JP3200865B2 - Monitoring VTR system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording start method of a monitoring VTR system used at a bank counter, an automatic teller machine corner, or the like.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional monitoring VTR system used in the above-mentioned places. In the figure, 1 is a monitoring camera, 2 is a timer, 3 is an intermittent recording V
TR.

Next, the operation will be described. A video signal photographed by the surveillance camera 1 is a constant time recording VTR.
3 has been entered. The intermittent recording VTR 3 uses exactly the same tape as a normal continuous recording VTR tape as a recording medium, and the tape is usually stopped, but the timer 2 is stopped at predetermined time intervals (for example, every one second). When the start signal is input from, the tape starts running,
When the vehicle has almost reached the steady running speed, a video signal for one frame is recorded on the tape. At this time, the running of the tape is controlled so that the recording track pitch on the tape is the same as during continuous running recording, so the number of recording tracks recorded on one tape, that is, the number of video frames, is Will be exactly the same. Since a video signal of 30 frames per second is input from the surveillance camera 1, if a 120-minute tape is used as a continuous recording tape,
Performing intermittent recording every second as in this example will result in 3/120
An image of 0 times, that is, every second for 60 hours is recorded on the tape. For example, if this is operated during the business hours of 10 hours a day, a monitoring record of about one week can be left.

[0004]

Since the conventional monitoring VTR system is configured as described above, even if there is no monitoring target such as a customer at a bank counter, the monitoring VTR system is provided at regular time intervals (this example). In this case, since recording is performed on the tape every second), there is a problem that the tape is wasted.

[0005] Further, at the time of reproduction for examining the recorded contents later, reproduction or fast-forward reproduction must be performed, including useless recorded images having no monitoring target, and it takes a long time to check the recorded contents. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. Intermittent recording is performed only when a monitoring target such as a customer exists, and the monitoring recording time per tape is drastically extended. Monitoring VT that does not require any useless scenes when checking recorded contents
The aim is to obtain an R system.

[0007]

A monitoring V according to the present invention.
The TR system includes monitoring target detection means, and gate means for allowing an intermittent recording start signal from the timer only when the monitoring target detection means detects the monitoring target, and outputs an output signal from the gate means to the intermittent recording VTR. Intermittent recording start signal. Also, as a monitoring target detecting means,
The presence or absence of a monitoring target is detected by inputting a video signal from a monitoring camera and detecting a change in a frequency distribution included in the signal.

[0008] Further, as a monitoring target detecting means, a filter for setting a pass band to a characteristic band of a frequency distribution of a signal photographed by a camera when no monitoring target exists,
/ 60 seconds or 1/30 seconds or less, and an output obtained by passing the video signal from the camera through the filter is integrated by the integration circuit, and the video signal from the camera is integrated for each field or for each frame. obtains the power of the filter output as a voltage value, is supplied to the first input of the differential absolute value circuit, whereas the video signal from the camera with a distinctive frequency components when the monitored does not exist, through the filter <br /> is, the includes a reference potential generating circuit for generating a voltage value that would occur when integrated by the integrating circuit, a voltage value supplied from the reference potential generating circuit, a second of the differential absolute value circuit is supplied to the input, and outputs the absolute value of the difference between these first and second inputs, the output of this is, if Kere greater than a certain threshold, a change in the pass band component of the filter Judge it was Comprises a threshold generator circuit and a comparison circuit for generating a monitored detection signal. The monitoring target detecting means includes a plurality of sets of constituent elements, and outputs a logical product output of the monitoring target detection signals from the plurality of sequences as a final monitoring target detection signal.

[0009]

The monitoring VTR system configured as described above has a VT system only when there is a start signal from the aforementioned gate.
Since R performs intermittent recording, intermittent recording is performed only when there is a monitoring target such as a customer, and the monitoring recording time per tape can be greatly extended. Therefore, at the time of checking the recorded contents, there is no need to see any useless records having no monitoring target.

[0010]

【Example】

Embodiment 1 FIG. FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. Reference numeral 4 denotes a monitoring target detector for detecting the presence of a monitoring target such as a customer with respect to a video signal input from a camera. Reference numeral 5 denotes a logical product of an output signal of the monitoring target detector 4 and an output signal of the timer 2. It is an AND circuit.

