JPS61192181A - Method and device for controlling exposure of image pick up device - Google Patents

Abstract

PURPOSE:To obtain approximately an appropriate exposure against the edge side part of an image picking-up subject by providing a window near the position of the edge side part of the subject when the clear image pick up of the edge side part of the image picking-up subject is needed and controlling the exposure to obtain the appropriate exposure to the window. CONSTITUTION:With the completion of a process by a horizontal slicing circuit 3 etc., a vertical direction width of a horizontal scanning line T2V line (from He of a horizontal scanning line) and the window W of a distance Wh that the horizontal direction width corresponds to time Th are set on the left edge side part of a hot rolled plate. When the outputting of the picture signal of one frame is completed, a vertical synchronizing signal Vsync is given to an integrating circuit 7. Thereby, the integrating circuit 7 outputs an integrated value Vin to a stop control circuit 8. The stop control circuit 8 subtracts the integrated value Vin that is given from the integrating circuit 7 from an object value Vref and controls the aperture of the stop of a television camera 21 so as to make the difference to zero, that is, to make both to coincide.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an exposure control method and device for an imaging device such as a television camera, and more specifically to a planar shape of a thick plate to be hot rolled. The present invention relates to an exposure control method for an imaging device and its device, which aims to more clearly image the edge portion of an object to be imaged, such as when an object is imaged by an imaging device for recognition and measurement.

[Prior art]

The inventors of the present invention have previously developed a "plate shape measuring device" (Japanese Patent Application No. 14724-1981) using composite images from multiple imaging devices.
No. 8) is proposed.

Specifically, this invention captures self-luminous near-infrared images of a hot-rolled thick plate using nine television cameras arranged in a 3x3 matrix to create one composite image, and Image processing the image to detect the position of each edge of the plank,
This ultimately measures the shape of the plate (planar shape, more specifically, external dimensions and linearity), and the devices are arranged so as to image each part of the plate to be measured. A signal indicating the rising and falling points of the image signal is created based on a plurality of two-dimensional TM imaging devices, image signals obtained by the imaging device, the level of the image signal is changed, and the signal is delayed. a slicer, and the rising edge based on the output signal of the slicer.

The present invention includes an edge position detection circuit that associates a falling point with a position of a captured image, and an arithmetic unit that associates and synthesizes position information obtained by the edge position detection circuit with the imaging field of view of each two-dimensional imaging device. Features.

[Problem that the invention seeks to solve]

However, the above-mentioned "plate shape measuring device" by the present inventors
In the invention, the exposure control of conventional imaging devices such as television cameras, specifically the aperture control method, is generally configured to open and close the aperture as appropriate so that the peak level of the imaged video signal is constant. It is true. For this reason, conventionally, for example, the following inconveniences have occurred.

Now, suppose that when a thick steel plate being hot rolled is imaged at the peak level of the image signal Vee, an image signal as shown by the solid line in FIG. When it is binarized, it becomes 2 as shown in Tbl in the same figure
A value signal is obtained. However, when the temperature difference between the imaged surfaces of the imaging object is large, the peak level Vee is constant, so the image signal at the edge portion where the temperature is low will be at a considerably low level, and as shown in Fig. 4 (8). The state will be as shown by the dashed line. Therefore, when this is binarized at the slice level Vs, as shown in FIG. 4 [C], the rise and fall of the image signal becomes gradual, and the edge position of the hot-rolled thick steel plate S becomes There was a possibility that it would be detected as a different position.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and
A predetermined area (
The present invention provides an exposure control method for an imaging device that can perform appropriate exposure in near value even for the edges of an object to be imaged by setting a window) and performing appropriate exposure control for this area, and the device. purpose.

The present invention provides a first threshold value for detecting the presence of an image of an object to be imaged in the image signal of each horizontal scanning line of one screen captured by an imaging device as a high level (or low level) portion of a 24-di signal. to sequentially binarize the signal, and define a predetermined width after a certain period of time from the rising (or falling) point of the signal obtained by this binarization as the vertical window width,
The image signal of each horizontal scanning line included within the vertical window width is binarized using a second threshold value, and the high level (or low level) part is used as the signal of the image to be imaged. A predetermined width after a certain period of time from the rising (or falling) point of the signal is defined as the horizontal window width, the image signal of each horizontal scanning line is delayed for a predetermined period of time, and the vertical window of this delayed image signal is The present invention is characterized in that signal values of portions included within the window width and the horizontal window width are sequentially integrated, and the exposure of the imaging device is controlled so as to make the integrated value coincide with a target value.

