JP2006033128A - Contour correction system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contour correction system for thinly emphasizing white lines to enhance a sense of sharpness by thinning the thickness of a white side correction waveform more than that of a black side correction waveform in a contour correction processing using a symmetric filter. <P>SOLUTION: An asymmetric filter is formed by changing coefficients of the filter in accordance with a feature quantity (e.g., gradient of waveform) of an input waveform. Thus, a correction waveform wherein the thickness of white side differs from that of black side is obtained and contour correction is carried out by using the correction waveform. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to various video apparatuses such as a television receiver (TV), a video tape recorder (VTR), a video disk (LD, DVD, video CD), and various image processing apparatuses that handle image data, and in particular, image contours. The present invention relates to a contour correction apparatus for improving the image quality by improving the sharpness of a portion.

  Conventionally, as a contour correction for improving the sharpness of a contour portion in order to improve image quality, a contour correction component is obtained by secondary differential processing, and the correction component is multiplied by an appropriate gain and added to an original signal. (For example, see Patent Document 1).

In these conventional techniques, the correction components extracted by the filter have the same thickness for both overshoot (white side shoot) and undershoot (black side shoot). Therefore, in the past, in order to obtain a sharp feeling, the sharpness was improved by changing the balance of the amplitude of the white side and the black side. FIG. 4 shows the configuration of a conventional contour correction apparatus. Reference numeral 401 denotes a video signal output terminal, 402 denotes a filter with a fixed coefficient, 403 denotes gain control means, 404 denotes an adder, and 405 denotes a video signal output terminal.
Japanese Patent Laid-Open No. 5-22633

  However, in the above-described conventional contour correction device, the white waveform and the black correction waveform have the same thickness, which gives the viewer the impression that the pixels (dots) constituting the video are large. Gives the impression that the video has a poor resolution.

  For this reason, in a CRT (cathode ray tube), processing for controlling the deflection speed of the electron beam with the first-order differential component of the video signal and emphasizing the white line is performed. As a result, the white line is corrected finely, so that the sense of resolution is improved and the sharpness of the entire screen is improved. However, a flat panel display represented by a liquid crystal display or a plasma display does not have an electron beam, so that it is impossible to make a white line thin by a conventional electron beam speed modulation process. For this reason, when the contour correction process is simply performed, the video has a poor resolution for the reasons described above.

  The present invention has been made in view of the above-mentioned problems of the prior art, and by making the thickness of the preshoot and overshoot different between the white side and the black side, the viewer feels fine dots with high resolution. It is an object of the present invention to provide a contour correction apparatus that makes it possible to provide

  In the present invention, the thickness of the correction waveform on the white side and the black side is changed so that the white line is emphasized finely, and the viewer is given an impression that the dots are fine and have high resolution. In order to realize this, picture detection means for detecting a picture of a signal from an input video signal, coefficient generation means for generating a filter coefficient based on the picture information obtained by the picture detection means, A filter configured on the basis of the coefficient obtained by the coefficient generation means, an amplitude control means for controlling the amplitude of the correction component extracted by the filter, an amplitude by the input video signal and the amplitude control means An addition means for adding the corrected correction component after the control is provided.

  As described above, by dynamically changing the filter coefficient according to the pattern, the thickness of the preshoot and overshoot can be changed between the white side and the black side, so that the dots are fine and have high resolution. It is possible to perform contour correction processing that can give a unique impression.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3.

(Embodiment 1)
FIG. 1 shows a configuration diagram of a contour correction apparatus according to the present invention. In FIG. 1, 101 is a video signal input terminal, 102 is a picture detection means for detecting a picture of the video signal, 103 is a coefficient generation means for generating a filter coefficient from the detection result by the picture detection means 102, and 104 is a coefficient. The filter is configured based on the coefficient generated by the generation unit 103, and extracts the contour correction component of the video signal. Reference numeral 105 denotes gain control means for performing amplitude control of the contour correction component extracted by the filter 104, 106 denotes an adder for adding the video signal and the contour correction component output from the gain control means, 107 Is a video signal output terminal.

