JPH06326942A - Method and device for controlling electronic display - Google Patents

Abstract

PURPOSE:To correct an image with white blur, black floating or the like by detecting the distributed state of display picture elements in a dark luminance part and a bright luminance part on a display screen and adjusting brightness and contrast in accordance with the distributed state. CONSTITUTION:An input picture obtained from a matrix part 2 is converted into a digital signal by an A/D conversion part 10. A black area control part 11 detects a dark luminance part in a display picture based upon a luminance signal in the input video signal. A white area control part 12 detects a bright part in the display picture. When the contrast of the display screen is not formed and both of the distribution value of display picture elements in the black area and that in the white area are less than reference values, the control parts 11, 12 respectively output control signals for reducing brightness and increasing contrast. The brightness and contrast signals are corrected by a control part 13 so that the brightness of the display screen is reduced and the contrast is increased.

Description

Detailed Description of the Invention

[0001]

This invention relates to an electronic display (L
The present invention relates to a video signal processing and display technology in a CD (liquid crystal), a PDP (plasma display), etc., and more particularly to a control method and an apparatus for an electronic display that makes a screen contrast good.

[0002]

2. Description of the Related Art In CRT electronic displays,
The beam current of the CRT is detected, and for example, when the entire display screen is bright, the brightness is lowered (ABL) and the contrast is lowered (ACL) to reduce the brightness of the display screen and prevent the image from being crushed.

On the other hand, a control device for an electronic display such as an LCD or PDP has, for example, the configuration shown in FIG. 4, and has an A / D converter 1 for digitally converting an input video signal (RGB primary color video signal) and the same input video. The matrix section 2 for obtaining the luminance signal Y (luminance of the screen) of the signal, the integrating section 3 for integrating the Y signal to detect the brightness amount of the display screen, and the predetermined coefficient different for each signal of the same brightness amount. The coefficient units 4 and 5 to be multiplied, the adder units 6 and 7 for respectively adding the signal multiplied by the coefficient and the bright and contrast control signals, and the control signals obtained by the adder units 6 and 7 are subjected to the above digital conversion. An amplification unit 8 for brightening and contrast-correcting a signal is provided.

In this case, in the same manner as described above, in the bright portion of the screen, the brightness of the bright and contrast can be reduced to correct the bright and contrast signals so that white is not destroyed. It should be noted that whiteout refers to a state in which gradation cannot be obtained in a bright portion of the display screen.

[0005]

By the way, in the adjustment of the brightness and the contrast of the electronic display,
It is effective for bright screens (although it is effective for whiteout), but for example, it cannot be corrected for images with few bright areas, and has no effect for images with black floating,
There was a problem that the image contrast was poor. It should be noted that the term "black floating" refers to a state in which the brightness of the dark portion (black) of the display screen is not sufficiently low.

The present invention has been made in view of the above problems, and an object thereof is not only to make the display image whiteout, but also to adjust the brightness and contrast not only for an image with few bright portions or an image with black floating. An object of the present invention is to provide a control method of an electronic display and an apparatus therefor capable of improving a display image.

[0007]

In order to achieve the above object, the present invention, when displaying an image by an input video signal on an electronic display, controls the brightness and contrast control signals by the luminance signal of the input video signal. In a control method of an electronic display, which is corrected to increase the brightness and contrast of the electronic display, a distribution state of a dark portion (black area) of the display screen and a bright portion (white area) of the display screen by the luminance signal. Is detected, and the bright and contrast signals are corrected for a portion equal to or less than a predetermined reference value to increase the bright and contrast of the screen of the electronic display.

[0008]

With the above means, the brightness of the display screen is detected by the distribution of the display pixels corresponding to the black area and the white area, and both the bright and contrast signals are corrected according to this distribution. For example, when there is no contrast, the bright and contrast signals are corrected so as to increase the contrast of the small display screen. Therefore, it is possible to correct not only whiteout, but also an image such as black floating, and an image with high contrast can be obtained.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An electronic display control method and apparatus according to the present invention detect a distribution of display pixels corresponding to a dark portion (black area) of a display screen and correspond to a bright portion (white area). The distribution of the display pixels to be detected is detected, the brightness and the contrast are adjusted according to the detection, and the distribution is widened to increase the contrast of the display screen.

Therefore, as shown in FIG. 1, this electronic display control device includes an A / D converter 10 for digitally converting the luminance signal Y of the input video signal (RGB primary color video signal) obtained by the matrix unit 2. A black area control unit 11 that detects the number of display pixels in a dark portion (black area) by the digital luminance signal Y, and a white area control unit 12 that detects the number of display pixels in a bright portion (white area) by the luminance signal Y.
And a control for outputting the control signal of the amplifier 8 in order to correct the D / A output (bright, contrast) of the microcomputer according to the detection signals from the black area controller 11 and the white area controller 12 in accordance with Table 1 below. Part 13
It has and. In the figure, the same parts as those in FIG. The black area and the white area are, for example, 15% to 20% of the relative luminance of the input video signal.
%.

