device for monitoring biscuit production used when the device also monitors the thickness and color of the biscuits.

Preferably, the device also determines if a rectangular Object is inclined relative to the path.

The signal processing device preferably contains reference data, which relate to the required size and color of the objects, and is arranged to trigger an alarm and / or corrective control The production facility provides for when the monitored items are not accurate enough correspond to the reference data.

There is now an embodiment of the invention in the form of a Example and with reference to the accompanying drawings. Show it Fig0 1 is a perspective view of a measuring head forming part of a biscuit dimension monitoring device and is mounted over a conveyor, Fig. 2 is a block diagram of the device, Fig. 3 is a diagram of an optical system that forms part of the device, 4 shows the orientation of a number of photosensitive elements relative to the conveyor; Figures 5A, 5B and 5C show the waveform and shaped output of one single scan of a biscuit, of multiple scans of a rectangular biscuit respectively.

the output for certain of the samples, Figures 6A and 6B, are similar Figures 5B and 5C, but for a rectangular biscuit which is relative to the Center line of the conveyor is inclined, Figs. 7A and 7B show scan lines and Waveforms for a circular biscuit, Figs. 8A and 8B show the monitoring the thickness and color of a biscuit or the waveforms it creates, and Fig. 9 is a block diagram of devices for monitoring the speed of movement a biscuit and to pay for the biscuits.

The biscuit monitor shown in Fig. 1 includes one Measuring head 1, which is slidably mounted on rails 2 and 3, so that its underside is about 100 mm above the surface of the conveyor 4 from which the biscuits 5 are made an oven (not shown) and transported to a packing station (not shown) feeds. The conveyor is dark colored for a purpose to be explained below in contrast to the light-colored biscuits.

The basis of the measuring head 1 is a line scanning camera with a self scanned linear array of photosensitive charge coupled devices (ccD), which receive light reflected from the biscuits. The camera feels the three 11 streets! 1 of the biscuits, i.e. pillars in the direction of the movement of the conveyor, and the individual street can be selected by sliding the head in each one any position over the conveyor.

The measuring head 1 contains devices for cooling the camera and the associated circuit, so that they can cope with the high ambient temperature at the furnace outlet and withstand the heat emitted by the biscuits and conveyor.

Fig. 2 shows the monitoring device with the above-mentioned CCD arrangement 6, the output of which is fed to a control and threshold circuit 7 via a line 8 will. The generated at the beginning of successive scans of the CCD array Pulses are also on a line 9 to the circuit 7 and the Stromkreisanord voltage 10 supplied, consisting of a counter and an edge detector ii, a memory 12 and a programmable logic arrangement (PLA) 13.

The circuit arrangement 10 carries signals from a microprocessor unit (MPU) 14, which contains a program memory 15, and is controlled by this The MPU 94 controls the switching device 16, which in turn is a lighting system 17 controls so that they can either floodlight the biscuit road optionally or deliver a number of individual light strips across the street.

A speed sensor 18 measures the speed of movement the biscuits on the conveyor and also creates impulses for counting the number of biscuits, passing the sensor.

The signals from the sensor 18 are fed to the MPU 14. The MPU provides a serial digital output on a line 19 for driving a line printer 20 ued / or a visual display unit (VDU) 21, which are each capable of an InTora mation regarding the condition of the monitored biscuits. The MPU also drives a digital-to-analog Converter 22 (D / A), which an analog signal on a line 23 to a measuring device 24 and / or to a Spring indicator 25 transmits.

The MPU 14 can, for example, be a device of the type Z80A, which is traded by the company Zilog Inc. of Cupertino, California, USA.

