JPH06348219A - Crt display switching device - Google Patents

Abstract

PURPOSE:To eliminate the disorder of a picture at the time of the switching of a system which switches CRT display signals from plural image output means (camera and computer in this example) and displays an image on one CRT. CONSTITUTION:When the image display is switched from, for example, a camera 1-2 to a camera 1-1 by extracting vertical synchronizing signals 9-1-9-3 in the CRT display signals from the image output means 1-1-1-3, a pseudo synchronizing signal which goes up to a level 'H' from the display end point of time of one picture of the camera 1-2 (i.e., rising point of time of the synchronizing signal 9-2 from the camera 1-2) to the display start point of time of one picture of the camera 1-1 (i.e., falling of the synchronizing signal 9-1 from the camera 1-1) to make the display of the CRT blank is generated and supplied to the CRT. After the switching, the synchronizing signal from the camera 1-1 is supplied to the CRT as it is. Similarly, when the display is switched from the camera 1-1 to the computer 1-3, a pseudo synchronizing signal is generated and supplied to the CRT 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in a centralized monitoring system or the like, selects one of CRT display signals output from a plurality of cameras or computers and selects a common CRT.
The present invention relates to a CRT display switching device for displaying an image on a screen.
In the drawings below, the same reference numerals indicate the same or corresponding parts.

[0002]

2. Description of the Related Art FIG. 3 shows an example of the configuration of a conventional CRT display switching device of this type. In the figure, 3 is a CRT, 1
(1-1, 1-2) are cameras as image output means, 1
(1-3) is also a computer, and 2 (2-1 to 2-
3) is the CRT 3 from the image output means 1-1 to 1-3, respectively.
Is a CRT display switching device which outputs one of the CRT display signals 2-1 to 2-3 to the CRT 3 and outputs the signal to the CRT 3. In this example, the relay 5 is used. .

In FIG. 3, a plurality of display signals 2-
1 to 2-3 are switched through the relay 5 irrespective of the timing of this signal, and the structure is simple. FIG. 4 shows another example of the configuration of a conventional CRT display switching device. In the switching device 4 of FIG. 6, 6 (6-1 to 6-
3) is an image storage memory for each of the image output means 1-1 to 1-3. In FIG. 4, each image output means 1-1
CRT display signals 2-1 to 2-3 from 1 to 3 are temporarily stored in the image storage memories 6-1 to 6-3, and one of the memories 6 is selected via the relay 5. , The display signal 2 is sequentially read from the selected memory 6 and the display timing is adjusted to be displayed on the CRT 3.

[0004]

However, in the system shown in FIG. 3, the relay 5 is irrelevant regardless of the timing of the display signal 2.
Since this display signal is switched, the synchronization signal to the CRT 3 is interrupted midway and synchronization is lost, and display disorder occurs at the time of switching, which gives an unpleasant feeling to the viewer.

In the system of FIG. 4, the display is not disturbed at the time of switching, but a high-speed and large-capacity image storage memory 6 adapted to the signal having the highest resolution of the screen to be displayed is required, which is not always economically effective. Not a method. The present invention is to solve the above problems, and provides a CRT display switching device that does not disturb the screen display when switching CRT display signals and does not require a high-speed, large-capacity memory. Is an issue.

[0006]

In order to solve the above problems, a CRT display switching device of the present invention is a CRT output from a plurality of image output means (1-1 to 1-3, etc.).
In a system for switching and selecting one of the display signals (2-1 to 2-3, etc.) and displaying it on a common CRT (3, etc.), a screen switching synchronization signal (vertical synchronization signal, etc.) from each CRT display signal ) Extracting means (synchronous signal extracting means 7)
-1 to 7-3), and at the time of the above switching, from the head portion of the screen switching synchronization signal of the switching source image output means to the tail portion of the screen switching synchronization signal of the switching destination image output means. During the period, a pseudo screen switching synchronizing signal (10A, 10B, etc., hereinafter referred to as a pseudo synchronizing signal) for leaving the CRT display blank is generated and given to the CRT, and thereafter, the screen switching synchronization of the image output means of the switching destination. A means for giving a signal to the CRT as it is (pseudo-synchronization signal generation means 8 and the like), and a signal other than the screen-switching sync signal in the CRT display signal for the CRT during the valid period of the pseudo-sync signal from the switching source image Means for switching from the output means to the image output means of the switching destination (relay 5
Etc.) and.

[0007]

When the image display is switched from the first image output means to the second image output means, the end point of the image display of one screen of the first image output means, that is, the CRT display signal in the signal is displayed. Pseudo as a synthetic synchronizing signal which rises when the vertical synchronizing signal rises and falls at the time when the image display of the second image output means starts, that is, when the vertical synchronizing signal in the CRT display signal falls. A synchronizing signal is generated, blanking (blank display) of the output period CRT of the pseudo synchronizing signal is performed, and thereafter, the vertical synchronizing signal of the second image output means is used as it is for the CRT display of the output image. To do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a functional configuration as one embodiment of the present invention, and FIG. 2 shows the timing of inputting / outputting a synchronizing signal to / from the pseudo synchronizing signal generating means of FIG. In FIG. 1, in addition to the relay 5, the switching device 4 is provided with 7 (7-1 to 7-3) synchronizing signal extracting means and 8 pseudo synchronizing signal generating means. Here, the synchronization signal extraction means 7-1 is the camera 1-1.
Is a means for extracting a vertical synchronizing signal 9-1 as a synchronizing signal for each screen from the CRT display signal 2-1 in the same manner. Similarly, the synchronizing signal extracting means 7-2, 7-3 are respectively for the cameras 1-2,
This is means for extracting the vertical synchronizing signals 9-2, 9-3 from the computer 1-3. Further, the pseudo sync signal generating means 8 is provided with a vertical sync signal 9 from each sync signal extracting means 7-1 to 7-3.
Vertical sync signal 10 to CRT3 by inputting -1 to 9-3
Is a means of making.

FIG. 2 shows the above synchronizing signals 9-1 to 9-1 in order from the top.
The timing of 9-3 and 10 is shown. The CRT in Figure 2
10A in the synchronizing signal 10 to the camera 1-2 indicates a pseudo synchronizing signal as a vertical synchronizing signal at the time of the display switching operation from the camera 1-2 to the camera 1-1, and 10B indicates from the camera 1-1 to the computer 1-3. The pseudo sync signal as a vertical sync signal at the time of display switching operation is shown. Generally, the vertical synchronizing signals 9-1 to 9-3 to the CRT 3 are generated at every switching time of the display for one screen, and the CRT is generated during the "H" level period of this signal.
The display state of 3 is a blank state. According to the present invention, the pseudo sync signal generating means 8 includes the camera 1-2 to the camera 1.
At the time of switching to -1, the synchronization signal 9-1 of the camera 1-1 generated next from the time when the synchronization signal 9-2 of the camera 1-2 is generated after the display of one screen of the camera 2 is completed. The pseudo sync signal 10A is generated until it disappears, and after switching, the CRT 3 displays from the beginning of one screen. During the generation period of this signal 10A, the CRT 3 is in the blank display state. The pseudo-synchronization signal generation means 8 generates the pseudo-synchronization signal 10A in this way, and the camera 1 after the generation.
-1 at the time when the first sync signal 9-1 disappears, after that, the sync signal 9-1 from the camera 1-1 is output as it is, and one screen of the camera 1-1 is always displayed on the screen of the CRT3. From the beginning. In this way, from the screen display of the camera 1-2 to the camera 1-
Switch to 1 screen display.

Similarly, when switching from the camera 1-1 to the computer 1-3, the pseudo sync signal generating means 8 similarly generates the computer 1-3 from the time when the sync signal 9-1 of the camera 1-1 is generated. Pseudo sync signal 10B is generated until the sync signal 9-3 disappears, and thereafter, the sync signal 9-3 from the computer 1-3 is output as it is, so that the screen of the computer is always displayed from the beginning. become.

The relay 5 is connected to the pseudo sync signal 10A,
During the generation period of 10B, the signals except the vertical synchronizing signal in the CRT display signal 2 are switched between the image output means 1 to be switched.

[0012]

As described above, according to the present invention, one of the image display signals output from each of the plurality of image output means is selectively switched to display the image on the common CRT. A pseudo sync signal for leaving the CRT screen in a blank state is generated by the generating means from the end time of the display of one screen of the switching source image output means to the start time of the display of one screen of the switching destination image output means. Since it is generated and given to the CRT, and thereafter, the synchronizing signal of the image output means of the switching destination is given to the CRT as it is, the display of the CRT is not disturbed. Further, since the display is switched in synchronism with each CRT display signal, there is no need to adjust the timing of the synchronization signal, and the high speed and large capacity memory is not required.

[Brief description of drawings]

FIG. 1 is a functional configuration diagram as an embodiment of the present invention.

FIG. 2 is a time chart showing timings of sync signals input and output by the pseudo sync signal generating means of FIG.

FIG. 3 is a diagram showing an example of a configuration of a conventional image display switching device.

FIG. 4 is a diagram showing another example of the configuration of a conventional image display switching device.

[Explanation of symbols]

 1 (1-1 to 1-3) Image Output Means 1-1 Camera 1-2 Camera 1-3 Computer 2 (2-1 to 2-3) CRT Display Signal 3 CRT 4 Switching Device 5 Relay 7 (7- 1 to 7-3) Sync signal extracting means 8 Pseudo sync signal generating means 9-1 Sync signal from camera 1-1 9-2 Sync signal from camera 1-2 9-3 Sync signal from computer 1-3 10 Sync signal to CRT 10A pseudo sync signal 10B pseudo sync signal

Claims (1)

[Claims] 1. C output from each of a plurality of image output means
In a system in which one of the RT display signals is switched and selected and displayed on a common CRT, a means for extracting a screen switching synchronization signal from each CRT display signal, and an image output means serving as a switching source at the time of the switching During the period from the beginning of the screen switching sync signal to the tail of the screen switching sync signal of the image output means which is the switching destination, a pseudo screen switching sync signal (hereinafter referred to as pseudo sync) in which the CRT display is in a blank state. A signal) to be provided to the CRT, and thereafter, the screen switching synchronization signal of the image output means of the switching destination is directly provided to the CRT, and the CRT to the CRT during the effective period of the pseudo synchronization signal.
A CRT display switching device comprising: means for switching a signal other than a screen switching synchronizing signal in the display signal from a switching source image output means to a switching destination image output means.