JP2000292123A - Shape measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shape measuring apparatus which enables stably measuring of the shape of an object during the conveying thereof without being affected by changes in temperature at an end part of the object nor reflection on a conveying roll. SOLUTION: In this shape measuring apparatus, image signals outputted from photo detectors 1 and 2 are inputted into an automatic gain control part 13 and a comparator part 7 through an image signal interface 5 or the like. At an automatic gain control part 13, the scanning cycle is controlled so that the maximum value of the wave height of a digital image signal reaches a target operation point and a floating threshold is determined by multiplying the maximum value of the wave height of the digital image signal by a coefficient. At the comparator part 7, the digital image signal inputted from an A/D conversion part 6 is compared with the threshold inputted from the automatic gain control part 13 to judge the position of the end part of an object 3. At this point, the automatic gain control of the image signal from the longitudinal photo detector 1 by the automatic gain control part 13 is shifted from ON to OFF when the position of the longitudinal end part of the object reaches a measuring position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shape measuring device, and more particularly to a shape measuring device capable of continuously measuring the shape and dimensions of a measured object by receiving radiation light from the moving measured object. Related to the device.

[0002]

2. Description of the Related Art FIG. 12 is a block diagram showing an example of a conventional shape measuring device. As shown in FIG. 12, the shape measuring device 60 is for measuring the shape, dimensions, and the like of the DUT 3 being transported by the plurality of transport rolls 4, and has a length above the DUT 3. Direction receiver 1 and width direction receiver 2
Is arranged. The length direction light receiver 1 and the width direction light receiver 2 optically scan the length direction (transport direction) and the width direction of the DUT 3, and receive light emitted from the DUT 3. The video signals output from the length direction light receiver 1 and the width direction light receiver 2 are input to the shape measuring device 60.

In the shape measuring device 60, video signals output from the lengthwise light receiver 1 and the widthwise light receiver 2 are input to an A / D converter 6 via a video signal interface 5 and converted into digital video signals. Is done. The digital video signal converted in this manner is supplied to the automatic gain control unit 1.
3 and the comparator 7. The automatic gain control unit 13 detects the peak value of the digital video signal, and controls the scanning cycle (scanning time) so that the peak value becomes the target operating point. Note that such a scanning cycle is also controlled by an upper / lower limit value by the scanning cycle controller 14 so that the video signal is not saturated. Also,
In the automatic gain control unit 13, a floating threshold obtained by multiplying the maximum value of the peak of the digital video signal by a factor (1 / N) is obtained, and this floating threshold is input to the comparator unit 7. Then, the comparator unit 7 compares the digital video signal input from the A / D conversion unit 6 with the floating threshold value obtained by the automatic gain control unit 13, and determines the end position of the DUT 3. .

The end positions in the length direction and the width direction of the DUT 3 determined by the comparator unit 7 are stored as two-dimensional image data in an image memory 11, and are stored in the image calculation unit 12. The shape and the like of the front end and tail end of the head are required.

[0005]

As described above, in the conventional shape measuring device 60, a digital video signal obtained by scanning the device under test 3 by the lengthwise light receiver 1 and the widthwise light receiver 2 is used. And the floating threshold value obtained by the automatic gain control 13, and the comparator 7 compares the DUT 3
Is determined.

However, the rising edge of the video signal at the end of the DUT 3 (tip, tail end, etc.) is inclined due to the temperature change caused by the difference between the temperature of the DUT 3 and the outside air temperature. I have. For this reason, when the threshold for end position determination is changed by the automatic gain control unit 13 according to the maximum peak value of the digital video signal as in the above-described conventional shape measuring apparatus 60, the comparator unit 7 determines the threshold. Measurement object 3
An error will occur at the end position of.

