KR100487371B1 - variable color space converter in image signal processor system - Google Patents

Abstract

The present invention provides a method for RGB processing a component signal at a constant rate according to the level of the signal in accordance with the characteristics of the display device, and a delay unit for delaying the Y signal of the input Y, Pb, Pr signal for a predetermined time; First and second level detectors for detecting the levels of the Pb and Pr signals among the input Y, Pb and Pr signals, and gain values for each level of a predetermined unit to define a gain value of the signals detected by the first and second level detectors. Gain for each level of the first and second look-up tables for designating a corresponding gain value for each level, a synchronization unit for synchronizing the respective devices, and a signal output through the first and second look-up tables and delay units It is configured to include a matrix portion for defining a value to calculate and output the R, G, B signals.

Description

Variable color space converter in image signal processing system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video signal processing system, and more particularly, to a display system in which a linear color space converting unit is programmable to smoothly implement color.

As shown in FIG. 1, in a conventional video signal system, R / G / B processing of a component signal is output through a scaler 20 through an input signal processor 10 and a series of signals having a resolution to be displayed are outputted. do.

The display unit 40 displays the signal through the driver 30 of the device to implement this signal.

Here, the change of the component to R / G / B is realized by the conversion equation of a matrix having a certain coefficient in the matrix shown in Equation 1, which can be processed analog or digital.

In this case, a series of changes have a constant ratio of gain regardless of the signal level due to a fixed coefficient value.

However, current display devices, unlike gamma characteristics of conventional CRTs, have a non-linear characteristic of color transmission and gradation according to the level of each signal in implementing colors.

This is achieved by extracting a signal from the Pr / Pb of the component between the same levels to implement RGB color, so that the same ratio of RGB colors does not come out according to the same level of signal on the characteristics of the display device (especially LCD).

Therefore, even if the user wants the color of the level, each RGB color will have a different feeling, so the program should be able to change the gain ratio according to the level.

Accordingly, an object of the present invention is to provide a method for RGB processing of a component signal at a constant rate according to a signal level in accordance with the characteristics of a display device.

Another purpose is to create a look-up table with different gain values depending on the level of the signal.

The variable color space conversion unit of the image signal processing system according to the present invention for achieving the above object is an input signal processing unit for performing A / D conversion and signal processing of the Y, Pb, Pr signal input from the outside; A variable color space converter configured to set a predetermined gain value for each level among Pb and Pr signals among the signals processed by the input signal processor, and calculate R, G, and B signals using the set gain value; Including a scaler for defining the brightness, gradation, and resolution of the image input from the outside through the R, G, B signal calculated by the variable color space conversion unit, and a display unit for displaying the image using the signal defined by the scaler It is composed.

In this case, the variable color space converting unit is a delay unit for delaying the Y signal of the input Y, Pb, Pr signal for a predetermined time, and the first to detect the level of the Pb and Pr signal of the Y, Pb, Pr signal input; First and second level detectors, first and second look-up tables that define gains for each level of a signal detected by the first and second level detectors by defining gain values for each level of a predetermined unit, and each device And a matrix unit configured to calculate R, G, and B signals by defining gain values for each level in the signals output through the first and second look-up tables and the delay unit. There are other features.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of a variable color space converter of a video signal processing system according to the present invention will be described with reference to the accompanying drawings.

2 illustrates a variable color space converter according to the present invention.

As shown in FIG. 2, an input signal processor 10 for performing A / D conversion and signal processing on Y, Pb, and Pr signals input from the analog color space converter 50 and the input signal processor 10 are processed. A variable color space converter 70 for setting R, G, and B signals by setting a predetermined gain value for each level through the Pb and Pr signals, and performing format conversion using the set gain value; A scaler 20 defining luminance, gradation, and resolution of an image input from the digital color space converter 60 through the R, G, and B signals calculated by the variable color space converter 70, and the scaler 20 The device driver 30 converts the signal into a signal for controlling the device using a signal defined in FIG. 2 and the display unit 40 displays the signal using the signal controlled by the device driver 30.

At this time, the variable color space conversion unit 70, as shown in Figure 3, the delay unit 71 for delaying the Y signal of the input Y, Pb, Pr signal for a predetermined time, and the input Y, Pb, Pr First and second level detectors 72 and 74 for detecting the levels of the Pb and Pr signals among the signals, and gain values defined for each level of a predetermined unit to define the gain values in the first and second level detectors 72 and 74. First and second look-up tables 73 and 75 for designating a corresponding gain value for each level of the detected signal; a synchronization unit 76 for synchronizing the devices; and first and second look-ups. It is composed of a matrix unit 77 that calculates and outputs R, G, and B signals by defining gain values for each level of the signals output through the up tables 73 and 75 and the delay unit 71.

