JPS61129993A - Picture change detection device - Google Patents

Abstract

PURPOSE:To make it unnecessary to monitor the picture by human eyes, by calculating the difference between the picture taken at any optional time and the picture taken right after that by a comparison device and deleting the memory of memory device by a deleting device. CONSTITUTION:A picture 13 which is taken by a photographing device 2 which can take photograph continuously is stored at a memory device 7. A picture 10 of an object 1 which is taken following the picture 3 is inputted to a comparator 12. Also an electric signal 5 is inputted to the comparator 12 as an output of the memory device. The comparator 12 calculates the difference of the electric signal 5 and electric signal 11, and its output 13 is inputted to instruction device 14. As a result, it repeats to output the same electric signal as the signal inputted to the memory device 7, and the memory is deleted by a deleting device 15.

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to an image change detection device that detects changes over time in images captured by a camera, etc., and requires a watcher to watch the image screen closely. The present invention provides a novel image change detection device that does not have the following problems.

(B) Conventional technology Conventionally, as a method for detecting changes in images captured by a camera, etc., there is a method for detecting changes in images captured by a camera, for example, in a device for monitoring the shape of an object such as a security television monitoring device. There were methods such as displaying the image on a display and constantly monitoring changes in it with the eyes of an observer, or recording it on a videotape and playing it back to detect changes in the image.

In addition, there is a TV monitoring system for chimneys at thermal power plants, which displays images of smoke emitted from the chimney on a TV screen, and detects whether the color of the smoke has changed from transparent or pale white to black due to incomplete combustion of the boiler. In the case of color monitoring devices, such as those used to monitor whether or not there is a problem, changes in color are monitored by the eyes of the observer.

(c) Problems to be solved by the invention However, in such a detection method, when using the observer's eyes, a person must always keep their eyes on the display screen, and when using recorded playback, A time delay occurs in detecting changes in the image. In addition, in cases where the video does not change for a long time, such as inside a bank at night, there are disadvantages such as fatigue of the monitor, wasted monitoring time, an increase in unnecessary parts of the video tape, and a long playback time. In the case of color monitoring, the same drawbacks exist, and in addition, there are also problems due to human factors such as variations in judgment due to individual differences among the monitors. The present invention eliminates the need to constantly monitor images with the human eye or record them on videotape, eliminates variations in judgment due to individual differences among observers, and detects changes in images when they occur. The object of the present invention is to obtain a video change detection device that can detect and issue an alarm and issue commands for screen display, recording, etc.

(2) Means for solving the problem A camera that photographs an object, a converter that converts the image of the photographed object into an electrical or optical signal and outputs it, and stores the output of this converter. A memory device, a comparator that calculates and outputs the difference between the output of the memory device and the output of the converter, and a command device that converts the output of the comparator into a command signal for operating other equipment. , an eraser for erasing the memory contents of the memory device, and the output of the converter of the video taken at any time within a certain period is stored in the memory device,
The comparator calculates the difference between the output of this storage device and the output of the converter of a video shot subsequent to the video, the output of this comparator is converted into the command signal by the command device, and the output of the comparator is calculated by the command device. At the end of a certain period, the memory in the memory is erased by the eraser, and the process moves to the next certain period, and the same operation as in the previous period is repeated.

(E) Function Therefore, in a device that takes the above-mentioned means, information on images shot at any point within a certain period, for example, information on the first image shot and information on images shot subsequently. The comparator can detect the difference, and if there is a difference, the command unit can command the operation of the device such as alarm, screen display, and recording. Also, when a certain period ends, the memory of the memory device is erased (so-called reset) and the information of the next period's video, for example the first video, is stored, so the comparator is It is possible to detect the difference between the information and the information of the subsequent video. In other words, even if the image in the previous period and the image in the current period are completely different, or only in brightness, this will not be detected as a change unless there is a change in the image within the same period. be able to. Also, when converting the output of the comparator into a command signal using a command device,
If you install a command device that does not emit a command signal when the output of the comparator is below a certain value, in cases where only the brightness of the image changes gradually (for example, in the morning, noon, and night), it is possible to If a certain value is sent appropriately, it is possible to not issue a command signal for activating the alarm, that is, it is possible to not issue an alarm regarding a change in the image visually.

