JPH045123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shape measuring device for a sheet product, and more specifically, to a sheet shape measuring device capable of measuring the planar shape of a steel plate in a hot rolling process more accurately and in a short time. .

Measurement of the shape of steel sheets during the hot rolling process is important for product quality control, but conventionally, the first measurement was
This was done using a device like the one shown in the figure.

That is, the thermal infrared rays emitted by the hot steel plate S itself moving in the direction of the outlined arrow (x-axis direction) move around the rotation axis 55 in the y-axis direction (direction orthogonal to the x-axis) parallel to the surface of the steel plate S. Steel plate S by the swingable reflector 50
A rotating polygon mirror 51 having a rotation axis perpendicular to the surface of
The rotating polygon mirror 51
is reflected in the direction of the concave mirror 52 and reflected onto the prism 53.
The configuration is such that the light is converged and incident on the photoelectric conversion element 54.

In such a configuration, main scanning is performed in the y-axis direction in FIG. 1 by rotating the rotating polygon mirror 51, and by swinging the reflecting mirror 50 in the direction of the arrow, the rotation in the y-axis direction by the rotating polygon mirror 51 is performed. The main scan is followed by a sub-scan that moves sequentially in the x-axis direction, and the photoelectric conversion element 54
Since the field of view repeatedly moves along the surface of the steel plate S in the y-axis direction, it is possible to measure the length dimension in the y-axis direction over the entire length of the steel plate S in the x-axis direction. Although not shown in FIG. 1, another set of devices having the same configuration as this was used to scan the steel plate S so that main scanning in the x-axis direction and sub-scanning in the y-axis direction were performed. The length dimension in both the x-axis and y-axis directions, that is, the external dimension is measured.

However, such conventional devices have the following problems.

First, in order to mechanically operate the rotating polygon mirror 51 and the reflecting mirror 50, it was necessary to keep the steel plate S stationary for a relatively long period of time during the rolling process. In addition, the resolution is low due to spot-like scanning by the photoelectric conversion element 54, which makes it difficult to grasp delicate shapes such as corners of the steel plate S. Also, the spot-like scanning means that the amount of data is small for analysis. Although the number of steps required is small, the degree of freedom in analysis and the ability to develop into advanced analysis methods are poor, and it is difficult to expect high accuracy.

Therefore, there has been a need for a measuring device that does not require the steel sheet S to stand still during the rolling process, has higher resolution, and has a higher degree of freedom and expandability in data analysis.

The present invention has been made in view of the above circumstances, and includes a plurality of two-dimensional imaging devices, each of which is arranged so as to partially image a plate material to be subjected to shape measurement, and has horizontal and vertical scanning functions. , a signal obtained by delaying the image signal obtained by horizontal scanning of the two-dimensional imaging device is used as a reference video signal, a signal obtained by performing addition processing on the image signal is used as a fall detection slice level signal, and the reference video signal a main slicer that performs binarization processing on the reference video signal using a signal obtained by further delaying and addition processing as a slice level signal for rising edge detection; and a main slicer that performs binarization processing on the reference video signal using a certain threshold value. Synthesizing the binary signals of the sub-slicer, the main slicer, and the sub-slicer,
The rising edge position that appears earliest and the falling edge position that appears latest are determined by an edge position detection circuit using a clock signal synchronized with the horizontal scanning time, and the rising and falling edge positions obtained by the edge position detection circuit are The object of the present invention is to provide a plate shape measuring device characterized by being equipped with an edge position memory that sequentially stores data in synchronization with vertical scanning, and an arithmetic unit that synthesizes and processes edge positions corresponding to each partial field of view in this edge position memory. That is.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to drawings showing embodiments thereof.

FIG. 2 is a block diagram showing the overall configuration of the plate shape measuring device according to the present invention.