Further, since the DUT 3 is transported by the transport roll 4, as shown in FIGS. 4 (a) and 4 (b) (showing the present invention), an end (for example, Part)
Is closer to the transport roll 4, the reflected light component from the transport roll 4 is superimposed on the radiated light from the DUT 3. For this reason, the end (tip) of the DUT 3 has an apparently advanced shape, and an error occurs in the position of the end of the DUT 3 determined by the comparator 7. Due to such an error due to the reflection on the transport roll 4, the two-dimensional image data on the image memory 11 has a long shape as shown in FIG. Thus, it becomes difficult to obtain an accurate shape or the like of the DUT 3 by the shape calculation unit 12.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and prevents erroneous recognition of an end position of an object to be measured due to a temperature change at the end of the object. An object of the present invention is to provide a shape measuring device capable of preventing erroneous recognition of an end position in a longitudinal direction of an object to be measured due to reflection on the object and stably measuring the shape of the object to be measured during transportation. .

[0009]

According to the first aspect of the present invention,
In a shape measuring device that optically scans an object under conveyance to measure the shape of the object, the scanning period of the image signal is set so that the peak value of the image signal output from the light receiving device becomes a target operating point. While controlling, an automatic gain control unit that calculates a threshold for end position determination based on the peak value of the video signal output from the light receiving device, a video signal output from the light receiving device and the automatic gain control unit A comparator for comparing the obtained threshold with the end to determine the end position of the device under test, and performing automatic gain control by the automatic gain control unit in accordance with the position of the end of the device under test determined by the comparator. An automatic gain control on / off unit for turning on / off, an image memory for storing the end position of the device under test determined by the comparator unit as image data, and an image memory for storing the image memory. And a shape calculation unit for determining the shape of the object based on the image data, wherein the automatic gain control on /
The off unit is a shape measuring apparatus characterized in that the automatic gain control by the automatic gain control unit is shifted from on to off when the end position of the device reaches a predetermined measurement position.

According to the first aspect of the present invention, the automatic gain control on / off section causes the end position in the longitudinal direction of the device to be measured to reach the measurement position, and the timing is such that the shape of the device to be measured is obtained. Since the automatic gain control of the video signal by the automatic gain control unit is shifted from ON to OFF, the rise of the video signal at the end of the DUT is inclined due to the temperature change at the end of the DUT. Even when the measurement is performed, it is possible to eliminate the measurement error of the end position of the measured object, so that the shape of the measured object being transported can be stably measured.

According to a second aspect of the present invention, in the first aspect of the invention, based on a scanning period of the video signal output from the light receiving device and an end position of the device under test determined by the comparator section. A speed calculating unit for calculating the speed of the object to be measured, and a measuring state of an end position of the object to be measured is determined based on a change in the speed of the object to be measured calculated by the speed calculating unit. The image processing apparatus further includes an end position correction unit that excludes image data corresponding to the end position of the measurement object from the image memory and performs interpolation.

According to the second aspect of the present invention, the speed calculating section calculates the speed of the object to be measured based on the scanning period of the video signal and the end position of the object to be measured, and the end position correcting section calculates the speed of the object. Since the measurement state of the end position of the measured object is determined based on this speed change, for example, image data having a large speed change per unit time is excluded from the image memory and interpolated by the preceding and following image data. Even when the end of the DUT has an apparently advanced shape due to reflection on the transfer roll, it is possible to eliminate erroneous recognition of the position of the end in the longitudinal direction of the DUT, and therefore, during the transfer. The shape of the object to be measured can be stably measured.

[0013] The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described, the light receiving device has a length direction light receiver that scans in a length direction corresponding to a transport direction of the object to be measured, and a width direction light receiver that scans in a width direction of the object to be measured, The automatic gain control unit independently controls a scanning cycle of each video signal so that a peak value of each video signal output from the length direction light receiver and the width direction light receiver becomes a target operating point, and The scanning cycle of the video signal when the peak value of the video signal output from the width direction light receiver reaches the target operating point is set as the initial scanning cycle of the video signal output from the width direction light receiver. The gain control on / off unit turns on / off only the automatic gain control of the video signal from the lengthwise light receiver by the automatic gain control unit according to the end position of the device under test determined by the comparator unit. With something like That.

