JPH0937238A - Display device for plural screens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a received video signal without deterioration and to display plural screens without use by one video image storage circuit of expensive components. SOLUTION: A video signal from a camera 2 is given to a synthesis circuit 10 via a changeover circuit 6 closed only for a display period. Furthermore, after the video signal of a camera 2-n is once written in a storage circuit, the read of the signal is controlled by a display control circuit so as not to be overlapped with the signal after other video signal of the camera 2 is selected and the result is given to the synthesis circuit 10 as a display signal of the camera 2-n and displayed on a video monitor 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-screen display device for inputting asynchronous video signals picked up by a plurality of cameras to a video storage circuit, extracting necessary portions of those screens, and displaying them on one monitor. It is about.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing a schematic construction of a video signal picked up by a plurality of television cameras and a multi-screen display device having a video storage circuit for storing the video signals. The operation will be described below. Cameras 2-1 and 2-2
The video signals from 2-n are low pass filters 2 respectively.
After cutting the high frequency components by 2-1 to 22-n, A
The signals are converted into digital signals by the / D conversion circuits 23-1 to 23n and temporarily stored in the video storage circuits 18-1 to 18-n, respectively. Next, after the display control circuit 19 determines the portion required for display, the read control circuits 29-1 to 29-n under the control of the display control circuit 19 respectively control the video storage circuits 18-1 to 18-. The portions required for display are sequentially read from n, and D / A conversion circuits 24-1 to 24-n
After being converted into an analog signal by means of, the synthesizing circuit 20 performs synthesizing and the images of a plurality of cameras are displayed on the video monitor 7.

[0003]

In the above-mentioned prior art,
Even if a signal source such as a high-resolution camera is used, all input video signals have high-pass components cut by a low-pass filter, and image quality is deteriorated by an A / D conversion circuit and a D / A conversion circuit. However, there is a problem in that it is not effective to use a high-resolution camera or the like. Also, a number of low-pass filters, A / D conversion circuits, D / A's corresponding to the number of input video signals are provided.
A conversion circuit and a video storage circuit are required, and there is a problem of cost increase due to the use of expensive parts.

A first object of the present invention is to display at least one video signal among a plurality of input video signals without deterioration. A second object of the present invention is to provide a multi-screen display device without using expensive low-pass filters, A / D conversion circuits, D / A conversion circuits, and video storage circuits for one circuit. .

[0005]

In order to achieve the above object, the present invention uses a video signal necessary for displaying one of a plurality of input video signals without deterioration as a reference signal and outputs a final video output. Determine the phase of the sync signal of the signal. Other input video signals are stored in the video storage circuit and displayed on the part other than the video signal which is displayed without deterioration. Therefore, it is read from the video storage circuit only for a necessary period and is combined with the video signal which is displayed without deterioration, and the final Output as a video signal. As a result, it is possible to output a video signal with almost no deterioration in the reference video portion. In addition, the image storage circuit for the image portion used as the reference is not required, and the circuit scale is reduced, resulting in a compact and low-priced device.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. The video signal 3 from the camera 2 is input to the switching circuit 6, and the switching circuit 27 controls the switching circuit 6 so that only the display portion 12 is allowed to pass through and the signal 13
Then, it is input to the synthesis circuit 10. On the other hand, the camera 2-1
The high-pass component of the video signal 4 is cut by the low-pass filter 21-1, converted into a digital signal by the A / D conversion circuit 25-1, and temporarily stored by the video storage circuit 11-1. The display control circuit 9 delays the portion required for display by t1 (shown in FIG. 2), the read control circuits 28-1 to 28-n read the display portion 14, and D
After being converted into an analog signal by the / A conversion circuit 26,
The signal 16 is input to the synthesizing circuit 10. Synthesis circuit 1
Output video signal 5 that is a combination of signal 13 and signal 16 by 0
Is obtained. Although the camera 2-n is omitted, it is stored in the video storage circuit 11-n in the same manner as described for the camera 2-1 and only the portion necessary for display is read out.
It is possible to delay and synthesize on the monitor.

[0007]

As described above, according to the present invention, the reference video signal can be directly displayed from the television camera without deterioration, and the performance relating to the image quality of the camera, the video monitor and the like can be sufficiently exhibited. Further, instead of changing the phases of all the video signals, the phase of the synchronization signal is adjusted to the reference video signal, so that the video storage circuit, A
It is not necessary to use expensive components such as a D / D conversion circuit, a D / A conversion circuit, and a filter circuit for one circuit, which is excellent in economic efficiency and can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a waveform chart for explaining one embodiment of the present invention.

FIG. 3 is a block diagram showing a conventional technique.

[Explanation of symbols]

 2, 2-1 to 2-n camera 3 video signal of camera 1 4 video signal of camera 2 5 output video signal 6 switching circuit 7 video monitor 9 display control circuit 10 combining circuit 11 video storage circuit 12 video display range of camera 1 13 display signal of camera 1 14 image display range of camera 2 16 display signal of camera 2 21-1 to 21-n low-pass filter 25-1 to 25-n A / D conversion circuit 26-1 to 26-n D / A conversion circuit 27 switching control circuit 28-1 to 28-n read control circuit

Claims (3)

[Claims] 1. A multi-screen display device for displaying a plurality of video signals, wherein at least one of the plurality of video signals is selected.
One video signal is a video signal directly sent from the television camera, the other video signal is a video signal stored in the image storage circuit, and a range for displaying each of the plurality of video signals is extracted. A multi-screen display device characterized by displaying. 2. The multi-screen display device according to claim 1, further comprising: a video switching circuit for inputting a plurality of video signals and extracting a part of one of the video signals, and a circuit for delaying the other video signals. A multi-screen display device, wherein a plurality of video signals are displayed on one screen by a circuit controlling them. 3. The multi-screen display device according to claim 2, wherein a circuit for switching one video signal among a plurality of input video signals and a sync signal from another input video signal are extracted, and the video is synchronized with the sync signal. A display control circuit having a function of controlling an image storage circuit for writing information by respective switching timing and reading timing, and a circuit for synthesizing a switched image and an image read from the image storing circuit A multi-screen display device characterized by.