JPH10257450A - Method and device for multiplexing video signals - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synthesize and multiplex plural video signals without lowering the resolution of the image by respectively partially thinning the plural video signals in the unit of a frame and time sequentially synthesizing the respective video signals later into one multiplexed video signal. SOLUTION: A synthesizing control circuit 6 generates a synthesizing control signal and applies it to a read control circuit 5 corresponding to an external command signal 7, an information signal 8 and the input detecting signals of input video signals A, B and C generated by detecting signal generating circuits 4a-4c, and additional signals corresponding to the identification information of input video signals A, B and C are outputted to a multiplexer 9 with a signal adder circuit. Then, the additional signals containing the identification information are added and time sequentially synthesized in the order of read during the blanking period of digital signals read out of memories 3a-3c corresponding to the input video signals A, B and C so that one multiplexed digital video signal can be provided. This multiplexed digital video signal is converted to a video signal D such as an NTSC signal by a signal converting circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multiplexing method and apparatus for combining a plurality of video signals into one video signal.

[0002]

BACKGROUND OF THE INVENTION Problems to be Solved by the Invention
2. Description of the Related Art In an aircraft, a helicopter, a simulator for operation training thereof, and the like, a plurality of different images are simultaneously displayed on various display devices.

Conventionally, when a plurality of asynchronous video signals are recorded by a recording device such as a VTR, a plurality of recording devices corresponding to the number of the video signals have been required.

However, when a plurality of recording devices are used, management of a tape or the like on which images are recorded and handling when reproducing images at the same time are troublesome.

[0005] Therefore, the screen is divided into two so that the two video signals correspond to the half of the screen with the image of one video signal and the other half of the screen with the other video signal. Multiplexing was taking place.

However, multiplexing of a video signal that divides a screen into two has a problem that the resolution of an image is reduced.

An object of the present invention is to provide a video signal multiplexing method and apparatus capable of solving the above problems.

[0008]

According to the video signal multiplexing method of the present invention, a part of each of a plurality of video signals is thinned out in units of frames, and after the thinning, the video signals are combined in a time series. It is characterized in that one multiplexed video signal is obtained. According to the method of the present invention, a plurality of video signals can be converted into one multiplexed video signal without reducing the resolution of an image.

A video signal multiplexing apparatus according to the present invention is capable of individually converting a plurality of asynchronous input video signals into digital signals and storing digital signals corresponding to the input video signals individually in frame units. Means for generating a control signal including information of a decimation ratio in units of frames of a digital signal corresponding to each input video signal, and information of a synthesis order in units of frames of the decimated digital signal, A means for generating a read signal for reading the stored digital signal according to the control signal and the decimation ratio and the synthesis order, and synthesizing the read digital signal in a time series to form one Means for outputting a multiplexed video signal. According to the device of the present invention, the present invention can be implemented,
Further, even if a plurality of input video signals are asynchronous with each other, they can be output as one multiplexed video signal.

In the apparatus of the present invention, there is provided means for detecting the presence or absence of the input of each input video signal, and when all the input video signals are input, the stored data are stored in accordance with a preset decimation ratio and synthesis order. When a digital signal is read out and there is no input video signal, the stored digital signal is read out according to a decimation ratio and a synthesis order according to the number and type of the input video signals. . Thus, it is possible to set an appropriate thinning ratio according to the content of each input video signal. Also,
By changing the thinning ratio according to the number and type of input video signals, unnecessary thinning can be eliminated, and the number of dropped frames in the reproduced image can be reduced.

In the apparatus of the present invention, there is provided means for adding a signal including identification information of an input video signal corresponding to the digital signal to a blanking period of each read digital signal. With this, each input video signal is added with its identification information and synthesized, and upon reproduction, a signal multiplexed based on the identification information is separated into a signal corresponding to the original input video signal and reproduced. Can be.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

The video signal multiplexing apparatus 1 shown in FIG. 1 has three input video signals A, B, and C which are asynchronous with each other.
And three AD conversion circuits 2a, 2b, and 2c corresponding to. Each input video signal A, B, C has a corresponding AD
The signals are individually converted into digital signals by the conversion circuits 2a, 2b, and 2c. The digital signal is an RGB signal or a digital signal composed of a luminance signal and a color difference signal.

Each of the A / D conversion circuits 2a, 2b, and 2c is provided with three frame memories 3a, 3b, and 3c corresponding to each other. Each digital signal output from the A / D conversion circuits 2a, 2b, and 2c is a clock synchronized with the corresponding input video signal A, B, and C,
a, 2b, and 2c are individually stored in the memories 3a, 3b, and 3c. In each of the memories 3a, 3b, 3c,
Each digital signal is stored in units of one frame, and a previously stored digital signal is overwritten by a previously stored digital signal, thereby deleting the previously stored digital signal.

