JP2006030351A - Display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the coloring that occurs in a contour portion in various video signals as against the problem that the cells of a contour section emphasized by appearance are colored in the contour section if there is a great luminance difference, from each other, of the cells in contact with each other in the contour section. <P>SOLUTION: In the video display device having a pixel structure arrayed with three primary colors RGB in stripes, the brightness ratios of the RGB displayed in the contour section are changed according to the contour featured values obtained from a contour featured value detection circuit so as to vary from the brightness ratios before correction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display device such as a television or a monitor using a panel having a pixel structure having a stripe arrangement of three primary colors RGB.

  Color video signals output from video processing circuits such as television receivers and computers are usually composed of RGB primary color video signals. These video signals are used in CRT (cathode ray tube), plasma, and liquid crystal display devices. Based on this, the color is displayed for each pixel, and an image is displayed. Conventionally, for such RGB video signals, contour correction processing is performed to perform video processing that emphasizes the contour portion of the video in order to give a sharp feeling to the projected video. When performing contour correction processing, if contour correction is performed independently for each of the RGB video signals, the chromaticity of the corrected pixel changes depending on the image, and coloring occurs in the contour portion. Will result in an unnatural image.

As a method for solving such a problem, for example, Patent Document 1 discloses a technique for contour correction using a luminance signal. The conventional contour correction method disclosed in this publication detects the level of the contour of the target pixel based on the RGB video signal level of each pixel and the RGB video signal level of the adjacent pixel, and the level and the target pixel in the target pixel. A contour correction amount is calculated based on the video signal level of each color. Then, based on the obtained contour correction amount, the video signal level to be displayed on the target pixel is corrected so that the ratio of each color does not change before and after the correction processing, thereby suppressing the coloring of the contour portion.
JP 2002-218493 A

  However, conventionally, when performing contour correction, the target pixel is the contour portion and the amount of contour correction is calculated based on the video signal level for each color, and the pixel in the contour portion displays a color different from the display color before correction. Although the outline is emphasized, the pixel structure of a display device such as a liquid crystal display or plasma has a stripe structure in which cells of each color RGB are alternately arranged. When the difference is large, there is a problem that the color of the cells in the contour portion is visually enhanced and the cells in the contour portion appear to be colored. Even when an image is displayed without performing contour correction, only the cells in the contour portion appear to be colored due to the RGB stripe structure.

  In addition, by emphasizing the contour image by contour correction, the contour cells appear to be more noticeably colored. For example, as shown in FIG. 2 (a), the background (r1, g1, b1) = (0%, 0%, 0%) is displayed in black on a display device having a cell structure aligned with R, G, B from the left. When a video signal that displays a white window of (r2, g2, b2) = (90%, 90%, 90%) is input, the pixels in the contour portion have the RGB ratio by conventional contour correction. It is assumed that (r3, g3, b3) = (92%, 92%, 92%) is corrected so as not to change. At this time, the color of the leftmost R cell of the white window is conspicuous for viewing, and the left side of the white window appears to be red, and similarly, the right side of the white window appears to be colored blue.

  In order to solve this problem, the present invention has a signal conversion means for converting an input RGB signal and a pixel structure having a stripe arrangement of three primary colors RGB, and displays an image based on the RGB signal generated by the signal conversion means. And a contour feature amount detecting means for obtaining a contour feature amount indicating a degree that each pixel of interest is a contour portion based on luminance information of the pixel of interest and its peripheral pixels obtained from the input RGB signal, and the contour Control means for controlling the signal conversion means based on a feature amount, the signal conversion means changing the value of the input RGB signal based on the value obtained by the control means, and the pixel of the contour portion The display device is characterized in that the display color is different from the display color before correction.

  By using the display device according to the present invention, in the display device having a RGB stripe structure as the pixel structure of the display device, each color is determined based on the degree of the outline of the target pixel with respect to various video signals and the video signal level of each color. Since the amount of correction is calculated so that the amount of correction is different from the original display color, it is possible to prevent coloring from occurring in the outline and to prevent unnatural images from being displayed. It becomes.

  Further, when the display device according to the present invention is used, the circuit configuration for calculating the contour correction amount can be simplified by reducing the color to be corrected based on the RGB cell arrangement of the pixel of interest, thereby reducing the cost. It becomes possible.

  The display device of the present invention has a signal conversion unit for converting an input RGB signal, and a video display device for displaying an image based on the RGB signal generated by the signal conversion unit, the pixel structure having a stripe arrangement of three primary colors RGB. And a contour feature amount detecting means for obtaining a contour feature amount indicating a degree of each contour pixel being a contour portion based on luminance information of the target pixel obtained from the input RGB signal and surrounding pixels, and based on the contour feature amount. Control means for controlling the signal conversion means, wherein the signal conversion means is a display device configured to change the value of the input RGB signal based on the value obtained by the control means, and is a pixel of an outline portion The display color is different from the display color before correction.

(Embodiment 1)
An embodiment of the display device of the present invention will be described below with reference to FIG.

  The liquid crystal display device 100 shown in FIG. 1 includes a video signal conversion circuit 1 to which an input RGB signal I is supplied and a video display device 2 in which a pixel structure to which an output of the video signal conversion circuit 1 is supplied has a stripe structure of three primary colors RGB. A contour feature amount detection circuit 3 for obtaining a contour feature amount indicating a degree that each pixel of interest is a pixel of a contour portion based on luminance information of each color in the pixel of interest and its surrounding pixels obtained from the input RGB signal I; A control circuit 4 for controlling the video signal conversion circuit 1 by an output from the contour feature quantity detection circuit 3 is provided.