In this case, the matrix unit 77 calculates the R, G, and B signals by using the following equation (2).

Equation 3 shows a basic equation for converting between 8-bit digital R / G / B data and Y / Cb / Cr having a general range of 16 to 235 in HDTV.

Y ₇₀₉ = 0.213R '+ 0.715G' + 0.072B 'R' = Y ₇₀₉ +1.540 (Cr-128)

Cb = -0.117R'-0.394G '+ 0.511B' + 128 G '= Y ₇₀₉ -0.459 (Cr-128) -0.183 (Cb-128)

Cr = 0.511R'-0.464G'-0.047B '+ 128 B' = Y ₇₀₉ +1.816 (Cb-128)

As described above, Equations 2 and 3 are examples of the format change of the color matrix. When the value of x / y / z is changed for the input component, the level of the output R / G / B is also changed.

Eventually, the level of the Pb / Pr signal is detected and the result is compared with the adjusted first and second look-up tables 73 and 75 to output the desired gain. It must be programmed and stored in each look-up table.

At this time, Pb / Pr adjusts the gain but not Y because the white balance is set in the part in charge of the display, so if the gain adjustment for Y is performed in the virtual color space converter, the white balance is broken. .

Fig. 5 (a) and (b) show a diagram comparing the present invention with the input and output of the gain-adjusted signal in this manner.

Referring to FIG. 5 (a) and (b), the conventional scheme FIG. 5 (a) has no choice but to convert the gain of the input signal to a constant ratio at any level, so that the transmittance of light for each RGB color in the LCD or PDP Although the problem caused by the characteristics of the gray scale is generated as it is, Figure 5 (b) is to program the interval to adjust the gain is output by the level is slightly changed by the level can be solved the existing problem.

For example, if you want to lower the ratio of red when the ratio of red is high and the brightness is high, but you want to keep the ratio at low level, you can set the interval as you want and store the gain of the look-up table as appropriate.

The programmable color space converter (VCSC) as described above can also be used to adjust uniformity or gamma because partial color change of the screen is possible.

As described above, the variable color space conversion unit of the image signal processing system according to the present invention has the following effects.

First, it is possible to widen the range of color implementation by allowing different color reproduction ratios according to the color level.

Second, the color space converter included and subordinated to the existing ICs was independent to secure an experimental basis for color reproduction review.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

1 is a view showing the configuration of a video signal processing system according to the prior art

2 is a diagram showing the configuration of a video signal processing system according to the present invention;

3 is a diagram illustrating a configuration of a variable color space conversion unit according to the present invention.

4 is a diagram illustrating a configuration of a look-up table in the variable color space conversion unit according to the present invention.

5 (a) and (b) are diagrams comparing the input and output of a gain-adjusted signal with the conventional scheme and the inventive scheme.

* Explanation of symbols for main parts of the drawings

10: input signal processing unit 20: scaler

30: device driver 40: display unit

50: analog color space converter

60: digital color space converter

70: virtual color space converter 71: delay unit

72, 74: level detector 73, 75: look-up table

76: synchronization unit 77: matrix unit

Claims (3)

An input signal processor for performing A / D conversion and signal processing on Y, Pb, and Pr signals input from the outside; Among the signals processed by the input signal processor, Pb and Pr signals are separated into a plurality of areas for each level, the lowest level area does not change gain, and at least one or more other areas change gain. A variable color space conversion unit for converting the format using the changed gains and calculating the R, G, and B signals; A scaler defining brightness, gradation, and resolution of an image input from the outside through the R, G, and B signals calculated by the variable color space converter; And a display unit for displaying an image by using the signal defined by the scaler. The method of claim 1, The display unit is a variable color space conversion unit of the image signal processing system, characterized in that the LCD, PDP. The method of claim 1, wherein the variable color space conversion unit A delay unit configured to delay the Y signal from the input Y, Pb, and Pr signals for a predetermined time; First and second level detectors for detecting levels of the Pb and Pr signals among Y, Pb and Pr signals inputted; First and second look-up tables defining gain values for each level of a predetermined unit and specifying corresponding gain values for each level of signals detected by the first and second level detectors; A synchronization unit for synchronizing the devices; And a matrix unit configured to calculate R, G, and B signals by defining a gain value for each level in the signals output through the first and second look-up tables and the delay unit. Color space converter.