JPH0644469A - Object detection system - Google Patents

Abstract

PURPOSE:To detect an object at a high speed. CONSTITUTION:An image pickup means 1 are mounted to prescribed positions in an area to be watched, thin out the scanning lines of picture signals obtained by picking up images in a prescribed form, find the difference between the picture signal obtained at this time and the picture signals obtained at preceding time, detect the presence of valid difference in difference signals, decides the presence of an intruder when the number of the scanning lines provided with the valid difference signals is within the range of the prescribed number of the scanning lines and sets an alarming flag at '1'. A control means 2 successively makes access to the image pickup means 11-1n and collects the picture signals from the pertinent image pickup means 1 when the alarming flag of the accessed image pickup means 1 is '1'.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detecting system for detecting the presence or absence of an object by processing an image signal picked up by an image pickup device such as a television camera.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As an object detection system, for example, an intruder detection system, an intruder detection system using a heat ray sensor, a beam sensor, or a surveillance camera is known. In particular, as an intruder detection system using a TV camera, for example, a method in which a surveillance camera and a heat ray sensor are combined and a surveillance camera is activated to detect an intruder when the heat ray sensor is detected, or a surveillance camera is used. There is a known method of detecting an intruder by performing appropriate image processing on the image signal captured in 1., but in the former case, it is necessary to install both a surveillance camera and a heat ray sensor, resulting in high cost. However, in the latter case, since complicated image processing such as pattern recognition of an intruder needs to be performed, there is a problem that the image processing is time consuming and not only expensive.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an object detection system which is inexpensive and has a high processing speed.

[0004]

In order to achieve the above object, the object detection system of the present invention is configured such that an image pickup section and a scanning line of an image signal picked up by the image pickup section are thinned out in a predetermined manner and at a predetermined time An image processing unit including an image processing unit that takes a difference from the image signal of the previous frame and generates a signal indicating the presence of an object when there is an effective difference signal in a predetermined number of scanning lines in the difference signal. And a control means for accessing a plurality of image pickup means in a predetermined order and collecting image data from the image pickup means when the accessed image pickup means generates a signal indicating that there is an object. To do.

[0005]

The image pickup means has an image pickup section and an image processing section. The image pickup section obtains an image signal in a predetermined warning range, and the image signal obtained by this image pickup section is supplied to the image processing means. The image processing unit thins out the scanning lines of the input image signal in a predetermined manner and obtains the difference from the image signal of the frame before the predetermined time. Then, it is determined how many scanning lines the effective difference signal in this difference signal is included, and only when there is an effective difference signal in the scanning lines within a predetermined number of ranges determined in advance. It is determined that there is an object, and a signal indicating that there is an object is generated.

A plurality of image pickup means are arranged, and these image pickup means are connected to the control means by one data transmission line. Then, the control means sequentially accesses the image pickup means in a predetermined order, and when detecting that the accessed image pickup means generates a signal with an object, collects image signals from the image pickup means.

[0007]

Embodiments will be described below with reference to the drawings.
FIG. 1 is a diagram showing a configuration of an embodiment when the object detection system according to the present invention is applied to an intruder detection system,
In the figure, 1 is an image pickup means, 2 is a control means, 3 is a data transmission line, and 4 is a public line.

The control means 2 is composed of a microcomputer and its peripheral circuits, and is composed of a plurality of image pickup means by one data transmission line 3, ie, n image pickup means 1 in the figure.
_It is connected to ₁ to 1 _n . The control means 2 is connected to the monitoring center by a public line 4 such as a public telephone line. The operation of the control means 2 will be described later.

As shown in FIG. 2, each of the image pickup means 1 ₁ to 1 _n is provided with an image pickup section 5 and an image processing section 6 each including an optical system and a CCD image pickup element. The image processing unit 6 includes a first memory 7, a signal compression unit 8, a second memory 9, and an intruder detection unit 10.
And an output control unit 11.

