KR20060018637A - Apparatus and method for adjusting color for display device - Google Patents

Abstract

The color adjusting apparatus and method disclosed herein converts an RGB image into an HSV image, instead of directly adjusting color using an RGB image provided to a display, and then combines the color and saturation information that can be obtained from the HSV image. To adjust the color of the image. In addition, by correcting not only the target color, but also the color adjacent to the target color, natural color adjustment can be performed without a tomography phenomenon.

Description

Apparatus and method for adjusting color for display device

1 is a block diagram of a color adjusting device according to a preferred embodiment of the present invention;

2 shows an RGB color model;

3 shows an HSV color model;

4 shows the distribution of skin tones in the HSV color model;

5 is a view showing a color adjustment result for the skin tone according to the present invention;

6 is a flowchart showing a color adjusting method according to a preferred embodiment of the present invention; And

FIG. 7 is a detailed flowchart of a color conversion process performed in operation 1700 of FIG. 6.

* Description of the symbols for the main parts of the drawings *

100: color control device 110: RGB-HSV conversion unit

130: color adjustment unit 150: color and saturation detection unit;

170: color mapping unit 190: HSV-RGB conversion unit

200: display

TECHNICAL FIELD The present invention relates to image processing, and more particularly, to an apparatus and method for adjusting the color of a displayed image.

Display devices such as televisions and monitors display images using RGB (Red, Green, Blue) colors. One of the colors most frequently displayed among the colors displayed on the display device may include a skin tone or a skin color. The skin tone is one of the most familiar colors visually seen by humans, and because the frequency of display on the display device is also high, the change in skin tone is more sensitive than the change in other colors.

As a method of controlling color of a display device currently being used, there is a method of increasing contrast of an image. In this method, the histogram of the image is extracted and the high and low values of the histogram are weakened to provide an overall smoothed image. However, this method has a problem that color distortion occurs throughout the image.

In particular, even when the same image data is input, there is a need for a new method for more precisely and precisely adjusting the color, considering that there is a slight difference in the color tone displayed by the display device.

Accordingly, it is an object of the present invention to provide a device and method capable of adjusting a desired color more accurately and precisely, which has been proposed to solve the above-mentioned problems.

According to a feature of the present invention for achieving the object of the present invention as described above, the color adjusting device is characterized by the color, saturation, and brightness of the first type of image composed of information based on red, green, and blue. A first image converting unit converting the image into a second type of image composed of basic information; A color adjusting unit which detects the hue and saturation information from the second type of image and adjusts a display range of a color to be adjusted based on the detected hue and saturation information; And a second image converting unit converting the second type of image adjusted by the color adjusting unit into the first type and outputting the converted image to the display device.

According to a feature of the present invention for achieving the object of the present invention as described above, the color adjustment method comprises: (a) color, saturation, and the like of a first type of image composed of information based on red, green, and blue; And converting the image into a second type of image including information based on brightness. (b) detecting the hue and saturation information from the second type of image and adjusting a display range of a color to be adjusted based on the detected hue and saturation information; And (c) converting the second type of image adjusted in step (b) into the first type and outputting the image to the display device.

(Example)

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

The novel color adjustment apparatus and method of the present invention, after converting an RGB image to an HSV image, adjusts the color of the image by using a combination of hue and chroma information of the image. In addition, by correcting not only the target color, but also the color adjacent to the target color, natural color adjustment can be performed without a tomography phenomenon.

1 is a block diagram of a color adjusting device 100 according to a preferred embodiment of the present invention.

Referring to FIG. 1, the color control apparatus 100 according to the present invention includes an RGB-HSV converter 110, a color adjuster 130, and an HSV-RGB converter 190.

The RGB-HSV converter 110 converts an RGB (Red, Green, Blue) image into an HSV (Hue, Saturation, Value) image. RGB images have configurations based on Red, Green, and Blue, while HSV images have configurations based on Hue, Saturation, and Value. Has Accordingly, the present invention converts an RGB image into an HSV image, detects unknown hue and saturation saturation information in the RGB image, and performs color adjustment using the same.

The color adjuster 130 detects color and saturation information from the converted HSV image, and displays a color (for example, visually sensitive color such as skin tone) to be adjusted based on the detected color and saturation information. Adjust the range. The HSV-RGB converter 190 converts the HSV image having the color range adjusted to an RGB image and outputs the converted RGB image to the display 200.

2 is a view showing an RGB color model, Figure 3 is a view showing an HSV color model.

2 and 3, various color models such as RGB, CMY, HSV Munsell, CIE, etc. are used to classify the color of the image data and to distinguish the characteristics of the image according to attributes such as color tone, brightness, and contrast. have.

Among these, the RGB model is a color model based on three primary colors of light, that is, red, green, and blue, and constitutes color by using a property of adding white light to various colors. It is also called an additive model because it adds a base color to create a new color. RGB models are used to represent colors with light, such as cathode-ray tubes (CRTs) and liquid crystal display (LCD) monitors. The HSV model is the color model most similar to the human visual model, and is based on the intuitive visual view of the human. The HSV model is based on hue, saturation, and lightness, unlike the RGB model, which is based on red, green, and blue.