[0011]

[Table 1] The black area control section 11 counts the black area detection section 11a that detects a black area (for example, 1 to 16; see FIG. 2) of a dark area of the screen based on the digital brightness signal, and the digital brightness signal of the black area. However, the first distribution number counter unit 11b that outputs the same count value when it is less than or equal to a predetermined value (for example, 5% of the total number of display pixels) and the first latching the count value (the number of black region distributions) And a D / A converter 11d for converting the distribution number latched in the first latch unit 11c into an analog signal.

The white area control unit 12 uses the digital luminance signal to display a white area (for example, 240 to
255; see FIG. 2).
And a second distribution number counter unit 12b that counts the digital luminance signal in the white area and outputs the same when the predetermined value (for example, 5% of the total number of display pixels) or less, and the count value (white The second latch unit 11c for latching the distribution number of the area) and the D / A conversion unit 11d for analog-converting the distribution number latched by the second latch unit 11c are provided.

The control section 13 has coefficient sections 13a and 13b for multiplying the detection signal of the distribution state of the black portion by the black area control section 11 by different predetermined coefficients, and a coefficient section for multiplying the detection signal by the white area control 12 by a predetermined coefficient. 13c and coefficient part 13a
Adder 13d that adds the detection signal of the black partial distribution state that has passed through to the bright signal of the D / A output of the microcomputer to obtain the bright control signal of the electronic display.
And an addition unit 13e for adding the detection signal of the white partial distribution state that has passed through the coefficient unit 13c to the contrast signal of the D / A output of the microcomputer, and the contrast control signal obtained by this addition unit 13e through the coefficient unit 13b. And an adder 13f for adding the detection signals of the black partial distribution state to obtain the contrast control signal of the electronic display.

Next, the operation of the electronic display controller and the operation of the control method will be described in detail with reference to the graphs of FIGS.

First, an image by an input video signal (RGB primary color video signal) is displayed on an electronic display (LCD or PDP).
And the like, the black area control unit 11 detects a dark portion of the display image based on the luminance signal (digital) of the input video signal, and the white area control unit 12 detects a bright portion of the display image. To detect.

As shown in FIG. 2, when the display image is bright and the screen contrast is high, for example, both the distribution number of display pixels in the black area and the distribution number of display pixels in the white area in FIG. (5% of the total number of display pixels) is exceeded.

In this case, the black area control section 11 and the white area control section 12 output a control signal that does not correct the brightness and the contrast, as is apparent from Table 1. That is, the first and second distribution number counter units 11
b and 12b are a black area detection unit 11a and a white area detection unit 1
D / A without outputting the count value of the number of detected distributions by 2a
The outputs of the conversion units 11d and 12d become zero. This allows
The bright and contrast signals of the D / A output of the microcomputer are used as the control signals as they are in the amplifier 8
, The contrast of the screen remains as it is, and as described in the conventional example, white is not crushed on a bright screen, for example.

On the other hand, as shown in FIG. 3, the display screen is not contrasted, and the number of display pixels distributed in the black region and the number of display pixels distributed in the white region are both reference values (total display). 5% or less of the number of pixels), the black area control unit 11 and the white area control unit 12
Outputs a control signal for lowering the brightness and increasing the contrast, as is clear from Table 1. That is, the first
The second distribution number counter units 11b and 12b output the count values of the distribution numbers detected by the black region detection unit 11a and the white region detection unit 12a, and the D / A conversion units 11d and 12d.
Outputs a control signal corresponding to the count value.

The output control signal of the D / A conversion section 11d is multiplied by a predetermined coefficient (negative value) in the coefficient section 13a, and this control signal is added to the bright signal which is the D / A output of the microcomputer. It is used as a bright control signal for the electronic display. Further, the output control signal of the D / A conversion unit 12d is multiplied by a predetermined coefficient (positive value) in the coefficient unit 13b, and the output control signal of the D / A conversion unit 12d is multiplied by the coefficient unit 13b.
A predetermined coefficient (a positive value) is multiplied by c.

The control signal passed through the coefficient unit 13c is added to the contrast signal which is the D / A output of the microcomputer in the addition unit 13e, and the signal of the addition result is the control signal passed through the coefficient unit 13b in the addition unit 13f. To be a contrast control signal for the electronic display.

As in the prior art, the control signal that has passed through the coefficient unit 13a is added to the D of the microcomputer by the addition unit 13d.
/ A output is added to the bright signal, and the addition result is used as the bright control signal of the electronic display.

