KR20030067485A - Method and apparatus for changing brightness of image - Google Patents

Abstract

PURPOSE: A method and apparatus for changing brightness of an image are provided to increase brightness of an image while maintaining color purity of the image. CONSTITUTION: A level increase rate corresponding to a degree of increasing brightness of three input color components is obtained according to a color gamut including the fourth color component(12). The input color components are scaled using the level increase rate, and the scaled result is decided as increase values of the input color components(14). The value of the fourth color component is obtained using the increase values(16). Output color components acquired by increasing the brightness of the input color components are obtained using the fourth color component and the increase values(18). The level increase rate is less than a predetermined value.

Description

Method and apparatus for changing the brightness of an image {Method and apparatus for changing brightness of image}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to image processing, and more particularly, to a method and apparatus for changing the brightness of an image for adjusting the brightness while maintaining the color and saturation of the image.

Recently, micro-displays such as liquid crystal displays (LCDs), liquid crystal on silicon (LCoS) or digital micro-mirror devices (DMDs) or plasma display panels (PDPs) Color display devices, such as Plasma Display Panels, are widely used for computer monitors or television receivers, and are growing in size in the market. However, in order to increase the output light amount of the display screen in preparation for the cathode ray tube, the display device employs a high output lamp or a high output electrode.

In order to increase the brightness of the output image without using a high power lamp or a high power electrode, any of the color components different from the three color components (hereinafter, the fourth color) in the three first, second and third color components 4 color display device with the addition of a component) is being released. The fourth color component may be obtained by transmitting or reflecting the filter of the fourth color component (hereinafter referred to as a fourth filter (not shown)) to the lamp of the display apparatus, and the brightness of the display apparatus when the fourth filter is a white filter. Is improved so that there is no need to use a high power lamp or high power electrode. As another example, when the fourth filter is any color, the color expression amount of the corresponding color gamut is abundant, thereby enabling high quality color expression in the display device. Therefore, there is a need for a method of extracting a fourth color component from three color components into four color components.

One of the conventional methods of changing the brightness of an output image that increases the brightness of the output image is described in US Patent No. US5,233,385 filed by Texas Instruments Incorporated, entitled "White light enhanced color field sequential projection". Is disclosed. The conventional method of adding a white filter to an R: Red, G: Green, and B: Blue three-color filter can spatially divide the filter section that generates color into four equal parts. In addition, the video frame is divided into four temporal sections in time, and the white filter section or the field sequential method in which the white light frame is added to the RGB is used. It can be increased in proportion to. However, this conventional method can increase the brightness of the output image in the display device, whereas the increase in brightness is an achromatic component, which causes a problem of lowering the original color purity (saturation) of the pixels in the output image.

Another method of changing the brightness of a conventional image is disclosed in US Patent No. US 5,929,843 filed by Canon Kabushiki Kaisha of Japan entitled "Image processing apparatus which extracts white component data". The conventional method disclosed herein extracts a white component from each RGB data when a red, green, blue, and white pixel unit is used for a binary liquid crystal display device, and halftones are extracted. pass to RGB and white display dots. The conventional method is characterized by generating a white component by obtaining a common minimum amount of the input red, green, and blue data and then nonlinearly converting it. That is, nonlinear models correspond to gamma, offset, and scale. As a result, the above-mentioned conventional method has the advantage of developing the white reinforcement of the previous surface sequential method on a pixel-by-pixel basis, and also determining the amount of white component applied according to a predetermined model, while non-coloring the color due to the addition of the white applied amount. We did not consider how to maintain the color purity to avoid. Therefore, when increasing the brightness of the output image, there is a problem that the color purity cannot be kept constant.

An object of the present invention is to provide a method of changing the brightness of an image which can increase the brightness of the image while maintaining the color purity of the image.

Another object of the present invention is to provide an apparatus for changing the brightness of an image that performs the brightness changing method of the image.

FIG. 1 is a diagram illustrating three input color components, first, second and third color components (eg, RGB) in a three-dimensional color space.

FIG. 2 is a diagram exemplarily showing four first, second, third and fourth color components, for example, RGBW in two dimensions using RG and W. FIG.

FIG. 3 is another diagram exemplarily showing four color components, for example, RGBW in two dimensions using RG and W. FIG.

4 is a flowchart illustrating a method of changing brightness of an image according to the present invention.

5 is a flowchart for explaining a preferred embodiment of the present invention for the tenth and twelfth steps shown in FIG.

FIG. 6 is a flowchart for explaining another preferred embodiment of the present invention for the tenth and twelfth steps shown in FIG.

FIG. 7 is a flowchart for explaining an exemplary embodiment of the present invention for the sixteenth step illustrated in FIG. 4.

FIG. 8 is a flowchart for explaining another embodiment of the present invention with respect to the eighteenth step shown in FIG. 4.

9 is a block diagram of an apparatus for changing brightness of an image according to the present invention.

FIG. 10 is a block diagram of a preferred embodiment of the present invention according to the present invention.

FIG. 11 is a block diagram of an embodiment according to the present invention of the increase ratio calculator shown in FIG. 9.

12 is a block diagram of another embodiment according to the present invention of the area determining unit shown in FIG.

FIG. 13 is a block diagram of another embodiment according to the present invention of the increase ratio calculator shown in FIG. 9.

FIG. 14 is a block diagram of an exemplary embodiment of the present invention of the increment calculator shown in FIG. 9.

FIG. 15 is a block diagram of a preferred embodiment of the present invention of the fourth color component calculator shown in FIG. 9.

FIG. 16 is a block diagram of another preferred embodiment according to the present invention of the fourth color component calculator shown in FIG.

FIG. 17 is a block diagram of another preferred embodiment of the present invention of the fourth color component calculator shown in FIG.

FIG. 18 is a block diagram of a preferred embodiment of the present invention of the output color component calculator shown in FIG.

19 is a block diagram of another embodiment according to the present invention of the output color component calculating unit shown in FIG.

According to another aspect of the present invention, there is provided a method of changing a brightness of an image, the method comprising: obtaining a level increase ratio corresponding to a degree of increasing brightness of input color components according to a color gamut including a fourth color component; Scaling the input color components by using and determining a scaled result as increments of the input color components, obtaining a value of the fourth color component using the increments, and And calculating output color components having increased brightness by using the value of the fourth color component and the increase values, wherein the level increase ratio is preferably equal to or less than a first predetermined value.

In accordance with another aspect of the present invention, an apparatus for changing a brightness of an image may include a level increase ratio corresponding to an increase in brightness of three input color components input from an external device based on an allowable light quantity ratio and the input color components. An increase value calculator for calculating the input color components according to the level increase ratio inputted from the increase ratio calculator, and outputting the scaled result as increase values of the input color components; A fourth color component value calculator which calculates a value of a fourth color component from the increase values input from the increase value calculator, and outputs the calculated value of the fourth color component and brightness of the input color components An output color component that calculates output color components of which the value is increased from the values of the increments and the fourth color component, and outputs the calculated output color components It is composed of a computation are preferred.

Hereinafter, the principle of the method and apparatus for changing the brightness of an image according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating three input color components, first, second and third color components (eg, RGB) in a three-dimensional color space.

2 illustrates four first, second, third and fourth color components, for example, RGBW (where W means fourth color component) in two dimensions using RG and W. FIG. As an illustration, the X axis corresponds to the sum of R and Wr (where Wr is the result of projecting W onto the R axis in RGB three-dimensional space), and the Y axis is G and Wg (where Wg is It represents the result of projecting W onto the G-axis in RGB three-dimensional space. For example, W may be expressed as a vector sum of RGB, and W is defined as W = {Wr, Wg, Wb} (where Wb is the result of projecting W onto the B axis in RGB three-dimensional space). Can be.

In order to change the brightness of the image as desired while maintaining the purity, the method and apparatus for changing the brightness of the image according to the present invention adopts a four-color processing method. The sum of any two color signals C ₁ and C ₂ is expressed as Equation 1 below as the inner product of the two vectors.

Here, C _i (1 ≦ _i ≦ 3) represents the color signal, mag _i represents the magnitude of the color signal, Uvec _i represents the direction vector of the color signal, and Dot represents the dot product, respectively.

In order to increase the amount of light in the input color signal C ₁ of the image illustrated in FIG. 1, when the fourth color signal C ₂ is mixed with the input color signal C ₁ of the image, a mixed color C ₃ appears. At this time, a mixed color (C ₃₎ is therefore in general with the input color signal (C ₁₎ of the image have a different direction vector, resulting in a color signal (C ₁₎ of the input image is increased, the amount of light, but is visible color change. Therefore, a correction process is required to make the mixed color C ₃ match the direction of the original image input color signal C ₁ . For example, the dot product of the fourth color signal C ₂ and the correction vector component C ₄ is then obtained to obtain a brightness-increased target vector C _{T that} matches the direction vector of the input color signal C ₁ of the image. It is performed as in Equation 2.