Fig. 3 shows the arrangement of the lighting system 17 relative to the Conveyor 4 and the CCD assembly 6. The floodlight is provided by two lamps 26 and 27, which are arranged on opposite sides of the arrangement 6 which are a light spot on the conveyor immediately below the assembly produce. The lighting with the narrow light strip is provided by a System which is offset to one side of the arrangement 6 and a tungsten halogen lamp 28 contains, as well as an illumination lens 30, a slotted diaphragm 31, a lens 32 and an inclined mirror -33. The latter plant produces three narrow ones Light bar on the conveyor (or on a biscuit on it) immediately below the arrangement 6; A horizontal .Diffuser 94 diffuses the light from the lamps 26 and 27 to provide uniform floodlighting over a predetermined range Generate area. As already mentioned above, the switching device determines 16 at the command of the lamp 14, which of the lamps, 26 and 27 together or 28, is energized shall be.

The CCD arrangement 6 is contained in a camera 34, which is a vertical Has lens system 35. The camera 34 and the lighting system 17 together form the measuring head 1. The camera 34 can be a device of the type CCD 1400, which is used by manufactured by Fairchild Camera and Instrument Company in the USA.

Fig. 4 shows schematically the position of the CCD arrangement 6 relative to the Conveyor 4. The optimal angle between the array and the longitudinal centerline CL of the conveyor is 450, which will be explained below.

When the gamera 34 is in operation, very little of this is caused by the lighting system generated light reflected from the conveyor 4, because - as in the preceding mentioned - the conveyor is dark in color. Therefore generate as long as the void Conveyor located below the camera, all elements of the CCD assembly throughout each sample just a very small dark stream, which is abundant below the Threshold value is determined by the control and threshold circuit 7. Therefore, the MPU 14 is not given an exit, but if a biscuit is under the If the camera is present, light will be reflected from the top of the biscuit and the number and location of the elements received by the CCD array Receiving light during any scan depends on the width and location of the relevant strip of biscuit from which during that particular one Scanning Light is received; it will be natural during successive scans various strips monitored as the biscuit moves under the camera.

A typical individual scanning of a biscuit 5 by the arrangement 6 is shown in Fig. 5A which also schematically shows the waveform (i) of the video signal shows that of the camera 34 as a result of the of a block in the area of the CCD element received light is generated. The waveform is roughly rectangular and so is shaped to give an exactly rectangular waveform (ii). The shaping is performed by finding the passage of the camera output through the threshold and then dropping the output below the threshold. The front and trailing edges of the square pulse waveform (ii) therefore correspond in shape very closely to the scanning of the edges of the biscuit (i.e. the ends of the scanned Strip of biscuit) during the relevant scan. Hence the length represents of the pulse represents the width of the biscuit as far as this individual scan is concerned is.

Figures 5B and 5C each show certain particularly significant ones Scan lines in relation to a rectangular biscuit 5, as well as the resulting Square waveforms. The first significant scan line ("scan olt) occurs as well the first corner 36 of the biscuit reaches the scanning position. It will be a very narrow one Pulse 37 generated. Other scans, such as lines 38 and 39 generate pulses 88 and 89, their trailing edges with the rear flank of pulse 37 are aligned as the right edge of the biscuit is parallel to the center line of the conveyor. However, the leading edges of the pulses are 88 and 89 progressively earlier. Subsequent scans follow this pattern until the corner 40 is reached ("scan e"), which gives rise to a pulse 41. Then generate provided that the biscuit is of uniform width, the scans like for example, the tactile lines 42 and 43 pulses 44 and 45 of the same length like impulse 41 and with aligned leading and trailing edges. this continues9 until the corner 46 is reached ("scan k"), which emits a pulse 47 generates0 More samples, such as 48 and 49, then generate pulses SO and 51, their leading edges with the leading edges of the pulses 41, 44, 45 and 47 are aligned because the left edge of the biscuit is parallel to the center line of conveyor 4 ist0 The trailing edges of the following pulses move, however progressing to the left, and this continues, bs the Ece 52 ("scan r") des Biscuit is reached, which gives rise to a last, very narrow pulse 530 The method of calculating the width of a rectangular biscuit is as follows. The occurrence of transitions from scanning the dark conveyor to scanning of a light biscuit and vice versa (i.e. the leading or trailing edges of the exit impulse) is clocked from the beginning of each sample.