That is, D of the microcomputer
The bright and contrast signals of the / A output are controlled by the control unit 1.
In step 3, the brightness of the display screen is lowered and the contrast is increased.

In other words, the bright and dark portions of the screen having a small number of distributions are corrected by the corrected bright and contrast control signals, so that the contrast of the display screen is increased. Therefore, the black floating on the display screen is also corrected, and an image with high contrast can be obtained.

When the number of distributions in the dark portion of the display screen is below the reference value and the number of distributions in the bright portion of the display screen exceeds the reference value, as is clear from Table 1, The bright signal of the D / A output of the microcomputer is corrected by the control unit 13 so as to lower the brightness of the display screen, and the contrast signal of the D / A output remains unchanged.

Further, when the number of distributions in the bright portion of the display screen is less than the reference value and the number of distributions in the dark portion of the display screen exceeds the reference value, as is clear from Table 1, The contrast signal of the D / A output of the microcomputer is corrected by the controller 13 so as to increase the contrast of the display screen, and the bright signal of the D / A output is left unchanged.

In this way, the distribution of dark portions (display pixels) and bright portions (display pixels) of the display screen of the electronic display is detected, and the D / of the microcomputer is determined according to the detected distribution state. A
Since the output bright and contrast signals are corrected, the white of the display screen will not be crushed as in the conventional case, and an image with high contrast can be obtained even with respect to black floating and the image quality can be improved. .

[0027]

As described above, according to the present invention, the distribution state of the display pixels in the dark portion and the bright portion of the display screen is detected, and the brightness and the contrast are adjusted according to the detected distribution state. I adjusted it to widen the distribution of the bright and dark areas.
It is possible to obtain not only the whiteout of the display image but also the image in which black is floating, etc., so that an image with high contrast can be obtained, and thus the display image can be improved.

[Brief description of drawings]

FIG. 1 is a schematic partial block diagram of a control device for an electronic display showing an embodiment of the present invention.

FIG. 2 is a schematic graph illustrating the operation of the control device for the electronic display shown in FIG. 1 and the operation of the control method.

FIG. 3 is a schematic graph illustrating the operation of the control apparatus for the electronic display shown in FIG. 1 and the operation of the control method.

FIG. 4 is a schematic block diagram of a conventional electronic display controller.

[Explanation of symbols]

 1, 10 A / D conversion section 2 Matrix section 8 Amplification section 11 Black area control section 11a Black area detection section 11b First distribution number counter section 11c First latch section 11d D / A conversion section 12 White area control section 12a White area detection unit 12b Second distribution number counter unit 12c Second latch unit 12d D / A conversion unit 13 Control unit 13a, 13b, 13c Coefficient unit 13d, 13e, 13f Adder unit

Claims (3)

[Claims] 1. When controlling an electronic display to display an image based on an input video signal on an electronic display, a brightness signal of the input video signal is used to correct the bright and contrast control signals to increase the brightness and contrast of the electronic display. In the method, the distribution state of a dark portion (black area) of the display screen and a bright portion (white area) of the display screen is detected by the luminance signal, and the bright portion is detected for a portion of a predetermined reference value or less. And a method of controlling an electronic display, characterized in that the contrast signal is corrected to increase the brightness and contrast of the screen of the electronic display. 2. Control of an electronic display for increasing the brightness and contrast of the electronic display by correcting the bright and contrast control signals according to the luminance signal of the input video signal when displaying an image based on the input video signal on the electronic display. In the method, the luminance signal is digitally converted, and a dark portion (black area) of the display screen and a bright portion (white area) of the display screen are converted by the digitally converted signal.
The distribution of the display pixels corresponding to is detected, and for the portion where the distribution is less than or equal to a predetermined reference value, the bright or contrast signal is corrected to be a bright or contrast control signal of the electronic display, and the number of distribution is predetermined. A method for controlling an electronic display, characterized in that, for a portion exceeding a reference value, the bright or contrast signal is used as it is as a bright or contrast control signal of the electronic display. 3. Control of an electronic display for increasing the brightness and contrast of the electronic display by correcting the bright and contrast control signals according to the luminance signal of the input video signal when displaying an image based on the input video signal on the electronic display. In the device, A / D conversion means for digitally converting the luminance signal, and a distribution of display pixels corresponding to a dark portion (black area) of the display screen is detected by the digitally converted signal, and the distribution is determined to be a predetermined reference. When it is less than the value, a black area control means for outputting a control signal for correcting the bright or contrast signal, and a distribution of display pixels corresponding to a bright portion of the display screen is detected by the digitally converted signal, When the distribution is less than a predetermined reference value, the contrast signal is corrected. And a white area control means for outputting a control signal for controlling the bright or contrast signal using the output control signals from the black area control means and the white area control means to obtain a bright or contrast control signal for the electronic display. An electronic display control device comprising: a control means.