Inside the camera box 1, there is a silicon vidicon camera (hereinafter simply referred to as a camera) 11, which is a two-dimensional imaging device equipped with a lens system 12, and this camera 1.
Nine sets of fiber links 13 are provided for converting analog electrical signals from 1 into optical signals.

The camera 11 uses a silicon vidicon camera, which covers both the visible light range and the near-infrared range (700~
1000nm), and by using an infrared filter that has transmittance characteristics in the near-infrared region to cut out the visible light region, it is possible to obtain a self-luminous near-infrared image of the hot steel sheet S. It is used to take images.

In addition, each field of view 11 of nine cameras 111 to 119
1' to 119' are arranged in a 3 x 3 matrix as shown in Figure 3, and the total area is approximately 5000 x 5000.
Form a composite field of view of mm. Each camera 111-11
The aspect ratio of the imaging fields of view 111' to 119' of 9 is 1:1, and each of the cameras 111 to 1
In this embodiment, the 19 fields of view 111' to 119' are each approximately 1800×1800 mm, with a slight overlap between adjacent camera fields of view.

Further, the coordinate (reference coordinate) system x-y of the synthetic field of view is set in a state slightly rotated counterclockwise with respect to the line direction of the rolling process indicated by the white arrow. This is the fourth
As shown in the figure, the relationship between the direction of the edge of the steel plate S and the direction of the scanning line, the video signal thereof, and the binary signal obtained by converting it into two levels of light and dark using a predetermined threshold value, the scanning line of the camera 11 is shown. If the direction of the image coincides with the edge of the steel plate S that is the object to be imaged, the video signal obtained by imaging this cannot accurately capture the boundary between the object and the background, and therefore this video signal is
When converted into a value, many bright level signals are generated due to subtle changes in the intensity of the video signal, but if the direction of the scanning line of the object and camera is rotated to make them non-parallel, the fifth signal will be generated. As shown in the figure, since the scanning line intersects the edge of the object, the video signal clearly captures the difference in the amount of infrared radiation between the object and the background, so if this is made into a binary signal, the scanning line intersects with the edge of the object. This is because the transition between the bright and dark levels occurs only at the point where the edge of the object intersects.

The nine cameras 111 to 119 are arranged in a 3x3 matrix, but the nine cameras 11
1 to 119 are collectively arranged in a narrower range (the shaded area in FIG. 3) than the overall field of view (synthetic field of view) to save installation space. In order to enable such a collective arrangement, eight cameras 111 to 114 and 116 to 119, excluding the central camera 115, are configured to take images in a tilted field of view.

FIG. 6 is an explanatory diagram of the tilted field of view.

Normally, the optical axis CL of the lens system 12 of the camera 11 is the central axis of the image pickup tube 11a, which is the image pickup section of the camera 11.
Although the imaging field of view FN centered on the optical axis CL of the lens system 12 is obtained by aligning it with CC, the central axis CL of the lens system 12 is shifted from the optical axis CC of the image pickup tube 11a as shown in FIG. In the case of the multiplied position CL', the specifications of the lens system 12, the separation distance between the optical axis CL of the lens system 12 and the central axis CC of the image pickup tube 11a,
It becomes possible to image the field of view FD, which is separated from the original optical axis CL of the lens system 12 by a distance determined by the distance between the lens system 12 and the object to be imaged, as a tilted field of view.

Therefore, in the device of the present invention, the individual fields of view of the nine cameras 111 to 119 arranged in a 3×3 matrix are combined into one composite field of view. camera 11
Rather than distributing them directly above the center of the fields of view 111' to 119' of cameras 1 to 119, eight cameras 111 to 114 and 116 to 119, other than the camera 115 arranged in the center, are tilted to enable imaging of the field of view. , are arranged in groups around the camera 115 arranged in the center in order to save installation space.

The fiber ring 13 connects each camera 111 to 11.
In order to prevent the generation of noise due to electromagnetic waves etc. from around the rolling mill during signal transmission between the camera control unit 9 and the camera control unit 2 described later, electrical signals and optical signals are mutually converted and transmitted using optical fiber as a medium. This is for the purpose of receiving and receiving information.