According to the third aspect of the invention, it is possible to measure the widthwise shapes of the tip and the tail of the object to be measured at a low temperature at an optimum scanning cycle. The shape in the width direction of the part and the tail end can be reliably measured.

According to a fourth aspect of the present invention, in the second aspect of the present invention, the object to be measured is transported by a plurality of transport rolls, and the end position correction unit determines the distance between the abnormal measurement positions where the measurement abnormality has occurred and the transport. The presence or absence of disturbance other than the reflection at the transport roll is determined by comparing the roll interval.

According to the fourth aspect of the invention, when a measurement error occurs due to the influence of disturbance other than the reflection on the transport roll, it is possible to appropriately perform a measure according to the disturbance, and The shape of the object to be measured can be measured more stably.

According to a fifth aspect of the present invention, in the first to fourth aspects, an end position for extracting only a video signal corresponding to a predetermined end position from the video signals output from the light receiving device. A gate section, an end peak point detection section that detects a peak value of the video signal extracted by the end position gate section, and the comparator section based on the peak value detected by the end peak point detection section. A threshold lower limit setting unit that sets a lower limit value of a threshold for end position determination used in, a threshold value determined by the automatic gain control unit and a lower limit value set by the threshold lower limit setting unit. An automatic threshold value setting unit that sets a threshold value that does not fall below the lower limit value by comparison.

According to the fifth aspect of the present invention, a peak value corresponding to the reflected light component from the transport roll is detected from the video signal output from the light receiving device, and the threshold value input to the comparator unit is set to this value. Since the lower limit value of the threshold value is set so as not to fall below the peak value, the threshold value for determining the end position in the length direction of the measured object is always larger than the reflected light component of the transport roll, and the Even if the end of the DUT has an apparently advanced shape due to reflection, erroneous recognition of the end position of the DUT in the longitudinal direction can be eliminated, and therefore, the DUT being transported can be recognized. The shape can be measured stably.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the peak value detected by the edge peak point detecting section is compared with a lower limit value set by the threshold lower limit setting section. The automatic threshold setting unit further includes a lower limit comparison counter unit that counts the number of times the peak value falls below the lower limit value, wherein the automatic threshold value setting unit continuously performs the predetermined number of times when the peak value falls below the lower limit value. The lower limit value is modified downward.

According to the sixth aspect of the invention, when the reflected light component changes due to the temporal change of the transport roll, it is possible to automatically follow the threshold for determining the end position in accordance with the change. Can be more stably measured.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

[0022] First Embodiment FIG. 1 is a block diagram showing a first embodiment of a shape measuring apparatus according to the present invention.

As shown in FIG. 1, the shape measuring device 30 comprises:
This is for measuring the shape, dimensions, and the like of the DUT 3 being transported by the plurality of transport rolls 4. Above the DUT 3, a lengthwise light receiver 1 and a widthwise light receiver as a light receiving device are provided. 2 are arranged. The length direction light receiver 1 and the width direction light receiver 2 optically scan the length direction (transport direction) and the width direction of the DUT 3, and receive light emitted from the DUT 3. Video signals output from the length direction light receiver 1 and the width direction light receiver 2 are input to the shape measuring device 30.

