KR20030060331A - Device for Controlling Picture Quality based on Digital input/output - Google Patents

Abstract

PURPOSE: A digital input/output based picture quality controller is provided to remove a digital-analog converter, an analog-digital converter and an analog-based picture quality control block, required for control picture quality, and realize a picture quality control function through a programmable access. CONSTITUTION: A digital input/output based picture quality controller includes a hardware block. The hardware block inputs a luminance signal and a color difference signal of video data to a digital image processor, controls picture quality according to a corresponding parameter. The picture quality controller directly outputs a signal whose picture quality has been controlled, output from the digital image processor, to a digital image output unit. The hardware block includes a register that varies a corresponding parameter to adjust picture quality through a programmable control method.

Description

Device for Controlling Picture Quality based on Digital input / output}

The present invention relates to an apparatus for adjusting image quality based on digital input / output.

The present invention implements sharpening, brightness, contrast, color, and color density adjustment, which are functions of the analog image quality adjusting device used in the conventional image quality adjusting, by removing the analog image quality adjusting device and other additional hardware, and adjusting the image quality. It relates to a digital image quality adjusting device unified the function of.

In general, various functions are provided to allow a user to adjust desired image quality of an image displayed on an image display device, and this is achieved through an interface using an OSD (Overlay Screen Display).

The above picture quality adjustment functions can be categorized as sharpening adjustment, brightness adjustment, contrast adjustment, color density adjustment, and color adjustment. First, there are sharpening adjustments to adjust the degree of high frequency components in the image, and second, brightness adjustments to adjust the degree of white components in the image. Third, the difference between the black and white components in the image There is a contrast adjustment to adjust the degree. Fourth, there is a color density adjustment to adjust the relative size of the R and G components included in the color components in the image. There is a color adjustment to adjust the level.

In addition, video display devices can be broadly classified into analog devices and digital devices. TVs using analog devices include CPT TV and projection TV, and digital devices include LCD TV and PDP TV. In conventional CPT TV, the image quality is adjusted for the analog signal, and the five kinds of sharpening, brightness, contrast, color density, and color adjustment are analogized in the R, G, and B spaces that have undergone luminance / color difference space and color coordinate conversion. Will be processed.

Conventionally, such an adjustment function has been performed in an analog manner despite being composed of a digital image processing unit and a digital image display device.

1 is a block diagram for adjusting image quality according to the prior art.

As shown in FIG. 1, after adjusting the image quality of the analog signal obtained by passing the digital image data output from the digital image processing unit through a digital-to-analog converter (DAC), the analog-to-digital converter (ADC) is again passed. It has a structure that delivers the digital video signal obtained to the digital video output unit.

2 is an example of implementing image quality adjustment excluding a sharpening adjustment function using a color coordinate conversion system.

In some cases, the image quality adjustment may be implemented digitally by modifying the color coordinate conversion system hardware as shown in FIG. 2, but in general, the conversion system hardware requires 9 multipliers and 6 adders to implement one function. We need to use 18 multipliers and 12 adders. In addition, as many separate multipliers are needed to combine the two functions, a significant number of multipliers and adder hardware must be used to implement all the desired functions.

3 is an example of implementing image quality adjustment excluding a sharpening adjustment function using a lookup table.

As shown in FIG. 3, the image quality adjustment can be implemented using the lookup table, and the image quality adjustment items for the R, G, and B signals are stored in the lookup table and output. However, such a structure stores the values to which the image quality adjustment is applied as the size of the lookup table, for example, values having 256 10-bit data resolutions outside the lookup table, and are stored in the lookup table each time the image quality adjustment is performed. Has the disadvantage of printing

The present invention is to remove the DAC block, the ADC block and the block responsible for the analog image quality adjustment function between the digital image processing unit and the digital image output unit, and implement the same function as the image quality adjustment device based on digital input and output.

Another object of the present invention is to unify the functions of the sharpening unit, the brightness unit, the contrast unit, the color concentration unit, and the color unit for adjusting the image quality.

It is still another object of the present invention to enable adjustment for image quality adjustment in a register access based programmable control scheme.

1 is a block diagram for adjusting image quality according to the prior art.

Figure 2 is an example of implementing the image quality adjustment except the sharpening adjustment function using a color coordinate conversion system.

3 is an example of implementing image quality adjustment excluding a sharpening adjustment function using a lookup table.

4 is a block diagram of a digital image processing unit and a digital image output unit having a hardware block for adjusting image quality based on digital input / output according to the present invention.