(f) Examples The details of the present invention will be explained using the drawings.

FIG. 1 is an example of an embodiment of the present invention. In FIG. 1, an image 3 taken by a camera 2 that continuously photographs an object 1 is converted into an electrical signal 5 by a converter 4, passes through a switch 6, and is input into a memory 7. be remembered. The switch 6 is arranged so as to pass only the electric signal of the first image of a certain period according to the signal 9 of the timer 8. A video 10 photographed by the camera 2 following the video 3 is converted into an electrical signal 11 by a converter 4 and input to a comparator 12 . Further, the electrical signal 5 stored in the memory 7 is also input to the comparator 12 as the output of the memory 7. Comparator 1
2 calculates the difference between the electric signal 5 and the electric signal 11 and outputs it as an output 13, and the output 13 is input to the command unit 14. In this embodiment, the converter 4 divides the image taken by the camera 2 into 525 scanning lines, and generates an electric signal consisting of a signal representing brightness and color and a signal for synchronizing scanning. It is arranged to convert into . Further, the memory device 7 is arranged so that it stores the input electric signal, repeatedly outputs the same electric signal as the input electric signal, and erases the memory by the signal 16 of the eraser 15. The comparator 12 inputs the electrical signal that is the output of the converter 4 and the electrical signal that is the output of the memory 7, and synchronizes the scanning of both signals with a signal that synchronizes the scanning of both signals. It is arranged to calculate and output the difference between the two.

Output 13 thus represents the difference in brightness and color between images 3 and 10. The command unit 14 inputs the output of the comparator 12 and calculates the difference between its absolute value and a predetermined reference value, and when the former is greater than the latter, command signals 17, 18,
19, alarm 20, screen display 21, recorder 2
2 is activated, and command signals are not output at times other than the above. It should be noted that the image capture device 2 is arranged to send continuously captured images 23 to a screen display device 21 and a recorder 22 so that they can be displayed on the screen and recorded, respectively. In this embodiment, regardless of the calculation result of the command unit 14, the next image is captured by the camera 2 following the image 10, and the same operation as described above is repeated. At the end of the above-mentioned fixed period, the eraser 15 outputs the signal 16 in response to the signal 24 of the timer 8.
is output. Therefore, the timer 8 outputs the signal 9 at the start of a predetermined fixed period, and outputs the signal 24 at the end of L. The memory 7 is erased by the signal 16 and is reset. When the next fixed period begins, the switch 6 is actuated by the signal from the timer 8 to pass the electric signal of the first image of the period, and thereafter the same operation as in the previous fixed period is repeated. Therefore, it does not matter whether the images shot in the previous certain period and the certain period are different, it is necessary to repeatedly detect the difference between the first image and the following image in each period. . Further, in this embodiment, the command device 14 is arranged so as not to issue a command signal if there is no difference between the first video taken within a certain period and the video taken subsequently by more than a predetermined value. Therefore, the above-mentioned operations are repeated one after another without activating the alarm or the like. Each device in FIG. 1 is electrically coupled as shown by the solid line in the figure, and electrical signals are transmitted in the direction of the arrow.

In another embodiment (not shown) of the present invention, the electrical signal which is the output of the converter 4 is also sent to the screen display 21 and the recorder 22 instead of the image 23 of FIG. 1 in the embodiment of FIG. It is arranged so that screen display and recording can be performed respectively, and has the same functions as the embodiment shown in FIG.

In another embodiment of the invention (not shown), instead of the transducer 4 of FIG. 1 of the embodiment of FIG. , into an electrical signal consisting of a signal representative of luminance (or color in another embodiment) and a signal for synchronizing scanning; The storage and calculation of the signal representing the color (luminance in the other embodiment) of the memory and comparator are omitted. Therefore, the output of the comparator ultimately indicates the difference in brightness (color in the other embodiment) between the two images to be compared.

