JP2006325014A - Television receiver and white balance adjustment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and inexpensively adjust white balance in a television receiver provided with a liquid crystal module. <P>SOLUTION: The television receiver includes an operation key 4 for inputting adjustment coefficients of R, G, and B, a remote controller 5 or a RS232C serial communication means 12, and a microcomputer 7 for rewriting a gamma table on the basis of adjustment coefficients. An RGB adjustment coefficient memory 8 is provided where adjustment coefficients are stored as adjustment settlement values when a chromaticity of a pattern image on a liquid crystal module 11 becomes target one. The microcomputer 7 reflects the adjustment settlement values on the gamma table to generate a gamma table for adjustment, and a gamma processing apparatus 10 is provided which performs gamma processing based on the gamma table for adjustment. Thus a pattern necessary for white balance adjustment can be outputted by using the gamma table for use in normal image processing. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a television receiver provided with a liquid crystal module and a white balance adjusting method in the television receiver.

  Conventionally, in this type of television receiver, the chromaticity of the video output to the liquid crystal module may vary due to the liquid crystal film thickness of the liquid crystal panel and the color of the backlight. In order to deal with this, prior to normal viewing, as shown in FIG. 2, it is necessary to adjust the white balance by performing gamma processing on the video signal using a gamma table having linear input / output characteristics.

  When performing such white balance adjustment, generally, an adjustment pattern is input from the outside, a pattern image output to the liquid crystal module is measured with a chromaticity meter or the like, and a variation in chromaticity is corrected ( Hereinafter, the pattern external input adjustment method is frequently used (see, for example, Patent Document 1).

In addition, there is a method (hereinafter referred to as a pattern internal generation adjustment method) in which an adjustment pattern is provided inside and adjustment is performed using the image so that it is not necessary to input the adjustment pattern from the outside.
JP-A-10-133163

  However, these methods have the following disadvantages.

  First, in the pattern external input adjustment method, it is necessary to prepare a signal generator that outputs an adjustment pattern, and an adjustment operator (such as a serviceman) must always carry the signal, which is inefficient. In addition, the output of the signal generator must be calibrated at all times, which is expensive to manage.

  On the other hand, in the pattern internal generation adjustment method, it is not necessary to prepare a signal generator. However, since an adjustment pattern must be built in the product, a memory for storing the pattern is required, and the cost for that is generated. If the number of patterns to be stored increases, it is necessary to increase the memory accordingly, and the cost further increases.

  It is an object of the present invention to provide a television receiver and a white balance adjustment method that can eliminate such disadvantages.

First, the television receiver according to claim 1 is a television receiver in which a video signal is subjected to gamma processing using an independent gamma table for each of R, G, and B, and is output to a liquid crystal module. Adjustment coefficient input means for inputting R, G, B adjustment coefficients, table rewriting means for rewriting the gamma table based on the adjustment coefficients, and the chromaticity of the pattern image on the liquid crystal module becomes the target chromaticity. Memory means for storing the adjustment coefficient as an adjustment confirmation value, table creation means for creating the adjustment gamma table by reflecting the adjustment confirmation value in the gamma table, and a gamma based on the adjustment gamma table. And gamma processing means for processing.
Further, the invention of the white balance adjustment method according to claim 2 is a method of adjusting white balance in a television receiver in which a video signal is subjected to gamma processing using an independent gamma table for each of R, G, and B and output to a liquid crystal module. An adjustment coefficient input step for inputting adjustment coefficients for R, G, and B upon adjustment, a table rewriting step for rewriting the gamma table based on the adjustment coefficient, and a chromaticity of the pattern image on the liquid crystal module as targets A memory step of storing the adjustment coefficient as an adjustment confirmation value when the chromaticity of the image becomes, a table creation step of creating an adjustment gamma table by reflecting the adjustment confirmation value in the gamma table, and the adjustment gamma And a gamma processing step of performing gamma processing based on the table.
According to a third aspect of the present invention, there is provided a white balance adjustment method including a chromaticity measurement step of measuring a chromaticity of the pattern image.