The size of the correction vector component (C ₄₎ (mag ₄₎ and the direction vector (Uvec ₄₎ the size of the input color signal (C ₁₎ (mag ₁₎ and the direction vector (Uvec _1), a fourth color signal (C ₂₎ It is a function of the magnitude (mag ₂ ) and the direction vector (Uvec ₂ ). Thus, the input color signal (C _1), the size (mag ₁₎ and the direction vector (Uvec _1), at least one fourth the size of a color signal (C ₂₎ (mag ₂₎ and a direction vector (Uvec ₂₎ changes in, The magnitude (mag ₄ ) and the direction vector (Uvec ₄ ) of the correction vector component C ₄ also change.

In this case, Equation 2 is not sufficient to naturally reproduce the color of the arbitrary input image C ₁ with four colors. Therefore, the value of the fourth color component should be determined in consideration of the range of the color gamut shown in FIG. 2. Because the four-color gamut is not the color range of the cube like the RGB three-color space, but has a maximum of ten cube-shaped color ranges.

When the range of the input gamut shown in FIG. 2 is a square of Org-R'-F-G ', the range of the output gamut becomes a hexagon connecting six vertices (Org-G'-A-D-B-R'). Here, the two triangles G'-G "-A and B-R'-R" are spaces in which color components cannot be expressed.

In FIG. 2, the input color components lying inside the rectangle Org-A'-F-B 'may increase in size while maintaining a vector direction when multiplied by a value of a constant size. However, if the color component is placed in a space other than the rectangle (Org-A'-F-B ') after increasing its size, multiplying the predetermined size by the color component causes the color component with the increased size to appear outside of the color space. Can be mapped to a location.

Therefore, in order to increase the brightness of the input color components inside the quadrangle (Org-R'-F-G ') within the representable range while maintaining the vector direction, two triangles (Org-G'- Colors inside A 'and Org-R'-B') and colors inside rectangle (Org-A'-F-B ') must be processed separately. In addition, in order for an increased value of colors lying inside two triangles (Org-G'-A 'and Org-R'-B') to exist within a range of colors that can be expressed, the corresponding values are determined according to the component ratio or coordinate of the corresponding color. The increase or amount of color should be controlled.

In addition, the size ratio of the rectangles Org-A'-F-B 'and the rectangles ADBF is equal to the output light amount of the fourth color component versus the output light amount of the first, second and third color components, that is, the RGB component. ratio is determined by the (villa or less, increase light quantity, and is denoted by _S L). That is, the rectangle Org-A'-F-B 'is a color gamut represented by the output light amount of the RGB component, and the rectangle ADBF is a gamut represented by the output light amount of the fourth color component. The two triangles (Org-G'-A 'and Org-R'-B') are color gamuts represented by a mixture of RGB and fourth color components. The light quantity increase ratio L _S is as shown in Equation 3 below.

Here, the light quantity increase ratio L _S is represented by the light quantity increase ratio (hereinafter referred to as component light quantity increase ratio) in each color component of RGB (L _{S_r} , L _{S_g} , L _{S_b} ), and E _r , E _g , E _b and E _w represent the light intensities in the R-channel, G-channel, B-channel and fourth color channel respectively output from the display device. E _{W_r} , E _{W_g} , and E _{W_b} are three color component-specific light intensities obtained by vector decomposition of the output light intensity E _W of the fourth color-channel into three color (for example, RGB) components. For example, the output light intensity of the R-channel, G-channel, and B-channel output from the display device is 100 (E _r = E _g = E _b = 100), respectively, and the output light of the fourth color-channel is output. When the intensity (E _W ) is decomposed into three color components, if the light intensity (E _{W_r} , E _{W_g} , E _{W_b} ) for each of the decomposed components is 40, 50, and 60, respectively, the component light quantity increase ratio (L _{S_r of} each of the three colors) , L _{S_g} , L _{S_b} ) are 0.4, 0.5, and 0.6, respectively. In this case, referring to FIG. 2, the length ratio of the line segment Org-R 'and the line segment FB in the rectangle (Org-R'-F-G') and the rectangle ADBF is 1: 0.4, and the line segments Org-G 'and The length ratio of the line segment FA is 1: 0.5.

FIG. 3 is another diagram exemplarily showing four color components, for example, RGBW in two dimensions using RG and W. FIG.

When the light intensity (E _{W_r} , E _{W_g} , E _{W_b} ) for each of the decomposed components in the fourth color channel is different, that is, W _r (where W _r is the length of the line segment FB) and W _g (where (W _g is the length of the line segment FA.), The color gamut shape of the fourth color component may be different. 3 is a diagram illustrating a changed color gamut in two dimensions.

Hereinafter, a method of changing brightness of an image according to the present invention will be described with reference to the accompanying drawings.

4 is a flowchart illustrating a method of changing a brightness of an image according to an exemplary embodiment of the present invention, wherein the input color components are scaled using a level increase ratio obtained according to a region to which the input color components belong (steps 10 to 14). Obtaining the value of the fourth color component and the output color components using the increment values (16th and 18th steps).

Referring to FIG. 4, a region to which three input color components, first, second and third color components belong, among the color gamuts illustrated in FIG. 2 are determined (step 10). Here, the three input color components are color signals generally used in image processing, such as RGB, luminance Y and chrominance signals CrCb, luminance Y and chrominance signals I and Q, and color. Brightness and purity (HLS: Hue Lightness Saturation) or the International Commission on Illumination (CIE) and luminance and chrominance signals (CIELAB or CIELUV). Hereinafter, to aid in understanding the present invention, three input color components are assumed to be RGB.

After the tenth step, a level increase ratio S ₁ corresponding to a degree of increasing the brightness of the input color components R ₀ , G _0, and B ₀ is obtained according to the determined region (step 12). According to the present invention, the degree to increase the brightness of the input color component (R _0, G ₀ and B ₀₎ of the region and the input color component belongs (R _0, G ₀ and B ₀₎ increases the amount of light (L _S May be determined in consideration of Herein, the light amount increasing ratio L _S may be set as shown in Equation 3 above, or may be set to any value, for example, 1, or may be set to a predetermined value which may be changed in advance.

FIG. 5 is a flowchart for explaining a preferred embodiment of the present invention with respect to the tenth and twelfth steps shown in FIG. 4, and determining a region to which input color components belong (steps 30 and 32). And the level increase ratio (the thirty-fourth to thirty-eighth steps).

According to an embodiment of the present invention, an input vector representing the input color components R ₀ , G _0, and B ₀ is defined as the boundary of the input color gamut, that is, the sides of the square (Org-R'-F-G '). Intersections R ₃ , G ₃ and B ₃ , which meet the boundary when extending to, are obtained as in Equation 4 below (Step 30).

, ,

Here, M ₁ corresponds to the maximum value of R ₀ , G ₀ and B ₀ , k ₁ may be, for example, 255 as the maximum value of the luminance level that the input color components may have, and the intersection point R ₃ , G ₃ and B ₃ ) can lie on the line G'-F or FR 'shown in FIG. 2, and when the input color components R ₀ , G ₀ and B ₀ correspond to Q points, the intersection point R ₃ , G ₃ and B ₃ ) correspond to point K.

After the thirtieth step, it is determined whether at least one of the intersections R ₃ , G ₃ and B ₃ is less than the first threshold (step 32). According to the present invention, the first threshold value may be expressed as in Equation 5 below.

Here, K ₃ means the maximum value (or minimum value) of the component light amount increase ratios L _{S_r} , L _{S_g} and L _{S_b} expressed in Equation 3 (hereinafter, referred to as an allowable light amount increase ratio). If the allowable light amount increase ratio K ₃ is 1 and k ₁ = 255, the first threshold value may be 127. Here, when at least one of the coordinates of the intersections R ₃ , G ₃ and B ₃ is less than the first threshold value, the input color components R ₀ , G ₀ and B ₀ are not fixed in the first scaling space. That is, it belongs to the two triangle regions (Org-G'-A 'and Org-R'-B') shown in FIG. However, if none of the coordinates of the intersections R ₃ , G ₃ and B ₃ are less than the first threshold, then the input color components R ₀ , G ₀ and B ₀ are fixed second scaling space, i.e. It belongs to the rectangular region (Org-A'-F-B ') shown in FIG.