The pulse corresponding to the start of the scan on line 9 (Fig. 2) the feeding of clock steps from the control and threshold circuit begins 7 into the counter and edge detector 11 via a line 54. The clock step rate is the same as the rate at which the CCD elements are polled. If the Scanning does not produce an output signal from circuit 7 because only the conveyor is from the camera is viewed, then the counter only counts the clock steps until the next pulse is received corresponding to the start of a scan. The counter is reset by the latter pulse and the count is ignored. on the other hand If there is a biscuit under the camera, the clock steps from the beginning of the sample counted as before, but if the leading edge of the shaped video signal, which is brought up via a line 55 from the circle 7, from the payer and the edge detector 11 is detected, then the count is according to the The leading edge is registered in the memory 12. The count continues, and the when the trailing edge is detected, the count reached is also stored in the memory 12 fed in. The count for the remaining part of the talk steps for this Sampling serves no useful purpose and is ignored.

The memory 12 now contains two payments, which the positions of the scanned flanks of the biscuit relative to the CCD array, and the distance between these edges is represented by the difference between the counts. Subsequent scans produce further counts 1 in memory 12 can be saved until it is full.

The MPU 14 monitors each scan to see if a single Couple of transitions has taken place. She then temporarily takes control of memory 12, and the counts are kept by the MPU under the control of the program processed in the memory 15. The operational processes within the store 12 are controlled by the programmable logic arrangement 13, which on Command of the MPU 14 instructions either from the edge detector 11 or from the MPU accepts.

If the PLA is directed by the edge detector, then will Data words of 12 bits are entered into a working memory of the MPU, with 11 bits the position of the transition relative to the first image carrier (pixel) of the arrangement 6 and the twelfth bit the status information relating to the transition suspects. When the MPU 14 instructs the PLA to read data from the memory 12 to calculate the parameters of the biscuit, then the PLA causes a readout of the data as an 8-bit group followed by a 4-Blt group.

The program in the memory 15 causes the MPU 14 to select the successive ones Counts to determine if the transition from dark to light is moving to the left has, as is the case from scan to to scan e in Figures 5B and 50, and determine whether the transitions from heB1 to dark remained coincident are, as is the case, from scan o to scan k. Following scanning e the next scans result in coincident transitions from dark to light up to sampling r and also result in coincident transitions from light to dark until sampling k.

When calculating the width of a biscuit, the required Calculations made based on the difference between the element numbers of the Minimum and maximum transition.

Because of the samples o to k between the corners 36 and 46 acquired knowledge, the minimum transition position is determined, and based on the Samples e through r between corners 40 and 52 becomes the maximum transition position certainly.

The data for the dark-light transitions and the cell-dark transitions are stored in two separate areas of the MPU's main memory, the may be referred to as "front arrangement" and "rear arrangement", respectively. The MPU 14 inspects the contents of the two arrangements to determine the group of scans, over which the two transitions have remained essentially coincident. It averages the counts between transitions for those samples only and multiplies the average by a "width constant n, which is the scanning angle and takes into account the distance along the line of the CCD array was scanned between successive sampling steps.

The MPU 14 then outputs data relating to the calculated biscuit width to a buffer memory in the MPU memory. Will be at regular intervals the average of this data is calculated and the data is taken over the lines 19 and 23 put on the display devices 20, 21, 24 and 25. If the results the calculations for a number of biscuits do not match the stored reference data match, the MPU 14 causes the operation of a Alarm device and / or gives a corresponding control loop on the production plant an operating command.

Occasionally, a biscuit moving on the conveyor is inclined relative to the direction of movement, as shown in Fig0 6 A ge. Such The situation must be determined by the MPU 14 or leads to an incorrect one Calculation of the width9 because the distance between the transitions for the samples between scan g and scan k for the specified direction of the incline either too short or too long to tilt in the opposite direction is. The tSU establishes the facts that the biscuit is inclined by measuring and comparing the midpoints of the leading and trailing edges of the biscuits. the Center points are determined based on the information from samples o to e between the corners 36 and 40, from which the center d is calculated, and due to the Samples k to r between corners 46 and 52 from which the center j is calculated will.