The camera control unit 2 has nine cameras 111~
119 and its lens systems 12, 12, .
It is connected to the fiber link 13 of 119, and includes a synchronous drive circuit 21, an image distortion correction circuit 22, a video processor 23, and a light reception level control circuit 24.
It is composed of etc.

The synchronization drive circuit 21 performs vertical and horizontal synchronization of each camera 111-119, and its signal is given to each camera 111-119 to perform vertical and horizontal synchronization of each camera 111-119.

The image distortion correction circuit 22 is a circuit that generates a correction signal to be superimposed on the sawtooth wave.
It has a function of correcting local output unevenness of the imaging unit of 119.

The video processor 23 provides the video signal after amplification and removal of noise components by a bandpass filter to the light reception level control circuit 24, display selector 43, and video selector 31.

As shown in FIG. 7, the light reception level control circuit 24 compares the peak value PL of the video signal actually obtained by the camera 11 with the set value TL so that the video signal becomes a predetermined set value. A signal FC for correcting and controlling the aperture value of the lens system 12 is applied to a motor 120 that operates the amount of opening and closing of the aperture of the lens system 12, so that the peak value PL and the set value TL match. And this setting level TL
is also given to the sub-slicer 33, which will be described later, as a threshold for binarizing the video signal. Signals from each video processor 23 are applied to the received light level control circuit 24 as well as to the edge calculation circuit 3. The edge calculation circuit 3 includes a video selector 31,
Main slicer 34, sub slicer 33, edge position detection circuit 35, edge position memory 36 and CPU 3
8, an interface, etc., and calculates the edge position of the steel plate S based on signals from nine cameras 111 to 119.

The analog video signals obtained by the nine cameras 111 to 119 and preprocessed by each video processor 23 are first given to the video selector 31, which is a multiplexer with nine inputs and one output. camera 11
One of the signals from signals 1 to 119 is selectively output to the A/D converter 32, and this switching command is issued by the first CPU 38.

The video signal converted into a digital signal by the A/D converter 32 is
The signal is supplied to the main slicer 34 and the sub-slicer 33 for digitization processing, and is converted into a binary signal indicating the rising and falling points of the video signal, that is, the point in time when the scanning line passes the edge of the image of the steel plate S. , this signal is given to the edge position detection circuit 35 and processed into a signal that correctly indicates the edge of the steel plate S.

FIG. 8 shows the main slicer 34 and the sub-slicer 33.
9 and 8 are explanatory diagrams showing the states of signals in each portion marked with ○ numbers.

The analog video signal output from the video processor 23 is converted by the A/D converter 32 into a digital video signal VD as shown by broken lines in FIG. Then, signal processing as described below is performed. Although this signal processing is performed digitally, it is shown in analog form in FIG. 9 for convenience of explanation.

The A/D converter 32 processes and transforms the input analog signal into a digital video signal VD and sends it to the adder 341 and shift register 342 of the main slicer 34.
and the comparator 331 of the sub-slicer 33.

Digital video signal given to adder 341
As shown in FIG. 9B, VD is added with a level up signal LU for raising its level by a predetermined amount, and is turned into a rear edge detection slice level signal whose level is raised by that amount, and is applied to a comparator 346. The digital video signal VD applied to the shift register 342 is delayed for a predetermined time by a shifter SC for a predetermined time delay as shown in FIG.
45,346. shift register 34
The reference video signal applied to 344 is further delayed for a predetermined time by a shift lock SC for delaying it for a predetermined time, and then is further applied to an adder 344.
The level up signal LU is added thereto and the resultant signal is applied to a comparator 345 as a front edge detection slice level signal shown in FIG.