If at least one of the coordinates of the intersections R ₃ , G ₃ and B ₃ is determined to be less than the first threshold value, the minimum value of the coordinates of the intersections R ₃ , G ₃ and B ₃ and the allowable amount of light increase. The result of multiplying the ratio K ₃ is subtracted from each coordinate (R ₃ , G ₃ or B ₃ ) of the intersection as in Equation 6 below (Step 36).

Here, R ₄ , G ₄ and B ₄ represent subtracted results, and Min (R ₃ , G ₃ and B ₃ ) represent the minimum value among R ₃ , G ₃ and B ₃ .

After the 36th step, the maximum value k ₁ of the luminance levels that the input color components R ₀ , G _0, and B ₀ may have is subtracted from the maximum value of the results R ₄ , G _4, and B ₄ . Next, the division is performed as in Equation (7), and the division result is determined as the level increase ratio S ₁ , and the flow proceeds to step 14 (step 38).

Here, Max (R ₄ , G ₄ , B ₄ ) represents the maximum value of the subtracted results R ₄ , G ₄ and B ₄ .

However, if none of the coordinates of the intersections R ₃ , G _3, and B ₃ is determined to be less than the first threshold value, the first predetermined value is determined as the level increase ratio S ₁ , and the process proceeds to step 14. Proceed (step 34). Here, the first predetermined value K ₄ is a value obtained by adding '1' to the allowable light amount increase ratio K ₃ . At this time, the allowable light amount increase ratio K ₃ is a predetermined value. Therefore, the first predetermined value K ₄ is also predetermined. At this time, the above-described level increase ratio is equal to or less than the first predetermined value.

FIG. 6 is a flowchart for explaining another preferred embodiment of the present invention with respect to the tenth and twelfth steps shown in FIG. 4, and determining a region to which input color components belong (steps 50 to 54). And the level increasing ratio (56th and 58th steps).

According to another embodiment of the present invention, the maximum value M1 and the minimum value M2 of the input color components R ₀ , G _0, and B ₀ are extracted (step 50). After the 50th step, K ₄ times the minimum value M2 is subtracted from the maximum value M1 (step 52). After the 52nd step, it is determined whether the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 is greater than the second threshold value (step 54). For example, the second threshold may be '0'. Here, when the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 is greater than the second threshold value, the input color components R ₀ , G _0, and B ₀ belong to the first scaling space. However, if the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 is equal to or less than the second threshold value, the input color components R ₀ , G _0, and B ₀ belong to the second scaling space.

If it is determined that the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 is greater than the second threshold value, the result of multiplying the minimum value M2 and the allowable light amount increase ratio K ₃ by the maximum The ratio between the result M1-K ₃ M2 and the maximum value M1 subtracted from the value M1 is calculated, and the ratio calculated as in the following Equation 8 is determined as the level increase ratio S ₁ , and the fourteenth ratio Proceed to step (step 56).

However, if it is determined that the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 is less than or equal to the second threshold value, the second predetermined value is determined as the level increase ratio S ₁ , and the process proceeds to step 14. Proceed (step 58). Here, the second predetermined value is determined independently of the input color components and is the same value as the first predetermined value K ₄ described above.

As a result, when the input color components R ₀ , G _0, and B ₀ belong to the first scaling space, the level increase ratio S ₁ is obtained according to the input color components R ₀ , G _0, and B ₀ . When the input color components R ₀ , G ₀ and B ₀ belong to the second scaling space, the level increase ratio S ₁ is obtained independently of the input color components R ₀ , G ₀ and B ₀ .

According to the present invention, the method of changing the brightness of the image shown in FIG. 4 may not provide a tenth step. In this case, the level increase ratio is obtained according to the color gamut in which the fourth color component is included (12th step).

Meanwhile, after the twelfth step, the input color components R ₀ , G _0, and B ₀ are scaled using the level increase ratio S ₁ , and the scaled result is input to the input color components R ₀ , G _0, and. B ₀ ) are determined as increments R ₂ , G ₂ and B ₂ (step 14).

According to an embodiment of the present invention, after the twelfth step, the level increase ratio S ₁ and the input color components R ₀ , G _0, and B ₀ are respectively multiplied, and the multiplied results are expressed as in Equation 9 below. Determine as increments R ₂ , G ₂ and B ₂ and proceed to step 16 (step 14).

After all, when the input color components _Ro , G _o and B _o belong to the second scaling space, the level increase ratio S ₁ is converted into the input color components _Ro , G _o and B _o . When multiplying, such as 9, the input vector direction of the color components (R _o, G _o and B _o) input color component and to increase the size of the (R _o, G _o and B _o) can be kept constant. For example, using Equation 9, the point P in FIG. 2 corresponding to the input color components R ₀ , G _0, and B ₀ corresponds to the increase values R ₂ , G _2, and B ₂ . It becomes P 'point.

However, when the input color components R ₀ , G ₀ and B ₀ belong to the first scaling space, the input color gamut of the input color gamut that meets the extension lines in the vector direction of the input color components R ₀ , G ₀ and B ₀ respectively From the intersection point IP ₁ and the intersection point IP ₂ of the output gamut, the level increase ratio S ₁ is obtained as shown in Equation 10 below.

Here, the intersection point IP ₁ corresponds to (R ₃ , G ₃ , B ₃ ) as the K point shown in FIG. 2, and the intersection point IP ₂ corresponds to the H point shown in FIG. 2. Therefore, Equation 10 determines the level increase ratio S _{1 based} on the length ratio between the line segment Org-H and the line segment Org-K. In this case, as shown in FIG. 2, since the line segment K-K 'and the line segment R'-B have the same slope, the intersection point IP with respect to the line segment Org-H corresponding to the intersection point IP ₂ is obtained. The ratio of the length between line segment Org-K corresponding to ₁ ) is the same as the ratio between the length of line segment Org-K 'to the line segment Org-R'. Here, the point K 'corresponds to (R ₄ , G ₄ , B ₄ ). As a result, when the input color signals R ₀ , G ₀ and B ₀ are the points Q, multiplying the level increase ratio S ₁ by the point Q, one point Q "in the output color gamut can be obtained.

Another method for calculating the level increase ratio S ₁ is to use points J 'and J' instead of point K '. As shown in FIG. 2, the line segment K-K 'and the line segment R'-B have the same slope as the line segment Q-J', so that the line segment Org-H corresponding to the intersection point IP ₂ is The ratio of the line segment Org-K corresponding to the intersection point IP ₁ is equal to the ratio of the line segment Org-J 'to the line segment Org-J. Here, the line segment Org-J corresponds to M1 in Equation 8, and the line segment Org-J 'corresponds to M1-K ₃ M2 in Equation 8. As a result, when the input color signals R ₀ , G ₀ , B ₀ are points Q, multiplying the level increase ratio S ₁ by the point Q, one point Q "in the output gamut can be obtained.

Meanwhile, since the increase values R ₂ , G _2, and B ₂ expressed in the above-described Equation 9 obtained in the fourteenth step are a result of increasing the brightness of the input color components R ₀ , G _0, and B ₀ , the increase is substantially effective. The fourth color component is included. Therefore, after the fourteenth step, the value W _out of the fourth color component is obtained using the increase values R ₂ , G ₂ and B ₂ (step 16). An embodiment of the present invention for the sixteenth step will be described as follows.

FIG. 7 is a flowchart for explaining an embodiment 16A according to the present invention for the sixteenth step shown in FIG. 4, wherein some of the increase values are determined as the value W _out of the fourth color component. stage (90th stage) to and the value of the fourth color component (W _out), the fourth color component values of the fourth color component in accordance with this is greater than the maximum value (k ₂₎ of the brightness level, which may have (W _out) Is updated (steps 92 and 94).

After the fourteenth step, the partial value W _m of the increment values R ₂ , G ₂ and B ₂ is determined as the value W _out of the fourth color component (step 90). Here, the partial value W _m may be the minimum value of the increase values R ₂ , G ₂ and B ₂ or the minimum value having a weight, and also the maximum value of the increase values R ₂ , G ₂ and B ₂ . It may be the result of subtracting the maximum value (eg, 255) of the luminance level that the three input color components may have from the value (eg, 511 when K ₄ = 1). Further, the maximum value of some value (W _m) is the increment of the (R _2, G ₂ and B ₂₎ 3 color component from among the minimum and maximum values of the "increasing value (R _2, G ₂ and B ₂₎ The result of subtraction 'can be averaged and used. The partial value W _m may be defined as in Equation 11 below.

