JPH06334902A - Picture quality compensating device - Google Patents

Abstract

PURPOSE:To provide a picture quality correcting device for making/difference in horizontal resolution unnoticeable between the judgement of a moving picture at the time of using a three-dimensional motion adaptive Y/C separating circuit and the judgement of a still picture. CONSTITUTION:A horizontal high band compensating device 11 compensates the horizontal high band component of a Y signal outputted from the three- dimensional motion adaptive Y/C separating circuit 10. Delay compensating circuits 12 to 14 respectively delay motion data, the Y signal and a C signal outputted from the circuit 10. A selector circuit 15 selects the Y signal outputted from the device 11 at the time of judging a moving picture or selects the Y signal outputted from a delay compensating circuit 13 at the time of judging a still picture. Consequently the deterioration of picture quality at the time of judging a moving picture can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a three-dimensional motion adaptive type Y /
The present invention relates to an image quality correction device that is used together with a C separation circuit to improve the image quality during a moving image in order to make the difference in horizontal resolution between when determining a moving image of a luminance component of a television image and when determining a still image.

[0002]

2. Description of the Related Art Advances in digitization of television signal processing have led to accurate separation of luminance (Y) signals and color (C) signals by a filter between frames such as three-dimensional motion adaptive Y / C separation. It became so. As a result, the high frequency component of the luminance signal can be correctly reproduced at the time of still image determination, and the image quality of the still image is improved.

FIG. 4 is a block diagram showing an example of a three-dimensional motion adaptive Y / C separation circuit (hereinafter abbreviated as a three-dimensional Y / C separation circuit). First, using FIG. 4, three-dimensional Y / C
The operation of separation will be described. In FIG. 4, the incoming composite video signal is input to the frame memory 1, delayed by one frame and input to the subtractor 2. The subtractor 2 obtains the difference value between the incoming composite video signal and the signal delayed by one frame. The frame memory 1 and the subtractor 2 are inter-frame filters, whereby an inter-frame comb filter is applied to extract a chroma component (C signal), which is input to the selection circuit 4. Further, along with this, since the difference between the Y signal frames, that is, the information on the motion is obtained, the output of the subtractor 2 is input to the motion detection circuit 3, and the motion detection circuit 3 minimizes erroneous detection. The waveform is shaped by the filter and the sensitivity adjustment, the magnitude value of the movement for each pixel is generated, and the selection circuit 4
To enter.

On the other hand, the incoming composite video signal is input to the vertical bandpass filter 5 and the horizontal bandpass filter 6 and subjected to vertical and horizontal bandpass filters in the chroma band in the field. As a result, a chroma signal is obtained from the horizontal bandpass filter 6 and input to the selection circuit 4. The selection circuit 4 receives a filter output between frames (a C signal output from the subtracter 2) or a filter output within a field (horizontal) depending on whether the image is stationary or accompanied by a motion according to the output signal of the motion detection circuit 3. One of the C signals output from the bandpass filter 6) is selected and output. Then, the subtracter 7 subtracts the C signal thus obtained from the incoming composite video signal to obtain the Y signal.

[0005]

The three-dimensional Y / C separation circuit is constructed as described above because the luminance component of a still image does not change between frames, but the phase of the chroma component is inverted. This is because if the one-frame difference is taken, only the C signal can be accurately separated, while the luminance component also changes in the moving image, so the frame difference becomes meaningless. Therefore, the separation filter at the time of moving image determination is inevitably constituted by a separation filter in the vicinity of the modulation frequency of the chroma signal in the field. Since the separation filter in this field separates the luminance component near the modulation frequency as a chroma component, the resolution of the luminance component is extended in a still image, but when it turns to a moving image, the high frequency component is suddenly lost and The resolution deterioration from image to video was very noticeable.

The present invention has been made in view of the above problems, and in order to make the difference in the horizontal resolution between the moving image determination and the still image determination when the three-dimensional Y / C separation circuit is used inconspicuous. Another object of the present invention is to provide an image quality correction device that improves image quality deterioration during moving image determination.

