JPH0198380A - Monitoring method by television camera - Google Patents

Abstract

PURPOSE:To prevent a malfunction such as mis-alarming of the device due to sudden change in the external lightness by installing a bill board in a monitoring visual field of a television camera and setting it to a monitoring object point of the television camera. CONSTITUTION:A bill board 1 whose surface is formed by, e.g., black and white parts is installed in the monitoring visual fields 2a, 2b of the television camera 2. The image pickup visual fields 2a, 2b including the bill board 1 are picked up by the television camera 1, its video output signal is sent to a CRT device and stored in a storage device. When a difference between the lightness of the picture element stored before and the value inputted newly is a prescribed value or above, it is recognized as the presence of the object moving and an alarm signal is outputted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a monitoring method using a television camera (hereinafter abbreviated as a television camera), and in particular, to a method for detecting moving people, cars, etc. and transmitting an output signal. The present invention relates to a method for detecting a moving object.

[Conventional technology]

In the conventional surveillance system using television cameras, the television camera is fixedly installed and the output signal of the television camera is transferred to a CRT (CRT).
At the same time, the CRT screen is divided into a large number of pixels, an address is assigned to each division, the video signal is sampled based on this address, and it is digitized according to the brightness. Quantized) image data is input into the memory at the corresponding address, the newly input image data is compared with the previously input image data,
An output signal was sent when there was a difference. According to this method, when the brightness changes due to sudden changes in weather or seasonal color changes, moving objects are falsely detected as if they were within the field of view, causing false alarms.

[Problem that the invention seeks to solve]

This invention can be used to detect moving objects by fixedly installing a television camera outdoors, even if the brightness of the detection range changes due to changes in the weather or differences in measurement time and season such as day and night. This enables the detection of moving objects.

The above and other objects and novel features of the present invention include:
It will become clear from the description of this specification and the accompanying drawings.

[Means and operations for solving the problems] A brief overview of representative inventions disclosed in this application and their effects will be as follows.

The present invention relates to a monitoring method using a television camera in which an image captured by a television camera is displayed on a display device such as a CRT device to monitor the state within the field of view of the television camera. A signboard consisting of a black part and a white part is fixedly installed, an imaging field including the signboard is imaged by a fixed television camera, and a video output signal of the television camera is sent to a CRT device to form an image.

On the other hand, the entire screen of a CRT is divided horizontally and vertically into a large number of sections, and each section is treated as one pixel and divided into a large number of pixels. Among these pixels, the pixel in which the signboard is reflected is determined as a monitoring pixel, an address is designated, and the brightness of this pixel is stored in a memory device.

Then, when the difference between the previously stored memory value and the newly input value is a certain value, it is determined that the object has moved and an alarm signal is issued.

In this way, since the signboard is installed at the monitoring target point, it is possible to monitor the area within the monitoring field under a constant environment without being affected by seasonal changes in color or sudden changes in the weather.

〔Example〕

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

As shown in FIG. 1, in the surveillance device using a television camera according to this embodiment, the signboard 1 is placed within the surveillance field of view 2a, 2b of the television camera 2.
It is fixedly installed at a position separated from the television camera 2 by a predetermined distance. As shown in FIG. 1, a light source 4 may be built into the signboard 1.

A stand 6 is provided at the lower end of the signboard 1, and by fixing the stand 6 to the ground 3, the signboard 1 can be erected on the ground 3.

In this embodiment, the sign l is constructed as a hollow cube.

As illustrated in FIG. 2, the front side 5 of the signboard 1 has a lower right half 7 and an upper half 8 in white, while a lower right half 9 and a upper right half 10 in black. has been done. A signboard having such a color configuration can be constructed by partially applying black paint to a white ground surface.

The black color may be replaced with other colors, and other appropriate changes may be made. For example, these black or colored portions may be used as characters such as "danger" or "no trespassing."

The light source 4 to be built into the signboard 1 may be any light source such as an incandescent lamp, a fluorescent lamp, a mercury lamp, a halogen lamp, or a laser generator.

The light source 4 can be turned on at night to display the signboard 1 within the field of view 2a, 2b of the television camera 2, and also by blocking the light emitted from the light source 4 of the signboard 1 by a moving object. It can be placed under a monitoring system that detects changes and issues alarms. One or more light sources 4 are installed.

