JPS61142895A - Processing unit of video signal - Google Patents

Abstract

PURPOSE:To reproduce an excellent color picture by detecting the polarity inversion of a subcarrier frequency between a color video signal and a reproduced video signal and using a signal delaying the color video signal by one line to output it as the reproduced video signal when no polarity inversion exists. CONSTITUTION:A color video signal is given as one input of a 1 line delay circuit 1 and a selection circuit 3. The selection circuits 3, 4 use a control signal of a field identification circuit 5 to select one of the two inputs as an output. Further, a correction control circuit 6 generates a signal being the result of ORring an output of the selection circuit 4 and a correction signal of the field identification circuit 5 to control a selection circuit 7. The selection circuit 7 selects the input to the selection circuit 3 when no correction region exists and selects the correction information at the correction region to the two inputs, the input to the selection circuit 3 and the correction information and gives the result as an output. Then a color video signal with continuous subcarrier frequency is obtained at the output of the selection circuit 7.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is a video signal processing device, particularly a digital magnetic recording and reproducing device (hereinafter abbreviated as VTR) that digitizes and records and reproduces color video signals. The present invention relates to a video signal processing device that can obtain a good color image even during non-normal playback (playback at a speed different from the recording speed).

[Conventional technology]

When performing non-normal playback such as high-speed playback with a digital VTR that records and plays back digitized color video signals, it becomes necessary to compose one field signal by combining video signals divided into multiple fields. .

In this case, if video signals divided into multiple fields are simply combined as they are, continuity of subcarrier frequencies may be lost, making it difficult to reproduce color video signals. For this reason, 1. For example, once a color video signal is separated into a luminance signal and a color signal,
A method is known in which the continuity of subcarrier frequencies is guaranteed using a color video signal obtained by adding a luminance signal to a color signal whose polarity has been inverted (referred to as C separation).

[Problem that the invention seeks to solve]

However, with the YC separation method, it is difficult to completely separate the color signals, and if this is to be achieved with high precision, the number of calculation circuits required will be enormous.

Therefore, an object of the present invention is to solve the above-mentioned problems and to realize a video signal processing device that reproduces a good color image even during non-normal reproduction with a simple circuit configuration without performing YC separation.

[Means for solving problems]

In order to achieve the above object, the present invention detects polarity reversal of the subcarrier frequency between a color video signal and a reproduced video signal, and when there is no polarity reversal, reproduces a signal delayed by one line from the color video signal. It is configured to be output as a video signal.

[Effect]

In a color video signal of the NTSC system, the polarity of the subcarrier frequency is inverted for each line. Therefore, if the polarity of the subcarrier frequency is reversed,
The line immediately before or after the corresponding line is a color video signal with the same polarity. That is, it is possible to preserve the continuity of subcarrier frequencies by reproducing color video signals whose polarities do not match at the position of one line before or one line after the corresponding line. Furthermore, since the polarity of the color video signal is inverted every frame, the polarity of the subcarrier frequency has a period of 4 fields. Then, depending on the correspondence between the field obtained by combining the information of multiple fields arriving at a specific line among the four types of fields and the multiple fields, those without polarity reversal are left as is, and those with polarity reversal are changed to 1. The purpose is to obtain a good reproduced image in which the continuity of the subcarrier frequency is guaranteed even during normal reproduction by reproducing the line at the previous or next position.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to examples. 1st
FIG. 1 is a diagram showing the configuration of an embodiment of a video signal processing device according to the present invention. Color video signal uses 1 line delay circuit 1
, and one input of the selection circuit 3. The signal delayed by one line by the one-line delay circuit l becomes the other input of the selection circuit 3. Similarly, the correction area signal indicating the code error area is sent to the selection circuit 4. A signal delayed by one line by the one line delay circuit 2 is input to the selection circuit 4.

On the other hand, the field identification circuit 5 compares the field information of the color video signal and the field information to be reproduced, and if the polarities of the subcarrier frequencies match, 1
Circuit 3. Selects the signal that is not delayed by a line, or selects the signal that is delayed by one line if the polarity is inverted.
A control signal such as the one selected in step 4 is generated. Further, when the polarity of the subcarrier frequency is inverted, a correction signal indicating the code error area is generated only during one line period immediately after the polarity inversion. The selection circuits 3 and 4 select one of the two inputs and output it in response to a control signal from the field identification circuit 5. Further, the modification control circuit 6 generates a signal that uses the ORed output of the selection circuit 4 and the modification signal of the field identification circuit 5 as a modification area, and controls the selection circuit 7. The selection circuit 7 selects and outputs the two inputs of the selection circuit 3 and the retouching information, selecting the selection circuit 3 when there is no retouching area, and selecting the retouching information for the retouching area. At the output of the selection circuit 7, a color video signal with continuous subcarrier frequencies is obtained. Therefore, it is possible to obtain a good reproduced image even during non-normal reproduction. On the other hand, during normal playback, the color video shield information and playback field information match, so both selection circuits 3 and 4 select the same information, so a good playback image can be obtained even during normal playback. Needless to say.

〔Effect of the invention〕

As described above, according to the present invention, good reproduced image quality can be obtained even during non-normal reproduction with a simple configuration, and its effects are extremely large. Although the present invention has been described with respect to color video signals of the NTSC system, it goes without saying that the present invention is effective for color video signals of other systems such as the PAL system.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of a processing apparatus according to the present invention. 1.2... 1 line delay circuit, 3, 4.7... Selection circuit, 5... Field identification circuit, 6... Modification control circuit. 'ffJ1 Figure

Claims (1)

[Claims] A memory for delaying the color video signal converted into a digital signal by one line, and a means for detecting polarity reversal of the subcarrier frequency between the color video signal and the reproduced video signal, wherein the polarity reversal of the subcarrier frequency is detected. If there is no polarity reversal, the color video signal delayed by the memory device is selected as the reproduced video signal. Processing equipment.