In another embodiment of the invention (not shown), a transducer corresponding to transducer 4 of FIG. 1 of the embodiment of FIG. arranged,
It has the same functions as the embodiment shown in FIG. 1 through the same operations.

FIG. 2 is a partial view of another embodiment of the invention. FIG. 2 shows the part A of the embodiment shown in FIG. 1 surrounded by the dotted line in FIG. 1, and the other parts of this embodiment are the same as the embodiment shown in FIG. are arranged. In FIG. 2, a converter 25 inputs an image taken by a camera, converts it into a digital optical signal and outputs it, and a photoelectric converter 26 receives this digital optical signal and converts it into an electrical signal. converter 25 and photoelectric converter 2
6 is connected with an optical fiber cable. Also, if the images 3 and 10 input to the converter 25 are the same as the images 3 and 10 of FIG. 1 of the embodiment of FIG. 1st
They are arranged to be the same as electrical signals 5 and 11 in the figure.

Therefore, the image 3 is converted by the converter 25 into a digital optical signal 27, and by the photoelectric converter 26 into an electrical signal 5, which is output. The image 10 is also converted into a digital optical signal 28 and an electrical signal 11 by the same operation as the image 3. Other operations are the same as in the embodiment shown in FIG.

FIG. 3 shows another embodiment of the invention. In Figure 3,
Object 1 is photographed by camera 2, the photographed image of object 1 is input, the image is divided into 525, and the 525 representative color values of the image of the division are converted into 525 electrical signals and output. a converter 4 for inputting the electrical signal, a memory 7 for storing and outputting any one of the 525 electrical signals;
, a comparator 12 that calculates and outputs the difference between the output of the memory and each of the 525 electrical signals that are the output of the converter, and a comparator 12 that calculates and outputs the difference between the output of the comparator and a predetermined reference value. Command device 1 that outputs a command signal to calculate and activate the alarm
4. An eraser 15 that outputs a signal for erasing the memory in the memory device 7 according to the signal from the timer 8, and a switch 6 that passes an electric signal according to the signal from the timer 8, and the timer 8 is set at the start point of a predetermined period of time. The circuit is arranged to output a signal for operating the switch 6 at the end of the process and the eraser 15 at the end of the process.

The image 3 of the object 1 taken by the camera 2 is transferred to the converter 4
is converted into 525 electrical signals 5 and output. The electrical signal 5 passes through a switch 6 activated by a signal 9 of a timer 8 and is input into a memory 7. In this embodiment, the switch 6 is arranged so as to pass only the 525 electrical signals from the converter 4 of the first image of a certain period according to the signal 9 of the timer 8. The memory device 7 stores one of the 525 input electrical signals 5 and outputs it as the electrical signal 51. An image 10 photographed by the camera 2 following the image 3 is converted into 525 electrical signals 11 by the converter 4 and input to the comparator 12, and an electric signal 51 is also input to the comparator 12. The comparator 12 calculates the difference between the electrical signal 51 and each of the 525 electrical signals 11,
This is output as output 13. The command unit 14 is the output 13
is input and calculates the difference from a predetermined reference value, and if the absolute value of output 13 is greater than the reference value, command signal 17 is input.
Output. That is, the difference between one of the 525 representative color values of the image 3 divided into 525 parts and each of the 525 representative color values of the image 10 is calculated, and the absolute value of the result, in this embodiment, the electric signal 51 The absolute value of the algebraic sum of the differences between 525 electric signals 11 and 525 electric signals 11 is used to determine a color change.

In this embodiment, regardless of the calculation result of the command unit 14, the next video is taken after video 10 by the camera, and the same operation as described above is repeated in order to compare the video with video 3.

