JPH07184209A - Method for transmitting or recording video signal - Google Patents

Abstract

PURPOSE:To transmit/record picture information twice that of a video signal transmitted/recorded substantially. CONSTITUTION:Field separation circuits 2A, 2B separate fields of 1st and 2nd video signals into odd number fields f1 and even number fields f2 respectively, a field difference detection circuit 3A(3B) respectively form a difference signal f3=f1-f2 (f3=f2-f1) being the subtraction of one field signal from the other field signal, the difference is converted into a high frequency signal by a frequency conversion circuit 4A(4B), a field difference recording circuit 5A(5B) superimposes the converted signal onto a signal for a horizontal scanning line period not in use in the vertical blanking period of the original other field signal, the superimposed signals from the circuits 5A, 5B are synthesized by a synthesis circuit 7, and the result is transmitted as a single video signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of transmitting or recording a video signal.

[0002]

2. Description of the Related Art Television signals and video tapes,
As a signal to be recorded / reproduced on a video disc or the like, an interlaced scanning type video signal such as NTSC or PAL is used.

In the case of transmitting / recording an image by such a video signal, the amount of the image targeted by the standard is limited.

Therefore, in order to transmit / record more image information by the video signal, a simple figure (including a character) is digitized (symbolized), and this is converted within the blanking period of the video signal. It is added and transmitted / recorded as a digital signal during the unused period.

[0005]

However, in the above-described image information addition (multiplexing) system, the images that can be added are limited to simple figures and characters.

Therefore, an object of the present invention is to solve the above problems and provide a method of transmitting or recording a video signal in which a natural image can be added.

[0007]

According to the present invention, in a method of transmitting or recording a video signal in which two types of video signals are superimposed, each of the video signals is separated into two different field signals, and then the video signals are mutually separated. A difference signal is formed by subtracting the other field signal from one different field signal, and the formed difference signal is superimposed on an area where the vertical blanking period signal of the one field signal is not used to obtain superimposition information. Get the field signal containing,
Further, the present invention is characterized in that the field signals including two different superimposition information obtained for each video signal are combined into one video signal.

[0008]

According to the present invention, two video signals can be combined and transmitted / recorded as a single video signal.

[0009]

1 is a block diagram of a video signal high-density transmission system according to an embodiment of the present invention. 2 is shown in FIG.
3 is a signal waveform diagram of each part shown in FIG. As shown in FIG. 1, the first video signal A of NTSC system and the second video signal B of NTSC system are input to the time axis correction circuit 1 so that the timings of the synchronization signals are matched with each other. The time axis is corrected. The first output from the time axis correction circuit 1
Image signal A is input to the first field separation circuit 2A and the odd field signal f1 and the even field signal f
2 and then input to the first field difference detection circuit 3A. Here, first, the input odd field signal f1 is temporarily stored in an appropriate memory, and the difference signal f3 is subtracted from the even field signal f2 that is subsequently input by subtracting the even field signal f2 from the odd field signal f1. Ask. The difference detection process represented by f3 = f1-f2 is performed for every two connected lines in one frame. A specific example thereof will be described with reference to FIG. If the odd field signal f1 in one frame is shown by the first horizontal line (line 1) and the even field signal f2 is shown by the second horizontal line (line 2), the difference signal f3 = f1-f
2 becomes as shown by (line 1-line 2).

The difference signal f3 thus detected from the first field difference detection circuit 3A for every two consecutive lines in one frame is compressed in the time axis in the first frequency conversion circuit 4A. , That is, the differential signal f3 ′ whose frequency has shifted to the high frequency band (see FIG. 2). f3 '=
(Line 1-line 2) ′}, and then output from the time axis correction circuit 1 in the first field difference recording circuit 5A and the time delay in each of the circuits 2A to 4A through the first delay circuit 6A. As shown in FIG. 2, the difference between the signals in the unused horizontal scanning line period in the vertical blanking period in the odd field signal of the first video signal A with a predetermined time delay taken into consideration is shown in FIG. The pulses are divided by the dividing pulse P and superimposed.

Regarding the second video signal B output from the time axis correction circuit 1, the second field separation circuit 2B,
The second field difference detection circuit 3B, the second frequency conversion circuit 4B, the second field difference recording circuit 5B, and the second delay circuit 6B perform the same processing as above, but the second field difference detection circuit 3B does. , F3 = f2 (even field signal) -f1 (odd field signal) is detected as the difference signal f3, and the second field difference recording circuit 5B produces a vertical signal in the even field signal of the second video signal B from the delay circuit 6B. The signals in the unused horizontal scanning line period in the blanking period are segmented by the differential segmenting pulse P for each signal f3 'and superimposed.