In FIG. 1, the shape measuring device 30 is input via the video signal interface 5 for taking in the video signals output from the length direction light receiver 1 and the width direction light receiver 2 and the video signal interface 5. An A / D converter 6 for converting the video signal into a digital video signal;
An automatic gain controller 13 and a comparator 7 to which the digital video signal converted by the A / D converter 6 is input are provided. Here, the automatic gain control unit 13 sets the A / D
The scanning period (scanning time) is controlled so that the peak value of the digital video signal converted by the conversion unit 6 becomes the target operating point, and an end obtained by multiplying the peak value of the digital video signal by a factor (1 / N). This is for obtaining a threshold for position determination. The comparator unit 7 compares the digital video signal input from the A / D conversion unit 6 with the threshold value obtained by the automatic gain control unit 13 to determine the end position of the DUT 3. . Note that the automatic gain control unit 13 independently controls the scanning cycle of each video signal so that the peak value of each video signal output from the length direction light receiver 1 and the width direction light receiver becomes the target operating point. Is available. Further, a scanning cycle control section 14 is connected to the automatic gain control section 13, and the scanning cycle obtained by the automatic gain control section 13 is controlled by upper / lower limit values so that the video signal is not saturated. ing.

Further, the shape measuring device 30 has an automatic gain control on / off unit for turning on / off the automatic gain control by the automatic gain control unit 13 in accordance with the end position of the DUT 3 determined by the comparator unit 7. 8 is provided. The automatic gain control on / off unit 8 can independently turn on / off the automatic gain control of each video signal from the length direction light receiver 1 and the width direction light receiver 2 by the automatic gain control unit 13. It has become.

Further, the shape measuring device 30 performs measurement on the object to be measured based on the scanning cycle of the digital video signal converted by the A / D converter 6 and the end position of the object 3 determined by the comparator 7. Speed calculator 9 for calculating the speed of 3
And the measurement state of the end position of the DUT 3 is determined based on the speed change of the DUT 3 calculated by the speed calculation unit 9 and corresponds to the end position of the DUT 3 in which the measurement abnormality has occurred. And an end position correction unit 10 for interpolating two-dimensional image data to be excluded from the image memory 11.

Further, the shape device 30 includes an image memory 11 for storing the end positions in the length direction and the width direction of the DUT 3 determined by the comparator unit 7 as two-dimensional image data; And a shape calculation unit 12 for obtaining the shape and the like of the tip end and the tail end of the DUT 3 based on the two-dimensional image data stored in the.

Next, the operation of the first embodiment of the present invention having such a configuration will be described.

In the shape measuring device 30, the video signals output from the lengthwise light receiver 1 and the widthwise light receiver 2 are input to the A / D converter 6 via the video signal interface 5 and converted into digital video signals. Is done. The digital video signal converted in this manner is supplied to the automatic gain control unit 1.
3 and the comparator 7. The automatic gain controller 13 detects the peak value of the digital video signal and controls the scanning cycle (scanning time) so that the peak value becomes the target operating point (FIGS. 2C and 3D and FIG. 3).
(See (a)). Note that such a scanning cycle is also controlled by an upper / lower limit value by the scanning cycle controller 14 so that the video signal is not saturated. Further, the automatic gain control unit 13 obtains a floating threshold value obtained by multiplying the maximum value of the peak of the digital video signal by a factor (1 / N), and inputs the floating threshold value or a fixed threshold value described later to the comparator unit 7 (FIG. 2). (See (c) and (d)). Then, the comparator unit 7 compares the digital video signal input from the A / D conversion unit 6 with the threshold value input from the automatic gain control unit 13, and determines the end position of the DUT 3.

The end positions in the length direction and the width direction determined by the comparator unit 7 are stored as two-dimensional image data in the image memory 11, and the tip and tail of the object 3 are measured by the shape calculation unit 12. The shape of the end and the like are required.

Here, the rising edge of the video signal at the end of the DUT 3 (tip, tail end, etc.) is inclined due to a temperature change caused by the difference between the temperature of the DUT 3 and the outside air temperature. ing. Therefore, in the shape measuring device 30 shown in FIG. 1, the end position of the DUT 3 determined by the comparator unit 7 is constantly monitored by the automatic gain control on / off unit 8, and is shown in FIG. As described above, at the timing when the end of the DUT 3 in the length direction reaches M (measurement position) immediately below the widthwise light receiver 2 and the shape of the DUT 3 is determined, the automatic gain control unit 13 performs the operation. The automatic gain control of the video signal from the lengthwise light receiver 1 is shifted from on to off (FIG. 2).
(B)). At the same timing, the value of the floating threshold value input from the automatic gain control unit 13 to the comparator unit 7 is fixed (see FIG. 2E).