[0007]

In order to solve the above-mentioned problems of the prior art, the present invention provides (1) three-dimensional motion adaptive Y / C separation for separating a composite video signal into a luminance signal and a chrominance signal. An image quality correction device for use with a circuit, comprising:
A horizontal high-frequency correction device that complements and outputs the horizontal high-frequency component of the luminance signal output from the dimensional motion adaptive Y / C separation circuit;
A first delay compensation circuit for delaying and outputting the luminance signal output from the three-dimensional motion adaptive Y / C separation circuit by a delay time by the horizontal high frequency correction device; and the three-dimensional motion adaptive Y / C A second delay compensating circuit for delaying and outputting the color signal output from the separation circuit by the delay time by the horizontal high frequency correction device, and delaying the motion data of the image by the delay time by the horizontal high frequency correction device A luminance signal output from the horizontal high frequency correction device is selected at the time of moving image determination by the output third delay compensation circuit and the motion data output from the third delay compensation circuit, and at the time of still image determination (1) An image quality correction device, comprising: a selection circuit that selects and outputs a luminance signal output from the delay compensation circuit of No. 1, and (2) provides a composite video signal with a luminance signal and a color. Belief 3D motion separates the preparative adaptive Y /
An image quality correction apparatus used together with a C separation circuit, comprising: a horizontal high frequency correction apparatus for supplementing and outputting a horizontal high frequency component of a luminance signal output from the three-dimensional motion adaptive Y / C separation circuit; A delay compensation circuit that delays and outputs the color signal output from the motion adaptive Y / C separation circuit by the delay time of the horizontal high-frequency correction device, and the horizontal high-frequency correction device at the time of moving image determination based on image motion data. And a gain selection circuit for controlling the correction gain of the horizontal high-frequency correction device to be small at the time of still image determination, the image quality correction device is provided. is there.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image quality correction device of the present invention will be described below with reference to the accompanying drawings. 1 is a block diagram showing a first embodiment of an image quality correction device of the present invention, FIG. 2 is a block diagram showing a second embodiment of the image quality correction device of the present invention, and FIG. 3 is a diagram showing the effect of the horizontal high frequency correction device. FIG.

In the image quality correction apparatus of the present invention, a horizontal high frequency correction apparatus that supplements horizontal high frequency components by adding harmonics by making the edges of the image steep is used. There are various examples of the horizontal high-frequency correction device, and the most suitable example is the one disclosed in Japanese Patent Application No. 3-313605 filed by the applicant of the present invention. FIG. 3 shows waveforms and frequency characteristics before and after improvement by the horizontal high frequency correction device. As shown in FIG. 3, according to the horizontal high-frequency correction apparatus according to this prior application, the edges of the image are made steep to add harmonics to compensate for high-frequency components, and an image with degraded frequency characteristics is naturally corrected. be able to. In addition, this horizontal high frequency correction device
It goes without saying that both movies have an effect.

First, a first embodiment of the image quality correction apparatus of the present invention will be described with reference to FIG. In FIG. 1, the incoming composite video signal is input to a three-dimensional Y / C separation circuit 10. The three-dimensional Y / C separation circuit 10 is configured as shown in FIG. 4, as described in the related art. The Y signal output from the three-dimensional Y / C separation circuit 10 is the horizontal high frequency correction device 1
1 and the delay compensation circuit 13 and the three-dimensional Y /
The C signal output from the C separation circuit 10 is the delay compensation circuit 1
4 and further, the image motion data output from the three-dimensional Y / C separation circuit 10 is input to the delay compensation circuit 12. The delay compensating circuits 12 to 14 delay and output the input signal in order to compensate for the delay time generated by the horizontal high frequency correction device 11.

The motion data output from the delay compensation circuit 12, the horizontal high frequency corrected Y signal output from the horizontal high frequency correction device 11, and the horizontal high frequency correction output from the delay compensation circuit 13 are applied. The non-Y signal is input to the selection circuit 15. The selection circuit 15 selects the Y signal output from the delay compensation circuit 13 that does not perform horizontal high range correction during still image determination according to the motion data, and performs horizontal high range correction during motion image determination. The Y signal output from 11 is selected and output. As a result, it is possible to correct the image quality deterioration at the time of moving image determination when the three-dimensional Y / C separation circuit 10 is used. Although the motion data is obtained from the three-dimensional Y / C separation circuit 10 in this embodiment, a motion detection circuit may be separately provided.

