KR100771635B1 - High-fidelity color reproduction method and apparatus for flat pannel display based on color appearance model - Google Patents

Abstract

A high-fidelity color reproduction method and an apparatus for a flat panel display based on a color appearance model are provided to reproduce a high quality color of the flat display by applying the color appearance model using circumference environment and considering a flare phenomenon generated in a surface of a flat display in a characteristic converting process. A high-fidelity color reproduction method and an apparatus for a flat panel display based on a color appearance model comprise the followings: a circumference environment detecting unit(200) for detecting light source information from the circumference environment; a driving power adjusting unit(300) for adjusting driving power from the detected light source information to a low power; a characteristic converting unit(400) for removing a flare phenomenon based on the adjusted driving power; a color appearance model applying unit(500) for the inputted image to an image in which visual characteristic is reflected; and an output image storing unit(600) for storing the converted image data as an output image.

Description

High-Fidelity Color Reproduction Method and Apparatus for Flat Pannel Display Based on Color Appearance Model}

1 is a block diagram illustrating an apparatus for high quality color reproduction of a flat panel display based on an ambient environment analysis and a color appearance model according to the present invention.

2 is a configuration diagram illustrating an ambient environment detector.

3 is a diagram illustrating a driving power control unit.

4 is a block diagram showing a characterization converter.

5 is a block diagram illustrating a color appearance model application unit.

<Explanation of symbols for main parts of the drawings>

100: image input unit 200: ambient environment detection unit

210: sensor operation unit 220: first output storage unit

230: second output storage unit 240: light brightness detection unit

250: color temperature detection unit 260: operation control unit

300: driving power control unit 310: primary lookup table

320: maximum luminance storage unit 330: power control unit

400: characterization converter 410: flare detector

420: secondary lookup table 430: XYZ control unit

500: color appearance model application unit 510: LMS conversion unit

520: LMS control unit 530: LMS inverse converter

540: Lab converter 550: Contrast controller

560: color control unit 570: Lab inverse conversion unit

580: XYZ inverse transform unit 600: output image storage unit

The present invention relates to high-quality color reproduction of flat panel displays, and more particularly, to the application of color appearance models in consideration of the surrounding environment in order to adaptively reproduce the image quality of the flat panel display in response to changes in various surrounding environments. The present invention relates to a device and a method for improving image quality in consideration of human visual characteristics.

The development of display elements and devices enables high brightness and accurate color reproduction so that a user can feel the image more realistically. At this time, after the characterization process in the dark room for high quality color reproduction and accuracy evaluation is reproduced in a fixed environment.

However, the environment in which the display is viewed may vary depending on where the user is or even in the same space. Therefore, in recent years, there is a need for a technique for newly expressing an image of a display according to a display viewing environment.

For this reason, an algorithm has been developed for color appearance models that are adaptive to the surrounding environment considering human visual characteristics.

This method is characterized by the process of changing all physical stimuli to human perceptive values for accurate color representation. At this time, the real-time implementation is difficult even in a computer that is currently commercially available due to the complicated formula structure in the process of converting the physical stimulus into the value perceived by the human and vice versa.

In order to solve this problem, the conventional methods for color reproduction of the display according to the surrounding environment are simply adjusting the gain value for each channel and in the case of LCD, the backlight is adjusted. These methods are characterized by the ability to easily change the image according to the changing environment by adjusting the brightness value of the overall image using several variables.

However, since only the brightness curve characteristic of the image is changed, there is a limit in not properly expressing the change in color.

In addition, another problem of the display according to the ambient light source is a flare phenomenon incident on the surface of the display and reflected back. This is especially true in the case of PDPs because the surface is made of glass.

This phenomenon is a phenomenon in which the saturation and contrast of the display is lowered. The general viewing environment already recognizes the image including this phenomenon, but since the flare does not occur in the dark room environment, the saturation image is recognized. . Therefore, eye fatigue increases due to an increase in color saturation and a change in a curve of visual characteristics occurring in a dark room environment.

Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to apply a color appearance model reflecting human visual characteristics in a changing ambient environment in a process of reproducing image quality of a flat panel display. The present invention provides a method of adaptively reproducing high-quality color according to the change and driving at low power in consideration of a flare phenomenon in a dark room environment.

An apparatus for high quality color reproduction of a flat panel display based on a color appearance model for achieving the object of the present invention, the image input unit for converting the input image of the flat panel display into the object-independent object color; An ambient environment detector configured to detect an ambient environment for applying a color model; A driving power adjusting unit for adjusting driving power from the surrounding environment information detected by the surrounding environment detecting unit; Characterization converter for removing the flare phenomenon based on the power delivered from the drive power control unit; A color appearance model application unit converting the image into the image reflecting visual characteristics by using the environment information transmitted from the environment detection unit; And an output image storage unit for storing the converted image as an output image.

According to an aspect of the present invention, there is provided a method for high-quality color reproduction of a flat panel display based on a color appearance model, the image input unit of the flat panel display converting an input image into an object-independent object color; Detecting, by the surrounding environment detector, the surrounding environment information for applying the color appearance model; A driving power adjusting unit adjusting driving power from the detected surrounding environment information; Removing a flare phenomenon based on the adjusted driving power by the characterization converter; Converting the color appearance model application unit into an image reflecting visual characteristics by using the detected surrounding environment information; And storing the converted data by the output image storage unit.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, an apparatus for high quality reproduction of a flat panel display based on a color appearance model according to an embodiment of the present invention includes an image input unit 100, an ambient environment detection unit 200, and a driving power control unit 300. , A characterization converter 400, a color appearance model application unit 500, and an output image storage unit 600.

The image input unit 100 converts the input RGB value into the independent object color XYZ from the transmitted broadcast signal and the standard video signal using Equation 1 below.

In the above description, RGB is an applied value for each channel of the display, and XYZ is a value obtained by converting RGB into an object color in an independent space using a matrix.
The ambient environment detection unit 200 stores the digital value transmitted from the sensor operation unit 210 in the first output storage unit 220 and the second output storage unit 230, and uses the light brightness detection unit 240 and The color temperature detector 250 detects light brightness and color temperature using Equation 2 below.

delete

Lux is the brightness value of the ambient light source calculated from the two output values. Ratio is the chromaticity value of the ambient light source. At this time, ch0 and ch1 are two output values of the sensor, and A and K are gain constants.

The operation controller 260 of the surrounding environment detector 200 transmits the values detected by the light brightness detector 240 and the color temperature detector 250 to the driving power controller 300 and the color appearance model application unit 500. do.

The driving power controller 300 adjusts power by determining the maximum brightness of the flat panel display by using the brightness of the ambient light transmitted from the ambient environment detector 200 to reproduce the brightness of the flat panel display adaptively to the surrounding environment. Can be.

The power consumption controller 310 of the driving power controller 300 is configured to display the flat panel display in the maximum luminance determiner 320 through the first lookup table 310 according to a signal transmitted from the ambient environment detector 200. The maximum brightness value can be selected. At this time, the human vision uses the phenomenon of Weber's law that can be perceived only when the stimulus changes more than the limit value in the fixed compliance state.

The power consumption adjusting unit 330 of the driving power adjusting unit 300 reduces driving power by lowering the maximum luminance so that human vision cannot perceive it. The luminance value is transmitted to the reference white of the characterization converter 400.

The characterization converter 400 detects the flare by using the illumination brightness value transmitted from the ambient environment detector 200 and converts the flare into a new characterization value in order to consider the phenomenon in which the ambient light is reflected from the surface of the flat panel display.

The flare detector 410 of the characterization converter 400 determines the reflectance of the flare according to the following Equation 3 according to the light brightness value transmitted from the ambient environment detector 200, and the second lookup table 420. To pass).

In the above, [XYZ] _Flare represents the XYZ value of the flare, R _bk Represents the reflectance of the display surface. M is the lux value of the ambient light source, and [XYZ] _Ambient represents the chromaticity value of the ambient light source.