Further, since the measured object 3 is conveyed by the conveying roll 4, the end (for example, the tip) of the measured object 3 is transferred to the conveying roll 4 as shown in FIGS. In the approaching state, the reflected light component (see reference sign R2 in FIG. 4B) from the transport roll 4 is superimposed on the radiated light from the workpiece 3 (see reference sign R1 in FIG. 4B), DUT 3
Has a shape that is apparently advanced. Note that, due to such an error due to reflection on the transport roll 4, as two-dimensional image data on the image memory 11,
As shown in FIG. 6, the shape of the DUT 3 is elongated in the length direction, and it is difficult for the shape calculation unit 12 to obtain an accurate shape and the like of the DUT 3. Therefore, in the shape measuring device 30 shown in FIG. 1, the speed calculation unit 9 determines the scanning period of the digital video signal converted by the A / D conversion unit 6 and the end of the DUT 3 determined by the comparator unit 7. The speed of the DUT 3 is calculated based on the position (see FIG. 5), and the end position correction unit 10 determines the measurement state of the end position of the DUT 3 based on the change in speed. Then, the two-dimensional image data corresponding to the end position of the DUT 3 where the measurement abnormality (for example, when the speed change per unit time is large like the times T1 and T2 in FIG. 5) is excluded from the image memory 11. To interpolate the image data before and after. FIG. 7 shows an example of two-dimensional image data after interpolation by excluding abnormal data from the two-dimensional data shown in FIG.
Shown in

As described above, according to the first embodiment of the present invention, the DUT 3 is controlled by the automatic gain control on / off unit 8.
When the end position in the length direction reaches M (measurement position) immediately below the width direction light receiver 2 and the shape of the DUT 3 is determined, the automatic gain control unit 13 causes the length direction light receiver 1 Since the automatic gain control of the video signal is shifted from ON to OFF, the image at the end of the DUT 3 is affected by the temperature change at the end of the DUT 3 (tip, tail, etc.). Even when the rising edge of the signal is inclined, it is possible to eliminate the measurement error of the end position of the DUT 3, so that the shape of the DUT 3 being transported can be stably measured.

According to the first embodiment of the present invention,
The speed calculating unit 9 calculates the speed of the DUT 3 based on the scanning cycle of the digital video signal and the end position of the DUT 3, and the end position correction unit 10 calculates the speed of the DUT 3 based on this speed change. The measurement state of the end position of the measurement object 3 is determined, and for example, two-dimensional image data having a large speed change per unit time is excluded from the image memory 11 and interpolated by the preceding and following image data. Even when the end (tip) of the DUT 3 has an apparently advanced shape due to reflection, erroneous recognition of the end position of the DUT 3 in the longitudinal direction can be eliminated, and therefore, the transport The shape of the DUT 3 inside can be measured stably.

In the above-described first embodiment, it is preferable that the automatic gain control of the video signal from the width direction light receiver 2 is always on.
When measuring the front end and the tail end of the device 3, the response of the automatic gain control cannot be sufficiently ensured, and the shape of the front end and the tail end of the DUT 3 in the width direction cannot be measured easily. . However, until the position of the end of the DUT 3 in the length direction reaches the position M directly below the light receiver 2 in the width direction, the automatic gain control unit 13 automatically controls the automatic gain of the video signal from the light receiver 1 in the length direction. Generally, an optimal scanning cycle corresponding to the temperature of the device under test 3 is determined by control. Therefore, in the above-described first embodiment, as shown in FIG.
The scanning cycle of the video signal when the peak value of the video signal output from the lengthwise light receiver 1 reaches the target operating point is reset as the initial scanning cycle of the video signal output from the widthwise light receiver 2 Is preferred. At this time, the automatic gain control on / off unit 8 always turns on the automatic gain control of the video signal from the width direction light receiver 2 by the automatic gain control unit 13, and the length direction light receiver 1 by the automatic gain control unit 13. Only the automatic gain control of the video signal from the device 3 is turned on / off according to the end position of the DUT 3 determined by the comparator unit 7. Thereby, the widthwise shape of the tip end and the tail end of the DUT 3 having a low temperature can be measured at the optimum scanning period, and therefore, the width direction of the tip end and the tail end of the DUT 3 can be measured. Can be reliably measured.