Referring back to FIG. 1, the color controller 130 detects hue and saturation information from the HSV image, and adjusts and outputs a target color based on the detected hue and saturation information. To this end, the color adjusting unit 130 has a configuration including a hue and saturation detector 150 and a color mapping unit 170.

The hue and saturation detector 150 detects hue and saturation information from the HSV image. The color mapping unit 170 adjusts the range of the target color in response to the hue and saturation information detected by the hue and saturation detection unit 150. Adjustment of the color range according to the present invention is as follows.

4 is a view showing the distribution of skin tone in the HSV color model, Figure 5 is a view showing the result of color adjustment for the skin tone according to the present invention. Hereinafter, for convenience of description, adjustment of the color for the skin tone will be described by way of example. The adjustment of the skin tone described herein is merely an example for adjusting any color among various colors, and various changes and modifications can be made without departing from the technical spirit of the present invention.

First, referring to FIG. 4, color information (Hue) in an HSV image is represented by an angle, and has a range of 0 ° to 360 ° (that is, 0 ° ≦ H ≦ 360 °). And, the saturation (Satuation) has a range of 0 to 1 (that is, 0≤S≤1). In this range of colors and angles, the skin tone is defined as having a color in the range H1 to H2 (ie H1 <H <H2) and having a saturation in the range 0 to M (ie 0≤S <M). do. At this time, the color of the skin tone serving as the source is called MH1, and the color of the skin tone serving as the destination is called MH2. In the present invention, the color MH1 of the skin tone to be the source and the color MH2 of the desired skin tone are respectively used by the user. The user designates a desired color through an application program and adjusts the tone of the designated color as desired.

FIG. 5 shows the result of color adjustment for skin tone when the user wants to adjust MH1 color to MH2 color when the skin tone has a color range of H1 <H <H2 and has a saturation range of 0≤S <M. Is shown.

First, referring to FIG. 5A, in the color adjusting apparatus 100 according to the present invention, the color range of the skin tone region belongs to the range of H1 <H <MH1, and the saturation range is 0 ≦ S. The color is adjusted (hatched) so that the color of the region (hereinafter referred to as the first region) in the range of <M is broadly mapped to the region (hereinafter referred to as the third region) in the range of H1 <H <MH2. Reference). In this case, the third region has a larger range than that of the first region, and the mapping scheme is represented as follows.

Referring to FIG. 5B, the color adjusting apparatus 100 according to the present invention includes a region except for the first region, that is, a region belonging to a range of MH1 ≦ H <H2 among the entire regions of the skin tone ( Hereinafter, the color of the second region is adjusted so that the color is narrowly mapped to the region (hereinafter referred to as the fourth region) in the range of MH2 ≤ H <H2 (see a portion indicated by dots). In this case, the fourth region has a smaller range than that of the second region, and the mapping scheme is represented as follows.

Here, the entire color range before the change composed of the first and second regions, and the entire color range after the mapping changed to the third and fourth regions by Equation 1 and Equation 2, are all the skin tone. It belongs to the color range H1 <H <H2.

The color adjusting device 100 may include any adjustment constant α for an adjacent color whose color belongs to the color range of the color to be changed, but whose saturation does not belong to the range of saturation of the color to be changed. Based on the mapping result (ie, Hmid) for the third and fourth regions, color mapping is performed. At this time, the mapping method for the surrounding color used is as follows.

Here, α is an adjustment constant used to prevent distortion of a color close to the color to be adjusted, and may use a constant input from a user or an arbitrary value determined by repeated experiments.

According to the color adjustment for the ambient color as shown in [Equation 3], the change of the hue between the color to be adjusted (that is, the skin tone) and the ambient color is gradually reduced. As a result, tomography does not occur between the color to be adjusted and the surrounding color, thereby enabling natural color adjustment and preventing distortion of the surrounding color due to color shift. Such color adjustment is performed sequentially from [Equation 1] to [Equation 3].

6 is a flowchart illustrating a color adjusting method according to a preferred embodiment of the present invention.

Referring to FIG. 6, in the color adjusting method according to the present invention, when an image is first input (step 1000), the format of the input image is converted from an RGB type to an HSV type (step 1100). Subsequently, color and saturation information are detected from the converted HSV type image (step 1500), and color adjustment is performed using the same (step 1700). The HSV-type image is converted back to an RGB-type image (step 1900), and the converted image is output to the display (step 2000). The color conversion process performed in step 1700 is as follows.

FIG. 7 is a detailed flowchart of a color conversion process performed in operation 1700 of FIG. 6. In FIG. 7, it is assumed that the skin tone has a color range of H1 <H <H2 and has a saturation range of 0 ≦ S <M. At this time, if the user wants to adjust the MH1 color to the MH2 color, the color adjustment method according to the present invention, the first color information that the image has a first region (that is, H1 <H≤MH1, 0≤S <M (Step 1710).

