JPH02220246A - Magnetic recording and reproducing device - Google Patents

Abstract

PURPOSE:To securely record a bit of necessary information by recording an input video signal to a recording medium from the time of detecting a variation of contents of the input video signal until a fixed time elapses or the variation disappears. CONSTITUTION:A video signal from a camera 1 is inputted to a video signal input terminal 3 of a VTR 2 and then inputted to a recording system device 4 and an A/D converter 7. The video signal inputted to the A/D converter 7 is converted into a digital signal and inputted to a field memory 8. Then, the digital video signal from the A/D converter 7 and a digital video signal delayed by one field by the field memory 8 are inputted to an adder 9 where a difference between the two input signals is compared and generated, and this output signal is detected by a detector circuit 10 to input its output signal to a timer circuit 6. A recording instruction signal is outputted by the timer circuit 6 to a control circuit 5 only for a set time after detecting the difference, and the recording system device 4 is worked under the recording state to carry out the VTR recording of the video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a magnetic recording/reproducing device mainly used for monitoring and observation.

Conventional technology Previously, magnetic recording and reproducing devices for monitoring and observation (jX
R) is called a time-lapse VTR, and it mainly uses an intermittent recording method that thins out and records the information of the video signal input by a camera etc. according to a preset recording time mode. For example,
A monitoring system has been used in which a sensor, such as a switch, is installed on the door of a room, and when the sensor is activated, the VTR is placed in recording mode.

Problems that the invention aims to solve However, with conventional time-lapse VTRs that use an intermittent recording method, information that is not truly needed is often recorded, and conversely, a scene that is truly necessary may be missed. There was a problem.

In addition, in a surveillance system using a time-lapse VTR,
The accuracy and accuracy of the sensor is extremely important; conversely, the sensor must be selected very precisely according to the purpose, and care must be taken to ensure that the sensor is not rendered inoperable by a third party. There was a problem that it had to be done.

The present invention solves the above problems and requires 1! I
The object of the present invention is to provide a magnetic recording/reproducing device that can reliably record information.

Means for Solving the Problems In order to solve the above problems, the present invention provides an analog-digital converter device that converts an input video signal input from a video input terminal into a digital signal, and an output digital signal of the analog-digital converter device. a delay device for delaying and the analog-to-digital converter 811'
and a timer device that outputs a recording command for a predetermined period of time from the generation of the output signal of the detection device, The input video signal is recorded on the recording medium for a predetermined period of time after a change occurs.

Effect With the above configuration, when a difference occurs between the input video signal converted into a digital signal by the analog-to-digital converter device and the delay time caused by the delay device, this difference is detected by the detection device and the output signal of the detection signal is generated. From time to time, the input video signal is recorded on the recording medium for a predetermined time by the timer device.

Embodiment The present invention does not provide a sensor function outside the VTR, but instead automatically detects and records the necessity of information from changes in information (video signal) input from a camera or the like. This information changes from a camera etc. to a VTR.
This refers to a change in the content (waveform) of the video signal sent to the camera, and after detecting this video change, it is recorded for a certain period of time or until the change disappears.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus showing one embodiment of the present invention.

The video signal from camera 1 monitoring the subject is a VTR.
One is input to the video signal input terminal 3 of No. 2, the other is input as a signal to be recorded to a recording system device 4 including a circuit system and a mechanism system for recording, and the other is used to determine whether there is information to be recorded. Therefore, the signal is first input to an analog-to-digital converter device (hereinafter abbreviated as A/D converter) 7. The A/D converter 7 converts the video signal from an analog signal to a digital signal, and this digital signal is then input to a field memory 8 for delaying this signal by one field. And A/D converter 7
1 with the digital video signal from the field memory 8
The digital video signal delayed by one field is sent to an adder 9.
The difference between the two human power signals is compared and generated. 2 to adder 9
When there is a difference between the human input signals, the difference output signal is detected by the detection circuit 10, and the output signal is input to the internal timer circuit 6. The timer circuit 6 transmits RFC (
A recording) command signal is output, and the recording system device [4 enters the RFC state via the control circuit 5, and the video signal is recorded on the VTR.

The time recorded is the time until the output signal of the detection circuit 10 disappears, or the time preset by the timer circuit 6 after this output signal is output.

Also, as usual, the VTR 2 is operated by an operation signal from the VTR's operation section 11. For example, when the RFC (recording) switch is pressed, the operation signal is input to the control circuit 5, and from this control circuit 5 the necessary information for recording is input. The command signal is input to the recording system device 4, and the video signal is recorded on the VTR.

In this way, differences in video signals between fields are detected using the field memory 8, and when a difference is detected,
By performing VTR recording until no difference is detected again for a certain period of time or until the time set in advance by the timer circuit 6 has elapsed, only the video signal to be monitored can be recorded.

In addition, in this embodiment, as a method for detecting a change in a video signal,
Although we have shown an example of using field memory 8 to detect differences between fields, in principle it is also possible to detect differences between frames, or if the memory is increased, differences between multiple fields/frames, or differences in horizontal scanning periods (between lines). A detection method is also possible.

Effects of the Invention As described above, according to the present invention, the difference in the input video signal during the delay time by the delay device is detected, and when the difference is detected, the input video signal is manually operated for a predetermined time by the timer device or until the difference is no longer detected. By recording the video signal, you can record only the necessary information (video signal) that you really want to monitor, without the need for a sensor, and with just the VTR, and you can search for the necessary scene after recording and retrieve the tape. It is possible to realize a monitoring system that is extremely effective in terms of usage and is relatively inexpensive. Further, the present invention is effective for both the intermittent recording method and the normal M-degree recording method as a VTR recording method.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a magnetic recording/reproducing apparatus showing one embodiment of the present invention. DESCRIPTION OF SYMBOLS 1...Camera, 2...VTR13...Video input terminal, 4...Recording system@position, 5...Control circuit, 6...
Timer circuit (timer device), 7.-A/D converter (analog/digital converter device), 8.
・Field memory (delay device), 9...Adder, 1
0...Detection circuit, 11...Operation unit. Agent Yoshihiro Morimoto

Claims (1)

[Claims] 1. An analog-digital converter device that converts an input video signal input from a video input terminal into a digital signal, a delay device that delays the output digital signal of the analog-digital converter device, and an output digital signal of the analog-digital converter device. A detection device that detects a difference between the signal and the output digital signal of the delay device, and a timer device that outputs a recording command for a predetermined time from the generation of the output signal of the detection device, A magnetic recording/reproducing device that records an input video signal on a recording medium for a predetermined period of time from when the input video signal is received.