Next, a second embodiment of the image quality correction apparatus of the present invention will be described with reference to FIG. In FIG. 2, the incoming composite video signal is input to the three-dimensional Y / C separation circuit 10. The three-dimensional Y / C separation circuit 10 is configured as shown in FIG. 4, as described in the related art. The Y signal output from the three-dimensional Y / C separation circuit 10 is the horizontal high frequency correction device 1
1 is input to the delay compensation circuit 14, and the motion data output from the three-dimensional Y / C separation circuit 10 is input to the gain selection circuit 16. Entered in. The delay compensating circuit 14 delays and outputs the input C signal in order to compensate for the delay time generated by the horizontal high frequency correction device 11.

The gain selection circuit 16 controls the correction gain selection function provided in the horizontal high-frequency correction device 11 in accordance with the motion data to minimize the gain so as not to perform horizontal high-frequency correction at the time of still image determination. , The gain is maximized so that horizontal high-frequency correction is performed when determining a moving image. This allows
It is possible to correct image quality deterioration at the time of moving image determination when the three-dimensional Y / C separation circuit 10 is used. In this example, 3
Motion data is obtained from the dimension Y / C separation circuit 10,
A motion detection circuit may be separately provided.

[0014]

As described in detail above, in the image quality correction apparatus of the present invention, the horizontal high frequency component is used to supplement the horizontal high frequency component in the luminance signal output from the three-dimensional Y / C separation circuit by the horizontal high frequency correction apparatus. Therefore, the difference in horizontal resolution between the moving image determination of the luminance component of the television image and the still image determination can be made inconspicuous. Therefore, the still image when the three-dimensional Y / C separation circuit is used. -There is an effect that it is possible to eliminate the unnaturalness caused by the difference in resolution between moving images.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a second embodiment of the present invention.

FIG. 3 is a diagram for explaining an effect of a horizontal high frequency correction device.

FIG. 4 is a block diagram showing an example of a three-dimensional motion adaptive Y / C separation circuit.

[Explanation of symbols]

 10 Three-dimensional motion adaptive Y / C separation circuit 11 Horizontal high-frequency correction device 12-14 Delay compensation circuit 15 Selection circuit 16 Gain selection circuit

Claims (2)

[Claims] 1. An image quality correction apparatus used together with a three-dimensional motion adaptive Y / C separation circuit for separating a composite video signal into a luminance signal and a color signal, wherein the three-dimensional motion adaptive Y / C separation circuit is used. A horizontal high-frequency correction device for supplementing the horizontal high-frequency component of the output luminance signal and outputting the luminance signal output from the three-dimensional motion adaptive Y / C separation circuit for a delay time by the horizontal high-frequency correction device. A first delay compensating circuit for delaying and outputting, and a second delay for delaying and outputting the color signal output from the three-dimensional motion adaptive Y / C separation circuit by a delay time by the horizontal high-frequency correction device. A motion compensation circuit, a third delay compensation circuit that delays the motion data of the image by the delay time of the horizontal high-frequency correction device, and outputs the motion data, and a motion data output from the third delay compensation circuit And a selection circuit that selects a luminance signal output from the horizontal high-frequency correction device and selects and outputs the luminance signal output from the first delay compensation circuit when a still image is determined. An image quality correction device characterized by. 2. An image quality correction apparatus used together with a three-dimensional motion adaptive Y / C separation circuit for separating a composite video signal into a luminance signal and a color signal, wherein the three-dimensional motion adaptive Y / C separation circuit is used. A horizontal high-frequency correction device that complements and outputs the horizontal high-frequency component of the output luminance signal, and a color signal that is output from the three-dimensional motion adaptive Y / C separation circuit for the delay time of the horizontal high-frequency correction device. The delay compensation circuit that delays and outputs the image and the motion data of the image makes the correction gain of the horizontal high-frequency correction device large at the time of moving image determination, and makes the correction gain of the horizontal high-frequency correction device small at the time of still image determination. An image quality correction apparatus comprising a gain selection circuit for controlling.