Next, in the synthesizing circuit 7, the odd field signal in the first video signal A from the first field difference recording circuit 5A and the even field in the second video signal B from the second field difference recording circuit 5B. The signals and the signals are respectively selected and combined to obtain a high-density video signal in which a frame is formed by both the signals, and the resultant signal is output.

The high-density video signal output from the synthesis circuit 7 is transmitted through the transmission circuit T, and the video signal reception / reproduction circuit 8 is transmitted.
Is output to the same circuit 8. Note that, for example,
When the synthesizing circuit 7 includes a television transmitter, the video signal receiving / reproducing circuit 8 includes a tuner capable of obtaining a baseband output in the television receiver. Further, instead of the transmission circuit T, a recording medium such as a tape or a disk can be used. In this case, the synthesizing circuit 7 and the reproducing circuit 8 are configured to correspond thereto.

The high-density video signal output from the video signal receiving / reproducing circuit 8 is separated into an odd field signal f1 and an even field signal f2 in the field separation circuit 9, and the odd field signal f1 has a first difference (f3). ′)
It is input to the detection circuit 10A and the first delay circuit 11A.

In the first difference (f3 ') detection circuit 10A, each difference signal f3 superimposed on the signal in the unused horizontal scanning line period in the vertical blanking period in the input odd field signal f1. ′ Is detected at a timing corresponding to that at the time of superposition, and is output together with the odd field signal f1. The first f3 reproducing circuit 12A extends the time axis of each differential signal f3 'from the f3' reproducing circuit 10A, that is, converts the frequency into the original differential signal f3 (low-frequency conversion). Then, the f2 (even field) reproduction circuit 13A outputs the difference signal f from the f3 reproduction circuit 12A.
3 and the odd field signal f from the f3 'detection circuit 10A
1 to reproduce the even field signal f2 in the first video signal A, and then in the first synthesizing circuit 14A, the even field signal from the f2 reproducing circuit 13A. The original first image in which f2 and the odd field signal f1 having a predetermined time delay in consideration of the time delay in each of the circuits 10A, 12A and 13A through the delay circuit 11A are combined to form a frame by both signals. The signal A is obtained and output.
The first video signal A output from the synthesizing circuit 14A is input to an appropriate first reproducing circuit 15A including a display, for example, and video information is reproduced.

Also for the even field signal f2 from the field separation circuit 9, the second f3 'detection circuit 10B,
Second delay circuit 11B, second f3 reproduction circuit 12B, f
1 reproduction circuit 13B, second synthesis circuit 14B, and second reproduction circuit 15B are processed in the same manner as above, but f1
In the reproduction circuit 13B, based on the difference signal f3 from the f3 reproduction circuit 12B and the even field signal f2 from the f3 ′ detection circuit 10B, an operation of f1 = f2−f3 is performed and the odd field in the second video signal B is calculated. The signal f1 is reproduced, and the synthesizing circuit 14B synthesizes the odd field signal f1 from the f1 reproducing circuit 13B and the even field signal f2 from the delay circuit 11B to obtain the original second video signal B.
To get

When the video signal is the three color primary color signals, that is, the R, G and B signals, the same processing as above may be performed for each signal.

[0018]

As described above, according to the present invention, it is possible to transmit / record image information twice as much as the image information originally transmitted / recorded by the video signal.

[Brief description of drawings]

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

FIG. 2 is a signal waveform diagram of each part in the embodiment.

[Explanation of symbols]

 1 time base correction circuit 2A, 2B field separation circuit 3A, 3B field difference detection circuit 4A, 4B frequency conversion circuit 5A, 5B field difference recording circuit 6A, 6B delay circuit 7 composite circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H04N 7/08 7/081 H04N 5/92 A 7/08 Z

Claims (1)

[Claims] 1. A method of transmitting or recording a video signal in which two types of video signals are superimposed, wherein each of the video signals is separated into two different field signals, and then each of the video signals is separated from one of the different field signals. A difference signal is formed by subtracting the other field signal, and the formed difference signal is superimposed on an unused area of the vertical blanking interval signal of the one field signal to obtain a field signal containing superposition information, Furthermore, a method of transmitting or recording a video signal, characterized in that a field signal including two different superimposition information obtained for each video signal is combined into one video signal.