Here, M ₈ is the minimum value of the increase values R ₂ , G ₂ and B ₂ , and M ₉ may have three input color components at the maximum value of the increase values R ₂ , G ₂ and B ₂ . Corresponding to the result of subtracting the maximum value of the luminance level, coefficients a ₁ , a _2, and a ₃ each represent a weight.

After operation 90, it is determined whether the value W _out of the determined fourth color component is greater than the third threshold (operation 92). Here, the third threshold value is the maximum value k ₂ of the luminance levels that the fourth color component may have, and is determined by the allowable light amount increase ratio K ₃ .

If it is determined that the determined value W _out of the fourth color component is less than or equal to the third threshold value, the process proceeds to step 18. However, if it is determined that the value W _out of the determined fourth color component is greater than the third threshold value, which is the maximum value k ₂ of the luminance level that the fourth color component may have, the value of the determined fourth color component ( W _out ) is updated to a third threshold value which is the maximum value k ₂ of the luminance levels that the fourth color component may have, and the flow proceeds to step 18 (step 94). For example, when K ₃ = 1, the third threshold may be 255.

After the sixteenth step, the output color components R _out , G _out, and B _out corresponding to the result of increasing the brightness of the input color components R ₀ , G _0, and B ₀ are converted into values of the fourth color component ( W _out ) and increase values R ₂ , G ₂ and B ₂ (step 18).

According to an embodiment of the present invention, it is assumed that the fourth color component created by the three input color components R ₀ , G _0, and B ₀ and the fourth color component reproduced by the fourth color channel are the same. At the time, after the sixteenth step as shown in Equation 12, the value of the fourth color component W _out is subtracted from the increase values R ₂ , G ₂ and B ₂ , and the subtracted results are output color components ( R _out , G _out and B _out ) (step 18).

That is, Equation 12 shows output color components R _out and G _out obtained when the combination ratios R _a , G _a and B _a of the input color components R ₀ , G ₀ and B ₀ are all the same. And B _out ).

However, if the input color components (R _0, G ₀ and B ₀₎ to the fourth color component and the fourth rather than the same as the fourth color component which is reproduced in a color channel fourth color seongbunga any color component is created by, That is, when vector-decomposed the output light intensity E _W in the fourth color channel into three color components, at least one of the sizes of the decomposed component light intensities E _{W_r} , E _{W_g} and E _{W_b} are different. In this case, another embodiment of the present invention for the eighteenth step shown in FIG. 4 is as follows.

8 is a flowchart illustrating another example (18A) of the present invention to the step 18 shown in Figure 4, the mixing ratio of (R _a, G _a and B _a) the value of the fourth color component And subtracting the result of W _out from the increase values R ₂ , G _2, and B ₂ (steps 110 and 112).

After the sixteenth step, the ratio between the component light intensities E _{W_r} , E _{W_g} and E _{W_b as} a result of vector decomposition of the output light intensity E _W in the fourth color-channel into three color components s made with the blend ratio _(a R, _a G and _a B) a fourth multiplying each component by a value (W _out) of the color component (the step 110). At this time, the mixing ratio _(a R, _a G and _a B) can be defined as the following equation (13).

Here, the function [F (a, b, c)] means the maximum value or the minimum value of the factors a, b, and c, and the coefficients b ₁ , b _2, and b ₃ are weights for each component.

After step 110, the multiplied results are subtracted from the increments R ₂ , G ₂ and B ₂ , and the subtracted results are determined as output color components R _out , G _out and B _out (112). step). As a result, the output color components R _out , G _out, and B _out obtained by the embodiment 18A shown in FIG. 8 are expressed by Equation 14 below.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the apparatus for changing the brightness of an image according to the present invention for performing the above-described brightness changing method will be described.

9 is a block diagram of an apparatus for changing a brightness of an image according to an exemplary embodiment of the present invention, which includes an area determiner 140, an increase ratio calculator 142, an increase value calculator 144, and a fourth color component value calculator 146. And an output color component calculator 148.

In order to perform the tenth step illustrated in FIG. 4, the region determiner 140 illustrated in FIG. 9 performs three input color components input from the outside through the input terminal IN1 from the region representing the color gamut illustrated in FIG. 2. Determining a region to which the first, second and third color components R ₀ , G _0, and B ₀ belong, and outputting the determined result to the increase ratio calculator 142 as the first control signal C1. . At this time, the area determination unit 140 corresponds to the allowable light amount increase ratio K ₃ inputted from the outside through the input terminal IN1 to which the three input color components R ₀ , G _0, and B ₀ belong. Can be determined.

In order to perform the twelfth step, the increase ratio calculator 142 inputs the input color components R ₀ , which are input through the input terminal IN1 in response to the first control signal C1 input from the area determiner 140. The level increase ratio S ₁ is calculated from G ₀ and B ₀ ), and the calculated level increase ratio S ₁ is output to the increase value calculator 144. At this time, the increase ratio calculator 142 may calculate the level increase ratio S ₁ corresponding to the allowable light amount increase ratio K ₃ .

Hereinafter, the configuration and operation of each of the embodiments of the present invention of the area determiner 140 and the increase ratio calculator 142 shown in FIG. 9 will be described as follows.

FIG. 10 is a block diagram of a preferred embodiment 140A of the area determiner 140 shown in FIG. 9 according to the present invention, and includes an intersection calculator 160 and a first comparator 162.

The intersection calculation unit 160 illustrated in FIG. 10 extends an input vector representing the input color components R ₀ , G _0, and B ₀ to the boundary of the color gamut to perform the thirtieth step illustrated in FIG. 5. When the intersection point (R ₃ , G ₃ and B ₃ ) that meets the boundary is calculated from the input color components R ₀ , G ₀ and B ₀ input from the outside through the input terminal IN2, the calculated intersection point (R ₃₎ , G ₃ and B ₃ ) may be output to the first comparator 162 and to the increase ratio calculator 142 through the output terminal OUT2.

To this end, the intersection calculation unit 160 includes a first maximum value extractor 170, a first divider 172, and a first multiplier 174. Here, the first maximum value extractor 170 extracts the maximum value among the input color components R ₀ , G _0, and B ₀ input through the input terminal IN2, and extracts the extracted maximum value from the first divider ( 172). The first divider 172 inputs the maximum value k ₁ of the luminance levels that the input color components R ₀ , G _0, and B ₀ may have from the first maximum value extractor 170. And divides the result into a first multiplier 174. The first multiplier 174 multiplies the input color components R ₀ , G _0, and B ₀ by the divided result input from the first divider 172, and intersects the multiplied results by R ₃ , G. ₃ and B ₃ ). As a result, the intersection calculation unit 160 serves to calculate the intersections expressed in Equation (3).

At this time, the first comparison unit 162 compares coordinates of the intersections R ₃ , G ₃ and B ₃ input from the intersection calculation unit 160 with the first threshold value, in order to perform the 32nd step. The result of the comparison is output to the increase ratio calculator 142 as the first control signal C1.

FIG. 11 is a block diagram of an embodiment 142A of the increase ratio calculator 142 shown in FIG. 9 according to the present invention. The first minimum value extractor 190, the second multiplier 191, and the first multiplier 191 may be used. A subtractor 192, a second maximum value extractor 194, a second divider 196, and a first bypass unit 198 are provided.

The first minimum value extractor 190, the second multiplier 191, and the first subtractor 192 of the increase ratio calculator 142A illustrated in FIG. 11 perform the 36th step, that is, Equation 6 Do it. Here, the first minimum value extracting unit 190 may be configured to determine the intersections of the intersections R ₃ , G _3, and B ₃ input through the input terminal IN3 in response to the first control signal C1 input from the area determining unit 140. The minimum value of the coordinates is extracted and the extracted minimum value is output to the second multiplier 191. To this end, the first minimum value extractor 190 may input the intersections R ₃ , G _3, and B ₃ from the area determiner 140 illustrated in FIG. 10, for example, the intersection calculator 160. It may also calculate itself from the input color components R _O , G _O and B _O input from the outside through the input terminal IN3. The above-described first minimum value extractor 190 only recognizes at least one of the intersections R ₃ , G _3, and B ₃ through the first control signal C1 as less than the first threshold value. The smallest minimum value among R ₃ , G ₃ and B ₃ ) is extracted. That is, when at least one of the coordinates of the intersections R ₃ , G _3, and B ₃ is not recognized as less than the first threshold value through the first control signal C1, the first minimum value extractor 190 The minimum value of the coordinates of the intersections R ₃ , G ₃ and B ₃ is not extracted. The second multiplier 191 multiplies the minimum value input from the first minimum value extractor 190 by the allowable light amount increase ratio K ₃ input from the outside, and outputs the multiplied result to the first subtractor 192. do. In this case, the first subtractor 192 subtracts the multiplied result input from the second multiplier 191 from each of coordinates R ₃ , G ₃ or B ₃ of the intersection, and subtracts the subtracted results from the second. Output to the maximum value extraction unit 194.