  According to the present invention, since a pattern necessary for white balance adjustment can be output using a gamma table used in normal video processing, a conventional white balance adjustment method (pattern external input adjustment method, pattern internal generation adjustment method) The white balance can be adjusted efficiently and inexpensively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the television receiver 1 includes an A / D converter 2 that converts an input analog video signal into digital video data, and a contrast of video digitized by the A / D converter 2. A video processing device 3 that processes video such as color and hue, a gamma processing device 10 having a look-up table that converts output luminance in accordance with the luminance level of the video signal processed by the video processing device 3, and video And a liquid crystal module 11 for displaying. A microcomputer (microcomputer) 7 is connected to the video processing device 3. The microcomputer 7 stores the operation key 4, the RS232C serial communication means 12, the remote control light receiving unit 6, the adjustment coefficient determined by the white balance adjustment, and the RGB adjustment coefficient memory 8 from which the adjustment coefficient is read out normally. The gamma table memory 9 used for normal and adjustment use is used as a buffer for transferring the gamma table used based on the normal viewing and the gamma table generated based on the white balance adjustment coefficient to the gamma processing device 10. It is connected. The remote control light receiving unit 6 outputs various control signals to the microcomputer 7 based on signals from the remote control 5. In the gamma table memory 9, an independent gamma table is stored for each of R, G, and B.

  Since the television receiver 1 has the above-described configuration, when performing the white balance adjustment in the television receiver 1, as described below, the microcomputer is based on the white balance adjustment flowchart FC shown in FIG. 7 and the adjustment operator perform various operations.

  First, the adjustment process is started (step S1 of the white balance adjustment flowchart FC), and the microcomputer 7 instructs the image processing device 3 to display the microcomputer software version, various image adjustment items, and the like. In response to this, the video processing device 3 displays the microcomputer software version, various video adjustment items, and the like on the liquid crystal module 11 (step S2 of the white balance adjustment flowchart FC).

  Next, the microcomputer 7 enters an operation for determining whether or not the white balance adjustment start key on the remote controller 5 has been pressed (step S3 in the white balance adjustment flowchart FC). If the microcomputer 7 determines that the white balance adjustment start key has been pressed, the microcomputer 7 reads the adjustment coefficient from the RGB adjustment coefficient memory 8 (step S4 in the white balance adjustment flowchart FC), and performs gamma table correction processing (white balance). Step S5) of the adjustment flowchart FC. Here, the gamma table correction process means that an adjustment gamma table is generated using the adjustment coefficient read from the RGB adjustment coefficient memory 8. As shown in FIG. 3, the gamma table is generated so that the output is constant with respect to the input. The generated gamma table is developed in the gamma table memory 9 and transferred to the gamma processing device 10. Since R, G, and B have the same value when not adjusted, a gamma table with the same output is generated for all of R, G, and B, as shown in FIG. As shown in FIG. 3, when a gamma table whose output is constant “48” with respect to the input is set in the gamma processing device 10, the output of the output is the constant output set in the gamma table memory 9. A uniform luminance pattern (raster image) is displayed on the entire screen (step S6 of the white balance adjustment flowchart FC).

  Next, the adjustment operator measures the chromaticity of an image output to the liquid crystal module 11 through the gamma processing device 10 in which the adjustment gamma table is set, and measures the chromaticity by using a chromaticity meter (not shown). The adjustment coefficient is changed using the operation key 4, the RS232C serial communication unit 12, or the adjustment coefficient input unit of the remote controller 5 so that the R, G, and B values become chromaticity coordinates. Then, the adjustment operator determines whether or not the output xy (chromaticity diagram coordinates) of the chromaticity meter has reached a target value. For example, when the target value is x = 0.300 and y = 0.300, if it is within ± 0.005, it is determined that the target has been reached.

  At this time, the microcomputer 7 checks whether or not any of the R, G, and B adjustment coefficients is changed (step S7 in the white balance adjustment flowchart FC). Are stored in the RGB adjustment coefficient memory 8 (step S8 of the white balance adjustment flowchart FC), and the process returns to the adjustment coefficient reading process (step S4 of the white balance adjustment flowchart FC). FIG. 4 exemplifies the gamma table having such a change, and the output value of R is set to “40” lower than the output value “48” of G and B. Then, the gamma table correction process (step S5 in the white balance adjustment flowchart FC) is executed again, and a raster image reflecting the output value of the gamma table whose adjustment coefficient is changed is output to the liquid crystal module 11 (white balance adjustment). Step S6) of the flowchart FC.

  Then, the adjustment operator measures the video on which the adjustment coefficient is reflected again with the chromaticity meter, and repeatedly changes the adjustment coefficient until the target chromaticity is reached. Then, the adjustment coefficient when the target chromaticity is reached is set as the adjustment confirmation value.