In the first embodiment, the two-dimensional image data corresponding to the end position of the DUT 3 where the measurement error has occurred is excluded from the image memory 11 by the end position correction unit 10. However, as a cause of such a measurement abnormality, the influence of disturbance other than the reflection on the transport roll 4 can be considered. Therefore, in the above-described first embodiment, as shown in FIG. 9, the end position correction unit 10 compares the interval between the abnormal measurement positions where the measurement abnormality has occurred and the transport roll interval. It is preferable to determine the presence or absence of a disturbance other than the reflection at the transport roll 4 based on whether or not the disturbance occurs. Accordingly, when a measurement error occurs due to the influence of disturbance other than the reflection at the transport roll 4, it is possible to appropriately perform a measure according to the disturbance, and the shape of the measured object 3 during transport is more stable. Can be measured.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment of the present invention is the same as the second embodiment shown in FIGS. 1 to 7 except that a threshold value not lower than a predetermined lower limit value is set as a threshold value input to the comparator unit 7. This is substantially the same as the first embodiment. In the second embodiment of the present invention, the same parts as those in the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description is omitted.

As shown in FIG. 10, the shape measuring device 40
Is a terminal for extracting only a video signal corresponding to a predetermined end position from video signals output from the length direction light receiver 1 and the width direction light receiver 2 in addition to the shape measuring device 30 shown in FIG. Based on the peak value detected by the end position peak section 15, the end peak point detection section 16 for detecting the peak value of the video signal extracted by the end position gate section 15, A threshold lower limit setting unit 17 for setting a lower limit value of a threshold for end position determination used in the comparator unit 7, a threshold value obtained by the automatic gain control unit 13, and a threshold lower limit setting unit 17. An automatic threshold value setting unit 18 is provided for setting a threshold value which does not exceed the lower limit value by comparing with the lower limit value.

As shown in FIGS. 4A and 4B, when the end (for example, the tip) of the DUT 3 is close to the transport roll 4, the DUT 3 transports the radiated light from the DUT 3. Roll 4
The reflected light component from is superimposed. Therefore, the second aspect of the present invention
In the embodiment, a peak value (maximum value) corresponding to a reflected light component from the transport roll 4 is detected from video signals output from the length direction light receiver 1 and the width direction light receiver 2, The lower limit value of the threshold value is set so that the threshold value input to the comparator unit 7 does not fall below this peak value. Specifically, first, the end position gate unit 15
From the video signals output from the length direction light receiver 1 and the width direction light receiver 2, only the video signal corresponding to a predetermined end position is extracted. At this time, the detection range of the peak point is specified based on the correction amount (interpolation position) by the end position correction unit 10 and the like. Next, by the end peak point detection unit 16,
The peak value of the video signal extracted by the end position gate unit 15 is detected. Then, the threshold lower limit setting unit 17
Thus, based on the peak value detected by the end peak point detection unit 16, the lower limit value of the end position determination threshold used in the comparator unit 7 is set.
The automatic threshold setting unit 18 compares the threshold value obtained by the automatic gain control unit 13 with the lower limit value set by the threshold lower limit setting unit 17, and sets a threshold value that does not fall below the lower limit value.

