JP2007194805A - Color transformation device and method, recording medium, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To transform an arbitrary color of an image signal to an arbitrary color according to the property of a display device or user's preference. <P>SOLUTION: In a microcomputer 27, an objective region of color transformation and desired target x and target y after transformation are set based on the user's operation, and a D factor value is calculated according to them. In a region value calculation unit 21, a region value k, which represents a length from the center of the objective region is sought for the entered image signal. In a matrix formation unit 22, a matrix of 3×3 is formed based on the region value k obtained from the region value calculation unit 21 and the D factor value from the microcomputer 27. In a matrix calculation unit 23, the entered image signal and the matrix of 3×3 are subjected to color transformation through operation. This invention is applicable to a television receiver which performs color transformation of an image signal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a color conversion apparatus and method, a recording medium, and a program, and in particular, can convert an arbitrary color of an image signal into a desired arbitrary color according to characteristics of a display device and user's preference. The present invention relates to a color conversion apparatus and method, a recording medium, and a program.

  In recent years, the transition from CRT (Cathode Ray Tube) as a display for displaying images to various flat panel displays is progressing. Typical examples of the flat panel display include an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), and an organic EL (Electro Luminescent) display.

  With regard to the conventional CRT, the final substance that determines the color of light is a phosphor, and the color that is mixed with the light emitted from the R, G, and B phosphors is the closest to the actual color. However, for flat panel displays, there are various factors that determine the color. For example, in the case of an LCD, the wavelength of backlight light, the color selection characteristics of a color filter, etc., and in the PDP, the phosphor is different from a CRT. Because of these factors, flat panel displays often differ significantly from CRT color reproduction.

  For this reason, in many flat panel displays, it is necessary to devise a method that makes the color reproduction of CRT as close as possible.

  In addition to this, when viewed from the end user, there is a demand not only that the color reproduction is close to that of a CRT, but also that the user wants to see his / her favorite color.

  A method for controlling the hue (hue) of a specific color as satisfying these two elements has been known so far, and for example, proposed in Patent Document 1. However, with the hue correction of a specific color proposed in Patent Document 1, it is possible to convert a selected color into an adjacent hue, but it is difficult to convert it into a hue in a completely different direction. This can be easily understood by using the xy chromaticity diagram shown in FIG.

  FIG. 1 is a diagram showing a general xy chromaticity diagram.

  In the xy chromaticity diagram, all the colors are expressed in this horseshoe shape, and the W point at the center corresponds to white (achromatic), and the vividness increases as it goes to the periphery in the horseshoe shape. (Saturation becomes higher), and the light around the chromaticity diagram becomes monochromatic light (pure color).

  Further, the triangle formed by the vertices of G, R, and B shown in the xy chromaticity diagram shows, as an example, a range that can be theoretically expressed on a display in the ITU-BT601 system supported by NTSC and the like. Reference symbols G, R, and B attached to the vertices represent pure green, red, and blue colors to which the vertices correspond, respectively. In the example of FIG. For convenience of explanation, all of the colors are represented by three types of hatches and white portions indicating green, red, and blue.

  Furthermore, arrows A1 and A2 shown on the xy chromaticity diagram represent the state of color change when the hue of a specific color is controlled by a conventional method as proposed in Patent Document 1. For example, the arrow A1 represents the state of color change when, for example, red is changed to the yellow direction or yellow is changed to the red direction, and the arrow A2 is, for example, blue to the red direction or red. It shows how the color changes when the color is changed in the blue direction.

JP 2005-198343 A

  As described above, in the conventional hue control, the color change can be moved only in a specific one-axis direction as indicated by the arrows A1 and A2. Therefore, for example, it is not possible to perform a flexible correction that changes the direction of various colors such as a little magenta in the cyan direction or a flesh color in the yellow direction.

  Although not shown, since a color difference signal is used to control the hue, there was no movement in the absence of color, that is, the white color indicated by the W point in FIG.

  Furthermore, there was no guideline when the end user controlled the hue, so it was difficult to see how many colors would change with the control.

  The present invention has been made in view of such a situation, and can convert an arbitrary color of an image signal into a desired arbitrary color according to the characteristics of the display device and the user's preference. To do.