Further, three timing signal and detection signal generation circuits 4a, 4b, 4c are provided in one-to-one correspondence with the input video signals A, B, C. Each of the timing signal and detection signal generation circuits 4a, 4b, 4c generates a timing signal synchronized with the corresponding input video signal A, B, C, and generates the corresponding input video signal A,
A detection signal is generated when B and C are input.

The timing signals include memories 3a, 3b and 3c for storing digital signals of input video signals A, B and C corresponding to each timing signal and detection signal generating circuits 4a, 4b and 4c, and a read control circuit. Sent to 5.
Since the input video signals A, B, and C are asynchronous with each other, each digital signal is written based on each timing signal.

Each detection signal is sent to the synthesis control circuit 6. Each detection signal has a corresponding input video signal A, B, C
A different signal is used for each input video signal A, based on the detection signal.
The presence or absence of B and C inputs is detected.

The synthesizing control circuit 6 generates a synthesizing control signal based on the command signal 7 from the outside, the discrete information signal 8 such as a switch, and the above-mentioned detection signal, and outputs it to the read control circuit 5. The synthesis control signal includes information for selecting a read timing signal from among the detection signal generation circuits 4a, 4b, and 4c, a thinning ratio in units of frames of digital signals corresponding to the input video signals A, B, and C; This corresponds to information on the compositing order of the thinned digital signal in frame units. The decimation ratio and the composing order correspond to the command signal 7 or a pre-programmed signal when all the input video signals A, B, and C are detected from the detection signal. If it is detected from the detection signal that the input of some of the input video signals is not input, as described later, the decimation ratio and the combination order according to the number and type of the input video signals are input. It is said.

The read control circuit 5 selects one of the detection signal generation circuits 4a, 4b and 4c for a read timing signal based on the synthesis control signal, and stores the read timing signal in accordance with the thinning ratio and the synthesis order. A read command signal for reading the read digital signal is generated. If all input video signals are input based on the read command signal, the stored digital signal is read out according to the command signal 7 or according to a pre-programmed thinning-out ratio and synthesis order, and a part thereof is read out. When there is no input video signal, the stored digital signal is read out in accordance with the decimation ratio and the combination order according to the number and type of the input video signals. The thinning ratio and the combination order depend on settings programmed in advance.

For example, all the input video signals A, B, C
And the information of the command signal 7 decimates each of the input video signals A, B, and C at an equal rate, and the order of the input video signal A, the input video signal C, and then the input video signal B is repeated. When synthesizing so that
A read command signal for thinning out each of the input video signals A, B, and C at a rate of two frames to three frames is generated. According to the read command signal, a digital signal for one frame is first read from the memory 3a corresponding to the input video signal A, and then the memory 3 corresponding to the input video signal C is read.
A digital signal for one frame is read from c, then a digital signal for one frame is read from the memory 3b corresponding to the input video signal B, and this is repeated. A read command signal to the memory 3a corresponding to the input video signal A is output at a timing at which the input video signal A can be read one frame out of three frames, and read to the memory 3b corresponding to the input video signal B. The command signal is output at a timing at which the input video signal B can be read one frame into three frames, and the read command signal to the memory 3c corresponding to the input video signal C is obtained by converting the input video signal C into three frames. It is output at the timing when one frame can be read. As a result, each of the input video signals A, B, and C is thinned out at a ratio of two frames to three frames.

Further, for example, all the input video signals A,
B and C are input, the input video signal A, the input video signal B, and the input video signal C are decimated at a ratio of 2: 2: 1. First, the input video signal A, then the input video signal B, and then the input video signal. The signal A, the input video signal B, and then the input video signal C may be combined so that the order is repeated. In this case, the input video signal A
And the input video signal B is decimated at a rate of 3 frames per 5 frames, and the input video signal C is decimated at a rate of 4 frames per 5 frames.

For example, there is no input video signal A, only the input video signal B and the input video signal C are input, and the information of the command signal 7 is
B and C are decimated in equal proportions, first input video signal A, then input video signal C, then input video signal B
In this case, the information on the input video signal A of the command signal 7 is ignored, and the composite control signal is obtained by thinning out the input video signals B and C at a rate of one frame to two frames, and C, and then generates a read command signal for thinning out the input video signal B. According to the read command signal, a digital signal for one frame is read from the memory 3c corresponding to the input video signal C, and then the memory 3 corresponding to the input video signal B is read out.
A digital signal for one frame is read from b, and this is repeated. Memory 3 corresponding to the input video signal B
b, the input video signal B is set to 2
The memory 3 is output at a timing at which one frame can be read out, and corresponds to the input video signal C.
c, a read command signal for the input video signal C is 2
It is output at the timing when one frame can be read out for each frame. As a result, the input video signals B and C are thinned out at a rate of one frame for every two frames.