[Example] Hereinafter, the present invention will be described in detail based on drawings showing practical examples thereof.

FIG. 5 is a schematic diagram showing the general configuration of a plate shape measuring device using the exposure control force method of the imaging device according to the present invention.

A reversible rolling mill M is installed in a rolling line in which a large number of rollers R, R, . . . are arranged side by side. This reversible rolling mill M rolls a hot-rolled thick steel plate S that is moved on rollers R, R, . . . in both directions indicated by the white arrows.

A television camera 21 is provided above one side of the reversible rolling iM.

The television camera 21 is controlled by a camera control unit 24 while being exposed by the device of the present invention, that is, an exposure control device 26 described later, and the near-infrared image of the hot rolled thick steel plate S taken by the television camera 21 is controlled by the camera control. After being sent to the unit 24 and subjected to preliminary processing such as noise removal and image distortion correction, it is input to the arithmetic unit 23.

Arithmetic unit F! i23 analyzes the image signal captured by the television camera 21, detects the edge position of the hot rolled thick steel plate S within the field of view F of the television camera 21, and measures the shape of the hot rolled thick steel plate S. Characteristic elements of the planar shape of the hot-rolled thick steel plate S measured in this manner are provided to the control device 22. The control device 22 controls the driving devices of the reversible rolling mill M, rollers R, R, etc. via the rolling mill control device 25 based on the characteristic elements of the planar shape of the hot-rolled thick steel plate S given from the calculation device 23. (not shown), etc., thereby rolling-forming the shape of the hot-rolled thick steel plate S into a designated shape.

Note that the edges of the field of view F of the television camera 21 and the hot rolled W-
The field of view F is set not to be parallel to the edge of the steel plate S, but to intersect with it at a slight angle. This is TV camera 2
This is because if the direction of the scanning line No. 1 and the direction of the edge of the hot-rolled thick steel plate S coincide, detection becomes somewhat difficult.

FIG. 1 is a block diagram showing the configuration of an exposure control device for an imaging device according to the present invention, shown together with the above-mentioned television camera 2 and lens system 20.

The television camera 21 includes a lens system 20 and a camera head 21.
It consists of an H1 scanning device 215 and the like, and the lens system 20 has a built-in diaphragm (not shown). This aperture is controlled to open and close by an aperture control circuit 8 as will be described later, thereby controlling the exposure of the television camera 21.

Further, the image captured by the camera head 21H is output to the scanning device 21S.

The image given to the scanning device 21S is scanned and converted into an image signal, and as described in i11, is output to the calculation circuit 23 etc. to perform calculations for measuring the planar shape of the hot rolled thick steel plate S. The signal is also applied to the vertical slice circuit 1, horizontal slice circuit 3, and delay circuit 6 of the exposure control device 26, which is the device of the present invention.

The vertical slice circuit 1 is a slicer that binarizes the image signal of each horizontal scanning line for one screen provided from the scanning device 215 at a predetermined slice level Sv, as shown in FIG. 2(a). In FIG. 2 (al), each protruding part of the Yamabushi indicates the presence of the hot-rolled thick steel plate S that is the object of imaging. In other words, the part indicates a horizontal scanning line with a high signal value. Since the image of the hot-rolled thick steel plate S appears white on the screen, the image signal is at a high level.

Therefore, the second [ffl (al) indicating the image signal of each horizontal scanning line of one screen is the position of the horizontal scanning line (of the field of view F of the camera 21) having a signal value equal to or higher than the appropriately set slice level Sν. vertical position) hot rolled thick steel plate S
This means that the statue of The signal sliced by this vertical slicing circuit 1 is a pulse-like binary signal in which the portion corresponding to the horizontal scanning line where the image of the hot-rolled thick steel plate S is located is continuously at a high level, as shown in Fig. 2). The signal is applied to the vertical window width setting circuit 2 as a signal.