  A color conversion device according to one aspect of the present invention is a color conversion device that performs color conversion of an input image signal, and in a target region for color conversion on an xy chromaticity diagram with respect to the xy chromaticity value of the image signal. A region value calculation means for normalizing a region value representing a distance from the center, and when the region value for the xy chromaticity value of the image signal is 1, the luminance value and the xy chromaticity value after color conversion are 3 × on the basis of the coefficient value calculating means for obtaining the coefficient value so as to become a desired value, the coefficient value obtained by the coefficient value calculating means, and the area value obtained by the area value calculating means. Matrix generating means for generating 3 matrixes, and color converting means for performing color conversion of the image signal using the 3 × 3 matrix generated by the matrix generating means.

  The region value may be a value that decreases as the distance from the center in the target region increases.

  The coefficient value calculating means obtains and stores the coefficient values at four corners of a predetermined area on the xy chromaticity diagram, and the coefficient value of the luminance value after the color conversion and the xy chromaticity value are It can be obtained by linear interpolation using the coefficient values at four corners.

  The image signal corresponding to the triangular chromaticity diagram having the horizontal axis x, the vertical axis y, and the xy chromaticity values for saturated G, B, and R as vertices is color-converted by the color conversion means. Display control means for superimposing on the image signal and displaying a screen corresponding to the superimposed image signal can be further provided.

  In response to the user's operation, the position of the user's desired xy chromaticity value when the region value is 1 with respect to the target region and the xy chromaticity value of the image signal is displayed on the triangular chromaticity diagram. Image display means for generating an image signal for display is further provided, wherein the display control means converts the image signal generated by the image generation means into the image signal subjected to color conversion by the color conversion means. A screen corresponding to the superimposed image signal can be displayed.

  A color conversion method according to one aspect of the present invention is the color conversion method of a color conversion apparatus that performs color conversion of an input image signal, and performs color conversion on an xy chromaticity diagram with respect to the xy chromaticity value of the image signal. When the region value representing the distance from the center in the target region is normalized and the region value with respect to the xy chromaticity value of the image signal is 1, the luminance value after color conversion and the xy chromaticity value are determined by the user. A coefficient value is obtained so as to be a desired value, a 3 × 3 matrix is generated based on the obtained coefficient value and the obtained region value, and the generated 3 × 3 matrix is used. And a step of performing color conversion of the image signal.

  A program according to one aspect of the present invention is a program that causes a computer to perform color conversion of an input image signal, and performs color conversion on the xy chromaticity diagram with respect to the xy chromaticity value of the image signal. The region value representing the distance from the center in the conversion target region is normalized, and when the region value with respect to the xy chromaticity value of the image signal is 1, the luminance value and the xy chromaticity value after color conversion are The coefficient value is obtained so as to become a desired value of the above, and a 3 × 3 matrix is generated based on the obtained coefficient value and the obtained region value, and the generated 3 × 3 matrix is And performing a color conversion of the image signal.

  A recording medium on which a program according to one aspect of the present invention is recorded is a program that causes a computer to perform color conversion of an input image signal, and the xy chromaticity value of the image signal is A region value representing the distance from the center in the target region of color conversion on the chromaticity diagram is normalized, and when the region value with respect to the xy chromaticity value of the image signal is 1, A coefficient value is obtained so that the xy chromaticity value becomes a value desired by the user, a 3 × 3 matrix is generated based on the obtained coefficient value and the obtained area value, and the generated Performing a color conversion of the image signal using a 3 × 3 matrix.

  In one aspect of the present invention, with respect to the xy chromaticity value of the input image signal, a region value representing a distance from the center in the target region of color conversion on the xy chromaticity diagram is obtained by normalization, When the region value with respect to the xy chromaticity value of the image signal is 1, the coefficient value is obtained so that the luminance value after color conversion and the xy chromaticity value become values desired by the user. Then, a 3 × 3 matrix is generated based on the obtained coefficient value and the obtained region value, and color conversion of the image signal is performed using the generated 3 × 3 matrix. Is called.

  According to the present invention, it is possible to convert an arbitrary color of an image signal into a desired arbitrary color according to the characteristics of the display device and the user's preference.

  Embodiments of the present invention will be described below. Correspondences between constituent elements of the present invention and the embodiments described in the specification or the drawings are exemplified as follows. This description is intended to confirm that the embodiments supporting the present invention are described in the specification or the drawings. Therefore, even if there is an embodiment which is described in the specification or the drawings but is not described here as an embodiment corresponding to the constituent elements of the present invention, that is not the case. It does not mean that the form does not correspond to the constituent requirements. Conversely, even if an embodiment is described here as corresponding to a configuration requirement, that means that the embodiment does not correspond to a configuration requirement other than the configuration requirement. It's not something to do.