First, the operation of the image pickup means 1 will be described.
The image pickup unit 5 is attached to a predetermined portion of a warning area, for example, a corner of the ceiling, and always takes an image of the predetermined area. The image signal output from the image pickup unit 5 is stored in the first memory 7. The capacity of the first memory 7 is arbitrary, but as described later, when an intruder is present, the image signal stored in the first memory 7 is transmitted to the control means 2. Therefore, it is desirable to be able to store as many frames as possible.

The image signals stored in the first memory 7 are sequentially read out and input to the signal compression section 8. The signal compression unit 8 is provided to reduce the image processing time and to detect an intruder with a simple configuration, and the scanning line of the image signal read from the first memory 7 has a predetermined configuration. Although the thinning processing is performed in this case, here, the thinning of the scanning lines is performed by a predetermined number of scanning lines for the human in the scanning lines extracted by the thinning, for example, at least two or more scanning lines output human information. In addition, for small animals such as cats, scan lines smaller than those for humans, for example, only one scan line is included so as to include the information. Specifically, it is as follows. For example, as shown in FIG. 3, when the image pickup means 1 is installed at one corner of the ceiling of the room 12 which is the monitoring area, if a human 13 and a small animal 14 are invaded, an image taken by the image pickup means 1 is displayed. When the image is directly output to the monitor screen, an image as shown in FIG. 4 is obtained. At this time, the human 13 can be assumed to be 1 m or more, and the height of the small animal 14 is smaller than that of the human 13. By thinning out the scan lines at appropriate intervals as indicated by the broken line in FIG.
There can be only one scan line that includes the image portion for.

How to decimate the scan lines, or how many scan lines of the extracted scan lines for humans and small animals are allowed to include these image portions,
The size of the object to be detected, the size of the object to be ignored, the condition of the monitoring area, the viewing angle of the imaging unit 5, the distance from the imaging unit 1 to the subject, and the like can be appropriately set. Of course, it is not limited to the examples. For example, as shown in FIG. 3, when the field of view of the imaging unit 5 extends not only to the floor surface but also to the wall surface, the small animal 14 does not appear in the upper part of the field of view. Also, the lower scanning lines may be thinned out more. The image signal compressed as described above is stored in the second memory 9.

The intruder detection unit 10 performs a predetermined process on the compressed image signal stored in the second memory 9 to detect the presence or absence of an intruder. First, the second memory 9 this time.
The difference between the image signal stored in the second memory 9 and the image signal previously stored in the second memory 9 is obtained. The process of obtaining the difference between the image signals can naturally be performed for each frame, but can be arbitrarily set according to the time when a person crosses the field of view of the imaging unit 5. For example, if it takes about 1 second for a human to cross the field of view of the image pickup unit 5, a frame may be extracted every 0.5 sec and the difference from the frame 0.5 sec before may be taken. In that case, it is natural that the signal compressing unit 8 performs a process of extracting a frame every 0.5 seconds in addition to the above-described thinning-out of scanning lines.

Next, the intruder detecting section 10 detects whether or not there is a valid difference in the difference signal. That is, the image signal also includes a noise component, and therefore, even when there is no intruder, the noise component generally causes some level other than zero to appear in the difference signal. A process of ignoring a signal having a level equal to or lower than a predetermined threshold value is performed.
This is the process of obtaining an effective differential signal. Then, if there is no valid difference signal, it is determined that there is no intruder,
When there is an effective difference signal, for example, when an intruder or a small animal enters the visual field of the image pickup unit 5 for the first time, it is detected how many scanning lines have the effective difference signal, and the effective difference signal is detected. When the effective difference signal is equal to or smaller than a predetermined number of scanning lines, for example, only one scanning line, the effective difference signal is determined to be due to a small animal and the effective difference signal is ignored, but it is effective. When the difference signal is within a predetermined number of scanning lines, for example, when there are effective difference signals in 2 to 4 scanning lines, it is determined that there is an intruder, and the output control unit 11 is notified. As a result, the output control unit 11 sets the alarm flag to a predetermined value, for example, "1".