The vertical window width setting circuit 2 is a vertical slice circuit.
Counting is started when the pulse-like binary signal given from I becomes high level for the first time after the vertical synchronization signal Vsync shown in FIG. 2 is given. As a result of this counting, the signal shown in FIG.
A high level portion is detected between a predetermined width T2v (specifically, set as the number of horizontal scanning lines like Tlv) after lν (specifically, set as the number of horizontal scanning lines). Each time, it outputs a processing start signal for causing the horizontal slice circuit 3 to start processing for the horizontal scanning line corresponding to the high level portion. Through the processing of this vertical direction window width setting circuit 2, the field of view F of the camera 21 is
The T2v lines after the Tlv line from the top are set as the vertical width of the window (FIG. 2(C)).

When the horizontal slice circuit 3 receives the processing start signal from the vertical window width setting circuit 2 as described above, it selects the horizontal scanning line corresponding to the position where the vertical window interval setting circuit 2 detects a high level at that time. As shown in FIG. 10, slicing is performed at a slicing level sh. The binary signal after slicing is given as an image signal to the left window horizontal width setting circuit 4 and the right window horizontal width setting circuit 5, respectively, as shown in FIG.

As shown in FIG. 2(h), the left window horizontal width setting circuit 4 sets the rising position at a position delayed by a certain time Th from the rising point of the binary image signal applied from the horizontal slicing circuit 3, and also from this rising position at the same position. Predetermined time Th
(Time Th is set as a time value) High level left window horizontal width signal HL with the delayed position as the falling edge
gate is created and output to the gate terminal of the analog switch 9 and the set terminal S of the flip-flop 11.

Output terminal Q of flip-flop ■1 is AND gate IO
The horizontal synchronizing signal H5ync shown in FIG. 2(1) is applied to the reset terminal R of this flip-flop Jl.

As shown in FIG. 2 (1), the right window horizontal width setting circuit 5 takes the falling point of the binary image signal applied from the horizontal slicing circuit 3 as the rising edge, and further sets the point in time after a predetermined time Th after this rising edge. Create a high-level right window horizontal width signal 11Rgate with a falling edge, and
It is output to the positive logic hexagonal terminal of the D gate 10. This AND
The output terminal of the gate 1-10 is connected to the gate terminal of the analog switch 9.

The analog switch 9 is closed during the period when a high level signal is applied to its gate m, and inputs the output signal from the delay circuit 6 to the integration circuit 7.

Therefore, each time the horizontal slicing circuit 3 starts slicing processing for each horizontal scanning line, the horizontal synchronizing signal Hsync is applied to the set terminal S of the flip-flop 11, and the flip-flop 11 is placed in the set state. For this reason,
When the left window horizontal width signal 1 (Lgate) is output from the left window horizontal width setting circuit 4, the flip-flop 11 is set and the analog switch 9 is closed during the output period. The right window horizontal width signal 1 obtained from processing the horizontal scan line of
When 1Rgate is output from the right window horizontal width setting circuit 5, the set state of the flip-flop 7 bit is maintained, so the right window horizontal width signal HRga
te is not applied to the gate terminal of analog switch 9, and analog switch 9 maintains an open state.

On the other hand, if the left window horizontal width setting circuit 4 does not output the left window horizontal width signal HLgate for each horizontal scanning line, the flip-flop 11 maintains the reset state, so the right window horizontal width Right window horizontal width signal HRga output from setting circuit 5
te is applied to the gate terminal of the analog switch 9, and the analog switch 9 is closed during the output period of the right window horizontal width signal HRga_to. The delay time Th of the image signal by the delay circuit 6 is set to be the same as the delay time of the binarized image signal by the left window horizontal width setting circuit 4.

The delay circuit 6 delays the image signal of each horizontal scanning line inputted from the camera control section 24 by the aforementioned predetermined time Th, and supplies the signal to the integration circuit 7 via the analog switch 9.

The integration circuit 7 is supplied with the horizontal synchronization signal Hsync, integrates the image signal input from the delay circuit 6 via the analog switch 9, and transmits the integrated 1 mVin to the aperture control circuit each time the horizontal synchronization signal H5sync is supplied. 8 and the integral value is deleted.

The aperture control circuit 8 receives the integral value V given from the integrating circuit 7.
This is a servo mechanism that controls the aperture of the lens system 20 of the television camera 21 so that the value obtained by subtracting in from the target value Vref of the image signal level becomes 0, that is, so that the two coincide.

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

First, we will explain the case where the hot-rolled thick steel plate S to be imaged is completely within the field of view F of the television camera 21, as shown in FIG. 3 (al). In this case,
A window W is set inside the left edge of the hot rolled thick steel plate S.