Also, for example, there is no input video signal B, only the input video signal A and the input video signal C are input, and the information of the command signal 7 includes the input video signal A, the input video signal B, and the input video signal C. Are thinned out at a ratio of 2: 2: 1, and the input video signal A, the input video signal B, the input video signal A, the input video signal B, and then the input video signal C are synthesized such that the order is repeated. The command signal 7
Is ignored, and the input video signal A and the input video signal C are thinned out at a ratio of 2: 1.
Digital signals are read from the memories 3a and 3c so that the order of the input video signal A, then the input video signal A, and then the input video signal C is repeated. Thus, the input video signal A is thinned out at a rate of one frame every three frames, and the input video signal C is thinned out at a rate of two frames every three frames.

Further, for example, each input video signal A, B, C
Is input, only the input video signal is read out without thinning out, in other words, at a rate of zero.

Further, based on the composite control signal, the read control circuit 5 generates an additional signal corresponding to the identification information of each of the input video signals A, B and C at a timing corresponding to the read command signal. The additional signal is output to the multiplexer 9 with a signal adding circuit.

In the multiplexer 9 with a signal adding circuit, an additional signal including identification information of the input video signal A is added during a blanking period of the digital signal read from the memory 3a corresponding to the input video signal A, An additional signal including the identification information of the input video signal B is added to the blanking period of the digital signal read from the memory 3b corresponding to B, and the blanking period of the digital signal read from the memory 3c corresponding to the input video signal C is added. , An additional signal including identification information of the input video signal C is added. Each digital signal to which the additional signal has been added is output to each memory 3 by the multiplexer 9.
a, 3b, and 3c are combined in a time series in the order of reading, so that one multiplexed digital video signal is obtained. The multiplexed digital video signal is converted by the signal conversion circuit 10 into a video signal D such as an NTSC signal.

According to the video signal multiplexing apparatus 1 having the above-described configuration, a part of each of the input video signals A, B, and C corresponding to the frames continuous in time series is decimated on a frame basis. By combining the signals A, B, and C in a time series, one multiplexed video signal can be obtained. As a result, a plurality of asynchronous video signals can be transferred to a single VT without reducing the resolution of the image.
It is possible to record on a single storage medium such as one video tape by a recording device such as R. Further, according to the above configuration, it is possible to change the setting of the thinning-out and the like according to the external command, and it is possible to set an appropriate thinning-out ratio according to the situation of each of the input video signals A, B and C. For example,
Depending on the situation, the thinning amount of the video signal of the image whose time change is large at that time can be made smaller than the thinning amount of the video signal of the image whose time change is small at that time. Further, according to the above configuration, each input video signal A,
By detecting the presence or absence of B and C inputs and changing the thinning ratio in accordance with the number and type of input video signals, unnecessary thinning can be eliminated and dropped frames in reproduced images can be reduced. Further, according to the above configuration, during the blanking period of each digital signal, a signal including identification information of the input video signals A, B, and C corresponding to the digital signal is added. The reproduced signal D can be separated into signals corresponding to the original input video signals A, B, and C for reproduction.

The present invention is not limited to the above embodiment. For example, the number of input video signals is not particularly limited.
Or four or more. The multiplexed video signal may be output as a digital signal without being converted into an NTSC signal or the like.

[0029]

According to the present invention, it is possible to provide a video signal multiplexing method and apparatus capable of combining and multiplexing a plurality of video signals without reducing the resolution of an image.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a video signal multiplexing apparatus according to an embodiment of the present invention.

[Description of Signs] 2a, 2b, 2c A / D conversion circuit 3a, 3b, 3c Memory 5 Read control circuit 6 Synthesis control circuit 9 Multiplexer with signal addition circuit

Claims (4)

[Claims] 1. A video characterized in that a part of each of a plurality of video signals is thinned out in frame units, and after the thinning out, each video signal is synthesized in a time series to form one multiplexed video signal. How to multiplex the signal. 2. A means for individually converting a plurality of mutually asynchronous input video signals into digital signals; a means capable of individually storing digital signals corresponding to each input video signal in frame units; Means for generating a control signal including information of the corresponding thinning ratio of the digital signal in frame units and information of the synthesis order of the thinned digital signal in frame units; and based on the control signal, the thinning ratio and Means for generating a read signal for reading the stored digital signal in accordance with the synthesis order; and synthesizing the read digital signal in time series to output one multiplexed video signal. And a video signal multiplexing device. 3. A means for detecting the presence or absence of input of each input video signal, wherein when all input video signals are input, the stored digital signal is converted according to a preset thinning ratio and synthesis order. 3. The read digital signal is read according to a decimation ratio and a synthesis order according to the number and type of input video signals when there is no input video signal input. 3. The video signal multiplexing device according to claim 1. 4. The video signal according to claim 2, further comprising means for adding a signal including identification information of an input video signal corresponding to the digital signal to a blanking period of each read digital signal. Multiplexer.