JPH06332399A - Method for controlling electronic display and device therefor - Google Patents

Abstract

PURPOSE:To improve picture quality by providing a contrasted image even on an LCD and PDP with a small dynamic range when the image is displayed on the LCD and the PDP, etc. CONSTITUTION:When the image by an input video signal is displayed on an electronic display, the input video signal (RGB primary colors video signals) is digital-converted by an A/D conversion part 1, and the digital-converted signal is corrected to a prescribed form by a correction pattern in a correction ROM 2. By the digital-converted signal, two bits data detecting the number of distributions of a display pixel corresponding to a dark part (black area) of luminance of a display picture by a black area detection part 3 and comparing and providing two different reference values, and two bits data detecting the number of distribution of the display pixel corresponding to a bright part (white area) of luminance of the display picture by a white area detection part 4 and comparing and providing two different reference values are obtained, and the obtained data are converted by an upper address conversion part 4 to be made the upper address of the correction ROM 2, and the prescribed correction pattern among plural correction patterns of the correction ROM 2 is selected, and the black area and the white area are corrected.

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 method and apparatus for controlling an electronic display that makes the screen bright and contrast good.

[0002]

2. Description of the Related Art In electronic displays such as LCDs and PDPs, it is necessary to display contrasted images in order to use them for wall televisions, for example.

However, LCDs and PDPs have a small dynamic range and it is difficult to obtain contrast. Therefore, for example, by detecting the drive voltage of the display pixel and adjusting the input video signal (RGB primary color video signal) according to the drive voltage, the display screen is crushed (or dark) or crushed (or black). ) Can be corrected.

It should be noted that the underexposure means a state in which the gradation of a bright image cannot be obtained, the underexposure is a state in which the gradation of a dark portion cannot be obtained, and the underexposure of black is sufficient for a dark portion. It refers to the state where it does not get dark.

[0005]

However, in the control method of the electronic display described above, the correction has been made up to now for the white crushing, and the correction for the black crushing has been desired. Therefore, there is a problem that it is difficult to obtain contrast in LCDs and PDPs having a small dynamic range.

Further, in order to obtain an image with good contrast, when the luminance distribution of the display screen by the input video signal is only in the middle, it is necessary to correct the input video signal.

The present invention has been made in view of the above problems, and an object of the present invention is to perform correction on both white crushed (or dark white) and black crushed (or black floating) of a display image, and L with a small range
An object of the present invention is to provide an electronic display control method and apparatus capable of obtaining an image with high contrast even on a CD or PDP.

[0008]

In order to achieve the above-mentioned object, the present invention, when an input video signal is digitally converted and subjected to predetermined processing to display a predetermined image on an electronic display,
The number of distributions of display pixels corresponding to a predetermined black area of the display screen is detected from the signal obtained by the digital conversion, and the number of distributions of display pixels corresponding to a predetermined white area of the display screen is detected. The gist is that the distribution numbers are compared with two different reference values, respectively, and the portions corresponding to the black region and the white region of the signal obtained by the digital conversion are corrected according to the comparison result.

[0009]

With the above means, the black area (dark area) and the white area (bright area) of the display screen are used.
The number of distributions of display pixels corresponding to is detected, and it is determined whether the number of distributions of one reference value A or less is small or not small, and the number of distributions exceeding the other reference value B (> A). It is determined whether or not there are many.

For example, in a blackout area of a display screen, the number of distributions below the reference value A is not small in the black area, and the reference value B
The number of distributions that exceed In the case of whiteout on the display screen, the number of distributions equal to or less than the reference value A decreases, and the number of distributions exceeding the reference value B increases.

The black crush and the white crush are determined by the above comparison, and the portions corresponding to the black area and the white area are corrected according to the determination, that is, the black crushed portion is corrected in the black floating direction. The correction of suppressing the brightness is performed on the whiteout portion.

As described above, since the input signal is corrected according to the distribution number of the display pixels corresponding to the black area and the white area,
For example, it is possible to correct both white crushing (or white sinking) and black crushing (or black floating), and the contrast of a displayed image can be obtained even with an LCD or PDP having a small dynamic range.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An electronic display control method and apparatus according to the present invention include an input video signal (RGB primary color video signal).
The number of distributions of the display pixels corresponding to the dark portion (black area) and the bright portion (white area) of the display screen is detected by the signal obtained by digitally converting the detected distribution number and the two different reference values. By comparison, a predetermined correction pattern is selected, the digitally converted signal is corrected by the selected correction pattern, the brightness of the display screen is corrected, and the image contrast is obtained.