When an image of the hot rolled rFJ steel sheet S is taken by the television camera 2I, image signals of each horizontal scanning line corresponding to the screen are sequentially outputted from the camera scanning device 21S.

This image signal is applied to a vertical slice circuit 1, a horizontal slice circuit 3, and a delay circuit 6.

The vertical slicing circuit 1 slices the image signal of the horizontal scanning line number 1, which is sequentially input as shown in FIG.
It is sequentially output to the vertical window width setting circuit 2 as a value signal.

The vertical window width setting circuit 2 receives a horizontal synchronization signal Hsy.
After nc is given, when the input binary signal first turns to high level, counting starts, and after this count reaches the predetermined number of lines T1ν, a high level signal is input. A processing start signal is given to the horizontal slice circuit 3 each time.

The horizontal slice circuit 3 to which the processing start signal is applied is configured to scan the horizontal scanning line 11ij (horizontal scanning line 1 at the upper end of the window W shown in FIG. The image signal of (S) is sliced at the slice level sh as shown in Fig. 2 (fl), and the second
It is applied to the left window horizontal width setting circuit 4 and the right I11 window horizontal width setting circuit 5 as a binary @image signal as shown in FIG. At this time, between the time when the image signal shown in FIG. 2 (fl) actually starts to rise and the time when the binary image signal shown in FIG. There is a delay of time Td in reaching sh.

The left window horizontal 1 frame setting circuit 4 is operated at a time when a predetermined time Th has elapsed from the rising edge of the binary image signal applied from the horizontal slicing circuit 3 as shown in FIG. (corresponding to the position of the scanning line Vs) for a predetermined time T
A high-level signal, that is, the above-mentioned left window horizontal signal GA TO is outputted over the analog switch 9.
to the gate terminal of. Therefore, from the left edge position of the hot rolled thick steel plate S on the horizontal scanning line Hs to the vertical scanning line V
The distance to the position s corresponds to the sum of the delay time Td and the predetermined time Th during binarization.

On the other hand, the image signal for 1 Jil 1947 horizontal scans given to the delay circuit 6 from the scanning device 21S is i! ! After a delay of the extended opening time Th, the signal is output to the analog switch 9 as shown by the solid line in FIG. In addition, in FIG. 3+8), the position of the image S' when the image of the hot-rolled thick steel plate S is delayed by the time Th is shown by a broken line. Then, as described above, when the time Td and the period Td have elapsed, the high level left window horizontal width signal HLgate outputted from the left window horizontal width setting circuit 4 is applied to the gate terminal of the analog switch 9, so that the analog switch 9 is closed for a predetermined time Th in FIG. 2 (as shown in kl and if in FIG. 2)
A predetermined time Th from the rising point of the image signal, which is delayed by the time Td until reaching the slice level sb after the image signal starts rising, is input to the integrating circuit 7. The integrating circuit 7 integrates the image signal value for this predetermined time Th.

At this time, the right window horizontal width setting circuit 5 outputs a signal so that the horizontal window width is also set on the right side of the image of the hot rolled thick steel plate S, but the left window horizontal width setting circuit 4 outputs a signal. Since the set state of flip-flop II is maintained by the left window horizontal width signal HLgate, the right window horizontal width signal lIR
No image signal is input from the delay circuit 6 to the integration circuit 7 while gaLe is being output.

This completes the processing of the horizontal scanning line l.

Then, when the same process is repeated for the subsequent predetermined number of lines T2v of horizontal scanning lines, the signal output from the vertical window width setting circuit 2 to the horizontal slicing circuit 3 becomes low level, and the horizontal slicing circuit 3 etc. Processing ends. As a result, as shown in FIG.
(up to e), a distance window W whose horizontal width corresponds to the time Th is set on the left side edge portion of the hot rolled thick steel plate S.

When the image signal for one screen has been outputted from the camera control section 24, the vertical synchronization signal V5ync is given to the integrating circuit 7. As a result, the integrating circuit 7 outputs the integrated value Vin to the aperture control circuit 8. The aperture control circuit 8 subtracts the integral value Vin given from the integration circuit 7 from the target value 'Jrer, and controls the opening degree of the aperture of the television camera 21 so that the difference becomes 0, that is, the two match. do.