Therefore, as shown in FIG. 9B, the comparator 346 receives the reference video signal obtained by delaying the digitized video signal VD by a predetermined time and the digital video signal VD.
The comparator 345 receives the reference video signal and a slice level signal for front edge detection which is obtained by delaying the reference video signal by a predetermined time and increasing the level by a predetermined value. Given.

Fig. 10 shows the digital video signal VD in Fig. 9b, a reference video signal obtained by delaying this by a shift lock SC, and a level up signal LU.
FIG. 3 is a schematic diagram showing the relationship between a slice level signal for rear edge detection obtained by increasing the level by 0.05, and a slice level signal for front edge detection obtained by further delaying by the shift clock SC and increasing the level by the level up signal LU.

That is, as described above, the reference video signal, the slice level signal for rear edge detection, and the slice level signal for front edge detection are obtained by processing the digital video signal VD, which is the original signal, and based on this, the edge detection of the measurement target is performed. I have to do it,
Accurate edge detection is possible without being affected by shading.

The slice level signal for rear edge detection and the reference level signal supplied to the comparator 346 are compared, and when the level of the slice level signal for rear edge detection becomes higher than the level of the reference video signal, the digital video signal VD is set to a high level. The fall of the level part, that is, the rear edge (in the image, from the bright part to the dark part, that is, the position where the steel plate S changes to the background)
A pulse signal as shown in FIG.
(reset) terminal.

The front edge detection slice level signal applied to the comparator 345 is compared with the reference video signal, and when the level of the reference video signal becomes higher than the level of the front edge detection slice level signal, the digital video signal is A pulse signal as shown in FIG. (SET) terminal.

When a signal indicating a front edge is input to the S terminal, the flip-flop 348 enters a set state and outputs a high level signal from its Q output terminal as shown in FIG. 9E, and a pulse signal indicating a rear edge is input to the R terminal. When input, it enters a reset state and stops outputting a high level signal from its Q output terminal. Therefore, flip-flop 3
The high level portion of the signal emitted from the Q output terminal 48 corresponds to the high level portion of the digital video signal VD, that is, the bright level portion of the image of the steel plate S. The signal from this Q output terminal is applied to one input terminal of an OR gate 351 of the edge position detection circuit 35.

The digital video signal VD applied to the comparator 331 of the sub-slicer 33 is equal to 1 of the set level TL of the light reception level of each camera 111 to 119 provided in the above-mentioned light reception level control circuit 24, as shown in FIG. 9A. It is compared with the sub-slice level SL, which is set to a value of /2, and is binarized into a portion at a higher level and a portion at a lower level than the sub-slice level SL, as shown by the broken line in FIG. As shown by the solid line, the signal is delayed by a predetermined time from the shift clock SC which is applied to the shift register 332 to delay it by a predetermined time, and is made into a signal that matches the time axis of the reference video signal, and is output to the edge position detection circuit 35.
It is applied to the other input terminal of OR gate 351.

The output signal of the sub-slicer 33 converts the digital video signal VD to a predetermined threshold SL (each camera 111 to 11
Since the signal is binarized at a value of 1/2 of the received light level TL of 9) and is made to match the time axis of the reference video signal, the digital video signal VD is either high level or low level. This determination is possible regardless of whether the main slicer 34 detects a front or rear edge. This is main slicer 3
4, when the edge of the steel plate S is not included in the imaging field of view of each camera 111 to 119, that is, when the camera 115
When the entire imaging field of view is occupied only by the image of the steel plate S, as in the field of view 115', the levels of the signals shown in FIG. Therefore, in such a case, the sub-slicer 33 can determine whether the imaging field of view of the cameras 111 to 119 captures the steel plate S or the background without using complicated software processing. Therefore, even when edge detection by the main slicer 34 is impossible, the sub slicer 33
As a result, a binary signal is obtained.