The surface of the signboard l (the front part facing the television camera 2) 5 is as follows:
For the above purpose, it is preferable to have a translucent structure.

FIG. 3 shows another embodiment of the invention.

In this embodiment, the surface of the signboard 1 is illuminated from the outside with a lighting device, and changes in reflected light on the surface of the signboard 1 are monitored using a television camera.
An illumination lamp lla with a mirror surface is attached to the top of the signboard 1, a similar lamp llb is installed on the side of the television camera 2, and a similar lamp 11c is installed behind the television camera 2. is installed so as to irradiate light onto the surface 5 of the signboard 1.

By lighting up the lamps 1la-11c at night, the signboard 1 can be displayed within the field of view 2a, 2b of the television camera 2, and it is also possible to display the signboard 1 within the field of view 2a, 2b of the television camera 2. Changes can be detected and monitored by television cameras.

In this way, the signboard 1 is fixedly installed at a position separated by the monitoring viewing distance of the television camera 2, and at night, the light source 4 and/or the lighting devices 11a-11c are turned on to perform surveillance by the television camera 2. Next, the principle of its operation will be explained using an example of an alarm device.

FIG. 4 shows a surveillance field of view 2a captured by a television camera 2.
, 2b are shown projected on the screen 12 of a display device such as a monitor television or a television receiver.

The screen 12 of the television receiver is divided horizontally and vertically into a large number of sections, and each section has one pixel.
It is identified by numbering as 3.

By specifying the address of a pixel on its CR7 screen 12, the television receiver memorizes the brightness of that pixel,
It has a memorization function.

By fixing the pixels 13 displayed on the CR7 screen 12, a moving object can be clearly captured due to a change in contrast.

In other words, a person wearing white clothing should wear the white part 7 of signboard l.
At 8, there is little change in color tone and recognition is difficult, but when this person reaches black (or colored part) 9.10, the color tone changes significantly and recognition becomes easier.

When recognizing a person wearing black (or colored) clothing,
This becomes easier in the white parts 7 and 8 of the signboard 1.

FIG. 5 shows that the video signal input from the television camera 2 is processed and
1 is an example of a circuit configuration diagram of a device that issues an alarm when an object to be monitored, such as an intruder, crosses the surface of a signboard 1. FIG.

In FIG. 5, the video output signal 14 sent out by the television camera 2 includes an image signal 15 and a synchronization signal IB,
Video/sync signal separation circuit! At 7, signal 15.18
are separated and sent to the A/D conversion circuit 18 and the synchronization signal control circuit 23, respectively.

The synchronization signal control circuit 23 sends a large number of divided synchronization signals 35 synchronized with the synchronization signal 18 to the level memory circuit 18 . Counter circuit 25. Sensor memory circuit 31. As shown in FIG.
2 is divided into a large number of vertical and horizontal sections 13 divided into sections.

The image signal 15 is digitized via the A/D conversion circuit 18, and stored as a brightness signal in the level memory circuit 18 in synchronization with the divided synchronization signal 35. The obtained contents are sent to the subtraction circuit 20. The subtraction circuit 20 subtracts the image signal value newly sent out via the bypass circuit 34 from the content stored in the memory circuit 18 immediately before, and the subtraction circuit 20 subtracts the image signal value newly sent out via the bypass circuit 34.
The error signal is sent to

The comparison circuit 21 has a sensitivity adjustment circuit 22 that sends out a reference brightness signal of an address corresponding to each address of the vertical and horizontal divisions 13 into which the noodles are divided, and the input signal is transmitted from the sensitivity adjustment circuit 22 at the division address. When the absolute value is larger than the reference value sent by , the output signal is sent to the OR circuit 24 .

The cursor or light pen 29 is connected to the cursor control circuit 3
0 to screen 12. ): sends a control signal to move the cursor point K (FIG. 4), sends a match signal to the sensor memory circuit 31 to move the cursor point corresponding to the selected section 13, and sends a control signal to move the cursor point K (FIG. 4) When the position matches the image of signboard l, the address of that section 13 is memorized.