If the allowable light amount increase ratio K ₃ is set to 1, the increase ratio calculator 142A shown in FIG. 11 may not provide the second multiplier 191. In this case, the first subtractor 192 subtracts the minimum value input from the first minimum value extractor 190 from each coordinate R ₃ , G _3, or B ₃ of the intersection, and subtracts the subtracted results to the second maximum value. Output to the extraction unit 194.

The second maximum value extractor 194 and the second divider 196 illustrated in FIG. 11 perform a 38 th step, that is, Equation 7. Here, the second maximum value extractor 194 extracts the maximum value among the subtracted results R ₄ , G ₄ , and B ₄ input from the first subtractor 192, and extracts the maximum value from the second maximum value extractor 192. Output to divider 196. The second divider 196 is the input color components (R _o, G _o and B _o), a maximum value input to the maximum value (k ₁₎ of the brightness level, which may have from the second maximum value extractor 194 The output is outputted through the output terminal OUT3 to the increase value calculator 144 as the level increase ratio S ₁ .

At this time, the first bypass unit 198 adjusts the first predetermined value to the level increase ratio S ₁ in response to the first control signal C1 input from the area determiner 140 to perform step 34. ) Is output through the output terminal OUT4. For example, when it is recognized that none of the coordinates of the intersections R ₃ , G _3, and B ₃ are smaller than the first threshold value through the first control signal C1, the first bypass unit 198 may perform the first bypass. 1 A predetermined value is output via the output terminal OUT4 as the level increase ratio S ₁ .

FIG. 12 is a block diagram of another embodiment 140B of the area determiner 140 shown in FIG. 9 according to the present invention, and includes a third maximum value extractor 210, a second minimum value extractor 212, and a second embodiment. The multiplication part 214, the 2nd subtraction part 216, and the 2nd comparison part 218 are comprised.

The region determiner 140B illustrated in FIG. 12 performs the 50th through 54th steps illustrated in FIG. 6. That is, in order to perform the fiftyth step, the third maximum value extractor 210 extracts the maximum value M1 of the input color components _Ro , G _o and B _o input from the outside through the input terminal IN4. The second minimum value extractor 212 extracts a minimum value M2 among the input color components _Ro , G _o, and B _o input from the outside through the input terminal IN4. At this time, in order to perform the 52nd step, the third multiplier 214 and the second subtractor 216 are provided. Here, the third multiplier 214 multiplies the minimum value M2 input from the second minimum value extracting unit 212 and the first predetermined value K ₄ , and multiplies the multiplied result by the second subtracting unit 216. Output The second subtractor 216 subtracts the multiplied result input from the third multiplier 214 from the maximum value M1 input from the third maximum value extractor 210 and compares the subtracted result with a second comparison. Output to the unit 218. The second comparator 218 performing the 54 th step compares the subtracted result input from the second subtractor 216 with the second threshold value, and compares the result of the increase as the first control signal C1 as an increase ratio. Output to the calculator 142.

FIG. 13 is a block diagram of another embodiment 142B of the increase ratio calculator 142 shown in FIG. 9 according to the present invention, and includes a fourth multiplier 231, a third subtractor 230, and a third agent. The mount portion 232 and the second bypass portion 234.

The increase ratio calculator 142B illustrated in FIG. 13 performs the fourth multiplier 231, the third subtractor 230, and the third divider 232 to perform step 56, that is, Equation 8. FIG. Prepare. Here, the fourth multiplier 231 multiplies the allowable light amount increase ratio K ₃ input from the outside to the minimum value M2 input from the area determiner 140, and multiplies the multiplied result by the third subtractor 230. ) The third subtractor 230 subtracts the multiplied result input from the fourth multiplier 231 from the maximum value M1 in response to the first control signal C1 input from the area determiner 140. The subtracted result is output to the third divider 232. To this end, the maximum value M1 and the minimum value M2 are the area determiner 140 shown in FIG. 9, for example, the third maximum value extractor 210 and the second minimum value extractor 212 shown in FIG. 12. ) May be respectively input to the third subtraction unit 230, and may be inputted from the outside through the input terminal IN1 from the input color components R _o , G _o and B _o by the increase ratio calculator 142 itself. After it is generated, it may be input to the third subtractor 230.

If the allowable light amount increase ratio K ₃ is 1, the increase ratio calculator 142B shown in FIG. 13 does not provide the fourth multiplier 231. In this case, the third subtractor 230 subtracts the minimum value M2 from the maximum value M1 in response to the first control signal C1 input from the area determiner 140, and subtracts the subtracted result from the third value. Output to the divider 232.

At this time, the third division unit 232 divides the maximum value M1 from the third subtraction unit 230 by the result of the subtraction of the maximum color value M1 among the input color components _Ro , G _o and B _o . Is outputted to the increase value calculator 144 through the output terminal OUT5 as the level increase ratio S ₁ . In this case, the second bypass unit 234 performing the 58th step may increase the level of the second predetermined value K ₄ in response to the first control signal C1 input from the area determiner 140. As S ₁ , it is output to the increase value calculator 144 through the output terminal OUT6. For example, when it is recognized that the result of subtracting K ₄ times the minimum value M2 from the maximum value M1 through the first control signal C1 is not greater than the second threshold value, the second predetermined value K ₄ is determined. As the level increase ratio S ₁ , the output signal is output to the increase value calculator 144 through the output terminal OUT6.

According to the present invention, the apparatus for changing the brightness of the image shown in FIG. 9 may not provide the area determiner 140. In this case, in order to perform the twelfth step, the increase ratio calculator 142 calculates the level increase ratio from the allowable light amount increase ratio K ₃ and the input color components input through the input terminal IN1.

Meanwhile, in order to perform the fourteenth step illustrated in FIG. 4, the increase value calculator 144 calculates the increase ratios of the input color components _Ro , G _o, and B _o input through the input terminal IN1 from the outside. Scaled in correspondence with the level increase ratio S ₁ input from the unit 142, and the scaled result is incremented values R ₂ , G ₂ and B of the input color components _Ro , G _o and B _o . ₂ ) to the fourth color component value calculating section 146 and the output color component calculating section 148.

FIG. 14 is a block diagram of an embodiment 144A of the increase value calculator 144 shown in FIG. 9 according to the present invention, and includes a fifth multiplier 250.

The fifth multiplier 250 of the increase value calculator 144A shown in FIG. 14 is externally provided through the level increase ratio S ₁ and the input terminal IN6 input from the increase ratio calculator 142 through the input terminal IN5. The multiplying input color components _Ro , G _o and _Bo are respectively multiplied, and the multiplied results are output as increasing values R ₂ , G ₂ and B ₂ . That is, the fifth multiplier 250 of the increase value calculator 144A calculates the increase values R ₂ , G ₂ and B ₂ as shown in Equation 9 below.

Meanwhile, in order to perform the sixteenth step, the fourth color component value calculator 146 calculates the fourth color component from the increase values R ₂ , G _2, and B ₂ input from the increase value calculator 144. calculating a value (W _out), and outputs the value (W _out) of the calculated fourth color component into an output color component calculation section 148. the

FIG. 15 is a block diagram of a preferred embodiment 146A of the fourth color component calculator 146 shown in FIG. 9 according to the present invention, and includes a third minimum value extractor 280 and a third comparer 282. And a first update unit 284 and a third bypass unit 286.

The third minimum value extracting unit 280 of the fourth color component value calculating unit 146A shown in FIG. 15 receives the input terminal IN7 from the increase value calculating unit 144 in order to perform the 90th step shown in FIG. The minimum value of the increase values R ₂ , G _2, and B ₂ inputted through the extraction is extracted, and the extracted minimum value is output to the third comparator 282 and the third bypass unit 286. In order to perform step 92, the third comparison unit 282 compares the minimum value input from the third minimum value extraction unit 280 with the maximum value k ₂ of the luminance level that the fourth color component may have. The result of the comparison is output to the first update unit 284 and the third bypass unit 286 as the second control signal C2. At this time, the third bypass unit 286 bypasses and outputs the minimum value input from the third minimum value extracting unit 280 in response to the second control signal C2 input from the third comparing unit 282. The output color component calculator 148 outputs the value of the fourth color component through the terminal OUT8. For example, when the third bypass unit 286 recognizes that the value W _out of the fourth color component is not greater than k ₂ through the second control signal C2 input from the third comparison unit 282, 3 The minimum value input from the minimum value extracting unit 280 is bypassed and output as the value of the fourth color component to the output color component calculating unit 148 through the output terminal OUT8.