FIG. 2 shows an example of a detailed configuration of the monitoring target detector 4. In FIG. 2, reference numeral 41 denotes an input terminal to which a video signal from a camera is input, and reference numerals 421 and 422 denote input terminals from the input terminal 41, respectively. Filter A and filter B 43 for extracting only a certain band component of the extracted video signal
Reference numerals 1 and 432 denote a filter A421 and a filter B4, respectively.
Integrating circuits A and B, 441, 442, for integrating the outputs of 22
451 is a reference potential generating circuit A and B, 451 is a difference absolute value circuit A for outputting the absolute value of the difference between the output of the integrating circuit A431 and the output of the reference potential generating circuit A441, and 452 is the output of the integrating circuit B432 and the reference potential. A difference absolute value circuit B, 461 for outputting an absolute value of a difference from the output of the generation circuit B442,
Reference numerals 462 denote threshold generation circuits A and B, respectively. 471 compares an output of the absolute difference circuit A451 with an output of the threshold generation circuit A461, and outputs a significant signal only when the former is larger than the latter. Similarly, 472 compares the output of the difference absolute value circuit B452 with the output of the threshold value generation circuit B462, and outputs a significant signal only when the former is larger than the latter. A logical product circuit for calculating the logical product of the outputs of the comparison circuit B472;
Is an output terminal of the monitoring target detector 4.

Next, the operation will be described. In FIG. 1, the video signal captured by the surveillance camera 1 is input to the constant time recording VTR 3 in the same manner as in the conventional example of FIG. It is input, and the presence or absence of the monitoring target is detected here.

Here, the detection method will be described in detail with reference to FIG. First, since the object photographed by the camera when there is no monitoring object such as a customer is mostly a fixed object such as a counter or a floor, for example, the floor or the counter is made to have a special stripe pattern or color, and the image signal is obtained. A certain characteristic is given to the frequency distribution. In this way, when a monitoring target such as a customer is present, the monitoring target occupies a relatively large part of the captured video signal, so that a large change appears in the characteristic frequency distribution. Therefore, it is sufficient to detect the change in the frequency distribution, and FIG. 2 performs such a function. That is, this signal is passed through a filter A421 in order to extract the characteristic frequency component from the camera video signal input from the input terminal 41. If the characteristic frequency component is divided into two bands, as in the configuration example here, this signal is simultaneously filtered by the filter B4.
22. If the band is divided into three,
Another system may be provided. Here, the case of two systems will be described. The output of the filter A421 is integrated by the integration circuit A431, and the power of the passband signal component of the filter A421 is formed as a voltage value. The time constant of this integration circuit is such that the integration value is a field (1/60)
(Seconds) or a frame (1/30 second). On the other hand, reference potential generation circuit A
From 441, a voltage value that would be generated when a video signal having a characteristic frequency distribution when there is no monitoring target passes through the filter A421 and is integrated by the integration circuit A431 is supplied. The output of the integrating circuit A431 and the output of the reference potential generating circuit A441 are input to the absolute difference circuit A451 of the next stage, where the absolute value of the difference between them is calculated. This is input to the comparison circuit A in the next stage, and if this value is larger than a certain value supplied from the threshold circuit A461, it is determined that one detection condition of the existence of the monitoring target is satisfied, and the logical product circuit 48 To the first input terminal. In order to further ensure the detection, the output of the filter B422 is used for the other characteristic frequency band, and the second detection signal indicating the presence of the monitoring target is output from the comparison circuit B472 in exactly the same manner as the above-described system. The signal is input to the second input terminal of the AND circuit 48. The AND circuit 48 outputs the monitoring target detection signal only when all the input signals are significant,
Output from

Thus, the monitoring target detector 4 supplies a significant signal to the first input terminal of the AND circuit 5 of FIG. 1 only when the monitoring target exists. On the other hand, the intermittent recording start signal is output from the timer 2 at preset time intervals (every second in this example), and is supplied to the second input terminal of the AND circuit 5. Therefore, only when the first input signal of the AND circuit 5 is significant, that is, only when the monitoring target is present, the activation signal supplied to the second input terminal is allowed, and the intermittent recording VTR 3 Will be supplied. In this way, the intermittent recording is performed only when the monitoring target exists.