Fig. 5 is a detailed block diagram of the digital picture quality adjusting hardware block shown in Fig. 4;

6 is a detailed block diagram of the sharpening adjustment unit.

7 is a graph showing the operation of the filtering error canceling unit of the sharpening adjustment unit;

8 is a graph showing the detailed operation of the filtering error canceling unit of the sharpening adjustment unit;

9 is a detailed block diagram of the contrast adjustment unit and the brightness adjustment unit.

Fig. 10 is a detailed block diagram of a color density adjusting unit when using a double clock of an operation clock.

FIG. 11 is a signal timing diagram of a color density adjusting unit shown in FIG. 10;

Fig. 12 is a detailed block diagram of a color density adjusting unit when using a one-time clock of an operation clock.

13 is a detailed block diagram of a color adjustment unit.

* Explanation of symbols for main parts of the drawings

10: sharpening adjustment unit 11: filter unit

12: filtering error removing unit 13: weighting unit

14: adder 20: contrast adjustment unit

30: brightness adjustment unit 40: color density adjustment unit

50: color adjustment unit 100: hardware block

A feature of the digital input-output based image quality adjusting device according to the present invention for achieving the above object is to input the luminance signal and the color difference signal of the image data into the digital image processing unit, and to adjust the sharpening, contrast adjustment, And a hardware block for adjusting brightness, color density, and color quality, and directly outputting the quality-adjusted signal output from the digital image processing unit to the digital image output unit.

The hardware block further includes a controller for selectively determining an offset according to a data valid range of the luminance signal.

The hardware block includes a register for adjusting image quality by varying each parameter by a programmable control method.

According to an aspect of the present invention, a hardware block having an image quality adjustment function is implemented in a digital image processing unit, whereby a DAC block, an ADC block, and By removing the analog based image quality adjusting block, the image quality adjusted signal output from the digital image processing unit may be directly output to the digital image output unit.

The hardware block receives a luminance signal and a color difference signal for each function, and adjusts each parameter by using a register to adjust sharpening, contrast, brightness, color density, and color by function. Implemented in a register-based programmable approach, the picture quality can be adjusted.

In addition, the hardware block unitizes each part to operate in conjunction with each part for sharpening, contrast, brightness, color density, and color for each function, and inputs one luminance signal and a color difference signal to adjust image quality. Can be.

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 digital input / output based image quality adjusting device according to the present invention will be described with reference to the accompanying drawings.

4 illustrates a digital image processing unit and a digital image output unit having a hardware block for adjusting image quality based on digital input / output according to the present invention.

FIG. 5 is a detailed block diagram of the digital image quality adjusting hardware block shown in FIG.

As shown in FIG. 5, the digital image quality adjusting hardware block 100 is largely divided into five parts of the sharpening control unit 10, the contrast adjusting unit 20, the brightness adjusting unit 30, the color density adjusting unit 40, and the color adjusting unit 50. Divided.

The sharpening control unit 10 inputs a luminance signal, outputs the filtering signal of the input luminance signal and the input luminance signal by adding the delayed signal, and the contrast adjusting unit 20 inputs a color difference signal.

The contrast adjusting unit 20 adjusts the intensity of the luminance signal and the color difference signal by multiplying the input color difference signal and the luminance signal by a predetermined gradient value, that is, the contrast adjustment coefficient.

The brightness adjusting unit 30 adds or subtracts a certain offset to the brightness signal and multiplies the brightness adjustment coefficient to adjust the brightness level of the brightness signal.

The color density adjusting unit 40 inputs a color difference signal, selectively multiplies the input color difference signal with a sine (SINE) and a cosine (COSINE) having a predetermined angle determined by the color density adjustment coefficient, and adds the multiplied values. Adjusts the color density of the chrominance signal.

That is, the color difference signal is input, and the color intensity of the color difference signal is adjusted by adding or subtracting the multiplied value by multiplying the returned value by giving the sine and cosine a constant angle value with respect to the input color difference signal.

The color adjusting unit 50 inputs a color difference signal and multiplies a predetermined gradient value (a product of a color adjustment coefficient and a contrast adjustment coefficient) with respect to the input color difference signal to adjust the color degree of the color difference signal.

The hardware block 100 may further include a controller (not shown) for selectively determining an offset according to a data valid range of a luminance signal or a color difference signal of an input image signal.