Flip-flop 3 of main slicer 34 applied to OR gate 351 of edge position detection circuit 35
The output signal from 48 and the output signal from the shift register 322 of the sub-slicer 35 are binary signals that set a high level between the front edge and the rear edge, or a binary signal that indicates the presence or absence of the steel plate S when the front or rear edge is not detected. The ninth signal, which is the binary signal shown in FIG.
An OR (logical sum) signal as shown in the figure is applied from an OR gate 351 to an S terminal of a flip-flop 353 and an inverter 357 via a noise cut filter 352.

The R terminal of the flip-flop 353 is supplied with a horizontal synchronizing signal as shown in FIG. As shown in Figure 2, the output signal from the Q output terminal becomes low level, and
When the OR signal from the OR gate 351 becomes high level and is applied to the S terminal, the flip-flop 353 enters the set state and the output signal from its Q output terminal becomes high level, and this signal is applied to the one-shot multi 354. . Therefore, even if there are multiple rising edges of the high level portion of the OR signal per scanning line, there will only be one rising edge of the high level portion of the signal. It is possible to accurately detect the conversion from the background to the steel plate S on the scanning line even when the background is attached to the steel plate S.

The one shot multi 354 provides a high level latch buffer rewrite pulse to the front edge latch circuit 355 as shown in FIG.

Further, the OR signal from the OR gate 351 applied to the inverter 357 is applied to the one-shot multi 358 as a signal whose level is inverted, as shown in FIG. This one-shot multi 358 outputs a latch buffer rewriting pulse shown in FIG.

Therefore, the latch buffer rewriting pulse included in the signal applied to the front edge latch circuit 355 is one per scanning line, and the latch buffer rewriting pulse contained in the signal applied to the rear edge latch circuit 359 is the high level of the analog video signal VD per scanning line. The number is the same as the number of sections (or the number of falling positions).

The counter 361 is supplied with a horizontal synchronizing signal as a clear signal CLR, and is supplied with a clock signal CLK as a counting target. Each time the clear signal CLR is applied to the counter 361, that is, each time the scanning by each of the cameras 111 to 119 moves to a new scanning line, the counter 361 is reset, and the counter 361 calculates the elapsed time from the time when the clear signal CLR was applied and reset. The information shown is provided to the front edge latch circuit 355 and the rear edge latch circuit 359.

Further, the level of the horizontal synchronizing signal is reversed by an inverter 362, and is applied as a clear signal CLR to the front edge latch circuit 355 and the rear edge latch circuit 359, and each time this clear signal CLR is applied to both latch circuits,
That is, each time scanning of a new scanning line is started, both latch circuits 355 and 359 are reset. Both latch circuits 355 and 359 latch the time value given by the counter 361 each time, that is, the position of the edge on each scanning line, when each latch buffer rewriting pulse of the signal .

A horizontal synchronizing signal is given as a load signal LD to both edge detectors 356 and 360, respectively, and when a high level pulse of this load signal LD is input, each edge detector 356 and 360
reads the information indicating the elapsed time latched in each latch circuit 355 and 359 at that time as a position on each scanning line of the front edge and rear edge, and outputs it to the edge position memory 36.

Therefore, since only one latch buffer rewriting pulse is applied to the front edge latch circuit 355 for each scanning line as shown in FIG. 356 and detected as the front edge position. In some cases, the rear edge latch circuit 360 is supplied with a plurality of latch buffer rewrite pulses as shown in FIG. Since the count value latched by the last latch buffer rewriting pulse shown above is read out by the rear edge detection value 360 and detected as the rear edge position, there is a low temperature area or deposits such as slag on the surface of the steel plate S as described above. Even in this case, the edge position of the steel plate S can be detected accurately.

Data indicating the edge position on each scanning line detected by the edge position detection circuit 35 in this manner (edge position) is sequentially provided to an edge position memory 36. The edge position memory 36 has a capacity for two screens, and contains one screen's worth of data, that is, one screen of data acquired prior to writing the edge position.
Direct memory access for screen data
The configuration is such that the data is transferred to the arithmetic unit 4 using a minicomputer via the O port 39, and these processes are controlled by the CPU 38.