For a SchrSglage. To the right, as shown, finds one quickly broad movement of the transition to the left instead of as normal, while for a lean angle a slow movement takes place to the left.

If the MPU determines that the rate of movement does not match the stored Reference data matches, then it determines the extent of the inclination and makes either a correction with regard to the calculations of the longitude and latitude or ignores the biscuit in question if the tilt is excessive.

To determine the length of a rectangular biscuit, do this Program the MPU 14, the corners 36, 40, 46 and 52 from the position changes of the successive ones Detect transitions described above and the transition position d in the middle between scans o and e and the transition position j in the center between samples k and r. The length of the biscuit is then calculated from these positions using the speed-dependent Length constant. Again, the effect and extent of the tilt in the Calculation considered.

For determining the width (i.e. diameter) of a circular Biscuits, a quite different calculation is made. According to the figures 7 A and 7 B is a first significant scan (referred to as "scan oil") tangentially to the biscuit and does not generate any impulse. A second scan produces a pulse 56. Subsequent scans produce pulses such as pulse 57 and 58, the leading and trailing edges of which progressively further to the left and to the rear, respectively occur on the right. This continues until a scan is achieved for the the trailing edge of the resulting pulse 59 is as far to the right as possible (i.e. the scan cuts the perimeter of the biscuit at the point that coincides with the Transverse diameter of the biscuit coincides). The count N for the trailing edge max of pulse 59 characterizes this point.

For subsequent scans, the leading edges of the pulses move, such as pulses 60 and 61, progressive Further to the left while the rear flanks move to the left. This continues until a sample is reached for which the trailing edge of the resulting pulse 62 is the furthest possible to the left (i.e. the scan intersects the perimeter of the biscuit at the opposite end of the transverse diameter).

The count Nmin for the leading edge of the pulse 62 characterizes This point.

The MPU 14 then calculates the biscuit diameter from (NmaX N) max min times a width constant, this constant being dependent on the scanning angle and the sampling interval between clock steps.

Since the biscuits may not turn out to be absolutely round7 it may be advantageous to monitor the diameter in the longitudinal direction of the conveyor rers. For this purpose, the MPU determines the number of attacks (scan p) at which the change rate the number of elements is the same as it is for a tangent normal to the direction of motion would be. Similarly, the MPU determines the sampling that is carried out by the Trailing edge of the biscuit goes and it then calculates the length from the sampling interval between the leading edge scan and the trailing edge scan and the difference in the number of elements of the transitions on these panels.

In order to awaken the thickness and the color of the biscuits, take action the MPU 14 the switch 16 (Figures 2 and 3), from the floodlight mode to switch to the light bar lighting mode, Figures 8 A and 8th B show three light bars spaced so that at least one bar hits the surface of every biscuit monitored, even if the biscuit is from an expected one Has moved the line of movement. The light bars are bright enough to accommodate the CCD array Pulses 64, 65 and 66 can generate even from a reflection of the lightbars from the dark colored conveyor. These reference pulses are indicated by circle 7 shaped to generate pulses 67, 68 and 69, respectively. In the absence of a biscuit these pulses are evenly spaced along the scan and have im essentially the same amplitude.

When a biscuit is then inserted under the camera in the middle, then the outer reference pulses 64 and 66 remain unchanged, but instead The pulse 65 generates a larger pulse 70 because the biscuit is lighter in color is and therefore more reflective. The amplitude A of the pulse es 70 therefore provides a measure of the color of the surface of the biscuit.

Since the light beams reach the conveyor at an acute angle, hits the light reflected from the surface of the biscuit due to its thickness of the biscuit in a different area of the CCD array. The pulse 70 is therefore Shifted to the left a distance d, which is an indication of the thickness of the biscuit is. The pulse 70 is shaped to produce a square pulse 71. If any there is a significant deviation of the value d from the standardized value, then caused the MPU 14 the production plant, in the following production the required one Action to be taken to correct the thickness. Every Upward or Downward movement of the conveyor would shift the reference pulses 67, 68 or 69 and would thus give rise to an incorrect measurement of the bi & kuit thickness In order to take such a movement into consideration, the location of the reference pulses is given before and after passing each biscuit monitored; monitored.