That is, the controller has a function of giving offset 16 according to the effective range of the luminance signal or the color difference signal of the input image data, that is, offset 16 when the effective range is 16 to 235 and offset 0 when the effective range is 0 to 255.

In addition, the hardware block 100 includes a register (not shown) for adjusting image quality by varying each parameter in a programmable control method.

As described above, the hardware block 100 receives a luminance signal and a color difference signal for each function in order to adjust sharpening, contrast, brightness, color density, and color for each function. The image quality is adjusted by implementing the register parameters in a register access-based programmable method using registers.

In addition, the respective parts are united to operate in conjunction with each of the functions for sharpening, contrast, brightness, color density, and color for each function, and the image quality is adjusted by inputting one luminance signal and a color difference signal.

That is, the hardware block 100, the hardware block inputs the luminance signal, the sharpening adjustment unit 10 for outputting the sum of the filtering signal of the input luminance signal and the delayed signal of the input luminance signal and the color difference, A contrast control unit 20 for inputting a signal and multiplying the input and output color difference signals and the luminance signal output from the sharpening adjustment unit 10 to adjust the contrast of the luminance signal and the color difference signal, respectively; A brightness offset unit 30 for adding or subtracting a predetermined offset to the luminance signal outputted from (20), multiplying the brightness adjustment coefficient, and adjusting the brightness degree of the luminance signal, and inputting a color difference signal, and adjusting the color density to the input color difference signal. Selectively multiply the sine and cosine having a certain angle determined by the coefficient, and add the multiplied values to adjust the color density of the chrominance signal. The color adjustment unit 50 adjusts the color degree of the color difference signal by multiplying a predetermined gradient value (the product of the color adjustment coefficient and the contrast adjustment coefficient) with respect to the color difference signal output from the color concentration adjustment unit 40. It is composed.

6 is a detailed block diagram of the sharpening adjustment unit 10.

As illustrated in FIG. 6, the sharpening adjustment unit 10 filters a band pass or band peaking based on a filter coefficient with respect to the input luminance signal and outputs a filtering signal. And a filtering error removing unit 12 for removing the error component generated after the filtering from the filtering signal, and a weighting unit 13 for emphasizing a high frequency component by weighting the bandpass filtering signal by a weighting factor. And an adder 14 which delays and adds the bandpass filtering signal and the input luminance signal.

The filter unit 11 is operated as a finite impulse response filter (FIR) using a filter coefficient reflecting desired filter characteristics.

7 shows a detailed operation of the filtering error remover 12 of the sharpening adjustment unit 10 graphically.

When the filter unit 11 of the sharpening adjustment unit 10 is used as the band peaking filter as shown in the upper part of FIG. 7, the banding filter coefficient for emphasizing the high frequency components is freely selected by the filter unit 11 to perform sharpening adjustment. do.

In addition, when the filter unit 12 is used as a band pass filter, the filter unit 11 filters by the filter coefficients as shown in the lower part of FIG. 7, and the filtered signal has a predetermined characteristic curve. 12) and the weight portion 13 are used at the same time.

8 shows a detailed operation of the filtering error canceling unit 12 of the sharpening adjustment unit 10 in a graph.

8 shows a case in which the filter unit 11 is used as a band pass filter, the signal filtered using the band pass filter characteristic has an error component, and the filtering error removing unit 12 is applied to a signal including the error component. Coring coefficient of) serves to remove the filtering error having a small signal level, the threshold coefficient serves as a kind of limiter having a threshold value for the filtered result, and the weighting coefficient of the weighting unit 13 is thus a filtering error elimination unit. It plays a role of emphasizing the remaining high frequency components of the band pass signal passed through (12).

9 shows the contrast controller 20, the brightness controller 30, and the detailed block diagram.

The contrast adjusting unit 20 has a function of adjusting the degree of contrast for the luminance component and the color difference signal by multiplying a gradient value (contrast adjustment coefficient) not only for the input luminance signal but also for the color difference signal.

The brightness adjusting unit 30 has a function of adjusting the degree of brightness of the brightness signal by adding or subtracting a predetermined offset value with respect to the brightness signal.

FIG. 10 shows a detailed block diagram of the color density adjusting unit 40 when using the double clock of the operation clock, and FIG. 11 shows a signal timing diagram of the color density adjusting unit 40 shown in FIG. will be.

Fig. 12 shows a detailed block diagram of the color density adjusting unit 40 when using the clock of 1 times the operation clock.

The color concentration adjusting unit 40 may be implemented by using the clock used twice or twice.