The arithmetic unit 4 performs linear transformation to combine data for one screen obtained by the individual cameras 111 to 119 into a composite field of view to create overall composite figure information, and converts the characteristic elements of this composite figure into a rolling machine. control system (not shown) as control information.

Linear transformation for combining the fields of view of the individual cameras 11 into a composite screen is performed as follows. Edges on one scan line in each individual field of view, i.e. rising edges,
The position of the falling point on the coordinate system X-Y of the individual field of view is (Xi, Y ₁ i), (Xi, Y ₂ i), and the position of this point on the coordinate system x-y of the composite field of view is (x ₁ i, y ₁ i), (x ₂ i,
y ₂ i), the relationship is as shown below.

x ₁ i＝X ₀ j−axj・Xi・cosθj −ayi・Y ₁ i・sinθj y ₁ i＝Y ₀ j−axj・Xi・sinθj −ayi・Y ₁ i・cosθj x ₂ i＝X ₀ j− axj・Xi・cosθj −ayi・Y ₂ i・sinθj y ₂ i=Y ₀ j−axj・Xi・sinθj −ayi・Y ₂ i・cosθj where, X ₀ j, Y ₀ j: Coordinates of synthetic visual field x− Parallel movement distance of the individual visual field X-Y with respect to y (in pixel units) axj, ayj: Magnification rate of the individual visual field with respect to the standard visual field θj: Rotation angle of the individual coordinate X-Y with respect to the composite coordinate x-y Also, the edge position calculation circuit 3 Timing I/O
Process control computer 9 via port 39
is connected to the process control computer 9
gives information necessary for measurement to the CPU 38.

The data accumulated in the edge position memory 36 is also read out by the CPU 42 and written as composite image information to the display ram 41 associated with the screen of the CRT monitor 6, and based on this, this composite screen is displayed on the CRT monitor 6. . Furthermore, in this embodiment, each of the cameras 111 to 119 has 1024 scanning lines, so the edge position memory is used to compress and synthesize the screen in the vertical direction of the CRT monitor 6, which has 512 scanning lines. The configuration is such that one line out of six scanning lines from No. 36 is extracted.

The keyboard 5 is configured to issue various scanning and control commands to the entire apparatus of the present invention via the keyboard interface 40, or to set various numerical values necessary for measurement, data processing, etc., and these are executed by the CPU 42. It is processed.

The video signal outputted from the video processor 23 is selected by a manual switching type display selector 43 with 9 inputs and 1 output, and the image capture screen of each of the individual cameras 111 to 119 is displayed on the CRT monitor 8.

The operation of the apparatus of the present invention configured as above will be explained below.

The steel plate S during the hot rolling process is captured by the camera 111.
When the cameras 111 to 119 are stopped at a predetermined position within the composite field of view formed by the fields of view 111' to 119' of the cameras 111 to 119, each camera 111 to 119 starts capturing an image.
The thermal infrared filter radiated from the steel plate S cuts out light rays below the visible light range (~700 nm) and selectively transmits only the near-infrared light, and the lens system 1
The image pickup tube 11 of each camera 111 to 119 via 2
a, 11a... are captured as thermal infrared images.
The analog electrical signal of the image captured by the image pickup tube 11a is converted into an optical signal by the fiber link 13, and sent to the fiber link 14 without noise through the optical fiber, where it is converted back into an analog electrical signal. It is given to the camera control unit 2.

The signal given to the camera control unit 2 is given from its video processor 23 to the received light level control circuit 24, and its peak level PL is
A signal FC is applied to the motor 120 to control the aperture value of the lens system 12 so that the peak level PL becomes equal to the set level TL by comparing the received light level PL with the set level TL given to the received light level control circuit 24. The amount of light incident on the cameras 111 to 119 is controlled. As a result, each camera 111 to 119
Since the light reception level is constant, its operation is stable, and the accuracy of edge detection by the main slicer 34 and the sub-slicer 33 is also improved.

