JPH06105331A - Television receiver - Google Patents

Abstract

(57) [Summary] [Purpose] To make the white balance constant for all luminance levels including the intermediate luminance level. [Structure] The R, G and B channels are respectively
The conversion tables 4, 5 and 6 are inserted. The conversion data stored in the conversion tables 4, 5 and 6 is created by the data creating circuit 12. This allows the gains to be set non-linearly independently for the R, G, and B channels.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver.

[0002]

2. Description of the Related Art Conventionally, white balance adjustment of a television receiver is performed by adjusting a bias level of a signal supplied to a display cathode-ray tube with respect to a "dark gray level" (low brightness level). Regarding (high brightness level), it is performed by adjusting the level of the signal supplied to the display CRT.

[0003]

In the above-mentioned conventional method, due to variations in the characteristics of the beam current sensitivity of the R, G and B phosphors, there is a difference between the "dark gray level" and the "white level". There is a problem that the white balance at the intermediate luminance level deviates from the required value.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a television receiver capable of setting a constant white balance for all luminance levels including an intermediate luminance level. And

[0005]

A television receiver according to claim 1 has an R channel, a G channel and a B channel.
Gain setting means (for example, the R channel conversion table 4, the G channel conversion table 5, the B channel conversion table 6, and the conversion table data creation circuit 12 of the embodiment) capable of independently setting the gain nonlinearly for each channel is provided. It is characterized by

A television receiver according to a second aspect is
A gain setting means is provided for each of the R channel, G channel and B channel and stores conversion data of the corresponding channel (for example, R channel conversion table 4, G channel conversion table 5, B channel conversion of the embodiment). Table 6) and conversion data creating means for creating conversion data stored in the conversion table (for example, conversion table data creating circuit 1 of the embodiment).
2) and, the conversion data creating means is an R channel,
When a signal of an intermediate brightness level is supplied to the G channel and the B channel, the white balance becomes a required value based on the output of the sensor that measures the brightness of each of the R, G, and B phosphors of the display CRT. Characterized by creating conversion data.

The television receiver according to claim 3 is
The conversion data creating means creates interpolation data between the conversion data regarding the intermediate luminance level and the conversion data regarding the high luminance level, and interpolation data between the conversion data regarding the intermediate luminance level and the conversion data regarding the low luminance level. Is characterized by.

[0008]

In the television receiver having the structure of the first aspect, the gain can be set non-linearly independently for the R channel, the G channel and the B channel. Therefore, the white balance can be set to be constant at all the brightness levels including the intermediate brightness level.

According to another aspect of the television receiver of the present invention, the R, G and B phosphors of the display cathode-ray tube are supplied when signals of intermediate luminance level are supplied to the R, G and B channels. Based on the output of the sensor that measures the luminance of, the conversion data for which the white balance is the required value is created and stored in the conversion table of each channel. Therefore, the white balance of the intermediate brightness level can be set to a required value.

According to another aspect of the television receiver of the present invention, the interpolation data between the conversion data regarding the intermediate luminance level and the conversion data regarding the high luminance level, and the conversion data regarding the intermediate luminance level and the conversion data regarding the low luminance level. Interpolation data between and are created. Therefore, the white balance can be set to a required value in the entire brightness area.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the configuration of an embodiment of a television receiver of the present invention. The R channel A / D converter 1 is
The analog R signal input to the channel is A / D converted and a digital R signal is output. The G channel A / D converter 2 A / D converts the analog G signal input to the G channel and outputs a digital G signal. The B channel A / D converter 3 A / D converts the analog B signal input to the B channel and outputs a digital B signal.

The R channel conversion table 4 stores the conversion data for the R channel, and inputs the digital R channel.
The R channel conversion data corresponding to the signal is output.
The G channel conversion table 5 stores the G channel conversion data and outputs the G channel conversion data corresponding to the input digital G signal. The B channel conversion table 6 stores the B channel conversion data and outputs the B channel conversion data corresponding to the input digital B signal.

The R channel D / A converter 7 D / A converts the R channel conversion data output from the R channel conversion table 4, and outputs analog R channel conversion data. The G channel D / A converter 8 is
The G channel conversion data output from the channel conversion table 5 is D / A converted to output analog G channel conversion data. B channel D / A converter 9
Performs D / A conversion of the B channel conversion data output from the B channel conversion table 6 and outputs analog B channel conversion data.

The display cathode-ray tube 10 includes analog R, G and B output from the D / A converters 7, 8 and 9.
The channel conversion data is received and the images corresponding to these are displayed. The R, G, B light sensor 11 measures the brightness of each of the R, G, B phosphors of the display cathode-ray tube 10. The conversion table data generation circuit 12, the R channel, the G channel, and the B channel have a dark gray level signal (low luminance signal), an intermediate luminance level gray signal,
Alternatively, when a white level signal (high brightness signal) is supplied, based on the output of the optical sensor 11, in accordance with the adjustment data input, R, G, and B channel conversion data for which the white balance becomes a required value is created, R and G respectively
And B conversion tables 4, 5 and 6 are output.