  A color conversion device according to one aspect of the present invention is a color conversion device that performs color conversion of an input image signal (for example, the television receiver 1 in FIG. 2), with respect to the xy chromaticity value of the image signal. region value calculation means (for example, the region value calculation unit 21 in FIG. 2) that obtains a region value (for example, region value k) that represents a distance from the center in the target region of color conversion on the xy chromaticity diagram; When the region value with respect to the xy chromaticity value of the image signal is 1, a coefficient value calculation means for obtaining a coefficient value so that the luminance value after color conversion and the xy chromaticity value become values desired by the user (for example, 2. A matrix generating means for generating a 3 × 3 matrix based on the microcomputer 27) of FIG. 2 and the coefficient value obtained by the coefficient value calculating means and the area value obtained by the area value calculating means. (For example, the matrix Comprises a section 22), using a matrix of the 3 × 3 generated by the matrix generating means, and a color conversion unit that performs color conversion of the image signal (e.g., matrix operation unit 23 of FIG. 2).

  The coefficient value calculation means obtains and stores the coefficient values at four corners of a predetermined area (for example, the maximum value area 252 in FIG. 10) on the xy chromaticity diagram, and the luminance value after the color conversion The coefficient values of the xy chromaticity values can be obtained by linear interpolation using the coefficient values at the four corners.

  An image signal corresponding to a triangular chromaticity diagram (for example, the triangular chromaticity diagram 201 in FIG. 9) having the horizontal axis x, the vertical axis y, and the xy chromaticity values for saturated G, B, and R as vertices, Display control means (for example, graphic superposition in FIG. 2) that superimposes on the image signal that has undergone color conversion by the color conversion means and displays a screen (for example, the screen in FIG. 9) corresponding to the superimposed image signal. Part 25).

  Corresponding to the user's operation, the target region (for example, the target region 212 in FIG. 9) and the position of the desired xy chromaticity value of the user when the region value is 1 with respect to the xy chromaticity value of the image signal Image display means (for example, the graphic generation unit 28 in FIG. 2) for generating an image signal for displaying (for example, the target point 222 in FIG. 9) on the triangular chromaticity diagram is further provided, and the display control is performed. The unit can superimpose the image signal generated by the image generation unit on the image signal subjected to color conversion by the color conversion unit, and display a screen corresponding to the superimposed image signal. .

  A color conversion method, program, or recording medium according to one aspect of the present invention provides a color conversion method, program, or recording medium for a color conversion device that performs color conversion of an input image signal, and the xy chromaticity value of the image signal. The region value representing the distance from the center in the color conversion target region on the xy chromaticity diagram is obtained by normalization (for example, step S66 in FIG. 12), and the region corresponding to the xy chromaticity value of the image signal When the value is 1, a coefficient value is obtained so that the luminance value and the xy chromaticity value after color conversion become values desired by the user (for example, step S39 in FIG. 11), the obtained coefficient value, Based on the obtained region values, a 3 × 3 matrix is generated (for example, step S67 in FIG. 12), and color conversion of the image signal is performed using the generated 3 × 3 matrix ( For example, the step of FIG. 68) comprises the step.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 2 is a diagram showing a configuration of an embodiment of a television receiver as a color conversion apparatus to which the present invention is applied.

  The television receiver 1 shown in FIG. 2 detects (determines) the color of an image signal input from a tuner, a video recording / reproducing apparatus, etc. (not shown), and operates the user's remote controller 2 on the image signal. According to the above, color conversion of the hue (hue) is performed, and an image corresponding to the image signal subjected to the color conversion is displayed on the display device 3.

  The remote controller 2 emits light to the television receiver 1 using a user command corresponding to a user operation as an optical signal.

  The display device 3 includes a flat panel display such as an LCD (Liquid Crystal Display), a PDP (Plasma Display Panel), or an organic EL (Electro Luminescent) display, and displays an image corresponding to an image signal from the television receiver 1. indicate. The display device 3 can also be configured by a CRT (Cathode Ray Tube).

  The display device 3 is input from a tuner, a video recording / playback apparatus, etc. (not shown) and has an image corresponding to the color-converted image signal and a triangular chromaticity representing an xy chromaticity diagram for the user to instruct color conversion. A figure etc. is displayed.

  By operating the remote controller 2 while viewing the image displayed on the display device 3 and the triangular chromaticity diagram, the user can select a color conversion target area (color conversion target area (color conversion target region)) on the triangular chromaticity diagram. Xy chromaticity value after desired color conversion (hereinafter referred to as purpose), such as selection of the target area), change of the size and position of the target area, or which color the target area should be converted to after color conversion x and purpose y (also referred to as Destination x, Destination y) can be instructed (input) to the television receiver 1.