In order to perform step 94, the first updater 284 may have a value of the fourth color component in response to the second control signal C2 input from the third comparator 282. The maximum value k ₂ of the luminance level can be updated, and the updated value W _out of the fourth color component is output to the output color component calculator 148 through the output terminal OUT9. For example, when the value of the fourth color component is greater than k ₂ , the first updater 284 recognizes the value of the fourth color component through the second control signal C2 input from the third comparator 282. Is updated to k ₂ , and the updated value W _out of the fourth color component is output to the output color component calculator 148 through the output terminal OUT9.

FIG. 16 is a block diagram of another preferred embodiment 146B according to the present invention of the fourth color component calculating unit 146 shown in FIG. 9, and includes a fourth maximum value extracting unit 320 and a fourth comparing unit 322. ), A fourth subtractor 324, a fifth comparator 326, a second updater 328, and a fourth bypass unit 330.

The fourth maximum value extracting unit 320, the fourth comparing unit 322, and the fourth subtracting unit 324 of the fourth color component value calculating unit 146B shown in FIG. To play a role. Here, the fourth maximum value extractor 320 extracts the maximum value among the increase values R ₂ , G _2, and B ₂ input from the increase value calculator 144 through the input terminal IN8, and extracts the maximum value. Is determined as a value of the fourth color component and output to the fourth comparator 322 and the fourth subtractor 324, respectively. The fourth comparison unit 322 compares whether the maximum value input from the fourth maximum value extraction unit 320 is greater than a third threshold value, which is the maximum value k ₂ of the luminance level that the fourth color component can have. The result of the comparison is output to the fourth subtraction unit 324 as the third control signal C3. When the fourth subtractor 324 recognizes that the maximum value, which is the output of the fourth maximum value extractor 320, is greater than the third threshold value through the third control signal C3 input from the fourth comparator 322. , K ₂ is subtracted from the maximum value output from the fourth maximum value extracting unit 320, and the subtracted result is output to the fifth comparing unit 326. However, if it is recognized through the third control signal C3 that the maximum value which is the output of the fourth maximum value extracting unit 320 is not greater than the third threshold value, the fourth subtracting unit 324 may set '0', for example. The result of subtracting k ₂ from k ₂ is output to the fifth comparison unit 326.

The fifth comparator 326 and the fourth bypass unit 330 perform a step 92. Here, the fifth comparator 326 compares the subtracted result input from the fourth subtractor 324 with the maximum value k ₂ of the luminance level that the fourth color component may have, and compares the result of the comparison. It outputs to 4th control part C4 to the 2nd update part 328 and the 4th bypass part 330, respectively. If the result subtracted by the fourth subtractor 324 is greater than k ₂ , the fifth comparator 326 generates the fourth control signal C4 such that the second updater 328 is enabled. However, if the result subtracted by the fourth subtractor 324 is not greater than k ₂ , the fifth comparator 326 generates the fourth control signal C4 such that the fourth bypass unit 330 is enabled. . The fourth bypass unit 330 is enabled in response to the fourth control signal C4 input from the fifth comparator 326 to bypass the subtracted result input from the fourth subtractor 324. The output color component calculator 148 outputs the fourth color component as a value of the fourth color component through the output terminal OUT10.

In order to perform step 94, the second updater 328 is enabled in response to the fourth control signal C4 input from the fifth comparator 326, so that the luminance level that the fourth color component may have. The value of the fourth color component is updated to the maximum value k _{2 of} and is output to the output color component calculator 148 through the output terminal OUT11.

FIG. 17 is a block diagram of another preferred embodiment 146C of the fourth color component calculator 146 shown in FIG. 9 according to the present invention, and includes a fifth maximum value extractor 340 and a fourth minimum value extractor. 342, sixth comparator 344, fifth subtractor 346, sixth multiplier 348, seventh multiplier 350, minimum value setter 352, adder 354, and And a seventh comparison unit 356, a third update unit 358, a fourth divider 360 and a fifth bypass unit 362.

The fifth maximum value extractor 340, the fourth minimum value extractor 342, the sixth comparator 344, and the fifth subtractor 346 of the fourth color component value calculator 146C illustrated in FIG. 17. The sixth multiplier 348, the seventh multiplier 350, the minimum value setter 352, the adder 354, and the fourth divider 360 perform the 90th step illustrated in FIG. 7. Do it. Here, the fifth maximum value extractor 340 extracts the maximum value among the increase values R ₂ , G ₂ and B ₂ input from the increase value calculator 144 through the input terminal IN9, and extracts the maximum value. The value is output to the sixth comparator 344 and the fifth subtractor 346. The sixth comparator 344 compares whether the maximum value input from the fifth maximum value extractor 340 is greater than the third threshold value, which is the maximum value k ₂ of the luminance level that the fourth color component has. The comparison result is output as the fifth control signal C5 to the fifth subtractor 346, the minimum value setter 352, and the adder 354, respectively. If the maximum input value is larger than the third threshold value, the sixth comparator 344 generates the fifth control signal C5 to enable the fifth subtractor 346. However, when the input maximum value is not greater than the third threshold value, the sixth comparison unit 344 generates the fifth control signal C5 to enable the minimum value setting unit 352. The minimum value setting unit 352 is enabled in response to the fifth control signal C5 to add the minimum value k ₂ 'of the luminance level that the fourth color component may have, for example,' 0 '. Will output The fifth subtractor 346 is enabled in response to the fifth control signal C5 input from the sixth comparator 344 to obtain k ₂ from the maximum value input from the fifth maximum value extractor 340. And subtracts the subtracted result to the sixth multiplier 348. The sixth multiplier 348 multiplies the subtracted result input from the fifth subtractor 346 by the coefficient a ₂ and outputs the multiplied result to the adder 354. Meanwhile, the fourth minimum value extractor 342 extracts a minimum value from the increase values R ₂ , G _2, and B ₂ input through the input terminal IN9 from the increase value calculator 144, and extracts the extracted minimum value 7. Output to the multiplier 350. The seventh multiplier 350 multiplies the extracted minimum value input from the fourth minimum value extractor 342 by the coefficient a ₁ , and outputs the multiplied result to the adder 354. The adder 354 adds one of the multiplied result output from the sixth multiplier 348 and the multiplied result output from the seventh multiplier 350 and one of the minimum values output from the minimum value setter 352, The added result is output to the fourth divider 360. For example, when the adder 354 recognizes that the output of the fifth maximum value extractor 340 is greater than the third threshold value through the fifth control signal C5, the adder 354 multiplies the result multiplied by the sixth multiplier 348. The result multiplied by the seventh multiplier 350 is added. However, if it is recognized through the fifth control signal C5 that the output of the fifth maximum value extractor 340 is not greater than the third threshold value, the adder 354 outputs the output of the minimum value setter 352 and the seventh. The output of the multiplication unit 350 is added.

According to the present invention, the fourth color component calculator 146C shown in FIG. 17 may not provide the sixth and seventh multipliers 348 and 350. In this case, the adder 354 adds one of the subtracted result output from the fifth subtractor 346 and the minimum value output from the minimum value setter 352 and the minimum value input from the fourth minimum value extractor 342. The result of the addition is output to the fourth divider 360.

The fourth divider 360 divides the added result output from the adder 354 by the coefficient a ₃ , and divides the divided result into the seventh comparator 356 and the fifth bypass unit 362. Print each.

The seventh comparator 356 and the fifth bypass unit 362 serve to perform step 92. Here, the seventh comparator 356 compares the divided result input from the fourth divider 360 with a third threshold value which is the maximum value k ₂ of the luminance level that the fourth color component may have. The result of the comparison is output to the third update unit 358 and the fifth bypass unit 362 as the sixth control signal C6. If the divided result output from the fourth divider 360 is greater than the third threshold, the seventh comparator 356 may enable the third updater 358 to enable the sixth control signal C6. Occurs. However, if the divided result output from the fourth divider 360 is not greater than the third threshold, the seventh comparator 356 may enable the fifth bypass part 362 to control the sixth control signal C6. Will occur). The fifth bypass unit 362 is enabled in response to the sixth control signal C6 input from the seventh comparator 356 to bypass the divided result input from the fourth divider 360. The output color component calculator 148 outputs the fourth color component as a value of the fourth color component through the output terminal OUT12.