Embodiment 2 FIG. In the first embodiment, the presence / absence of the monitoring target is determined based on the video signal supplied from the monitoring camera 1. However, the monitoring target may be detected using another means completely independently of the video signal. Good. FIG. 4 shows a configuration example in the case of using infrared rays as a second embodiment.

In the figure, the light emitted from the infrared light emitting element 61 is cut off only when the object to be monitored is present and does not reach the infrared light receiving element 62, so that the output from the infrared light receiving element 62 drops. The fall of this signal is inverted by the inversion logic circuit 63 to become a significant signal, and the first
Therefore, the intermittent recording is performed only when the monitoring target exists.

Embodiment 3 FIG. Instead of the detection means using infrared rays in the second embodiment,
FIG. 5 shows an example using a distance camera that can measure the distance to the target object. When the monitoring target enters the measurement range, the change detection circuit 72 detects that a change occurs in the distance output from the distance camera 71.

Embodiment 4 FIG. Depending on the state of the imaging target, the monitoring target detector 4 in the first embodiment may be able to detect the change simply by changing the average luminance of the field or the frame without requiring the filter A or the filter B in FIG. . In this case, the configuration shown in FIG. 3 is obtained by eliminating the necessity of the series of the filter A421 and the filter B422 in FIG. 2 and the AND circuit 48.

In the above description, a VTR is used as a recording device. However, any device can be used as long as it can record video signals intermittently and reproduce it later. For example, a still image file device using a DAT may be used.

[0020]

As described above, the monitoring VTR system according to the present invention allows the intermittent recording start signal from the timer only when there is a detection condition by using the monitoring target detector. The intermittent recording is performed only when the tape is present, so that the monitoring recording time per tape can be significantly extended.

In addition, there is an effect that it is not necessary to watch a useless video having no monitoring target during reproduction.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a monitoring VTR system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating an example of a monitoring target detector according to the present invention.

FIG. 3 is a configuration diagram showing another monitoring target detector according to the present invention.

FIG. 4 is a configuration diagram illustrating an example of a monitoring VTR system when another monitoring target detection unit according to the present invention is used.

FIG. 5 is a configuration diagram illustrating an example of a monitoring VTR system using still another monitoring target detection unit according to the present invention.

FIG. 6 is a configuration diagram showing a conventional monitoring VTR system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 surveillance camera 2 timer 3 intermittent recording VTR 4 monitoring target detector 5 AND circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/76-5/956 H04N 7/18 G11B 15/02

Claims (3)

(57) [Claims] 1. A monitoring camera, a timer and an intermittent recording VT
Is composed of a R, each time the intermittent recording start signal from the timer occurs, the monitoring VTR system for intermittently recording a video signal captured by the monitoring camera, a video signal from the surveillance camera Enter the
By detecting changes in the frequency distribution contained in the signal.
A monitoring target detecting means for detecting the presence or absence of the monitoring target, and only when the monitoring target is detected by the monitoring target detecting means,
A monitoring VTR system, comprising: gate means for permitting an intermittent recording start signal from the timer, wherein an output signal from the gate means is used as an intermittent recording start signal to the intermittent recording VTR. 2. The monitoring target detecting means includes a monitoring target.
Characteristics of frequency distribution of signal captured by camera when not present
Filter with a certain band as a pass band and time constant 1/6
A camera having an integration circuit of 0 second or 1/30 second or less
The video signal from
The field of the video signal from the camera
Power of the above filter output for each or every frame
Pressure value and supplied to the first input of the absolute difference circuit
On the other hand, characteristic frequency components when the monitoring target does not exist
Video signal from a camera with
That would occur when integrated by the integration circuit.
A reference potential generating circuit for generating a voltage value;
The voltage value supplied from the generation circuit is calculated by the difference absolute value circuit.
Of the first input and the second input.
Output the absolute value of the difference between
If it is larger, there is a change in the pass band component of the above filter
To generate a monitoring target detection signal.
A threshold value generating circuit and a comparing circuit;
The monitoring VTR system according to claim 1. 3. The monitoring target detecting means according to claim 2, wherein
Multiple sets of components are provided, and monitoring from these multiple sets
The logical product output of the viewing target detection signal is output to the final monitoring target detection signal.
2. The monitoring according to claim 1, wherein the output is performed as a signal.
VTR system.