The secondary lookup table 420 converts the flare reflectance into an XYZ value, and the XYZ control unit 430 converts the flare reflectance into an XYZ value in consideration of flare characteristics using the transferred flare XYZ value. Transfer to the application unit 500.

The color appearance model application unit 500 may visualize the human image using the brightness and the color temperature transmitted from the characteristic environment detection unit 200 to the image transmitted from the characterization converter 400 through a process of adapting to the changing environment. Convert to the considered image.

The LMS converter 510 of the color appearance model application unit 500 converts the converted object color XYZ of the characterization converter 400 into a visual characteristic value LMS. In this case, the following equation is used to convert the visual characteristic value (LMS) into the following equation (4).

[LMS] is a value in which the stimulus value of the display is converted into a value in consideration of visual characteristics, and a is a transformation matrix variable.

The LMS control unit 520 of the color appearance model application unit 500 converts the visual characteristic value LMS converted by the LMS conversion unit 510 into the brightness value of the ambient light transmitted from the ambient environment detection unit 200. Adjust using Equation 5 below to comply with the color temperature.

는 순응된 상태에서 시각적으로 인식하는 값이며, 이때,

는 PDP의 값을 시각적으로 변환한 값이고,

주변광원의 값을 시각 특성이 고려된 공간으로 변환한 값이다. 또한, R_adp 는 주위환경에 대한 순응비이며, Y_1x 는 최대휘도에 대한 PDP의 비이며, Y_2x 는 최대휘도에 대한 주변광원의 비이다. From above

Is a visually recognized value in the acclimatized state, where

Is a visual representation of the value in the PDP,

The value of the ambient light source is converted into a space considering visual characteristics. Also, R _adp is the compliance ratio to the surrounding environment, Y _1x is the ratio of PDP to maximum luminance, and Y _2x is the ratio of ambient light source to maximum luminance.

The LMS inverse transform unit 530 of the color appearance model application unit 500 inversely converts the adjusted visual characteristic value LMS into the physical stimulus value XYZ.

The lab transform unit 540 of the color appearance model application unit 500 converts the converted physical stimulus value XYZ into a lab having a uniform color space.

The contrast control unit 550 of the color appearance model application unit 500 adjusts the contrast curve of the image in the uniform color space using Equation 6 below.

는 순응된 상태에서의 새로운 대비 곡선이다. 이때

는 주위 환경 변환의 상수이며,

는 은 대비 곡선의 지수이다. 여기서,

는 현재 상태의 값,

는 현재의 주변 밝기이고,

는 재현하고자 하는 환경의 주변 광원의 밝기이다. From above

Is the new contrast curve in the acclimatized state. At this time

Is a constant for the environment transformation,

Is the exponent of the curve. here,

Is the value of the current state,

Is the current ambient brightness,

Is the brightness of the ambient light source of the environment to be reproduced.

The color adjusting unit 560 of the color appearance model application unit 500 adjusts the color in the uniform color space.

The lab inverse transform unit 570 of the color appearance model application unit 500 inversely converts the uniform color space Lab converted by the contrast controller 550 and the color controller 560 into physical stimulus values.

The XYZ inverse transform unit 580 of the color appearance model application unit 500 outputs an image to which the color appearance model is applied by inversely converting the inversely transformed physical stimulus value into RGB.

The output image storage unit 600 stores the converted RGB of the color appearance model application unit 500 as an output image of the flat panel display.

The apparatus for high quality color reproduction of a flat panel display based on the color appearance model configured as described above operates as follows.

First, the image input unit 100 obtains an input image from a broadcast signal, converts the input image into an object-independent object color, and transmits the converted image to the characterization converter 400.

The light brightness value is transmitted to the driving power control unit 300 among the information on the ambient light detected by the ambient environment detection unit 200, and the light brightness and color temperature are transmitted to the color appearance model application unit 500.