  The television receiver 1 includes an area value calculation unit 21, a matrix generation unit 22, a matrix calculation unit 23, an RGB conversion unit 24, a graphic superimposition unit 25, a light receiving unit 26, a microcomputer 27, and a graphic generation unit 28. The

  The image signals input to the television receiver 1 are Y color difference signals (Y, CB, CR), and Y, CB, CR are input to the area value calculation unit 21 and the matrix calculation unit 23. Hereinafter, in order to distinguish from the converted Y color difference signal, the input Y color difference signal is referred to as Yo, CBo, CRo, and the converted Y color difference signal is referred to as Yn, CBn, CRn.

  The region value calculation unit 21 detects which target region that is set as a target for color conversion on the xy chromaticity diagram and includes Yo, CBo, and CRo of the input pixel. When included in the target region, a region value k (0 ≦ k ≦ 1) that is a value indicating how far the input Yo, CBo, CRo is from the center of the target region is obtained. This region value increases as it is closer to the center of the target region, and decreases as it is farther from the center.

  The region value calculation unit 21 supplies the matrix generation unit 22 with the area number (area number) of the target region including Yo, CBo, and CRo of the input pixels and the obtained region value k.

  The matrix generation unit 22 is supplied with the region value k and the area number of the target region from the region value calculation unit 21, and from the microcomputer 27, the xy chromaticity value after color conversion desired by the user for each target region ( That is, D (destination) coefficients α, γ, and β, which are coefficient values obtained according to the purpose x and the purpose y), are supplied.

  The matrix generation unit 22 generates and generates a 3 × 3 matrix for each input pixel based on the area number of the target region of the input pixel, the region value k, and the D coefficients α, γ, and β. The 3 × 3 matrix is supplied to the matrix calculation unit 23.

  This 3 × 3 matrix is expressed by the following equation (1) when the input Yo, CBo, and CRo are not included in any target region.

  In this case, the result of the matrix calculation is Yo, CBo, CRo = Yn, CBn, CRn, and the color of the Y color difference signal does not change. On the other hand, when the input Yo, CBo, CRo is included in any of the target areas, the area value calculation unit 21 obtains the area value k (0 ≦ k ≦ 1). Further, when the user desires color conversion, D coefficients α, γ, and β, which are coefficient values obtained according to the objective x and the objective y, are supplied from the microcomputer 27.

  Therefore, when the input Yo, CBo, and CRo are included in any of the target areas, the 3 × 3 matrix is expressed by the following equation (2).

  The matrix calculation unit 23 performs an arithmetic operation on Yo, CBo, CRo of the input pixels and the 3 × 3 matrix from the matrix generation unit 22, so that the Y color difference signals (Yn, CBn, CRn) is obtained, and the obtained Yn, CBn, and CRn are output to the RGB conversion unit 24.

  The RGB conversion unit 24 performs matrix conversion of Yn, CBn, and CRn from the matrix calculation unit 23 into G, B, and R, and outputs the converted image signals G, B, and R to the graphic superimposing unit 25.

  The graphic superimposing unit 25 superimposes the image signals Gg, Bg, Rg for user interface from the graphic generating unit 28 on the image signals G, B, R from the RGB converting unit 24, and the superimposed image signals Gm, Bm. , Rm is displayed on the display device 3.

  The light receiving unit 26 receives light in which a user command issued from the remote controller 2 is converted into an optical signal, and supplies the received user command to the microcomputer 27.

  The microcomputer 27 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and executes user commands from the light receiving unit 26, various programs, and the like. Thus, various processes are executed.

  Specifically, the microcomputer 27 supplies the region value calculation unit 21 with xy chromaticity values (xmin, xmax, ymin, ymax) of two symmetrical angles of each set target region. In the television receiver 1 of FIG. 2, eight target areas can be set, and the set value of each target area is supplied from the microcomputer 27 to the area value calculation unit 21.

  The microcomputer 27 also sets the D coefficient α for each target area calculated according to the target x and the target y, which are xy chromaticity values after color conversion desired by the user set for each target area. , Γ, β are supplied to the matrix generator 22.

  That is, the D coefficients α, γ, and β are coefficient values obtained according to chromaticity values that the user desires after color conversion.