Therefore, as shown in FIG. 1, the control device for this electronic display corrects the A / D converter 1 for digitally converting the input video signal (RGB primary color video signal) and the digitally converted signal. A correction ROM 2 storing a plurality of different correction patterns, and the number of distributions of display pixels in a dark portion (black area) of the display screen is detected by the digital conversion, and the same number of distributions and two reference values A are detected. , B (A <B) in comparison with Table 1 below.
The black area detection unit 3 for outputting 2-bit data shown in FIG. 2 and the digitally converted signal detect the distribution number of display pixels in a bright portion (white area) of the display screen, and the same distribution number and two reference values Table 1 below comparing values A and B
The white area detecting section 4 for outputting the 2-bit data shown in FIG. 2 and the upper area for converting each 2-bit data (total 4-bit data) from the black area detecting section 3 and the white area detecting section 4 into the upper address of the correction ROM 2 The address conversion unit 5 is provided. Note that, in FIG. 1, the γ (gamma) correction unit 6, the double speed conversion unit 7, the D / A conversion unit 8 and the like are already known, and therefore description thereof will be omitted.

[0015]

[Table 1] Regarding Table 1 above, it is "1" when the number of distributions having the reference value A or less is small, and "0" when the number of distributions having the reference value A or less is not small. Further, it is "1" when the number of distributions exceeding the reference value B is large, and is "0" when the number of distributions exceeding the reference value B is not large.

Therefore, as shown in FIG. 2, the black area detection unit 3 detects the distribution number of the display pixels corresponding to the dark portion (black area) of the display screen by the input signal, and the reference value A or less. The number of detected distributions of is small or not small, is the number of detected distributions exceeding the reference value B large,
Alternatively, 2-bit data is output depending on whether there is not much. Specifically, for example, when the number of distributions of black areas equal to or less than the reference value A is large and the number of distributions of black areas exceeding the reference value B is large, that is, when the display screen is in a blackout state,
From the above Table 1, it becomes 2-bit data of "01". In addition,
Black area is 15% to 20% of the relative brightness of the display screen
Is the range.

Further, the white area detecting section 4 detects the distribution number of the display pixels corresponding to the bright portion (white area) of the display screen by the input signal, and whether the distribution number is the reference value A or less. , 2 depending on whether or not the reference value B is exceeded
Output bit data. Specifically, for example, the reference value A
When the number of distributions of the following white areas is not small and the number of distributions of the white areas exceeding the reference value B is large, that is, when the display screen is in a white crushed state, 2-bit data of "10" is obtained. The white area is in the range of 15% to 20% with respect to the relative luminance of the display screen, like the black area.

The correction ROM 2 stores nine types of correction patterns in which the curves a to f shown in FIG. 5 are combined, and the upper address conversion unit 5 converts the data from the black area detection unit 3 and the white area detection unit 4 into data. Based on this, the upper address of the correction ROM 2 is generated.

Next, the operation of the control apparatus for the electronic display having the above-described structure and the operation of the control method will be described with reference to the graphs of FIGS.

First, as shown in FIG. 3, the case where the contrast of the display screen is not taken, for example, the case of the black floating state and the white sinking state will be described. For example, for the black area, the display of the reference value A or less is performed. The distribution number of pixels is small, and the distribution number of display pixels exceeding the reference value B is small,
In the white area, the number of distributions of display pixels having the reference value A or less is small, and the number of display pixels exceeding the reference value B is small.

In this case, as is apparent from Table 1, the black area detection unit 3 outputs 2-bit data of "10",
The white area detection unit 4 outputs 2-bit data of "10".

The higher-order address conversion unit 5 to which the above-mentioned "10" and 4-bit data of "10" have been input is corrected ROM2.
Among the plurality of correction patterns, the upper address for selecting the correction pattern of the curve shown in FIG. 6 (the pattern combining the curves a and e of FIG. 5) is output.

As a result, the input video signal is corrected by the correction ROM 2
Is corrected by a predetermined correction pattern (pattern shown in FIG. 6), that is, the black area is corrected so that black is sunk, and the white area is corrected by increasing white. Therefore, since both blackening and whitening of the display screen are corrected, it is possible to display a high-contrast image even if the electronic display is an LCD or PDP having a small dynamic range.

The digital video signal corrected by the correction ROM section 2 is gamma-corrected by the already-known γ-correction section 6, and the double-speed conversion section 7 and D / A conversion section 8 are further added.
Is converted into a predetermined value and used as a display drive signal for the LCD or PDP.

Here, supplementing the explanation about FIG. 5,
The curve indicated by “a” in the figure is corrected so that the black floats when the black of the display image is crushed due to the large number of black display pixels.
The curve indicated by b in the figure is corrected so as to sink the black when the number of black display pixels is small and the black of the display screen is floating. The curve indicated by d in the figure is corrected so that white is emphasized when the white of the display screen is dark. The curve by e in the figure is
When the number of display pixels of white is large and the white of the display screen is crushed, the correction is performed so as to sink the white.

