JPH022486A - Movement adaptive controller - Google Patents

Abstract

PURPOSE:To efficiently record a picture by outputting a start signal when movement information obtained from a difference between a signal delayed from an input video signal by one field and a non-delayed signal exceeds a prescribed frequency within a prescribed period to record a picture for a fixed period. CONSTITUTION:An image signal picked up by a camera 11 is inputted to a VTR 12 and A/D converted by an A/D converter 13. The converted digital signal is inputted to a movement detecting part 14. The detecting part 14 compares a signal delayed by one field with a non-delayed signal to find out movement information. When movement frequency or movement size within a prescribed period exceeds a prescribed value, a movement information analyzing part 15 outputs a start signal and sets up the VTR 12 to a picture recording mode for a prescribed period. When the succeeding start signal is inputted during the picture recording, picture recording is continued for a prescribed time from the input. Thus, picture recording can be efficiently executed and the device is preferable to a burglar-proof camera.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a motion adaptation system that can be used as a device for controlling a video tape recorder (hereinafter referred to as VTR) that records images from a surveillance camera, for example. Regarding a control device.

(Prior art) In recent years, in the field of security assurance, surveillance V
TR is popular. Recording techniques for surveillance VTRs can be roughly divided into two types.

The first method is to intermittently transmit video signals from surveillance cameras to VT.
This is a method for recording in R. In this system, in order to achieve long-time tape recording, the VTR is intermittently switched to recording mode to reduce wasteful use of tape.

The second method uses an infrared sensor or the like and starts recording on the VTR when there is a reaction to the sensor.

(Problem to be solved by the invention) According to the first method, V
Since TR performs recording by intermittent feeding, there are many unnecessary recording portions of the tape. Furthermore, since the tape is fed intermittently at predetermined intervals, important movements of the subject may be missed.

The second method is expensive because it requires the use of a sensor separate from the camera. Furthermore, if the orientation of the sensor and the orientation of the camera do not match, meaningless monitoring will continue.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motion adaptive control device that does not waste a recording medium and enables efficient recording of moving images using relatively simple means.

[Structure of the Invention] (Means for Solving the Problems) The present invention detects the movement of an image by obtaining the difference between a delayed signal obtained by delaying a human video signal by one field or one frame period and a non-delayed signal using a motion detection means. By detecting the information and analyzing the motion information by the motion information analysis means, a start signal is output when the frequency or magnitude of the motion information in a preset period exceeds a predetermined percentage, and the start signal is is supplied, the controlled device is operated for a predetermined period of time, and when a start signal is input again during this operation period, the operation period of the controlled device is continued for the specified period based on this start signal. It consists of:

(Operation) The above means determines whether or not there is motion information in the video signal itself, so the motion video is accurately detected and the controlled device (for example, a VTR) is recorded only when the motion information is appropriate. Since this is done, there is no waste of recording media.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, and is an example applied to, for example, a crime prevention monitoring system.

A captured video signal from the camera 11 is supplied to a VTR 12 and an analog-to-digital (A/D) converter 13.
is supplied to The A/D converter 13 digitizes the analog video signal and supplies it to the motion detection section 14 . A/D
The number of digital bits in the converter 13 is selected depending on the performance of the camera 11 and the intended use of the system.

The motion detection unit 14 obtains the difference between a delayed signal obtained by delaying the digital video signal by one field or one frame period and a non-delayed signal to detect motion information of an image. The motion information detected here is supplied to the motion information analysis section 15. The motion information analysis section 15 outputs a start signal when the frequency or magnitude of motion information in a preset period exceeds a predetermined percentage. This start signal is supplied to the VTR control section 16. When the start signal is supplied, this VTR control section 16 causes the controlled device, that is, the VTR 12, to perform recording operation for a predetermined period of time, and when the start signal is input again during this operation period, the VTR control section 16 uses this start signal as a reference to perform recording operation for a predetermined period of time.
12 operating periods can be made to continue for the certain period of time.