At the end of the above-mentioned fixed period, the signal 24 of the timer 8 is activated.
This activates the eraser 15 and outputs the signal 16, thereby erasing the memory in the memory 7. When the next fixed period begins, the switch 6 is actuated by the signal from the timer 8 to pass the electrical signal from the converter 4 for the first image of the period, and thereafter the same operation as in the previous fixed period is repeated. In this embodiment, by switching the switch, the converter 4 can divide the photographed video into 525 parts and convert the 525 representative brightness values of the video of the division into 525 electrical signals. can calculate the arithmetic mean value and algebraic sum of 525 input electrical signals, store and output them, and comparator 1
2 can calculate the arithmetic mean value and algebraic sum of 525 electrical signals that are the outputs of the converter 4, and calculate the difference with the output of the memory device, and the command unit 14 can calculate the calculation contents of the comparator 12. For each of the following combinations, calculate the difference between the output of the comparator 12 and a predetermined reference value, and if the absolute value of the output is greater than the reference value, output a command signal and activate the alarm. arranged to operate. That is, the combination is 4
-1) The converter 4 converts the representative value of the color of the image into an electrical signal, 4-2) The converter 4 converts the representative value of the brightness of the image into an electrical signal, 7-1) The memory 7 inputs 7-2, storing and outputting any one of the 525 electrical signals
7-3) The memory unit 7 calculates the arithmetic mean value of the 525 input electric signals, stores it, and outputs it. 7-3) The memory unit 7 calculates the algebraic sum of the 525 input electric signals and outputs it. 12-1) The comparator 12 calculates and outputs the difference between the output of the memory 7 and each of the 525 electrical signals, that is, the instantaneous value, which is the output of the converter 4. -2) 5 where the comparator 12 is the output of the memory 7 and the output of the converter 4;
12-3) 525 comparators 12 which are the output of the memory 7 and the output of the converter 4; The following combinations of the eight cases of calculating the algebraic sum of electrical signals and calculating and outputting the difference from the algebraic sum, namely, 4-1), 7-1) and 12-1), 4-1), 7-1) and 12-2
), 4-1) and 7-2) and 12-1), 4-1) and 7-
2) and 12-2), 4-1) and 7-3) and 12-3),
4-2) and 7-1) and 12-1), 4-2) and 7-1)
and 12-2), 4-2) and 7-2) and 12-1), 4-
2) and 7-2) and 12-2), 4-2) and 7-3) and 1
2-3).

Each device in FIG. 3 is electrically coupled as shown by the solid line in the figure, and electrical signals are transmitted in the direction of the arrow.

(G) Effects of the Invention According to the present invention, the difference between an image taken by a television camera or the like within an arbitrary fixed period and an image taken subsequently can be detected without using the human eye or a videotape. It can be detected, and the screen can be displayed or recorded at the time of detection.

Furthermore, it is possible to determine whether the difference between the two images is equal to or greater than a certain value without using human eyes. In addition, since the above detection and judgment can be performed at regular intervals, it is possible to move the camera to many objects to be photographed and detect changes in the image within a certain period of time, or to detect changes in the brightness of the image of a certain object to be photographed. Even if the color changes gradually over time, if a certain period of time is sent appropriately, it is possible to detect a minute change in the image and not activate an alarm. Furthermore, by installing a converter at the transmitting end and a photoelectric converter at the receiving end, connecting them with an optical fiber cable, and using optical signals, it is possible to send a large amount of video information to the receiving end. If only a change in the brightness or color of an image needs to be detected, only that change can be detected. In addition, when it is desired to detect only a change in brightness or color of a single brightness or color image, the electric signal of the first image by the converter is converted into an analog signal, this instantaneous value is stored in a memory device, and a comparator is used to detect the change in brightness or color of the image. If the device is arranged to calculate the difference between the instantaneous value and the instantaneous value of the analog electrical signal obtained by the converter of the image taken subsequent to the image, the change can be detected without using the signal for synchronizing the scanning. can. In addition, the average value of the digital electrical signal of the first image taken by the converter within a certain period of time is stored in a memory, and a comparator is used to compare the average value with the digital electric signal of the image taken subsequent to the image. If it is arranged to calculate the difference with the average value within time, it is possible to detect a change in the average value of the brightness and/or color of both the images.