As described above, according to the second embodiment of the present invention, from the video signals output from the lengthwise light receiver 1 and the widthwise light receiver 2, the reflected light component from the transport roll 4 The corresponding peak value (maximum value) is detected, and the lower limit value of the threshold value is set so that the threshold value input to the comparator unit 7 does not fall below this peak value. Even when the threshold value for determining the position of the part is always greater than the reflected light component of the transport roll 4 and the end (tip) of the DUT 3 is apparently advanced due to reflection on the transport roll, Erroneous recognition of the end position in the longitudinal direction of the DUT 3 can be eliminated, so that the shape of the DUT 3 being transported can be stably measured.

In the above-described second embodiment, the lower limit value of the threshold value for determining the end position is fixedly set, but the reflected light component of the transport roll 4 decreases with time. Therefore, it is preferable that the threshold value for the edge position determination set by the threshold lower limit setting unit 17 is also reduced in accordance with the temporal change of the reflected light component of the transport roll 4. In this case, as shown in FIG. 11, the peak value detected by the end peak point detecting unit 16 is compared with the lower limit value set by the threshold lower limit setting unit 17, and the peak value is set to the lower limit value. Using the shape measuring device 50 further provided with a lower limit comparison counter unit 19 for counting the number of times below the threshold value, the automatic threshold setting unit 18 allows the peak value to be continuously reduced by the predetermined number of times specified by the counter setting unit 20 to the lower limit. It is preferable to correct the lower limit value downward when the value falls below the value. Accordingly, when the reflected light component changes due to the change with time of the transport roll 4, it becomes possible to automatically follow the threshold for determining the end position in accordance with the change, and the shape of the DUT 3 being transported can be further improved. Measurement can be performed stably.

[0042]

As described above, according to the present invention, it is possible to prevent erroneous recognition of the end position of an object to be measured due to the effect of a temperature change at the end of the object, and to prevent the position of the object from being reflected by a transport roll. It is possible to prevent erroneous recognition of the end position in the length direction of the object to be measured, and to stably measure the shape of the object to be measured during transportation.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a shape measuring apparatus according to the present invention.

FIG. 2 is a diagram showing an example of a relationship between a video signal of a light receiver (lengthwise light receiver) and automatic gain control in the shape measuring apparatus shown in FIG.

3 is a time chart showing an example of a relationship between a scanning cycle of a light receiver (lengthwise light receiver) and automatic gain control in the shape measuring apparatus shown in FIG.

FIG. 4 is a diagram showing an example of a video signal of a photodetector (lengthwise photodetector) in the shape measuring apparatus shown in FIG.

FIG. 5 is a diagram for explaining an apparent speed change of an object to be measured due to a measurement error of an end position in a length direction of the object to be measured.

FIG. 6 is a diagram showing an example of two-dimensional data affected by reflection on a transport roll among two-dimensional data stored in an image memory.

FIG. 7 is a view showing an example of two-dimensional data after interpolation by removing abnormal data from the two-dimensional data shown in FIG. 6;

8 is a time chart showing another example of the relationship between the scanning cycle of the light receiver and the automatic gain control in the shape measuring apparatus shown in FIG.

FIG. 9 is a diagram for explaining the relationship between the measurement error of the end position in the length direction of the object to be measured and the transport roll interval.

FIG. 10 is a block diagram showing a second embodiment of the shape measuring apparatus according to the present invention.

11 is a block diagram showing a modification of the shape measuring device shown in FIG.

