JPH04115676A - Video signal processor - Google Patents

Abstract

PURPOSE:To avoid unsightly displays of only noise by supplying arbitrary video data when the input of a video signal does not come and synthesizing them with the picture by the respective video signals. CONSTITUTION:When the input of a video signal does not come only to the second channel, a selecting circuit 11 reads digital video signal data (a) and after that reads video level data (b) of a constant level from a video data level part 10 by the timing signal of a timing generating part 12. When the both signals are synthesized with making the clock frequency at D/A conversion into half compared to the clock frequency at A/D conversion, it becomes a waveform (c) and the picture of a monitor screen by the synthesized signal becomes as indicated W the upper half part of a figure. Thus, a picture V2 is monochromatically displayed with the one color of white or black and so on and the flicker of display such as a sandy face owing to noise is eliminated completely.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a video signal processing device used to divide and synthesize multiple video signals onto a single monitor screen, for example.

<Prior Art> This type of video signal processing device is used, for example, in a security system, to manage each image in order to simultaneously monitor images generated by video signals from multiple security cameras installed at required monitoring points. It is used for purposes such as dividing a single monitor screen in a room and displaying it compositely on this screen.

Such a conventional video signal processing device has a configuration as shown in FIG. 6, which illustrates a case where two types of video signals are combined and processed. That is, the synchronization separators 1a and 1b separate the synchronization signal from the video signal of each channel, and further separate the synchronization signal from the video signal of each channel.
The converters 2a and 2b convert the video signal into a digital signal using a clock generated at the timing of the synchronization signal, and then temporarily store the converted digital video data in each memory 3a and 3b.

Subsequently, the select circuit unit 5 selects the memory 3a based on the timing signal from the timing generator 6.

3b is sequentially selected and digital video data is read from it, and is synthesized based on the synchronization level from the synchronization data section 4, and this synthesized digital video data is transferred to the D/
The A conversion section 7 converts the signal into an analog signal based on the clock signal from the timing generation section 6, and further, the output buffer amplifier 8 shapes the output level and gives it drive capability, and displays it on a monitor screen.

<Problems to be Solved by the Invention> By the way, in the above-mentioned security system, there are cases where a video signal is no longer input to the corresponding channel. For example, when a video signal as shown in FIG. 7(a) is input to the first channel, if the input of the video signal of the second channel disappears, the input waveform of this channel becomes unstable, and for example, as shown in FIG. (b). When these two signals are combined by setting the clock frequency for D/A conversion to 1/2 of the clock frequency for A/D conversion, a waveform as shown in the same figure (C) is obtained, and the result of this combined signal is As shown in Figure 8, the image on the monitor screen shows a normal image as shown by the vertical line on the left half, but on the right half it becomes an image that looks like a sand surface due to only noise. The image flickers, etc., result in an extremely unsightly image as a whole.

The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a video signal processing device that can perform signal processing so as not to result in an unsightly image as a whole even when a part of the video signal is not input. This is a technical issue.

Means for Solving the Problems> In the present invention, as a technical means for achieving the above-mentioned problems, a video signal processing device is configured as follows. That is,
In a video signal processing device that performs signal processing so as to divide and display composite images on the same screen based on video signals respectively input to a plurality of input terminals, a means for determining whether or not a video signal is input to each input terminal; a memory that individually stores each video signal input from a terminal; a video data section that stores arbitrary video data in advance; and a video data section that sequentially reads out video signal data from each of the memories using a timing signal for signal synthesis, and performs the discrimination. a signal synthesizing section that reads out the video data of the video data section and synthesizes it with the video signal data when the memory in which no video data is stored is read from the memory according to information from the means. There is.

<Operation> If there is no video signal input only to the second input terminal, this can be determined by the discriminating means and discriminating information can be obtained.

Next, when the signal synthesis unit sequentially reads video signal data from each memory based on the signal synthesis timing signal and synthesizes them, a memory that does not store video signal data because no video signal has been input. When the reading order comes, the video data is read out from the video data section based on the above-mentioned discrimination information and combined with the video signal data from the memory. This composite signal is displayed on a monitor screen, etc., so the display area of the screen corresponding to the input terminal where there was no video signal will be white or black if a certain level signal is set as video data. Displayed in one color.

Therefore, there is no flickering of the display like a sandy surface due to noise alone, unlike in the conventional case.