Such processing is performed each time one screen is imaged, and each time the exposure of the television camera 21 is corrected and controlled in a direction that makes it more appropriate. In FIG. 2(f), 01, □□□), the image signal after the exposure has been corrected as described above is shown by a dash-dot line. By correcting and controlling the exposure in this way, the rise of the image cLL signal becomes more steep. In other words, an image of the edge of the hot-rolled thickness mIPiis is captured more accurately. In such a case, the level of the image signal at the center of the hot rolled thick steel plate S may become saturated (overexposed) as shown in FIG.
The level of the image signal in the edge portion, which is the object of imaging, approaches an appropriate value.

Moreover, if the rise of the image signal becomes steeper, as is clear from FIG. 2(f), the time Td from when the image signal starts rising until it reaches the slice level sh
becomes shorter. This means that the horizontal distance from the edge of the image S' of the hot-rolled thick steel plate S delayed by time Th in FIG. This means that the delayed image S' of the thick steel plate S approaches the edge (the window W does not protrude to the left of the edge), and therefore the exposure control process is performed for a position closer to the edge. , closer to the appropriate exposure value.

By the way, when the hot-rolled thick steel plate S to be imaged is not completely within the field of view F of the television camera 21, or when a composite screen is created using a plurality of television cameras 21, 21... As shown in FIG. 3 (bl), the window W is set only on the right side of the hot rolled thick steel plate S.

That is, in the case as shown in FIG. 3(b), the binary signals from C to C in FIG.
The rising edge of the binary image signal is not detected since it is at a high level from the time when it is applied. Therefore, the left window horizontal width signal I is output from the left window horizontal width setting circuit 4.
Since to is never output, the flip-flop 11 remains in the reset state without being sent, and a low-level signal continues to be applied to the negative logic terminal of the AND gate 10. On the other hand, the right window horizontal width setting circuit 5
A high-level right window horizontal width signal HRgate is outputted at predetermined time intervals Th from the falling point of the binary image signal of 1547th horizontal scanning line shown in FIG. 2(g) as shown in FIG. 2(1). This right window horizontal width signal HRga Le
is applied from the AND gate) 10 to the gate terminal of the analog switch 9, thereby closing the analog switch 9. Then, while the analog switch 9 is closed, the delay circuit 6
The image signal delayed by the time Th is outputted from the integrator 7 to the integrator 7, and the integrator 7 integrates this value. The above process is repeated for one screen as in the case where the window W is set on the left side, and thereafter the aperture control circuit 8 similarly controls opening and closing of the aperture.

In this case, the horizontal distance 1@Wd between the window W shown in the third report) and the edge of the delayed image S' of the hot rolled thick steel plate S is
As shown in FIG. 3<f), ' corresponds to the time Td' from the time when the image signal reaches the slice level sh at the time of falling to the time when the image signal completely falls. Therefore, when the exposure correction control as shown by the dotted line in FIG. 2 is performed, the time Td' becomes longer because the point at which the image signal falls below the slice level sh at the time of its fall becomes later. Becomes shorter. Therefore, the horizontal distance ′ between the window W and the edge of the hot-rolled thick steel plate S shown in Part 3) also becomes shorter, and the window W approaches the edge of the hot-rolled thick steel plate S. The same effect as when the window W is set on the left side described above is achieved.

〔effect〕

As explained above, in the present invention, when it is necessary to clearly image the edge of the image, a window is set at a position close to the edge of the image, and the exposure is set appropriately for this window. Control exposure. Therefore, approximately appropriate exposure for the edge portion of the object to be imaged is possible.

Also, the horizontal distance from the edge of the delayed image that is subject to actual exposure control to the position where the window is set is the horizontal distance on the screen corresponding to the time from the rise of the image signal until it reaches the slice level. Therefore, as the exposure is corrected, this distance becomes smaller successively, and the window asymptotically approaches the edge of the delayed image of the object to be imaged.

Therefore, more accurate exposure control will be performed.