FIG. 12 is a block diagram showing a conventional shape measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Length direction light receiver 2 Width direction light receiver 3 DUT 4 Transport roll 5 Video signal interface 6 A / D conversion part 7 Comparator part 8 Automatic gain control on / off part 9 Speed calculation part 10 Edge position correction part 11 Image memory 12 Shape calculation unit 13 Automatic gain control unit 14 Scan cycle control unit 15 Edge position gate unit 16 Edge peak point detection unit 17 Threshold lower limit setting unit 18 Automatic threshold setting unit 19 Lower limit comparison counter unit 20 Counter setting unit 30,40,50 Shape measuring device

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA13 AA22 BB13 BB15 DD11 FF01 FF04 JJ02 JJ05 JJ09 JJ25 MM22 PP16 QQ00 QQ03 QQ24 QQ25 QQ29 QQ31 RR06

Claims (6)

[Claims] A shape measuring apparatus for optically scanning an object to be measured during transportation to measure the shape of the object to be measured, wherein an image is obtained such that a peak value of a video signal output from a light receiving device becomes a target operating point. Along with controlling the scanning cycle of the signal, an automatic gain control unit that determines a threshold for end position determination based on the peak value of the video signal output from the light receiving device, the video signal output from the light receiving device and A comparator unit for comparing the threshold value obtained by the automatic gain control unit to determine the end position of the device under test, and the automatic gain control unit according to the end position of the device under test determined by the comparator unit An automatic gain control on / off unit for turning on / off an automatic gain control by an image memory; an image memory for storing, as image data, an end position of the device under test determined by the comparator unit; A shape calculation unit for obtaining the shape of the device under test based on the image data stored in the memory device, wherein the automatic gain control on / off unit is configured to operate when the end position of the device under test reaches a predetermined measurement position. A shape measuring apparatus, wherein the automatic gain control by the automatic gain control section is shifted from on to off. 2. A speed calculation unit for calculating a speed of the device under test based on a scanning period of a video signal output from the light receiving device and an end position of the device under test determined by the comparator unit. The measurement state of the end position of the DUT is determined based on the change in the speed of the DUT calculated by the speed calculation unit, and the image data corresponding to the end position of the DUT having the measurement abnormality is displayed on the image. 2. The shape measuring apparatus according to claim 1, further comprising: an end position correcting unit that excludes from a memory and performs interpolation. 3. The device according to claim 1, wherein the light receiving device includes a length direction light receiver that scans in a length direction corresponding to a transport direction of the object to be measured, and a width direction light receiver that scans in a width direction of the object to be measured. The automatic gain control unit independently controls a scanning cycle of each video signal so that a peak value of each video signal output from the length direction light receiver and the width direction light receiver becomes a target operating point, and Setting the scanning cycle of the video signal when the peak value of the video signal output from the width direction light receiver reaches the target operating point as the initial scanning cycle of the video signal output from the width direction light receiver; The gain control on / off unit turns on / off only the automatic gain control of the video signal from the lengthwise light receiver by the automatic gain control unit according to the end position of the device under test determined by the comparator unit. Claims characterized by the following: Or the shape measuring apparatus according. 4. The object to be measured is transported by a plurality of transport rolls, and the end position correction unit compares the interval between the abnormal measurement positions where the measurement abnormality has occurred with the transport roll interval to determine the position other than the reflection at the transport roll. 3. The shape measuring apparatus according to claim 2, wherein the presence or absence of a disturbance is determined. 5. An end position gate for extracting only a video signal corresponding to a predetermined end position from the video signals output from the light receiving device, and a video signal extracted by the end position gate. An edge peak point detection unit that detects the peak value of the edge value, and a lower limit value of an edge position determination threshold used in the comparator unit based on the peak value detected by the edge peak point detection unit. A threshold lower limit setting unit to perform, and an automatic threshold setting for comparing a threshold value obtained by the automatic gain control unit with a lower limit value set by the threshold lower limit setting unit to set a threshold value which does not fall below the lower limit value. The shape measuring apparatus according to claim 1, further comprising a unit. 6. A method for comparing a peak value detected by said end peak point detecting section with a lower limit value set by said threshold lower limit setting section to count the number of times said peak value falls below said lower limit value. The automatic threshold setting unit corrects the lower limit value downward when the peak value continuously falls below the lower limit value for a predetermined number of times. The shape measuring device according to claim 5.