On the other hand, as shown in FIG. 4, when the contrast of the display screen is set, in the black area, the number of distributions of display pixels equal to or lower than the reference value A is not small, and the display pixels exceeding the reference value B are displayed. Is not large, and the number of display pixels with the reference value A or less is not small in the white area,
The number of display pixel distributions exceeding the reference value B is not large. In this case, as apparent from Table 1, the black area detection unit 3 outputs 2-bit data “00”, and the white area detection unit 4 outputs
Outputs 2-bit data of "00".

The high-order address conversion unit 5 to which the above-mentioned "00" and 4-bit data "00" are input is corrected ROM2.
Of the plurality of correction patterns, the upper address for selecting the correction pattern of the curve indicated by e and f in FIG. 5 is output.

As a result, the input video signal is corrected by the correction ROM 2
Therefore, the correction is performed so that the black area remains unchanged and the white area remains unchanged. Therefore, the contrast remains in the black area and the white area.

In this way, the distribution numbers of the dark and bright parts (display pixels) of the display screen of the electronic display are detected, and the correction pattern for correcting the input video signal is switched in accordance with the detected distribution numbers. Since the same dark and bright areas are corrected, it is possible to obtain an image with high contrast by, for example, correcting both black highlights (or black shadows) and white shadows (or white sinking), and thus dynamic range Even with a small LCD, PDP, or the like, an image with high contrast can be obtained.

[0030]

As described above, according to the present invention, a dark area (black area) and a bright area (white area) of the display screen are darkened by a signal obtained by digitally converting an input video signal (RGB primary color video signal). ), The number of distributions of display pixels corresponding to) is detected, the detected number of distributions are compared with two different reference values to select a predetermined correction pattern, and the digitally converted signal is corrected by the selected correction pattern. Since the plurality of correction patterns are used as the correction data for the dark portion and the light portion, the image having a high contrast is obtained by correcting both the dark portion (black area) and the light portion (white area) of the display screen. LCD with a small dynamic range
It is possible to display an image with high contrast even on a PDP or the like, and it is possible to improve the image quality.

[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.

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

FIG. 5 is a graph diagram of a schematic correction pattern for explaining the operation of the control device for the electronic display shown in FIG. 1 and the operation of the control method thereof.

FIG. 6 is a graph diagram of a schematic correction pattern for explaining the operation of the control device for the electronic display shown in FIG. 1 and the operation of the control method thereof.

[Explanation of symbols]

 1 A / D conversion section 2 Correction ROM 3 Black area detection section 4 White area detection section 5 Upper address conversion section 6 γ correction section 7 Double speed conversion section 8 D / A conversion section a, b, c, d, e, f correction Pattern curve

Claims (3)

[Claims] 1. A distribution of display pixels corresponding to a predetermined black area of a display screen by a signal obtained by digitally converting an input video signal and subjecting it to predetermined processing to display a predetermined image on an electronic display. Detect the number,
The number of distributions of display pixels corresponding to a predetermined white area on the same display screen is detected, the detected number of distributions is compared with two different reference values, respectively, and the signal obtained by the digital conversion according to the comparison result is detected. A method for controlling an electronic display, characterized in that a portion corresponding to a black area and a white area is corrected. 2. When the input video signal is digitally converted and subjected to predetermined processing to display a predetermined image on an electronic display, the number of distributions of display pixels corresponding to a predetermined black area of the display screen is detected by the digitally converted signal. In addition, the number of distributions of display pixels corresponding to a predetermined white area on the same display screen is detected, the detected number of distributions is compared with two different reference values, respectively, and stored in advance according to the comparison result. Control of an electronic display, characterized in that one of a plurality of correction patterns is selected, and a portion corresponding to a black area and a white area of a signal obtained by the digital conversion is corrected by the selected correction pattern. Method. 3. Input video signal (RGB primary color video signal)
In a control device of an electronic display for digitally converting and digitally performing a predetermined process to display a predetermined image on an electronic display, a storage unit that stores a plurality of correction patterns in advance to correct the digitally converted signal in a predetermined manner, With the digitally converted signal, while detecting the distribution number of display pixels corresponding to a predetermined black region of the display screen,
The number of distributions of display pixels corresponding to a predetermined white region of the display screen is determined by a black area detection unit that compares the detected number of distributions with two different reference values and outputs the comparison result, and the digitally converted signal. A white area detecting means for detecting and comparing the detected number of distributions with two different reference values and outputting the comparison result; and output signals of the black area detecting means and the white area detecting means for the upper address of the storage means. Address conversion means for converting into one of a plurality of correction patterns by the address obtained by the address conversion means, and the selected correction pattern corresponds to the black area and the white area of the digitally converted signal. A control device for an electronic display, characterized in that a portion is corrected.