In this case, the sensor operation unit 210 of the ambient environment detection unit 200 transmits two output values received through sensor driving to the first output storage unit 220 and the second output storage unit 230.

The light brightness detector 240 and the color temperature detector 250 detect light brightness and color temperature by using two output values transmitted from the first and second output storage units 220 and 230, respectively, and operate the control unit 260. To pass).

The operation control unit 300 transmits the light brightness to the driving power control unit 300 as a switch circuit, and transmits the light brightness and color temperature to the color appearance model application unit 500.

In addition, the primary lookup table 310 of the driving power control unit 300 stores the brightness in the maximum brightness storage unit 320 according to the detected light brightness, and uses the flat power in the power consumption control unit 330. Induces a reduction in drive power of the display.

The flare detector 410 of the characterization converter 400 obtains the reflected light of the flat panel display reflected by the ambient light and configures it as the secondary lookup table 420 to obtain the XYZ of the flare. The XYZ control unit 430 adjusts the object color XYZ using the XYZ of the flare obtained from the secondary lookup table 420.

The color appearance model application unit 500 converts the changed physical stimulus value XYZ transmitted from the characterization conversion unit 400 into a value corresponding to the light brightness and color temperature transmitted from the ambient environment detection unit 200, and outputs the output image storage unit. Save to 600.

In this case, the LMS converter 510 converts XYZ into a LMS that is a human visual model, and the LMS controller 520 converts the converted LMS to a light brightness and color temperature transmitted from the surrounding environment detector 200. Convert to The LMS inverse transform unit 530 converts the converted LMS into XYZ, which is a physical stimulus value, and the Lab transform unit 540 converts the lab into a lab, which is a color equal space considering visual and visual characteristics.

The contrast controller 550 adjusts the contrast of the visual characteristics by changing the curve of the L axis in this space, and the color controller 560 adjusts the color in the ab chromaticity space. The lab inverse transform unit 570 inverts the adjusted Lab to XYZ.

Finally, the XYZ inverse transform unit 580 inversely converts the inversely converted object color into RGB data and outputs the adjusted image to the output image storage unit 600. Accordingly, the output image storage unit 600 The converted image is stored as an output image of the flat panel display.

The present invention described above can be applied to flat panel display devices such as PDPs and LCDs, as well as to general CRT TVs, monitors and other video devices, and can be equally applied to analog TVs, digital TVs, and satellite TVs. In addition, it can of course be applied to all NTSC, PAL, SECAM method.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the above-described embodiments, and the present invention is not limited to the above-described embodiments without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can, of course, make various changes and make such changes as fall within the stated claims.

As described above, the apparatus for high quality color reproduction of a flat panel display based on the color appearance model according to the present invention enables high quality color reproduction of a flat panel display by applying a color appearance model using an ambient environment, and also a characterization conversion process. By considering the flare that occurs on the surface of the flat panel display in the dark room has the advantage that can reproduce the same color as seen in everyday life with low power drive in the dark room.

In addition, since the influence of the ambient light source is acquired in real time by using a sensor, the contrast and the color of the image can be adjusted in more detail when the color appearance model is applied, and thus there is an advantage of reproducing high quality images in real time.

The present invention can be used for all output devices such as PDPs, LCDs, CRTs, and the like, and can also be used in environments where the environment is fixed, such as Internet shopping malls and electronic museums. This invention is susceptible to various modifications and implementations without departing from the scope of the following claims.

Claims (10)