If it is determined in operation 1710 that the color information of the image belongs to the first region, the color of the image is adjusted using Equation 1 (operation 1720). The result of color adjustment performed in operation 1720 is as shown in FIG. 5A, and colors belonging to the first area are mapped to a third area wider than the first area. Subsequently, when it is determined in operation 1710 that the color information of the image does not belong to the first region, whether the image belongs to the second region (that is, MH1 ≦ H <H2 and 0 ≦ S <M). It is determined whether or not (step 1730).

As a result of the determination in operation 1730, if it is determined that the color information of the image belongs to the second region, the color of the image is adjusted using Equation 2 (operation 1740). The result of color adjustment performed in step 1740 is as shown in FIG. 5B, and colors belonging to the second area are mapped to a fourth area narrower than the second area. Subsequently, if it is determined in operation 1730 that the color information of the image does not belong to the second region, whether the image belongs to the third region (that is, H1 <H <H2, M≤S≤1.0). It is determined whether or not (step 1750).

If it is determined in operation 1750 that the color information of the image belongs to the third region, the color of the corresponding image is adjusted using Equation 3 (step 1760). Step 1760 adjusts the color of adjacent colors that have the same color range as the skin tone, but whose saturation is not in the range different from the skin tone.

As described above, the color adjusting apparatus and method according to the present invention adjusts the color of the image by using a combination of the color and saturation of the image. In addition, by correcting not only the target color (that is, skin tone) but also the color adjacent to the target color, a fault is not generated between the color to be adjusted and the surrounding color. This becomes possible.

In the above, the configuration and operation of the circuit according to the present invention are shown in accordance with the above description and drawings, but this is merely described, for example, and various changes and modifications are possible without departing from the spirit of the present invention. .

The invention can also be embodied as computer readable code on a computer readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, and may also be implemented in the form of a carrier wave (for example, transmission over the Internet). Include. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

According to the present invention as described above, it is possible to perform a more accurate and fine color adjustment in the display device.

Claims (13)

A first image conversion unit converting a first type of image composed of red, green, and blue based information into a second type of image composed of information based on hue, saturation, and lightness; A color adjusting unit which detects the hue and saturation information from the second type of image and adjusts a display range of a color to be adjusted based on the detected hue and saturation information; And And a second image converter configured to convert the image of the second type adjusted by the color controller into the first type and output the converted image to a display device. The method of claim 1, wherein the color control unit A hue and saturation detector for detecting the hue and saturation information from the second type of image; And In response to the detected hue and saturation information, the range of color to be adjusted is divided into first and second areas, and image data of a color belonging to the first area is larger than the first area. And a color mapping unit for mapping the image data of the color belonging to the second area to a fourth area smaller than the second area. The method of claim 2, And the entire color range before the change composed of the first and second regions and the entire color range after the mapping composed of the third and fourth regions are the same. The method of claim 2, The color mapping unit may include an arbitrary adjustment constant and the third and fourth values for an adjacent color whose color belongs to the color range of the color to be changed, but whose saturation does not belong to the range of saturation of the color to be changed. And color mapping is performed based on the result of the mapping to the region. The method of claim 1, The range of color to be adjusted is input from the outside through a user interface. The method of claim 4, wherein The adjustment constant is a color control device, characterized in that the constant to prevent distortion of the color close to the color to be adjusted. (a) converting a first type of image composed of information based on red, green, and blue into a second type image composed of information based on hue, saturation, and lightness; (b) detecting the hue and saturation information from the second type of image and adjusting a display range of a color to be adjusted based on the detected hue and saturation information; And (c) converting the second type of image adjusted in step (b) into the first type and outputting the image to a display device. 8. The method of claim 7, wherein step (b) (b-1) detecting the hue and saturation information from the second type of image; And (b-2) in response to the detected hue and saturation information, dividing the range of the color to be adjusted into first and second regions; And (b-3) Map image data of a color belonging to the first area to a third area larger than the first area, and map image data of a color belonging to the second area to a fourth area smaller than the second area. And a step of mapping each. The method of claim 8, And the entire color range before the change composed of the first and second regions and the entire color range after the mapping composed of the third and fourth regions are the same. The method of claim 8, The step (b) may include any adjustment constants for the adjacent colors whose colors belong to the color range of the color to be changed, but whose saturation does not belong to the range of saturation of the color to be changed; And performing color mapping on the basis of the mapping result for the fourth region. The method of claim 7, wherein The range of color to be adjusted is input from the outside through a user interface. The method of claim 10, The adjustment constant is a color adjustment method, characterized in that the constant to prevent distortion of the color close to the color to be adjusted. A computer-readable recording medium having recorded thereon a program for executing the method of any one of claims 7 to 12 on a computer.

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