The sensor memory circuit 31 time-divides and counts the sweep of the television camera in synchronization with the divided synchronization signal 35 sent out by the synchronization signal control circuit 23, and sends an output signal to the OR circuit 24 when it matches the memory contents. do.

The OR circuit 24 compares the output of the comparison circuit 21 and the output of the sensor memory circuit 31, and drives the counter circuit 25 when there are inputs at the same time. The counter circuit 25 counts the number of output pulses from the OR circuit 24, and sends an output signal to the comparison circuit 28 when the number exceeds the reference value. Comparison circuit 26
has a sensitivity adjustment circuit 28 and sends a reference signal for each screen section 13 to the comparison circuit 2B. When the absolute value of the input signal of the comparison circuit 2B is larger than the reference signal, the comparison circuit 2B sends an alarm signal to the alarm circuit 27 to issue an alarm.

The output of the comparison circuit 2B is also sent to the moving object memory circuit 32 and stored as a moving object in the memory corresponding to the address of one section 13, and the output corresponding to that address is sent to the video signal output circuit 33.

〔Effect of the invention〕

According to this invention, the signboard l is installed within the monitoring field of the television camera 2, and this is set as the monitoring target point of the television camera 2, so that sudden changes in the brightness of the outside world, such as changes in weather or color changes depending on the season, This makes it possible to detect moving objects without causing false alarms or other malfunctions of the device.

By incorporating a light source inside the sign, the sign will be visible even at night when the image is captured by a television camera, and the image of the light source will not be affected by the brightness of the outside world. , which is always constant and does not cause malfunctions such as false alarms of the device due to sudden changes in the brightness of the outside world, making it possible to detect moving objects.

In addition, by illuminating the surface of the signboard with a lighting device, the signboard can be similarly displayed at night, and it is also possible to detect moving objects without causing malfunctions due to sudden changes in brightness in the outside world. do.

[Brief explanation of the drawing]

The drawings illustrate embodiments of the invention. Figure 1: Schematic diagram of the monitoring device Figure 2: Schematic diagram of the surface of the signboard Figure 3: Other schematic diagram of the monitoring device Figure 4: Screen of the television receiver Figure 5: Circuit configuration diagram of the alarm generating device 1 : Sign board 2: TV camera 2a, 2b : View * size 3: Ground 4: Light source 5: Sign surface (front part) 6: Stand 7: White part 8: 〃 9: Black part 10: tt 11a, llb, llc: Illumination lamp 12: TV receiver screen 13: Pixel (section) 14: Video output signal 15: Image signal 16: Synchronization signal 17: Video synchronization signal separation circuit 18: A/D conversion circuit 19: Item zero # level memory Circuit 20: Subtraction circuit 21: Comparison circuit 22: Sensitivity adjustment circuit 23: Synchronous signal control circuit 24: OR circuit 25: Counter circuit 26: Comparison circuit 27: Alarm circuit 28: Sensitivity adjustment circuit (weighting circuit) 29: Cursor 30: Cursor control circuit 31: Sensor memory circuit 32: Moving object memory circuit 33: Video signal output circuit 34: Side path circuit 35: Split synchronization signal: Cursor point Patent applicant Tokyo Electric Power Company Co., Ltd. Fukuko Electric Co., Ltd. Agent Patent Attorney Yoshihiro Sato

Claims (1)

[Scope of Claims] 1. In a monitoring method using a television camera in which an image captured by a television camera is displayed on a display device to monitor the state within the field of view of the television camera, a signboard is set within the field of view of the television camera. The image is captured by a TV camera with a fixed field of view including the signboard, and the entire screen is divided into a large number of pixels and displayed on a display device. A monitoring method using a television camera, characterized in that the brightness of the pixel at the specified position changes compared to the already stored brightness of the pixel at the designated position, and a signal is sent out when the brightness of the pixel at the specified position changes. 2. The monitoring method according to claim 1, wherein the surface of a signboard fixedly installed within the field of view of a television camera is irradiated with light by an illumination device, and changes in reflected light from the surface of the signboard are monitored. 3. The monitoring method using a television camera according to claim 1, wherein the signboard has a front side facing the television camera that is semitransparent and has one or more built-in light sources.