However, the effective difference signal is generated not only when a human or a small animal invades, but also when the sunshine changes or when the illumination is turned on. However, when the sunshine changes or the illumination is turned on, the image signal level changes in a wide range, so that an effective difference signal is generated in all or almost all scanning lines, and the intruder there. When the effective difference signal is generated in a predetermined number or more of scanning lines, the detection unit 10 does not regard an intruder and ignores it.

By performing the above processing, the intruder detection unit 10 sets the alarm flag to a predetermined value when the intruder first enters the visual field of the image pickup unit 5. The intruder detection unit 10 can be composed of, for example, a microprocessor.

Next, the operation of the control means 2 will be described.
Control means 2 accesses the image pickup means 1 ₁ to 1 _n for each predetermined period, instructs the transmission of alarm flag. The output control unit 11 of the image pickup means 1 _m (m = 1,2, ..., n) that has been accessed notifies the control means 2 of the value of the alarm flag via the data transmission line 3. When the control means 2 receives the alarm flag, the control means 2 identifies the value, and if the value of the alarm flag is “0”, there is no intruder, so the next image capturing means 1 _{m + 1} is accessed.
If the value of the warning flag is "1", then the transmission of the image signal is instructed. Upon receiving this instruction, the control means 1 _m
The output control unit 11 adds the image signal read from the first memory 7 after the response signal to the instruction signal and sends the image signal to the data transmission line 3.

When the control means 2 takes in the image signal, the control means 2 notifies the surveillance center via the public line 4 of the taken image signal together with an alarm signal indicating the presence of an intruder. As a result, in the surveillance center, the image pickup means 1
_The alarm lamp corresponding to _{m + 1} is turned on or the alarm bell sounds, and the image signal transmitted from the image pickup means 1 _{m + 1} is displayed on the monitor.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications can be made. For example, in the above embodiment, the presence or absence of an intruder is identified only by the number of scanning lines that generate the effective difference signal, but in addition, the number of pixels of the effective difference signal in the extracted scanning lines is also detected, It is also possible to detect an intruder based on the height and width of the object.

In the above embodiment, the intruder detection is performed, but the invention can be applied to detection of various objects such as detection of a product on a belt conveyor or detection of a vehicle.

Further, in the above embodiment, the control means 2 transmits the alarm signal to the monitoring center through the public line, but the control means 2 itself may be provided with an alarm lamp or alarm bell. In addition, it is preferable that the control means 2 is provided with a device for filing the image signal transmitted from the image pickup means 1.

[0022]

As is apparent from the above description, according to the present invention, how many scanning lines among the scanning lines extracted from the image signal obtained by the image pickup means have the effective difference signal. Since the object detection can be performed only by performing a simple process of detecting, it is possible to perform the object detection processing at high speed, and does not require a heat ray sensor or the like outside the camera unlike the conventional case. Therefore, it can be constructed at low cost. Further, in the present invention, it is possible to arbitrarily set which position on the screen the scanning line is to be extracted at what interval.
This makes it possible to detect a desired object.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment in which an object detection system according to the present invention is applied to an intruder detection system.

FIG. 2 is a diagram showing a configuration of an imaging unit.

FIG. 3 is a diagram for explaining an object detection method according to the present invention.

FIG. 4 is a diagram for explaining an object detection method according to the present invention.

[Explanation of symbols]

1 ... Imaging means, 2 ... Control means, 3 ... Data transmission line, 4 ...
Public line, 5 ... Image pickup unit, 6 ... Image processing unit, 7 ... First memory, 8 ... Signal compression unit, 9 ... Second memory, 10 ... Intruder detection unit, 11 ... Output control unit.

Claims (1)

[Claims] 1. An image pickup unit and a scanning line of an image signal picked up by the image pickup unit are thinned out in a predetermined manner, and a difference between the image signal of a frame before a predetermined time is taken, and the difference signal is within a predetermined number range. Image pickup means including an image processing unit that generates a signal indicating that an object is present when there is an effective difference signal on the scanning line, and a plurality of image pickup means are accessed in a predetermined order. An object detection system comprising: a control unit that collects image data from the image pickup unit when a certain signal is generated.