  When there is a user command from the light receiving unit 26, the microcomputer 27 selects a target area to be subjected to color conversion on the xy chromaticity diagram in accordance with the user command, and the selected target area. Xy chromaticity values (xmin, xmax, ymin, ymax) of two symmetry angles are set, and xmin, xmax, ymin, ymax, etc. of the set target area are supplied to the area value calculation unit 21, or the target area The objective x and objective y, which are the xy chromaticity values after color conversion desired by each user, are set, and D coefficients α, γ, and β are calculated for each target area according to the objective x and objective y that have been set. The calculated D coefficients α, γ, β for each target region are supplied to the matrix generation unit 22.

  Further, the microcomputer 27 represents an xy chromaticity diagram, a triangular chromaticity diagram having xy chromaticity values for saturated (pure) G, B, and R as vertices, each target region, and an object after each color conversion. Information such as x and purpose y is supplied to the graphic generation unit 28.

  Based on information from the microcomputer 27, the graphic generation unit 28 displays image signals Gg, Bg for user interface for displaying each target region and a triangular chromaticity diagram indicating the purpose x and the purpose y after color conversion. , Rg and the generated image signals Gg, Bg, Rg are supplied to the graphic superimposing unit 25.

  FIG. 3 is a block diagram illustrating a configuration example of the region value calculation unit 21.

  3 includes a GBR conversion unit 41, a linear γ correction unit 42, an XYZ conversion unit 43, an xy conversion unit 44, a target region detection unit 45, and a region value calculation unit 46.

  The target area detection unit 45 in FIG. 3 uses xy chromaticity values (hereinafter, also simply referred to as x and y values) when detecting whether or not an input image signal is included in the target area. Therefore, first, the GBR conversion unit 41, the linear γ correction unit 42, the XYZ conversion unit 43, and the xy conversion unit 44 convert the Y color difference signals Yo, CBo, CRo of the input pixels into x, y values. I do.

  The GBR conversion unit 41 converts Y color difference signals Yo, CBo, and CRo of input pixels into G, B, and R signals, and the signals converted into GBR are supplied to the linear γ correction unit 42. The arithmetic expression at this time is expressed by the following expression (3) in the ITU-BT601 system supported by NTSC and the like.

  Further, in the ITU-BT709 system that is compatible with high vision and the like, it is expressed by the following equation (4).

  The linear γ correction unit 42 performs linear γ correction for linearizing the signal converted to GBR from the GBR conversion unit 41.

  That is, when calculating the x and y values from the GBR, the GBR needs to be linear as light. However, on the transmission side that transmits (outputs) the signal to the television receiver 1, the signal is transmitted after being subjected to CRT γ correction, so that the GBR signal is linear in the output from the GBR conversion unit 41. It is not.

  Since γ on the transmission side is 1 / 2.2 of the normalized input signal, it is necessary to perform the power of 2.2 on the GBR signal in order to return it to linearity. However, if it is simply raised to the power of 2.2, in the quantized digital signal, if the input level is low, there is a possibility that 0 is output although it is not actually 0.

  Therefore, the linear γ correction unit 42 normalizes the GBR signal by 1, performs approximation of γ to the normalized GBR signal, thereby performing linear γ correction, and obtains the signals Gγ, Bγ, Rγ after the linear γ correction. , Supplied to the XYZ converter 43. As an approximation method, the following equations (5) and (6) are used.

  When the G signal normalized by 1 is 0.04045 or less (the same applies to B and R signals)

  When the G signal normalized by 1 is greater than 0.04045 (the same applies to B and R signals)

  The XYZ conversion unit 43 converts the signal converted to Gγ, Bγ, Rγ from the linear γ correction unit 42 into an X, Y, Z signal, and converts the converted X, Y, Z signal to the xy conversion unit 44. Supply. The arithmetic expression at this time is expressed by the following expression (7) in the ITU-BT601 system.

  In the ITU-BT709 system, it is expressed by the following equation (8).

  The xy conversion unit 44 obtains Yxy from the signal converted into X, Y, and Z. The x and y values obtained here are the xy chromaticity values of the input pixels, and are supplied to the target area detection unit 45. The arithmetic expression at this time is expressed by the following expressions (9) and (10).

  The target region detection unit 45 includes an area selection unit 51, a selector 52, and a normalization unit 53, and the target region where x and y obtained by the xy conversion unit 44 are set as targets for color conversion. In other words, a process is performed to detect whether it is included in (a region surrounded by xmin, xmax, ymin, and ymax which are x and y values of two symmetry angles).