An image input unit for converting and inputting an input image of the flat panel display into an independent object color; An environment detection unit for detecting light source information from the environment for applying a color appearance model; A driving power controller configured to adjust driving power to low power from light source information detected by the surrounding environment detector; A characterization converter configured to remove a flare phenomenon based on the adjusted driving power in the driving power controller; A color appearance model application unit for converting the input image into an image reflecting visual characteristics by using the detected light source information in the surrounding environment detection unit; And And an output image storage unit for storing the image data converted by the color appearance model as an output image. The method of claim 1, The ambient environment detector; A first output storage unit and a second output storage unit for storing an output of the sensor through a sensor operation power supply; A light brightness detector for detecting light brightness and a color temperature detector for detecting a color temperature by using the information obtained from the first and second output storage units; And And a motion control unit for transmitting the detected ambient environment information to the driving power control unit and the color appearance model application unit. The method of claim 1, The driving power control unit A primary lookup table for determining a maximum brightness from the detected light brightness of the surrounding environment; A maximum luminance storage unit for storing the maximum luminance determined in the primary lookup table; And And a power controller configured to adjust power by using the maximum luminance transmitted from the maximum luminance storage unit. The method of claim 1, The characterization converter A player detector that detects a flare using the light brightness detected by the ambient environment detector; A second lookup table configured to determine flare XYZ by applying the detected light brightness; And And an XYZ control unit for removing flare XYZ from the input image determined by the secondary lookup table. The method of claim 1, The color appearance model application unit; An LMS converter converting the image transmitted from the characterization converter into LMS data in consideration of human visibility; An LMS controller adjusting the light brightness and color temperature transmitted from the ambient environment detector; An LMS inverse converter for converting the LMS converted by the LMS controller into XYZ, which is a physical stimulus value; A Lab converter for converting the XYZ transformed by the LMS inverse converter into Lab, which is a color equal space; A contrast control unit for converting an image into a contrast curve corresponding to the light brightness transmitted from the surrounding environment detector; A color controller converting the color into a color corresponding to the color temperature transmitted from the surrounding environment detector; A Lab inverse transform unit which inversely converts the Lab of the converted color uniform space into XYZ, which is a physical stimulus value; And A high-quality color reproduction device of a flat panel display based on a color appearance model, characterized by comprising an XYZ inverse transform unit which inversely converts inversely converted XYZ into RGB data. Converting the input image into an independent object color and inputting the image input unit of the flat panel display; Detecting, by the surrounding environment detector, light source information from the surrounding environment to apply the color appearance model; Adjusting a driving power to a low power by the driving power adjusting unit from the detected light source information; Characterizing converter to remove the flare phenomenon based on the adjusted drive power; Converting, by the color appearance model application unit, the input image into an image reflecting visual characteristics by using the detected light source information; And And an output image storage unit outputting and storing the image data converted by the color appearance model. The method of claim 6, The surrounding environment detecting unit detects the surrounding environment information for applying the color appearance model; In order to apply the color appearance model, the information about light brightness and color temperature is detected using two output values of the sensor, and the color appearance model is transmitted to the driving power control unit and the color appearance model application unit through an operation control unit. A high quality color reproduction method for flat panel displays based on. The method of claim 6, The driving power adjusting unit may adjust driving power from the detected surrounding environment information. Characterization conversion of the power by determining the power corresponding to the light brightness of the surrounding environment through the first lookup table, storing the data for the maximum brightness storage, and adjusting the power to a stage that cannot be visually distinguished. A high quality color reproduction method of a flat panel display based on a color appearance model characterized in that it is transmitted to the unit. The method of claim 6, Considering a flare phenomenon based on the adjusted driving power of the characterization converter; The values corresponding to the light brightness and the color temperature obtained by the surrounding environment detector are converted to XYZ by flare using a second lookup table and then detected from the data of the input image. A high quality color reproduction method of a flat panel display based on a color appearance model, which comprises eliminating XYZ caused by flare and transferring it to a color appearance model application unit. The method of claim 6, Converting the color appearance model application unit to the image reflecting the visual characteristics by using the detected ambient environment information; The input physical stimulus value XYZ is converted to LMS considering the visual characteristics, and this value is adjusted to the value considering the compliance characteristics by using the ambient environment information transmitted from the surrounding environment detection unit, and then inversely converted to the physical stimulus value XYZ, and inversely transformed. A high-quality color reproduction method of a flat panel display based on a color appearance model, characterized by converting XYZ to Lab, which is a uniform color space, and then inversely converting to XYZ by adjusting contrast and color.

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