<Example> Hereinafter, a preferred example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a block configuration of an embodiment of the present invention when four video signals are synthesized, and in the same figure,
Components that are the same as or equivalent to those in FIG. 6 are given the same reference numerals and their explanations will be omitted. Then, the A/D converters 2a to 2
d and memories 3a to 3d are individually provided corresponding to each channel, and each synchronization separation unit 9a to 9d individually provided corresponding to each channel determines whether or not a video signal is input and The discrimination information is outputted to the timing generator 12, and when a video signal is input, a synchronization signal is extracted from the video signal.

The video level data section 10 stores in advance video level data of a partial level that is output when no video signal is input. The timing generation section 12 synchronizes the digital video signal data of each memory 3a to 3d, the video level data of the video level data section 10, and the synchronization level data section 4 based on the input presence/absence determination information from each synchronization separation section 9a to 9d. A timing signal for extracting level data and a clock signal for D/A conversion are output.

Next, the operation of the above embodiment will be explained. The basic processing operation of the video signal is the same as in the case of FIG. 6, and only the different points will be explained. The synchronization separators 9a to 9d determine whether or not a video signal is input and output the determination signal to the timing generator 12, and if a video signal is input, they extract a synchronization signal from the video signal. Separate A/
The video signals are outputted to the D converters 2a to 2d, and each video signal is converted into digital video signal data and temporarily stored in each of the memories 3a to 3d, as in the case of FIG.

If there is no video signal input only to the second channel, the select circuit 11 reads the digital video signal data as shown in FIG. ,
Partial level video level data as shown in FIG. 2(b) is read out from the video data level section 10. When these two signals are combined with the clock frequency for D/A conversion being 1/2 times the clock frequency for A/D conversion, the result is shown in the same figure (C
), and the image on the monitor screen resulting from this composite signal is as shown in the upper half of FIG.

That is, images V,, V3. V, is the first .V, as shown by the vertical line in the figure. Each video signal of the third and fourth channels is displayed, and the image v2 is a display of video level data as shown in plain color in the same figure, and is displayed in one color such as white or black, for example, There is no flickering of the display like a sandy surface due to noise, unlike in the past.

As mentioned above, when compositing images in the horizontal direction, the clock frequency during D/A conversion is set to 1/2 or 1/2 times that of A/D conversion.
This can be done by multiplying the image by 3 times, but since the number of scanning lines is determined by the television system for compositing images in the vertical direction, the number of scanning lines is thinned out during A/D conversion, and
This can be achieved by performing D/A conversion while thinning out the data or by thinning out scanning lines during D/A conversion. For example, Fig. 4 shows a case where the vertical lines of four video signals are thinned out to 1/4 and four images ■, ~■4 are arranged vertically and synthesized. Set the clock frequency during conversion to D/
Four images V with four times the clock frequency at the time of A conversion,
This is a case where .about.v4 are arranged in the horizontal direction and synthesized. In the same way, it is of course possible to synthesize images from four or more video signals, and the arrangement of the images is not fixed and can be changed arbitrarily. Furthermore, the video level data is not limited to a fixed level, but any video data can be set.

<Effects of the Invention> As described above, according to the video signal processing device of the present invention, when no video signal is input, arbitrary video data is supplied and synthesized with the image generated by each video signal, so that conventional noise can be eliminated. It is possible to eliminate the unsightly appearance caused by displaying an image solely by the user.

[Brief explanation of the drawing]

Fig. 1 is a block configuration diagram of an embodiment of the present invention, Fig. 2 is a waveform diagram for explaining the synthesis of video signals, Fig. 3 is an explanatory diagram of a display image by the synthesized signal, and Fig. 4 is an illustration of other images. FIG. 5 is an explanatory diagram of another display image; FIG. 6 is a block diagram of the conventional device; FIG. 7 is a waveform diagram for explaining the synthesis of video signals; FIG. 8 is an explanatory diagram of a display image based on the composite signal. 3a-3 9a-9 d...Memory d...Synchronization separation section (discrimination means) 0...Video level data section (video data section) 1...
Select circuit (signal synthesis section)

Claims (1)

[Claims] (1) In a video signal processing device that performs signal processing such that each image resulting from video signals input to a plurality of input terminals is divided and displayed on the same screen in a composite manner, a means for determining whether or not a video signal is input to each input terminal; , a memory that individually stores each video signal input from each input terminal, a video data section that stores arbitrary video data in advance, and sequentially reads video signal data from each of the memories using a timing signal for signal synthesis; and a signal synthesizing section that reads the video data of the video data section and synthesizes it with the video signal data when the memory in which no video data is stored is read from the memory according to the information from the discriminating means. video signal processing equipment.