To determine the speed of movement of the biscuits 5 on the conveyor 4 to measure, is either a conventional tachometer generator or preferably one Non-contact speed sensor 18 is used as shown in FIG. The sensor 18 includes two reflective photodetectors 72 and 73 located above the conveyor in FIG Position are brought, and these detectors are each closed so that they set the inputs of a counter 74 and reset. The counter 74 counts the clock steps from a source 75 with a stable pulse repetition rate. Of the Counter is activated by the leading edge of a pulse received from the Detector 72 is generated when a biscuit passes under it. The counter counts the talct steps until the leading edge of a pulse which is from the second Detector generated when the same biscuit passes under it, a memory 76 he's enough. The count is then read out into the memory and the counter 74 deferred. The count gives a measure of the speed of movement. The count is counted up for each biscuit that falls under the detectors 72 and 73 passes through. When the MPU 14 receives data related to the speed of the Movement is required, then it interrogates the memory 76 and transmits at the same time a signal on gate 77 via line 78 to continue counting during the query to prevent. The clock steps from the source 75 is frequency divided by the divider 79. The divided impulses form one Clock for setting and resetting the counter 80. The counter 80 pays the pulses generated by detector 72 during the period set by the clock Period of time can be generated. At the end of this period the count is in memory 81 read out and the counter 80 cleared. The circle therefore counts the number of biscuits, which pass through detector 72 during this period of time. The count will advanced during each subsequent period. The count in memory 81 is read out by the 1PU 14 if necessary; another handover to the Memory is prevented during readout. The continuous measurement of the Speed of movement of the biscuits is required because in speed short-term changes occur frequently in the usual conveyor. The MPU 14 requests accurate data relating to the actual speed of movement of each monitored Biscuits along its entire length.

It would be possible to measure the width and length of the biscuits by palpation the biscuits in the transverse direction, d. H. by arranging the CCD array 6 perpendicular to measure to the center line of the conveyor. However, when scanning the biscuits persist at an angle of 40 (or about 450) to the center line, significant advantages.

It has been found that when scanning perpendicularly one Biscuits of 100 mm have sufficient accuracy in determining the dimensions can only be achieved when about 1000 scans are performed. This means, that 2000 transitions are measured, and since each transition has 12 bits of memory in the Requires memory 12, there are 2000 memory words of 12 bits 3e Sponge cake needed. A suitable component for the memory 12 is the usual one 16 K byte RAM. Such a memory would therefore, after monitoring only 16,000 / 2,000 = 8 biscuits must be filled, which is not a very large sample.

Using the scan of 450 in accordance with the present invention and by finding the corners of rectangular biscuits and the smallest and largest counts for round biscuits, the average formation by the MPU can be quite successful performed and can for a much smaller number of scans per bisque consequently many more biscuits are included in the sample0 As the number Samples per biscuit is greatly reduced while the speed of the biscuit remains constant, the sampling time is reduced accordingly. That means that CCD-Eleoent has longer time to accumulate charge before it is polled 0 Each Element therefore generates a larger output signal for a given illumination or conversely, requires less light for a given output signal. It is very advantageous to reduce the amount of light, so that by the lamps 26, 27 and 28 energy consumed in the measuring head 1 is reduced. The lower the ambient temperature, in which the CCD array operates, the fewer of the elements generated dark noise and the better the signal-to-noise ratio of the camera output. On the other hand, the larger the output signals from the elements, the better it is the signal-to-noise ratio. A compromise can be reached between the reduced Ambient temperature and the strong output signal, which has a great overall benefit compared to the much faster scan speed that for perpendicular scanning is required. Although the above description refers to the sampling at 45 relates which is an optimal value, it is not essential that the angle is 450. Angles between about 300 and about 600 would be acceptable, however the advantages over perpendicular scanning become less, the more there are the angle approaches the perpendicular.

A closer approximation of the scan direction to the direction of the centerline of the conveyor is also disadvantageous because a larger arrangement (with associated larger counts) was needed to scan the same biscuit width.