  As described above, since up to eight target areas can be set, xmin, xmax, ymin, and ymax can have eight combinations (n = 0 to 7). However, the target areas are set so as not to overlap each other. Thereby, the continuity of the color after conversion is maintained.

  The area selection unit 51 receives x, y of the pixel obtained by the xy conversion unit 44 and xmin, xmax, ymin, ymax for each target region from the microcomputer 27. In the example of FIG. 3, only the input of xmin, xmax, ymin, ymax for each of four target areas is shown, but xmin, xmax, ymin, ymax is entered. In addition, xmin, xmax, ymin, and ymax for each target area are also input to the selector 52.

  Assume that the area selection unit 51 detects a target region including x, y from the xy conversion unit 44 when x, y from the xy conversion unit 44 satisfies the following expressions (11) and (12). Then, n (0 to 7) at that time is supplied to the selector 52 as an area number, and the values of x and y are supplied to the calculators 61-1 and 61-2 of the normalization unit 53, respectively.

  If the x and y values obtained by the xy conversion unit 44 do not belong to any target region, the area number n is 8.

  The selector 52 selects xmin, xmax, ymin, ymax of the target region corresponding to the area number n supplied by the area selecting unit 51, and the selected xmin is calculated by the calculator 61-1 and the calculator of the normalizing unit 53. 62-1 and the selected xmax is supplied only to the calculator 62-1. The selector 52 supplies the selected ymin to the calculator 61-2 and the calculator 62-2 of the normalization unit 53, and supplies the selected ymax only to the calculator 62-2.

  The area number n from the area selection unit 51 is also supplied to the selector 71, the selector 72, and the distance calculation unit 73 of the region value calculation unit 46 via the selector 52.

  The normalizing unit 53 includes computing units 61-1 and 61-2, computing units 62-1 and 62-2, and dividing units 63-1 and 63-2.

  The arithmetic units 61-1 and 62-1 and the division unit 63-1 calculate where the input x is from xmin to xmax, normalize, and use the normalized xnor of the region value calculation unit 46. It supplies to the distance calculation part 73. That is, the arithmetic unit 61-1 subtracts xmin from the input x, the arithmetic unit 62-1 subtracts xmin from xmax, and the division unit 63-1 calculates x calculated by the arithmetic unit 61-1. -Normalize by dividing xmax-xmin calculated by the calculator 62-1 from xmin. This arithmetic expression is expressed by the following expression (13).

  The calculators 61-2 and 62-2 and the division unit 63-2 calculate and normalize the y value where y is input from ymin to ymax, as in the case of x. The normalized ynor is supplied to the distance calculation unit 73 of the region value calculation unit 46. That is, the arithmetic unit 61-2 subtracts ymin from the input y, the arithmetic unit 62-2 subtracts ymin from ymax, and the division unit 63-2 calculates y calculated by the arithmetic unit 61-2. -Normalize by dividing ymax-ymin calculated by the calculator 62-2 from ymin. This arithmetic expression is expressed by the following expression (14).

  The region value calculation unit 46 includes selectors 71 and 72, a distance calculation unit 73, a multiplier 74, and a limiter 75, and obtains a region value k based on xnor and ynor from the normalization unit 53.

  Here, the microcomputer 27 stores a gain coefficient and a limiter value for each target region, and the region value calculation unit 21 stores xmin, xmax, x, y values of two symmetry angles for each target region. In addition to supplying ymin and ymax, a gain coefficient for each target region and a limiter value for each target region are also supplied. In the example of FIG. 3, only the input of the gain coefficient and the limiter value for each of the four target areas is shown, but it is set similarly to the case of xmin, xmax, ymin, ymax for each target area. The gain coefficient and limiter value for each of up to eight target areas are input.

  The area number n from the selector 52 is supplied to the selector 71, the selector 72, and the distance calculation unit 73, and is further supplied to the matrix generation unit 22 via the selector 72. The gain coefficient (0 ≦ gain coefficient <2) for each target area from the microcomputer 27 is supplied to the selector 71. The limiter value (0 ≦ limiter value ≦ 1) for each target area from the microcomputer 27 is supplied to the selector 72.

  The selector 71 selects the gain coefficient of the target area corresponding to the area number n from the selector 52 and supplies the selected gain coefficient to the multiplier 74.

  The selector 72 selects the limiter value of the target area corresponding to the area number n from the selector 52 and supplies the selected limiter value to the limiter 75.