In the above embodiment, the present invention was described as an example in which the present invention is used to measure the outer shape of a hot-rolled thick steel plate. The present invention is effective.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram showing the configuration of the device of the present invention, FIG. 2 is a timing chart for explaining its operation, and FIG. 3 shows the setting position of the window. Figure 4 is an explanatory diagram of the conventional method.
FIG. 5 is a schematic diagram of a plate shape measuring device which is an application example of the present invention. 1... Vertical slice circuit 2... Vertical window width setting circuit 3... Horizontal slice circuit 4...
- Left side window horizontal width setting circuit 5... Right side window horizontal width setting circuit 6... Delay circuit 7... Integrating circuit 8... Squeezing control circuit W... Wind S... Hot rolling W, Steel plate F
---Camera field of view patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono (a) (Figure 3, No. 412)

Claims (1)

[Claims] 1. To detect the presence of an image to be imaged as a high level (or low level) part of a binary signal in the image signal of each horizontal scanning line of one screen imaged by an imaging device. the first of
The signal is sequentially binarized using a threshold value of The image signal of each horizontal scanning line is binarized using a second threshold value, and the high level (or low level) part is used as the signal of the image of the object to be imaged, and the rising (or falling) of the signal of this image is ), a predetermined width after a certain time from the point in time is determined as a horizontal window width, the image signal of each horizontal scanning line is delayed for a predetermined time, and the delayed image signal is within the vertical window width and within the horizontal window width. 1. An exposure control method for an imaging device, comprising: sequentially integrating signal values of portions included in the image pickup device, and controlling exposure of the imaging device so that the integrated value coincides with a target value. 2. A first method for detecting the presence of an image of an object to be imaged as a high level (or low level) part of a binary signal in the image signal of each horizontal scanning line of one screen imaged by the imaging device.
The signal is sequentially binarized using a threshold value of The image signal of each horizontal scanning line is binarized using a second threshold value, and the high level (or low level) part is used as the signal of the image to be imaged. ) is determined as a horizontal window width, the image signal of each horizontal scanning line is delayed for a predetermined time, and the delayed image signal is included within the vertical window width and within the horizontal window width. 1. An exposure control method for an imaging device, characterized in that the exposure of the imaging device is controlled so as to sequentially integrate the signal values of the portions of the image pickup device to match the integrated values with a target value. 3. The image signal of each horizontal scanning line of the screen imaged by the imaging device is set at a first threshold value for detecting the presence of the image of the object to be imaged as a high level (or low level) part of the binary signal. a first slicer that sequentially binarizes; and a vertical window that sets a predetermined width after a certain period of time from the rising (or falling) position of the binary signal obtained by the first slicer as the vertical window width. The image signal of each horizontal scanning line within the vertical window width set by the width setting circuit and the vertical window width setting circuit is binarized using a second threshold value, and the high level (or low level) portion thereof is a second slicer that takes as a signal of an image to be imaged, and a horizontal window width that is a predetermined width after a certain period of time from the rising (or falling) position of the signal of the image binarized by the second slicer. a delay circuit that delays the image signal of each horizontal scanning line by a predetermined time; and a vertical window width setting circuit that delays the image signal of each horizontal scanning line by a predetermined time; an integrating circuit that integrates a portion included within the window width and located within the horizontal window width of each horizontal scanning line; and controlling the opening and closing of the aperture of the imaging device to make the integrated value of the integrating circuit match a target value. 1. An exposure control device for an imaging device, comprising: an aperture opening/closing mechanism. 4. The image signal of each horizontal scanning line of the screen imaged by the imaging device is set at a first threshold value for detecting the presence of the image of the object to be imaged as a high level (or low level) part of the binary signal. a first slicer that sequentially binarizes; and a vertical window that sets a predetermined width after a certain period of time from the rising (or falling) point of the binary signal obtained by the first slicer as the vertical window width. The image signal of each horizontal scanning line within the vertical window width set by the width setting circuit and the vertical window width setting circuit is binarized using a second threshold value, and the high level (or low level) portion thereof is a second slicer that takes as a signal of an image to be imaged; and a predetermined width from the fall (or rise) point of the signal of the image binarized by the second slicer is set as a horizontal window width. a horizontal window width setting circuit; a delay circuit for delaying the image signal of each horizontal scanning line for a predetermined time; and a delay circuit for delaying the image signal delayed by the delay circuit within the vertical window width determined by the horizontal window width setting circuit. an integrating circuit that integrates a portion included in the horizontal scanning line and located within the horizontal window width of each horizontal scanning line; and an aperture opening/closing mechanism that controls opening and closing of the aperture of the imaging device so that the integral value of the integrating circuit matches a target value. An exposure control device for an imaging device, comprising: