JPH03168796A - Image switching device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image signal switching device used, for example, to sequentially switch images from a plurality of personal computers and display them on a single display device (monitor). It is. [Prior Art] Conventionally, when switching and displaying multiple images on a single display device, it was simply a matter of replacing cables or using a mechanical switch such as a rotary switch. Also, switching was performed by sending a switching signal from the outside to the control means using an image signal switching circuit (video multiplexer) with an additional control circuit. [Issues to be solved by the invention I] Conventional systems that replace cables or use SWs are laborious to operate because they require manual intervention, and systems that use switching circuits require separate control lines. There were other inconveniences. [Means for Solving the Problem] The present invention has been made in view of the above-mentioned conventional problems, and includes a plurality of video signal transmitting means and a specific code pattern added to the video signal from the video signal transmitting means. a circuit for detecting a specific code pattern included in the video signal; a circuit for switching the video signal from the video signal sending means in accordance with the specific code pattern detected by the detection circuit; The present invention proposes an image switching device having a display device that displays a signal.

[Function] The image switching device of the present invention mixes a specific code pattern of a predetermined time into a video signal, and switches the displayed video by detecting the signal of the specific code pattern. [Example] An example of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a block diagram of the entire image switching device of the present invention, FIG. 2 is an image as a code pattern, and FIG. 3 is a circuit diagram for pattern detection.

Reference numerals P1 to Pn indicate n personal computers as video signal sending means, and the video signals of each personal computer are sent to a switching device 2 (video multiplexer) via cables C1 to Cn, respectively. Each video signal is applied to a video multiplexer 2 having the necessary number of lines, and simultaneously applied to code pattern detection circuits 31 to 3n. When the code pattern detection circuits 31 to 3n detect a slam corresponding to each of the preset personal computers P1 to Pn, they send the result to the control circuit 4. The control circuit 4 generates an address signal based on the signals from each of the code pattern detection circuits Ia31 to Ia3n. applied to video multiplexer 2. The video multiplexer 2 selects a video of the personal computer according to the applied address signal, and displays the video by applying it to the display device 5 (monitor).

Next, to explain the actual operation, each computer P1~
Pn is the set pattern image (
(for example, as shown in Figure 2) is created in advance using a program and displayed on the screen of a display device for a certain period of time. When the switching circuit receives the signal, the signal is applied to the multiplexer 2 and also to the code pattern detection circuits 3l to 3n.

The operation of the code pattern detection circuit will now be explained with reference to FIG. The code pattern detection circuit passes the video signal from each personal computer through a video amplifier 6 to a comparator 7.
and is applied to the synchronization signal separation circuit 8. The converter 7 performs discrimination according to the brightness level of the video signal and applies it to the input portion of the register 10. Further, the synchronization signal separation circuit 8 separates and detects a vertical synchronization signal and a horizontal synchronization signal from the video signal and applies them to the clock signal generation circuit 11. The clock signal generation circuit generates a signal corresponding to the center of the screen among the horizontal synchronization signals in a specific order based on the vertical synchronization signal, and applies it to the register 10 as a clock, and the register 1o stores data corresponding to the signal from the comparator 7. , applies the data stored in the digital comparator 9 in accordance with the clock. The digital comparator 9 compares a pattern set in advance for each personal computer with the data in the register lo, and sends out a detection signal if they match. In response to this signal indicating a match, the video multiplexer 2 transfers the video signal from the matching PC to the display device! ! 5 and display it.
If the external computer applies a selection signal of the personal computer to be displayed to the control circuit 4, the video signal of the desired personal computer can be displayed. [Effects of the Invention] Since the present invention is constructed as shown above, images can be selected simply by connecting the video signal cable to the switching circuit. Also, in the code pattern, multiple horizontal operations are combined into one signal, but the same operation can be performed even if the signal is divided horizontally.

[Brief explanation of the drawing]

Claims (1)

[Claims] a plurality of video signal transmitting means; a circuit for adding a specific code pattern to the video signal from the video signal transmitting means;
a circuit for detecting a specific code pattern included in the video signal; a circuit for switching the video signal from the video signal sending means according to the specific code pattern detected by the detection circuit; and displaying the signal from the switching circuit. An image switching device characterized by having a display device.