For a scan angle of 45 are those performed by the MPU 14 Calculations are also easier and quicker to perform; Although the device has been described with reference to monitoring rectangular and round biscuits it could obviously also be used for monitoring the parameters of others Biscuit molds can be used, such as generally rectangular biscuits with slightly curved edges. Besides, they could also be used for monitoring others moving objects.

Instead of light, other forms of radiation can also be used, such as, for example Ultrasound, can be used, and other radiation-sensitive ones can be used as well Element can be used in place of the charge coupled device.

L e r s e i t e

Claims (13)

Dimension monitoring device A p riot: 1. Dimension monitoring device to monitor at least the width (as defined in the description) of one Object, characterized by a radiation source for illuminating the object, while the object is on a predetermined linear section of a path Moved along, a video camera with a scanned linear array of radiation sensitive Elements diagonally across the path at an angle of 30 to 600 to the Bswew direction of the object and arranged during successive scanning. to generate an electrical signal in response to the impact of a of the on successive strips of the object reflected Radiation acts on it, with the number of elements receiving the radiation at every moment depends on the length of the strip from which the in The radiation received at the specific moment is reflected, whereby the through each sample generated signal represents the length of the corresponding strip, as well as signal processing devices that respond to the electrical signals, in order to calculate from data derived for certain selected ones of the samples to form a signal to represent the width of the object. 2. Apparatus according to claim 1, characterized in that the signal processing device-with Regarding the surveillance of a rectangular object is effective for determining the scan or scans that affect the maximum width of the object relates (relate), and to calculate the breadth of the object from data that relate to that sample or samples. 3. Apparatus according to claim 1 or 2, characterized in that the signal processing device is effective to determine an inclination of the Subject and to take this inclination into account in the calculation. 4. Apparatus according to claim 1, characterized in that the Signal processing device with respect to a generally circular object is effective to determine which-ron all scans for the object include the operation of the element, which worked in the scan direction first, and which scan drove the operation of the element that last worked in the scan direction and around the width of the object to determine from the data relating to these samples. Device according to any one of the preceding claims, characterized in that that the signal processing device contains a first clock, devices to determine the leading edge and the trailing edge of the electrical signals, and means for storing the clock step count with reference to the leading edge and the s trailing edge for all samples of object0 6 device according to Claim 5, characterized in that the device for storing the clock step counts operates to keep the counts concurrently for a number of consecutive numbers Stores items0 7. Apparatus according to any preceding claim, characterized characterized in that the signal processing device contains a microprocessor, which works in such a way that it measures the breadth of the object or the intersection the Calculates the width of the number of consecutive objects and triggers an alarm and / or the operation of the production plant changes if this width or the Average width does not correspond to a reference value. 8. Device according to any preceding claim, characterized in that that the signal processing device is also effective in the form that it is a the length (as defined in the description) of the object representing the signal generated by calculation from data for certain selected ones of the samples be derived, 9. Apparatus according to any preceding claim, further characterized by means of projecting a number of radiation beams onto the reference surface, so that reflected images of the bundles are received by a group of the elements, and facilities responsive to one another's reception of the images Group of elements as a result of reflection of at least one of the bundles from the surface of a monitored object to provide a representation of the thickness of the object form. 10. Device according to any one of the preceding claims, characterized by means that are responsive to a change in the amplitude of a signal, which is generated by the arrangement when the radiation from the surface of a monitored object is reflected, compared to one Reflection from a reference surface to show the relative brightness of the color of the object display in comparison to the reference area. iIo device according to any preceding claim, characterized by a second clock and means for counting the clock steps that during the movement of a monitored object between two reference positions which determines the speed of movement of the object will. 12. Device according to any one of the preceding claims, characterized in that that the angle is 450. 13. The apparatus of claim 1 and essentially tie in the preceding with reference to the accompanying drawings. 14o biscuit making plant including that in each of the foregoing Claims claimed device which is arranged to monitor the dimensions of biscuits moving on a conveyor.