  102 is for detecting the pattern of the video signal, and the object to be detected is, for example, the angle of inclination of the waveform, information on whether it is monotonously increasing or monotonically decreasing, or the peak of the waveform or valley And so on. In the following description, it is assumed that the angle of inclination and whether it is monotonously increasing or monotonically decreasing are detected. Hereinafter, the information obtained by 102 will be referred to as “tilt information”.

  The inclination information detected at 102 is input to the coefficient generation means 103. 103 calculates a filter coefficient from the amount of inclination.

  Here, the filter configuration will be described. For example, the filter may be a 3-tap symmetric FIR filter as shown in FIG. In FIG. 2, S1 is a video signal, 201 (1) and 201 (2) are delay circuits, 202 (1) to 202 (3) are multiplication circuits, and 203 is an addition circuit. As an operation of the circuit, first, the input video signal S1 is delayed by the delay circuits 201 (1) and 201 (2), and each of the input signal S1 and each of the delay circuits 201 (1) to 201 (2). Output signals S201 (1) to S201 (2) are multiplied by coefficients K1 to K3 shown in FIG. 2 by multiplication circuits 202 (0) to 202 (3), respectively, and then added together by addition circuit 203.

The coefficient generation means 103 in FIG. 1 generates the values K1 to K3. It is assumed that the balance between the sizes of K1 and K3 changes according to the inclination information from the pattern detection means 102. As shown in (1), the conventional symmetric filter has a method of taking a symmetric coefficient around K2.
(K1, K2, K3) = (a, b, a) (1)
On the other hand, in the present invention, the value of “a” or “c” shown in (2) is changed according to the inclination information from 102.
(K1, K2, K3) = (a, b, c) (where a ≠ c) (2)
In this way, the filter coefficient can be changed according to the pattern, and as a result, the phase of the filter characteristics can be changed, and thereby the correction waveforms with different thicknesses are extracted between the white side shoot and the black side shoot. can do. If the ratio between K1 and K3 is changed according to the inclination of the waveform, the thickness of the white shoot and the black shoot can be optimally controlled according to the pattern.

  FIG. 3 shows a correction waveform extracted by the filter of the present invention. In FIG. 3, (a) is an input signal, (b) is a waveform of a correction component extracted by the filter of the present invention, and (c) is a waveform of the correction component extracted by a conventional symmetric filter. Thus, according to the filter of the present invention, the thickness can be changed between the white side shoot and the black side shoot.

  In addition, since the three-tap filter has been described here as an example, three coefficients K1 to K3 are generated. However, if the number of filter taps is different from this example, it is necessary to generate coefficients corresponding to the number of taps. Needless to say.

  The correction component obtained by the filter 104 is input to the gain control means 105. 105 controls the amplitude by multiplying the correction component by an appropriate gain. The white side and the black side may be amplitude controlled at the same rate, or may be independently amplitude controlled.

  The correction component after amplitude control at 105 is input to 106. 106 adds the video signal and the correction component. Finally, the video signal output from 106 is output from 107.

  Thus, by dynamically changing the filter coefficient according to the pattern, the thickness of the preshoot and overshoot can be changed between the white side and the black side, and the dots are fine and high resolution to the viewer. It is possible to give such an impression.

  The present invention is not limited to a CRT (cathode ray tube), and can be used in various display devices. Particularly, in a display device used outdoors and a display device used in a situation where external light conditions change. This also greatly contributes to providing high-resolution images.

The block diagram of the outline correction device in the embodiment of the present invention Block diagram showing a configuration example of a filter of the contour correction device Diagram showing the waveform of the filter Block diagram showing the configuration of a conventional contour correction device

Explanation of symbols

Reference Signs List 101 Video signal input terminal 102 Picture detection means 103 Coefficient generation means 104 Filter 105 Gain control means 106 Adder 107 Video signal output terminal

Claims (2)

Picture detection means for detecting a picture of the signal from the input video signal, coefficient generation means for generating a filter coefficient based on the picture information obtained by the picture detection means, and obtained by the coefficient generation means A filter configured based on a coefficient, an amplitude control means for controlling the amplitude of the correction component extracted by the filter, and the correction component after the amplitude control is performed by the input video signal and the amplitude control means And an adding means for adding. 2. The contour correcting apparatus according to claim 1, wherein the corrected video signal has a white line thickness equal to or thinner than that before correction.

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