As shown in FIG. 10, when an operation occurs in the first double clock state or the up and down views of the 1x clock, the sine and cosine functions use one block by using the feature of obtaining the return value of each other as phase shift. It is possible to implement, which can be described with reference to FIGS. 10 and 11.

The color density adjusting unit 40 inputs the CB and CR color difference signals, and the color difference signal by a combination of sine and cosine having a predetermined angle determined by the color density adjustment coefficient with respect to the input color difference signal. Outputs CB 'and CR' color difference signals by adjusting the degree of color concentration.

The data alignment unit of FIG. 10 aligns the two color difference signals as shown in the timing chart of FIG.

CB '= CBcosθ + CRsinθ

CR '= CRcosθ-CBsinθ

In the second case, the 1x clock state can be implemented as shown in Fig. 12 using the sine and cosine functions, respectively.

FIG. 13 shows a detailed block diagram of the color adjustment unit 50. As shown in FIG.

The color adjusting unit 50 adjusts the color accuracy of the color difference signal by multiplying a predetermined gradient value (the product of the color adjustment coefficient and the contrast adjustment coefficient) with respect to the inputted CB and CR color difference signals as shown in FIG. Output the signal.

As described above, the digital input / output based image quality adjusting device according to the present invention has the following effects.

Programmable control of the image quality adjustment function by eliminating the DAC, ADC, and analog based image quality control blocks, which were required to perform image quality adjustments in conventional analog and digital spaces, including devices consisting of a digital image processing unit and a digital image output unit. When implementing with Access (Programmable Access), unified functions to implement the image quality adjustment in the prior art, it is possible to eliminate unnecessary hardware, resulting in cost savings.

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.

Claims (6)

A hardware block for inputting a luminance signal and a color difference signal of image data into a digital image processing unit, and adjusting image quality of sharpening, contrast, brightness, color density, and color adjustment by respective parameters; And an image quality control signal output from the digital image processing unit directly to the digital image output unit. The apparatus of claim 1, wherein the hardware block comprises a register configured to adjust image quality by varying each parameter by a programmable control method. The apparatus of claim 1, wherein the hardware block further comprises a controller configured to selectively determine an offset according to a data valid range of the luminance signal. The method of claim 1, wherein the hardware block is A sharpening adjustment unit configured to input a luminance signal, and output the sum of the filtered signal of the input luminance signal and the delayed signal; A contrast controller for inputting a chrominance signal, and controlling the contrast of the luminance signal and the chrominance signal by multiplying the input chrominance signal and the luminance signal by a contrast adjustment coefficient; A brightness adjusting unit for adding or subtracting a predetermined offset with respect to the brightness signal and multiplying the brightness adjustment coefficient to adjust the brightness degree of the brightness signal; A color density adjusting unit configured to input a color difference signal and adjust a degree of color density of the color difference signal by a combination of a sine (SINE) and a cosine (COSINE) having a predetermined angle with respect to the input color difference signal; And a color adjusting unit configured to input a color difference signal and multiply the input color difference signal by a product of a color adjustment coefficient and a contrast adjustment coefficient to adjust a color degree of the color difference signal. The method of claim 1, wherein the hardware block is A sharpening adjustment unit configured to input a luminance signal, and output the sum of the filtered signal of the input luminance signal and the delayed signal; A contrast controller for inputting a chrominance signal, and controlling the contrast of the luminance signal and the chrominance signal by multiplying the input chrominance signal and the luminance signal output from the sharpening controller by a contrast adjustment coefficient; A brightness adjusting unit for adding or subtracting a predetermined offset with respect to the luminance signal output from the contrast adjusting unit, and adjusting a brightness degree of the luminance signal by multiplying the brightness adjusting coefficient; A color density adjusting unit configured to input a color difference signal, and adjust a degree of color density of the color difference signal by a combination of a sine (SINE) and a cosine (COSINE) having a predetermined angle with respect to the input color difference signal; And a color adjusting unit configured to adjust the degree of color of the color difference signal by multiplying the color difference signal output from the color density adjusting unit by the product of the color adjustment coefficient and the contrast adjustment coefficient. According to claim 4 or 5, wherein the sharpening adjustment unit A filter unit for performing a band pass or band peaking filtering on the input luminance signal to output a filtering signal; A filtering error remover which removes an error component of the filtering signal; A weighting unit for weighting the bandpass filtering signal to emphasize high frequency components; And And an adder configured to delay and add the bandpass filtering signal and the input luminance signal.