The converter stores the algebraic sum of the digital signal of the first image within a certain period of time, and the comparator stores the algebraic sum of the digital signal of the image taken subsequent to the image and the algebraic sum of the digital signal within a certain period of time. If the image is arranged to calculate the difference between the two images, if the brightness and/or color of each of the plurality of sections of the image is different, and the arrangement is different between the two images, for example, the former image is If the upper half of the image is white and the lower half of the image is black, and vice versa, this can not be detected as a change in the image. In other words, when monitoring smoke emitted from a chimney, even if the smoke image changes due to wind direction, etc., if the proportion of the smoke image in the image does not change or if the rate of change is below a certain value, an alarm is issued. Instead, the device can detect this by changing the color. Furthermore, even if a solid image moves within the screen, it may not be detected, but the device may detect this by changing the brightness.

According to the present invention, there are many effects as explained above, and these effects can be used alone or in combination to improve shape, brightness,
A novel image change detection device capable of monitoring and inspecting changes in color and the like can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of an image change detection device according to the present invention. FIG. 2 is a partial block diagram showing the configuration of another embodiment of the image change detection device according to the present invention. FIG. 3 is a block diagram showing the structure of another embodiment of the image change detection device according to the present invention. The symbols of the main parts in the figure are as follows. 1. Object 7. Memory device 13. Output 2. Photographer 8. Timer 14. Command unit 3. Video 9
．． Signal 15. Eraser 4. Converter 10. picture
16. Signal 5. Electrical signal 11. Electrical signal 17.
Command signal 6. Switch 12. Comparator 18. Command signal 19. Command signal 20. Alarm 21. Screen display 22. Recorder 23. Video 24. Signal 25. Converter 26. Photoelectric converter 27. Optical signal 28. Optical signal 51. Electrical signal A. part

Claims (1)

[Scope of Claims] 1) A camera that photographs an object, a converter that converts the photographed image of the object into an electrical or optical signal and outputs it, and a memory that stores and outputs the output of the converter. a comparator that calculates and outputs the difference between the output of the storage device and the output of the converter;
It has a command device that converts the output of the comparator into a command signal for operating other equipment and outputs the command signal, and an eraser that erases the memory of the memory device, and the camera can take pictures at any time within a certain period of time. storing the output of the converter of the converted video in the storage device;
The comparator calculates a difference between the output to the storage device and the output of the converter of a video shot subsequent to the video, and the output of the comparator is converted into the command signal by the command device;
At the end of the certain period, the memory in the memory is erased by the eraser, and the change in the image is detected by moving to the next certain period and repeating the same operation as in the previous period. Image change detection device. 2) The image change detection device according to claim 1, wherein the camera continuously photographs the object. 3) Claim 1, wherein the converter divides the image of the object into a plurality of parts and converts them into electrical or optical signals.
The image change detection device according to item 1 or 2. 4) The image change detection device according to claim 1, 2 or 3, wherein the electric or optical signal comprises a signal representing the brightness and color of the image and a signal for synchronizing scanning. 5) The image change detection device according to claim 1, 2 or 3, wherein the electric or optical signal comprises a signal representing the brightness or color of the image and a signal for synchronizing scanning. 6) Claim 1, wherein the electric or optical signal is a signal representing only the brightness or color of the image.
The image change detection device according to item 2 or 3. 7) The image change detection device according to claim 1, 2, 3, 4, 5 or 6, wherein the electric or optical signal is a digital signal. 8) The comparator calculates the difference between the output of the storage device and the output of the converter, an instantaneous value, an average value within a certain period of time, or an algebraic sum within a certain period of time. 1
The image change detection device according to any one of items 7 to 7. 9) According to any one of claims 1 to 8, the command unit calculates a difference between the output of the comparator and another value and converts it into the command signal. Image change detection device.