The signal from the video processor 23 is also applied to the edge position calculation circuit 3, and is first input to its video selector 31.

A video selector 31 with 9 inputs and 1 output sends signals from each video processor 23 that preprocessed images captured by nine cameras 111 to 119 to a CPU 38.
are sequentially selected and output to the A/D converter 32 according to the command. The signal converted into a digital signal by this A/D converter 32 is given to a sub-slicer 33 and a main slicer 34, and further to an edge position detection circuit 3.
5, the edge on each scanning line, in other words, the position where the scanning line intersects the edge of the image of the steel plate S is detected.

The edge positions on each scanning line detected by the edge position detection circuit 3 are sequentially input and stored in the storage area for one screen of the edge position memory 36.

When edge detection for one screen and storage of the data (edge position) are completed in this way,
The CPU 38 gives commands to the video selector 31 and the edge position memory 36 to cause the video selector 31 to switch images, and also to make the video selector 31 switch images.
6, the edge position data for one screen that has already been acquired is output to the arithmetic unit 4 via the direct memory access I/O port 37, and at the same time, data is sent from the edge position detection circuit 35 to the area for another screen. The edge position of the next image to be received is stored.

The arithmetic unit 4 converts the edge position of each individual field of view sent from the edge position memory 36 into the reference coordinates x-y of the composite image according to the conversion formula, and combines the individual fields of view for nine screens into the composite field of view, The characteristic elements of the planar shape of the steel plate S on this composite field of view are output to a control device of the rolling mill or the like.

As described above, the plate shape measuring device according to the present invention has the following features:
Because it uses multiple two-dimensional imaging devices, it is possible to measure with high resolution and precision even when measuring objects with large shapes, and because it uses a television camera as the two-dimensional imaging device. The scanning time is extremely short. Comparing these points with the conventional example described above, the resolution of the conventional example is limited to about 100 x 100, but in this example,
The scanning time is about 2500 x 500, and the scanning time required in the conventional example is about 4 to 5 seconds, but in this example, it is about 9/15 seconds, so high resolution can be achieved without the need to hold the measurement target still. scanning becomes possible.

Further, the position of the edge of the measurement target imaged by the main slicer, that is, the edge position, is detected based on the image signal obtained by the image pickup device, the level of the image signal is changed, and the signal is delayed. Since the image signal is binarized using this method, the edge position can be detected extremely accurately. By adding a sub-slicer with a simple configuration that binarizes the image signal using a predetermined threshold value, it is possible to compensate for the case where the edge position cannot be detected by the main slicer. is no longer necessary.

Furthermore, the apparatus of the present invention can obtain a larger amount of data than the conventional apparatus, making it possible to perform various types of more advanced analyzes that were not possible with the conventional apparatus.

Furthermore, in this embodiment, by using a television camera that is capable of capturing images in a tilted field of view, multiple television cameras can be arranged in one place instead of being distributed directly above the center of each field of view, thereby saving installation space. It is possible.

Note that in this example, a silicon vidicon camera with good sensitivity characteristics in the near-infrared region is used as a two-dimensional imaging device to capture a thermal infrared image of a hot steel sheet, eliminating the need for lighting equipment. By using , it becomes possible to measure regardless of the temperature of the steel plate.

In addition, the main slicer in this embodiment generates a signal obtained by increasing the level of the image signal and a signal obtained by delaying the image signal.
Furthermore, although the configuration is such that a signal indicating both the front and rear edges of the image signal is obtained by increasing the level of this signal, other processing methods are also possible.