  The distance calculation unit 73 calculates how close xnor and ynor from the normalization unit 53 are to the center of the target region corresponding to the area number n, sets the value as VOL, and supplies the VOL to the multiplier 74. . Note that the target area surrounded by xmin, xmax, ymin, and ymax may be a rectangle, so the center here is the center of gravity. For example, VOL is calculated to be 1 when it is the center of gravity of the region surrounded by xmin, xmax, ymin, and ymax, and 0 when it is on the side of xmin, xmax, ymin, and ymax.

  For example, the calculation formula of VOL is expressed by the following formula (15).

  The multiplier 74 multiplies the VOL obtained by the distance calculation unit 73 by the gain coefficient of the target region selected by the selector 71 and supplies the VOL multiplied by the gain coefficient to the limiter 75. The limiter 75 limits the VOL from the multiplier 74 with the limiter value of the target area selected by the selector 72, and supplies the VOL limited by the limiter value to the matrix generation unit 22 as the area value k.

  When the area number n supplied from the selector 52 is 8 (that is, when x and y obtained by the xy conversion unit 44 do not belong to any target region), the distance calculation unit 73 forcibly VOL = 0. That is, in this case, the region value k = 0.

  FIG. 4 is a diagram illustrating the concept of the region value k obtained by the region value calculation unit 21.

  In the example of FIG. 4, the x-axis represents xnor (0 ≦ xnor ≦ 1), which is the normalized value of x, and the y-axis represents yor (0 ≦ ynor ≦ 1), which is the normalized value of y. The z-axis represents the region value k (0 ≦ k ≦ 1) when the gain coefficient = 1 and the limiter value = 1.

  In the target area, the area value is smooth until xnor or ynor is outside the area (for the sake of convenience, assuming 1 <xnor, ynor or xnor, ynor <0) to the center of the area (xnor, ynor = 0.500). k is increasing.

  That is, by performing color conversion using a 3 × 3 matrix (formula (2) described above) obtained based on such a region value k, color conversion is performed only within the target region to be color-converted. Even in this case, it is possible to maintain the continuity between the color in the target area subjected to color conversion and the color outside the area not subjected to color conversion.

  Next, the 3 × 3 matrix (coefficient) generated by the matrix generation unit 22 will be described in detail with reference to FIG.

  In the example of FIG. 5, the microcomputer 27 receives the user command via the light receiving unit 26, thereby setting the target x and the target y after the color conversion desired by the user for each target region, and the display device Depending on the corresponding matrix coefficient of either ITU-BT601 or 709 and the purpose x and purpose y, the D coefficient (Y coefficient) α of the Y signal and the D coefficient (CB coefficient) β of the CB signal for each target area, A D coefficient (CR coefficient) γ of the CR signal is obtained, and the obtained D coefficient value for each target region is supplied to the matrix generation unit 22.

  First, the case of the ITU-BT601 system will be described. In the ITU-BT601 system, the following equations (16) to (18) are established. The 3 × 3 coefficient on the right side of the equation (18) is an ITU-BT601 matrix coefficient and is set in the microcomputer 27 in advance.

  On the other hand, from the equations (9) and (10), the following equations (19) and (20) are derived.

  Therefore, from the equation (18), the following equations (21) to (23) are obtained.

  Here, the input Y signal is Yo, the converted (output) Y signal is Yn, the input CB signal is CBo, the converted CB signal is CBn, the input CR signal is CRo, and the converted CR signal is CRn When chromaticity values (namely, objective x, objective y) in CBn and CRn are x, y, the following equations (24) to (26) are obtained.

  In this way, in the microcomputer 27, based on the matrix coefficients of the ITU-BT601 system and the converted objective x and objective y, the D coefficient α of the Y signal for each target area, the D coefficient β of the CB signal, and The D coefficient γ of the CR signal is obtained.

  Furthermore, when these formulas (24) to (26) are represented by determinants, they are represented by the following formula (27).

  On the other hand, when nothing is changed with respect to Yn, CBn, and CRn after conversion, Yn, CBn, CRn = Yo, CBo, and CRo may be obtained. When expressed by a determinant, the following equation (28) is obtained.

  Here, the 3 × 3 coefficient on the right side of Equation (27) (the coefficient when changing the color) is the coefficient A, and the 3 × 3 coefficient on the right side of Equation (28) (the coefficient when the color is not changed). Is the coefficient B, it is considered that the actual coefficient is obtained by multiplying the difference between the coefficient A and the coefficient B by the region value k as a gain and adding it to the coefficient B.