FIG. 2 shows an example of the configuration of the motion detection section 14. The luminance component of the input digital video signal is delayed by one field, for example, in a field delay circuit 141 and then supplied to a subtracter 142 . The subtracter 142 obtains the difference between the delayed signal and the non-delayed signal and outputs this as motion detection information. It is possible to determine whether or not the subject image is moving by calculating the difference between the same line portions of data between fields, as shown in the principle diagram in FIG. If the difference is large, it means that the image has moved, and if the difference is zero, it means that there is no movement.

FIG. 3 shows an example of the configuration of the motion information analysis section 15 and the control section 16. The motion information is provided to a comparator 151.

The comparator 151 is given a comparison level from the level setting section 152 in order to set a threshold level for the difference signal. Even if this is a difference signal between fields, the difference level will be small if the subject is a thin shadow. Furthermore, if the background imaged by the camera 11 is a white wall and the moving subject is a white car, the level of the difference will be small. Therefore, depending on the background imaged by the camera 11 and the target to be monitored, region(
In order to set the detection level (subject), a comparison level for freely setting the detection level is supplied from the level setting section 152.

If there is a difference in power that exceeds the comparison level, comparator 15
A detection signal is obtained from 1. This detection signal is sent to the adder 1
53 and a latch circuit 154. With this integrator, it is possible to obtain the amount of detected signal obtained during one field period, for example. In other words, the rate and frequency of movement during one field period can be detected as a digital quantity. This is so that if the subject is, for example, a single plover, it can be removed as a monitoring target. Further, the latch circuit 154 performs a latch operation in vertical synchronization, but the latch timing can be switched by a frequency divider 156 depending on the speed of movement of the subject. This is because the level of the differential signal may be insufficient in one field period for a slow-moving subject. therefore,
The latch cycle is set depending on the subject to be monitored.

The output of the latch circuit 154 is supplied to a determination circuit 155 that determines its level. This determination circuit 155 outputs a trigger pulse in synchronization with the latch timing if the output of the latch circuit 154 is equal to or higher than a predetermined level.

The trigger pulse is supplied to, for example, tll of the control unit 16 and a stable multi-bye break circuit 161. When the output of the monostable multivibrator circuit 161 is at a high level, the VTR 12 is set to recording mode.

FIG. 5 is a timing chart for explaining an example of the operation of the above device. FIG. 4A shows a trigger pulse obtained from the determination circuit 155. Recording of the VTR 12 is started by this pulse and continues for a preset time. If the trigger pulse occurs again while the VTR 12 has not finished the recording mode, the previously set time is extended based on this generation point, and recording is continued. The recording time can be set by adjusting the time constant of the monostable multivibrator 161 to M. In addition, in a system using a microcomputer, this is possible by setting a timer time.

In the above embodiments, the video signal source is a camera, but the source is not limited to this, and may be a broadcast signal. Furthermore, although the recording medium has been described as a tape in a VTR, other recording media such as a semiconductor memory or a disk may be used.

[Effects of the Invention] As explained above, according to the present invention, it is possible to detect the movement of an image with a simple configuration and generate a control signal so that only necessary scenes can be efficiently recorded on a recording medium. can. Furthermore, since the motion information is detected by processing the video signal itself, the detection target and the imaging target accurately match.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing a circuit example of a motion detection section, FIG. 3 is a diagram showing a circuit example of a motion information analysis section, and FIG. 4 is a diagram showing a circuit example of a motion information analysis section. FIG. 5 is a principle diagram shown to explain the principle of detection, and a timing chart shown to explain an example of the operation of the device of the present invention. 11...Camera, 12...VTR, 13...Analog-digital converter, 14...Motion detection unit, 15...
-Motion information analysis section, 16...III section. Figure 1 Figure 2 ■ Kaku 3 Ward 12: V TR

Claims (1)

[Scope of Claims] Motion detection means for detecting image motion information by obtaining a difference between a delayed signal obtained by delaying an input video signal by one field or one frame period and a non-delayed signal, and said motion in a preset period. When the frequency or size of information exceeds a predetermined percentage,
a motion information analysis means that outputs a start signal; when the start signal is supplied, the controlled device is operated for a predetermined period of time, and when the start signal is input again during this operation period, the control device is operated based on this start signal; A motion adaptive control device comprising: control means for causing the operation period of the controlled device to continue for the certain period of time.