As explained above, the plate shape measuring device according to the present invention includes a plurality of two-dimensional imaging devices each having a horizontal and vertical scanning function, each of which is arranged so as to partially image a plate material to be subjected to shape measurement; A signal obtained by delaying an image signal obtained by horizontal scanning of a two-dimensional imaging device is used as a reference video signal, a signal obtained by performing addition processing on the image signal is used as a slice level signal for fall detection, and further added to the reference video signal. A main slicer that performs binarization processing on the reference video signal using a signal subjected to delay and addition processing as a slice level signal for rising edge detection, and a sub-slicer that performs binarization processing on the reference video signal using a certain threshold value. and an edge position detection circuit which synthesizes the binary signals of the main slicer and the sub-slicer and determines the position of the rising edge that appears earliest and the position of the falling edge that appears the latest using a clock signal synchronized with the horizontal scanning time. an edge position memory that sequentially stores rising and falling edge positions obtained by the edge position detection circuit in synchronization with vertical scanning, and an arithmetic unit that performs a synthesis process of edge positions corresponding to each partial field of view in this edge position memory. Because it is equipped with
The scanning speed is fast, and it is possible to perform high-resolution scanning even on a moving measurement target without having to stop it, and the main slicer is used to delay the image signal and combine the processed signals such as addition processing to generate binary signals. processed,
Since the edge position is detected, the detection accuracy of the edge position is high. Furthermore, since it is equipped with a sub-slicer, even if the main slicer cannot detect the edge position, it can be compensated for, eliminating the need for complex software processing, and The present invention has excellent effects, such as being able to perform various types of sophisticated analyzes with a large amount of data.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of an example of a conventional hot steel sheet shape measuring device, FIG. 2 is a block diagram showing an outline of the configuration of a sheet shape measuring device according to the present invention, and FIG.
The figure is also an explanatory diagram showing the arrangement of the television camera, its field of view, and the positional relationship between the composite screen and the steel plate formed thereby, and Figures 4 and 5 are the relationship between the direction of the scanning line of the television camera and the edge direction of the steel plate, and Explanatory diagram showing the relationship between the video signal and the binary signal, No. 6
The figure is an explanatory diagram of the tilted field of view, Fig. 7 is an explanatory diagram of the method of controlling the light reception level of the television camera, Fig. 8 is a block diagram of the main slicer, sub-slicer, and edge position detection circuit of the apparatus of the present invention, and Fig. 9 is An explanatory diagram showing the states of each signal, FIG. 10 is a schematic diagram showing the main part of FIG. 9(b). 2...Camera control unit, 3...Edge calculation circuit,
4... Arithmetic device, 11,111-119... Silicon vidicon camera, 11a... Image pickup tube, 12...
...Lens system, 22... Image distortion correction circuit, 23...
Video processor, 33... Sub-slicer, 34...
...Main slicer, 35...Edge position detection circuit, 3
6...Edge position memory.

Claims (1)

[Scope of Claims] 1. A plurality of two-dimensional imaging devices, each of which is arranged so as to partially image a plate material to be subjected to shape measurement, and has horizontal and vertical scanning functions, and a horizontal scanning device of the two-dimensional imaging device. A signal obtained by delaying the image signal obtained from the above is used as a reference video signal, a signal obtained by performing addition processing on the image signal is used as a falling detection slice level signal, and further delay and addition processing is performed on the reference video signal. a main slicer that performs binarization processing on the reference video signal using a signal as a slice level signal for rising edge detection; a sub-slicer that performs binarization processing on the reference video signal using a certain threshold; a main slicer and a sub-slicer. an edge position detection circuit which synthesizes the binary signals of and determines the position of the rising edge that appears earliest and the position of the falling edge that appears latest using a clock signal synchronized with the horizontal scanning time; and the edge position detection circuit. The rise I got,
A plate shape measurement device comprising: an edge position memory that sequentially stores falling edge positions in synchronization with vertical scanning; and an arithmetic unit that performs synthesis processing of edge positions corresponding to each partial field of view in this edge position memory. Device. 2. The plate shape measuring device according to claim 1, wherein the two-dimensional imaging device is capable of capturing images in a tilted field of view by shifting the optical axis of the lens system and the central axis of the imaging section.