In order to perform step 94, the third updater 358 is enabled in response to the sixth control signal C6 input from the seventh comparator 356, so that the luminance level that the fourth color component may have. The value of the fourth color component is updated to the third threshold value, which is the maximum value k ₂ , and is output to the output color component calculator 148 through the output terminal OUT13.

The output color component calculator 148 shown in FIG. 9 outputs the output color components R _out and G that increase the brightness of the input color components _Ro , G _o and B _o to perform the eighteenth step. _out and B _out ) of the increment values R ₂ , G _2, and B ₂ input from the increment calculation unit 144 and the values of the fourth color components input from the fourth color component value calculation unit 146 ( W _out ) and the calculated output color components R _out , G _out, and B _out are output through the output terminal OUT1.

FIG. 18 is a block diagram of a preferred embodiment 148A according to the present invention of the output color component calculator 148 shown in FIG. 9, and is composed of a sixth subtractor 390. As shown in FIG.

The sixth subtractor 390 illustrated in FIG. 18 uses a fourth color through the input terminal IN11 from the increase values R ₂ , G _2, and B ₂ input from the increase value calculator 144 through the input terminal IN 10. Subtract the value W _out of the fourth color component input from the component value calculator 146 and output the subtracted results as output color components R _out , G _out, and B _out through the output terminal OUT14. . That is, the sixth subtraction unit 390 calculates the output color components R _out , G _out, and B _out as shown in Equation 12.

FIG. 19 is a block diagram of another embodiment 148B according to the present invention of the output color component calculator 148 shown in FIG. 9, and is composed of an eighth multiplier 400 and a seventh subtractor 402. .

An eighth multiplier 400 shown in Figure 19 is the mixing ratio of the input color components to carry out the illustrated first step 110 in Figure 8 (R _a, G _a and B _a) of the fourth through the input terminal IN12 The multiplier multiplies the value W _out of the fourth color component input from the color component value calculator 146, and outputs the multiplied results to the seventh subtraction unit 402. To perform step 112, the seventh subtraction unit 402 increases the input from the increased value calculation section 144, the results of the multiplications from the eighth multiplier 400 through an input terminal IN13 value (R _2, Subtract from G ₂ and B ₂ ), and output the subtracted results through the output terminal OUT15 as output color components R _out , G _out and B _out .

As a result, the apparatus for changing the brightness of an image according to the present invention shown in FIG. 9 inputs three input color components R ₀ , G ₀ , B ₀ through an input terminal IN1, and then outputs four types through the output terminal OUT1. It can be seen that the output color components of R ₀ , G ₀ , B ₀ , W _out are outputted.

As described above, since the method and apparatus for changing the brightness of the image according to the present invention adaptively adjusts the level increase ratios of the brightnesses for adjusting the brightness of the input color components according to the input color components in consideration of the gamut, Clipping of the color components can be prevented, and the problem of a decrease in purity when the brightness of the output image is increased by adding a fourth color component can be solved. Therefore, the same color and purity as the input color components can be solved. It is possible to obtain an output image having only increased brightness while maintaining saturation, and has an effect of simply converting three input color components into four output color components.

Claims (36)