First, in order to adjust the white balance at low brightness, signals of dark gray level are set to R, G and B.
Input to the channel, conversion table data creation circuit 12
On the basis of the output of the optical sensor 11 according to the adjustment data input, DC of each of the R, G and B channels.
The conversion data of the R, G and B conversion tables 4, 5 and 6 is rewritten with the conversion data thus created by changing the bias to change the R, G and B channel conversion data. Make it the required value. The input levels of the A / D converters 1, 2 and 3 of the R, G and B channels and the D / of the R, G and B channels when such adjustment is performed
The relationship with the output levels of the A converters 7, 8 and 9 is shown in FIG.
Shown in (a), (b) and (c).

Next, in order to adjust the white balance at high brightness, a white level signal is input to the R, G and B channels, and the conversion table data creating circuit 12 adjusts it based on the output of the optical sensor 11. In accordance with the data input, R, G, and B channel conversion data that changes the slopes of the gains of the R, G, and B channels are created, and the created conversion data is used as the R, G, and B conversion tables 4, 5, and 6. The converted data is rewritten so that the output of the optical sensor 11, that is, the white balance has a required value. R and G when such adjustment is performed
3 (a) shows the relationship between the input levels of the A / D converters 1, 2 and 3 of the B and B channels and the output levels of the D / A converters 7, 8 and 9 of the R, G and B channels.
Shown in (b) and (c).

Two of the dark gray and white levels mentioned above.
In the white balance adjustment by measuring only the points, the white balance may deviate from the required value because the sensitivity curves of the phosphors differ among R, G, and B at the intermediate brightness level. Therefore, a signal requiring intermediate luminance is input to the R, G, and B channels, and the conversion table data creation circuit 12 determines the gain of each of the R, G, and B channels according to the adjustment data input based on the output of the optical sensor 11. R, G to change
And B channel conversion data are created, and the conversion data of the R, G and B conversion tables 4, 5 and 6 are rewritten with the created conversion data so that the output of the optical sensor 11, that is, the white balance becomes a required value. On this occasion,
Since the conversion table data creation circuit 12 has already adjusted the high-luminance and low-luminance conversion data, it creates the interpolated conversion data other than the measurement points in order to have continuity with the set conversion data at the intermediate brightness. Then, the conversion data is created so that the white balance has a required value in the entire luminance region. A / D of R, G, and B channels when such adjustment, that is, conversion data creation is performed
Input levels of converters 1, 2 and 3 and R, G and B
The relationships between the output levels of the D / A converters 7, 8 and 9 of the channels are shown in FIGS. 4 (a), (b) and (c).

In this way, a constant white balance can be obtained at all brightness levels.

[0019]

According to the television receiver of the first aspect, the gain can be set non-linearly independently for the R channel, the G channel and the B channel, so that all the luminance levels including the intermediate luminance level can be set. In, the white balance can be set to be constant and faithful image reproduction becomes possible. Also, by adjusting the gains in the vicinity of the selected luminance level of the selected channels of the R, G, and B channels, it becomes possible to partially emphasize or partially erase the display image.

According to the television receiver of claim 2,
When an intermediate luminance level signal is supplied to the R channel, G channel, and B channel, white balance is required based on the output of the sensor that measures the luminance of each of the R, G, and B phosphors of the display CRT. Since the conversion data as a value is created and stored in the conversion table of each channel, the white balance of the intermediate brightness level can be set to a required value.

According to the television receiver of claim 3,
Since the interpolation data between the conversion data regarding the intermediate luminance level and the conversion data regarding the high luminance level and the interpolation data between the conversion data regarding the intermediate luminance level and the conversion data regarding the low luminance level are created, the total luminance is calculated. The white balance can be set to a required value in the area.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a television receiver of the present invention.

FIG. 2 is a diagram showing white balance adjustment at a low luminance point in the embodiment of FIG.

FIG. 3 is a diagram showing white balance adjustment at a high luminance point in the embodiment of FIG.

FIG. 4 is a diagram showing white balance adjustment at intermediate luminance in the embodiment of FIG.

[Explanation of symbols]

 4 R channel conversion table 5 G channel conversion table 6 B channel conversion table 10 CRT for display 11 R, G, B light sensor 12 conversion table data creation circuit

Claims (3)

[Claims] 1. A television receiver comprising gain setting means capable of independently and independently setting gains for R channel, G channel and B channel. 2. The gain setting means is an R channel,
It is provided in G channel and B channel respectively,
It has a conversion table for storing the conversion data of the corresponding channel and a conversion data creating means for creating the conversion data stored in the conversion table, wherein the conversion data creating means is an R channel, a G channel and a B channel. When a signal of an intermediate luminance level is supplied to, the conversion data for which the white balance becomes a required value is created based on the output of the sensor that measures the luminance of each of the R, G, and B phosphors of the display CRT. The television receiver according to claim 1, wherein: 3. The conversion data creating means includes interpolation data between the conversion data regarding the intermediate brightness level and the conversion data regarding the high brightness level, and between the conversion data regarding the intermediate brightness level and the conversion data regarding the low brightness level. The television receiver according to claim 2, wherein interpolation data is created.