  As points for performing white balance adjustment, when the video level is 255 gradations, as shown in FIG. 2, a low gradation side adjustment point (for example, “48”) and a high gradation side adjustment point (for example, , “200”), and the white balance of the entire input video level is adjusted. Here, although there are two adjustment points “48” and “200” in FIG. 2, an arbitrary number of adjustment points can be set. In the case of fine adjustment, it is also possible to suppress variations in the color of the liquid crystal module over the entire video signal level by increasing the adjustment points. As the number of adjustment points increases, the adjustment coefficient storage area of the RGB adjustment coefficient memory 8 increases, but the adjustment pattern only changes the output value of the gamma table to a constant output, and the memory due to the increase of the adjustment pattern. No additional installation is required. In addition, there is a method in which the adjustment point is adjusted to about 2 to 4 points by limiting the adjustment point to a point having a large color variation according to the characteristics of the liquid crystal module, thereby suppressing the overall variation.

  Here, the white balance adjustment work is completed, and the target chromaticity is obtained.

  After the white balance adjustment operation is completed in this way, in the normal viewing state, the analog video signal is converted into a digital signal by the A / D converter 2, processed by the video processing device 3, and gamma processed by the gamma processing device 10. Is output to the liquid crystal module 11.

  At this time, the microcomputer 7 reads the adjustment confirmation value from the RGB adjustment coefficient memory 8 and reflects this adjustment confirmation value in the gamma table. Then, after the input / output characteristics of the gamma table are appropriately changed and the adjustment gamma table is created, it is used at the time of gamma processing in the gamma processing apparatus 10. FIG. 5 shows an example of the adjustment gamma table, in which the R output value is set lower than the G and B output values. As a result, it is possible to output an image in which the chromaticity variation of the liquid crystal module 11 is corrected in the normal viewing state.

  In this way, the gamma table used during normal viewing can be used to output the pattern necessary for white balance adjustment, compared to the conventional white balance adjustment methods (pattern external input adjustment method, pattern internal generation adjustment method). The white balance can be adjusted efficiently and inexpensively.

It is a control block diagram of the television receiver according to the present invention. It is a graph which shows the input-output characteristic of the gamma table at the time of no adjustment. 6 is a graph showing input / output characteristics of a gamma table at the start of white balance adjustment. It is a graph which shows the input-output characteristic of a gamma table after the completion of white balance adjustment. It is a graph which shows the input-output characteristic of the gamma table in which the white balance adjustment coefficient was reflected. It is a figure which shows a white balance adjustment flowchart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Television receiver 2 ... A / D converter 3 ... Video processing device 4 ... Operation key (Adjustment coefficient input means)
5. Remote control (adjustment coefficient input means)
7. Microcomputer (table rewriting means, table creating means)
8. RGB adjustment coefficient memory (memory means)
10: Gamma processing device (gamma processing means)
11: Liquid crystal module 12: RS232C serial communication means (adjustment coefficient input means)
FC: White balance adjustment flowchart

Claims (3)

A television receiver in which a video signal is subjected to gamma processing using an independent gamma table for each of R, G, and B and output to a liquid crystal module,
Adjustment coefficient input means for inputting R, G, and B adjustment coefficients;
Table rewriting means for rewriting the gamma table based on the adjustment coefficient;
Memory means for storing the adjustment coefficient as an adjustment confirmation value when the chromaticity of the pattern image on the liquid crystal module reaches a target chromaticity;
Table creation means for creating an adjustment gamma table by reflecting the adjustment confirmation value in the gamma table;
A television receiver comprising: gamma processing means for performing gamma processing based on the gamma table for adjustment. When adjusting the white balance in a television receiver in which a video signal is gamma processed using an independent gamma table for each of R, G, and B and output to a liquid crystal module.
An adjustment coefficient input step for inputting adjustment coefficients for R, G, and B;
A table rewriting step of rewriting the gamma table based on the adjustment coefficient;
A memory step of storing the adjustment coefficient as an adjustment confirmation value when the chromaticity of the pattern image on the liquid crystal module reaches a target chromaticity;
A table creation step of creating an adjustment gamma table by reflecting the adjustment confirmation value in the gamma table;
And a gamma processing step of performing gamma processing based on the gamma table for adjustment.   The white balance adjustment method according to claim 2, further comprising a chromaticity measurement step of measuring chromaticity of the pattern image.

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