(a) obtaining a level increase ratio corresponding to a degree of increasing brightness of three input color components according to a color gamut including a fourth color component; (b) scaling the input color components using the level increase ratio and determining the scaled result as increments of the input color components; (c) obtaining a value of the fourth color component using the increment values; And (d) obtaining output color components of which the brightness of the input color components is increased using the value of the fourth color component and the increase values, wherein the level increase ratio is less than or equal to a first predetermined value; How to change the brightness of the image. The method of claim 1, wherein the brightness of the image is changed. (e) determining a region to which the input color components of the first, second and third color components belong in a color gamut composed of two or more regions, and proceeding to step (a), Wherein (a) is the brightness increase method of the image, characterized in that to obtain the level increase ratio according to the area determined in the step (e). The method of claim 2, wherein the steps (e) and (a) are performed using a light intensity increase ratio, and the light intensity increase ratio is variable in advance. The method of claim 3, wherein step (e) Obtaining intersections that meet the boundary when an input vector representing the input color components extends to the boundary of the gamut; And Determining whether at least one of the coordinates of the intersection is less than a first threshold value, If at least one of the intersections is less than the first threshold, the input color components belong to an unfixed first scaling space, and if none of the intersections is less than the first threshold, the input color components are The brightness changing method of the image, characterized in that belonging to the fixed second scaling space. The method of claim 4, wherein the first threshold value is determined by an allowable light increase ratio that is a maximum value or a minimum value among component light increase ratios of the light increase ratio. The method of claim 4, wherein step (a) (a1) when it is determined that at least one of the coordinates of the intersection is less than a first threshold value, the allowable light quantity corresponding to the maximum value or the minimum value among the component light quantity increase ratios of the minimum value among the coordinates of the intersection point and the light quantity increase ratio. Subtracting the result of multiplying the increase ratio from each of the coordinates of the intersection; (a2) dividing the maximum value of the luminance levels of the input color components by the maximum value of the results subtracted in the step (a1), determining the divided result as the level increase ratio, and performing the step (b) Proceeding; And (a3) if it is determined that none of the coordinates of the intersection is less than the first threshold value, determining the first predetermined value as the level increase ratio, and proceeding to step (b). How to change the brightness of the image characterized by. The method of claim 4, wherein the first threshold is determined as follows. (Wherein K ₃ represents an allowable light increase ratio corresponding to a maximum or minimum value among the component light increase ratios, the light increase ratio is represented by the component light increase ratios in each color component, and k ₁ represents the above The maximum value of luminance level that an input color component can have.) The method of claim 4, wherein each of the coordinates of the intersection points R ₃ , G _3, and B ₃ is obtained as follows. , , Where R ₀ , G ₀ and B ₀ represent the input color components, M ₁ corresponds to a maximum value of the R ₀ , G ₀ and B ₀ , and k ₁ may have the input color components. The maximum value of the luminance level.) The method of claim 3, wherein step (e) Extracting a maximum value and a minimum value of the input color components; Subtracting a first predetermined value multiple of the minimum value from the maximum value; And Determining whether the result of subtraction is greater than a second threshold value; If the result of the subtraction is greater than the second threshold, the input color components belong to a non-fixed first scaling space. If the result of subtraction is less than or equal to the second threshold, the input color components are fixed second scaling. How to change the brightness of the image, characterized in that belonging to the space. The method of claim 9, wherein step (a) If it is determined that the result of subtraction is greater than a second threshold value, the result of multiplying the minimum value and the allowable light amount increase ratio corresponding to the maximum value or the minimum value among the component light amount increase ratios of the light amount increase ratio is subtracted from the maximum value. Calculating a ratio between the result and the maximum value, determining the calculated ratio as the level increase ratio and proceeding to step (b); And if it is determined that the result of subtraction is less than or equal to the second threshold, determining a second predetermined value as the level increase ratio, and proceeding to step (b). The method of claim 3, wherein step (b) And after the step (a), multiply the level increase ratio and the input color components, determine the multiplied results as the increase values, and proceed to step (d). The method of claim 3, wherein step (c) (c1) after step (b), determining some of the increments as the value of the fourth color component; (c2) determining whether the value determined in step (c1) is greater than a third threshold value, and if it is determined that the value determined in step (c1) is less than or equal to the third threshold value, proceeding to step (a); And (c3) if it is determined that the value determined in step (c1) is greater than the third threshold value, updating the value of the fourth color component with the third threshold value, and proceeding to step (d). Equipped, The third threshold is a maximum value of the luminance level that the fourth color component may have, and is determined by an allowable light increase ratio corresponding to a maximum value or a minimum value among component light increase ratios of the light increase ratio. How to change the brightness of the image characterized by. The method of claim 12, wherein the partial value corresponds to a minimum value of the increase values. The method of claim 12, wherein the partial value corresponds to a result of subtracting a maximum value of luminance levels of the three input color components from a maximum value among the increase values. . The method of claim 12, wherein the partial value is obtained by subtracting a maximum value of luminance levels of the three input color components from a maximum value of the increase values and a minimum value of the increase values. How to change the brightness of the image, characterized in that. The method of claim 3, wherein step (d) After the step (c), subtract the value of the fourth color component from the increase values, and determine the subtracted results as the output color components. The method of claim 3, wherein step (d) (d1) After the step (c), the fourth color component comprises blending ratios created by the ratios between the light intensities of the components resulting from vector decomposition of the output light intensity in the fourth color channel into the three input color components. Multiplying the value of each component; And (d2) subtracting the results multiplied in the step (d1) from the increase values and determining the subtracted results as the output color components. 7. The method of claim 6, wherein the first predetermined value is a value obtained by adding 1 to the allowable light increase ratio. The method of claim 10, wherein the second predetermined value is a value obtained by adding 1 to the allowable light increase ratio. An increase ratio calculator for calculating a level increase ratio corresponding to an increase in brightness of input color components input from the outside from an allowable light quantity ratio and the input color components; An increase value calculator for scaling the input color components according to the level increase ratio input from the increase ratio calculator and outputting the scaled result as increase values of the input color components; A fourth color component value calculator for calculating a value of a fourth color component from the increase values input from the increase value calculator and outputting the calculated value of the fourth color component; And An output color component calculating unit configured to calculate output color components that increase the brightness of the input color components from the increase values and the values of the fourth color component, and output the calculated output color components, wherein the level increase ratio Is less than a first predetermined value. The apparatus of claim 20, wherein the brightness changing device of the image A region determining unit which determines a region to which the first, second, and third color components, which are three input color components input from the outside, belong in a fourth color gamut, and outputs the determined result as a first control signal, And the increase ratio calculator calculates the level increase ratio in response to the first control signal. 22. The method of claim 21, wherein the area determining unit determines the area belonging to the input color component in accordance with an allowable light amount increase ratio corresponding to a maximum value or a minimum value among the component light amount increase ratios of the light amount increase ratio, and calculates the increase ratio. The unit calculates the level increase ratio in response to the allowable light amount increase ratio. The method of claim 22, wherein the area determiner An intersection calculation unit for calculating an intersection point that meets the boundary from the input color components when the vector representing the input color components is extended to the boundary of the color gamut; And And a first comparator for comparing the coordinates of the intersections input from the intersection calculator with a first threshold value, and outputting the compared result as the first control signal. The method of claim 23, wherein the intersection calculation unit A first maximum value extracting unit extracting a maximum value of the input color components; A first dividing unit dividing a maximum value of the luminance levels of the input color components by the maximum value input from the first maximum value extracting unit; And a first multiplier configured to multiply the input color components by the divided result input from the first divider and output the multiplied results as coordinates of the intersection. The method of claim 23, wherein the increase ratio calculation unit A first minimum value extracting unit extracting a minimum value among coordinates of the intersections input from the intersection calculating unit in response to the first control signal; A first subtractor configured to subtract the minimum value input from the first minimum value extractor from each of the coordinates of the intersection and output the subtracted results; A second maximum value extracting unit which extracts a maximum value of the subtracted results inputted from the first subtracting unit; A first division unit dividing a maximum value of the luminance levels of the input color components by the maximum value input from the second maximum value extraction unit, and outputting the divided result to the increase value calculation unit as the level increase ratio; And And a first bypass unit configured to output a first predetermined value as the level increase ratio in response to the first control signal. The method of claim 25, wherein the increase ratio calculator And a second multiplier configured to multiply the minimum value input from the first minimum value extracting unit with the allowable light amount increase ratio input from the outside, and output the multiplied result to the first subtracting unit, And the first subtractor subtracts the multiplied result input from the second multiplier from each of the coordinates of the intersection point. The method of claim 22, wherein the area determiner A third maximum value extracting unit extracting a maximum value of the input color components; A second minimum value extracting unit which extracts a minimum value among the input color components; A third multiplier that multiplies the minimum value by a first predetermined value and outputs a multiplied result; A second subtractor configured to subtract the multiplied result input from the third multiplier from the maximum value input from the third maximum value extractor and output a subtracted result; And And a second comparing unit comparing the subtracted result input from the second subtracting unit with a second threshold value and outputting the compared result as the first control signal. The method of claim 27, wherein the increase ratio calculation unit A third subtractor configured to subtract the minimum value from the maximum value in response to the first control signal, and output a subtracted result; A third divider which divides the maximum value among the input color components as a result subtracted by the third subtractor and outputs the divided result as the level increase ratio; And And a second bypass unit configured to output a second predetermined value as the level increase ratio in response to the first control signal. The method of claim 28, wherein the increase ratio calculation unit And a fourth multiplier configured to multiply the minimum value by the allowable light amount increase ratio and output the multiplied result to the third subtractor. And the third subtractor subtracts a result multiplied by the fourth multiplier from the maximum value in response to the first control signal. The method of claim 22, wherein the increase value calculator And a fifth multiplier configured to multiply the level increase ratio input from the increase ratio calculator and the input color components, and output the multiplied results as the increase values. The method of claim 22, wherein the fourth color component value calculation unit A third minimum value extracting unit extracting a minimum value among the increase values input from the increase value calculating unit and outputting the extracted minimum value; A third comparing unit comparing the minimum value input from the third minimum value extracting unit with a maximum value of the luminance level that the fourth color component may have, and outputting the compared result as a second control signal; A third bypass unit for bypassing the minimum value input from the third minimum value extracting unit to the output color component calculating unit as the value of the fourth color component in response to the second control signal; And In response to the second control signal, update the value of the fourth color component to the maximum value of the luminance level that the fourth color component can have, and update the updated value of the fourth color component to the output color component. And a first updater for outputting to the calculator. The method of claim 22, wherein the fourth color component value calculation unit A fourth maximum value extracting unit extracting a maximum value among the incremented values input from the increase value calculating unit and outputting the extracted maximum value; A fourth comparing unit comparing the maximum value input from the fourth maximum value extracting unit with a maximum value of the luminance level that the fourth color component may have, and outputting the compared result as a third control signal; In response to the third control signal, the luminance level that the fourth color component may have from the maximum value input from the fourth maximum value extraction unit or the maximum value of the luminance level that the fourth color component may have. A fourth subtractor configured to subtract the maximum value and output the subtracted result; A fifth comparing unit comparing the subtracted result input from the fourth subtracting unit with a maximum value of the luminance level of the fourth color component and outputting the compared result as a fourth control signal; A fourth bypass unit for bypassing the subtracted result input from the fourth subtractor as a value of the fourth color component in response to the fourth control signal input from the fifth comparator; And In response to the fourth control signal input from the fifth comparing unit, updating the value of the fourth color component to a maximum value of the luminance level that the fourth color component can have, and updating the updated fourth color component. And a second updater for outputting a value to the output color component calculator. The method of claim 22, wherein the fourth color component value calculation unit A fifth maximum value extracting unit which extracts a maximum value among the incremented values input from the increase value calculating unit and outputs the extracted maximum value; A sixth comparing unit which compares the maximum value input from the fifth maximum value extracting unit with a maximum value of the luminance level that the fourth color component can have, and outputs the compared result as a fifth control signal; A minimum value setting unit outputting a minimum value of a luminance level of the fourth color component in response to the fifth control signal input from the sixth comparison unit; In response to the fifth control signal input from the sixth comparator, the maximum value of the luminance level that the fourth color component may have is subtracted from the extracted maximum value input from the fifth maximum value extractor. A fifth subtractor configured to output a subtracted result; A fourth minimum value extracting unit extracting a minimum value among the increase values input from the increase value calculating unit, and outputting the extracted minimum value; An adder configured to add the subtracted result input from the fifth subtractor or the minimum value output from the minimum value setter and the minimum value input from the fourth minimum value extractor in response to the fifth control signal; A fourth divider which divides the added result input from the adder by a predetermined first coefficient; A seventh comparison unit which compares the divided result input from the fourth division unit with a maximum value of the luminance level that the fourth color component may have, and outputs the compared result as a sixth control signal; A fifth bypass unit bypassing the divided result input from the fourth divider in response to the sixth control signal input from the seventh compare unit; And In response to the sixth control signal input from the seventh comparator, updates the value of the fourth color component to the maximum value of the luminance level that the fourth color component can have, and updates the updated fourth color And a third updater for outputting component values to the output color component calculator. The method of claim 33, wherein the fourth color component value calculation unit A sixth multiplier for multiplying the subtracted result input from the fifth subtractor by a predetermined second coefficient and outputting the multiplied result to the adder; And And a seventh multiplier for multiplying the extracted minimum value input from the fourth minimum value extracting unit by a predetermined third coefficient and outputting the multiplied result to the adding unit. The adder adds a multiplied result input from the sixth multiplier or a multiplied result input from the seventh multiplier in response to the fifth control signal. Device for changing the brightness of the image. The method of claim 22, wherein the output color component calculation unit And a sixth subtractor configured to subtract the value of the fourth color component from the increase values and output the subtracted results as the output color components. The method of claim 22, wherein the output color component calculation unit An eighth multiplier for multiplying the mixing ratios of the input color components with the value of the fourth color component and outputting the multiplied results; And And a seventh subtractor configured to subtract the results multiplied by the eighth multiplier from the increase values and output the subtracted results as the output color components.