  In the display device configured as described above, for example, as shown in FIG. 2A, a video display device having a stripe structure in which the pixel structure of the display device is arranged in the order of R, G, B from the left. In addition, in the black display where the video signal level of each color of the background is (r1, g1, b1) = (0%, 0%, 0%), (r2, g2, b2) = (90%, 90%, 90%) Consider a case where a video signal that displays a white window is input.

  First, the details of the conventional method for detecting the contour feature amount are described in Patent Document 1 described above, and thus detailed description thereof will be omitted and will be briefly described.

  Here, since the configuration of the conventional contour correction circuit is the same and only the calculation method is different, it will be described with reference to FIG. In the conventional contour correction circuit, first, based on the video signal level for each color of the target pixel and its surrounding pixels obtained from the input RGB signal, the contour feature amount detection circuit 3 determines the degree to which the target pixel is the contour portion. calculate.

  Specifically, the difference in the video signal level or the second derivative amount between the pixel of interest and the pixel adjacent to the pixel of interest in the horizontal direction is calculated for each color of RGB. The feature amount a of the contour portion is obtained from the calculated value for each color of RGB. Then, the obtained contour feature amount a is output to the control circuit.

The control circuit 4 controls the video signal conversion circuit so that the contour portion is not colored when performing contour correction on the contour portion of the image displayed based on the feature amount a output from the contour feature amount detection circuit. The signal b to be output is output. FIG. 2A shows this state. First, in order to perform contour correction so as not to cause coloring, the video signal levels of the respective colors after correction of the contour portion X1 are set to the same ratio (r3 , G3, b3) = (92%, 92%, 92%). The contour portion is emphasized by suppressing occurrence of coloring before and after the correction. However, in the case where the display device for displaying the image signal with the edge enhancement is a display device in which the pixel structure such as liquid crystal or plasma has a stripe structure of RGB three primary colors, the leftmost edge cell portion of the white window A phenomenon occurs in which the color R of Y1 is conspicuous for viewing, the port side of the white window is red, and similarly the star cell outline cell portion Y2 of the white window is colored blue.

  This is a problem that occurs in the case of a display device in which the pixel structure has a stripe structure of the three primary colors of RGB without performing contour correction. However, by performing contour correction, coloring is further emphasized. Further, this coloring seems to be more noticeably colored as the pixel structure is larger, depending on the size of the pixel structure of the display device.

  Therefore, when such a video signal is input, the control circuit 4 of the present invention outputs a signal c for controlling the control circuit 4 in accordance with the value b input from the contour feature amount detection circuit. The control signal c is output so that the contour portion is not colored. The situation will be described with reference to FIG.

  When the same video signal described with reference to FIG. 2A is input, the conventional correction processing method is colored at the left end of the contour portion X1, so the video signal level correction amount for each color of the contour portion X1. Make it weaker in steps as you go out. If the video signal level of each color of the white window before correction is (r2, g2, b2) = (90%, 90%, 90%), the display color of the contour portion X1 after contour correction is, for example, (r4, g4, b4) = (85%, 90%, 92%). In this way, in order to suppress the pixel display color of the contour portion from appearing colored in the outermost cell of the contour portion, colors with different video signal level ratios before and after correction are displayed.

  As a result, in the case of a conventional display device having a stripe structure of RGB three primary colors, when a video signal as shown in the example is input for various video signals, the contour correction processing performs contour correction. The outermost cell of the part is colored and can suppress what was very unnatural video, it is possible to suppress the coloring of the contour part for various video signals, natural and sharp The attached video can be displayed.

(Embodiment 2)
Another embodiment of the present invention is a display device characterized in that the color to be corrected by the control circuit is only one of R, G, and B. The method for detecting the contour feature amount of the display device of the present embodiment is the same as that described in the above (Embodiment 1), and thus the description thereof is omitted. In the method as described in (Embodiment 1) for various video signals, a conventional contour correction amount calculated for each color is taken into consideration for each color in consideration of the array of RGB cells of the display device. Further corrections have been made.

  In the display device according to the present embodiment, the video signal level of only one of the RGB cells that are the outermost part of the contour portion is changed in consideration of the arrangement of the RGB cells. For example, when a video signal in which a white window is displayed in black display is input as a video signal in a display in which the pixel structure is arranged in the order of R, G, and B from the left, with respect to the calculated correction amount, The contour part weakens only R and the right end weakens only B. As a result, the arithmetic circuit can be simplified and the cost can be reduced.

  The present invention has the same effect in a display device having a display screen having an RGB stripe structure, and can provide a high-quality image to the viewer by improving the coloring of the outline. To do.

The figure explaining the operation | movement of the circuit for performing the outline part coloring improvement of the display apparatus in 1st Example of this invention. The figure which shows the reference example at the time of using the same display device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Video signal conversion circuit 2 Video display apparatus 3 Contour feature-value detection circuit 4 Control circuit

Claims (2)

Signal converting means for converting an input RGB signal, a video display device having a pixel array having a stripe arrangement of three primary colors RGB, displaying an image based on the RGB signal generated by the signal converting means, and the input RGB signal Based on the obtained luminance information of the target pixel and its surrounding pixels, contour feature amount detecting means for obtaining a contour feature amount indicating the degree to which each target pixel is a contour portion, and controlling the signal conversion means based on the contour feature amount Control means, and the signal conversion means displays the input RGB signals by changing the values based on the values obtained by the control means. The display device according to claim 1, wherein the display color of the pixels in the contour portion is changed only for one color of the outermost cell of the contour portion.

Images