  Therefore, the 3 × 3 matrix generated by the matrix generation unit 22 and supplied to the matrix calculation unit 23 is obtained by the following equation (29). That is, the above-described expression (2) is a right expression of the expression (29).

  Note that the equation (2) (the right side of the equation (29)) when the region value k = 1 is the coefficient A of the right equation of the equation (27). That is, the D coefficient value is a coefficient obtained based on the objective x and the objective y when the region value k = 1.

  As described above, the microcomputer 27 supplies the matrix generation unit 22 with D coefficients α, β, and γ that become the user's desired purpose x and purpose y after conversion to the matrix generation unit 22 for each target region. 22 processes the equation (29) based on the region value k from the region value calculation unit 21 and the D coefficients α, β, γ corresponding to the area number n from the region value calculation unit 21 to obtain 3 × Three matrices can be generated.

  Note that if the input pixel is not included in any target region (in the case of area number n = 8 from the region value calculation unit 21), the region value k = 0, so that it is also derived from equation (29). As described above, the above-described equation (1) is supplied to the matrix calculation unit 23 as a 3 × 3 matrix.

  That is, the matrix calculation unit 23 is supplied with a 3 × 3 matrix generated based on the region value k and area number n from the region value calculation unit 21 and the D coefficient value for each target region from the microcomputer 27. The

  Then, the matrix calculation unit 23 performs an arithmetic operation on the 3 × 3 matrix from the matrix generation unit 22 obtained as described above with Yo, CBo, and CRo of input pixels, thereby performing color conversion. The Y color difference signals (Yn, CBn, CRn) of the pixels are obtained, and the obtained Yn, CBn, CRn are output to the RGB conversion unit 24.

  As described above, the color conversion is performed based on the D coefficients α, β, and γ that become the user's purpose x and purpose y after the conversion, and the region value k that indicates how far from the center of the target region. Therefore, for the pixels outside the target area, color conversion is not performed, and for the pixels inside the target area, the user's purpose x, Color conversion is performed so as to achieve the purpose y.

  As a result, the target area is color-converted so that the user's purpose is x and y while maintaining the continuity between the color in the target area where color conversion is performed and the color outside the target area where color conversion is not performed. be able to.

  Next, similarly, the case of the ITU-BT709 system will be described. In the ITU-BT709 system, the following equations (30) to (32) are established. Note that the 3 × 3 coefficient on the right side of Equation (30) is an ITU-BT709 matrix coefficient, and is preset in the microcomputer 27.

  Therefore, from the equations (19) and (20), the following equations (33) to (35) are obtained.

  Here, the input Y signal is Yo, the converted (output) Y signal is Yn, the input CB signal is CBo, the converted CB signal is CBn, the input CR signal is CRo, and the converted CR signal is CRn When chromaticity values (namely, objective x, objective y) in CBn and CRn are x, y, the following equations (36) to (38) are obtained.

  As described above, in the microcomputer 27, the D coefficient α of the Y signal, the D coefficient β of the CB signal, and the D coefficient of the CR signal are also determined based on the matrix coefficient of the ITU-BT709 system and the converted objective x and objective y. The coefficient γ can be obtained.

  The subsequent processing is the same as in the case of the ITU-BT601 system, and a description thereof will be omitted because it will be repeated.

  Next, with reference to FIG. 6, an example of a target area to be subjected to color conversion and the color conversion will be described. In the television receiver 1 of FIG. 2, eight target areas that can be converted can be set. Here, four representative target areas will be described.

  In the example of FIG. 6, an xy chromaticity diagram is shown. In the example of FIG. 6, the illustration of the horseshoe shape that expresses all the colors described above with reference to FIG. 1 is omitted.

  The triangle shown in this xy chromaticity diagram represents the maximum color area 101 that can be expressed theoretically on an NTSC (ITU-BT601 system) display, and the W point at the center is white (achromatic). Correspondingly, the vividness increases (saturation increases) toward the periphery of the maximum color region 101, and monochromatic light (pure color) is produced at the boundary around the chromaticity diagram. That is, the vertex G of the maximum color region 101 represents saturated (ie, pure) green, vertex B represents saturated (pure) blue, and vertex R is saturated (pure). ) Represents red.

  Further, on the xy chromaticity diagram, the target areas 111 to 114 that are the target of color conversion and the target points that the user desires after conversion (ie, target x, target y) for each of the target areas 111 to 114 121 to 124 are shown.

  For example, the user indicates an area mainly representing white (xmin = 0.28, xmax = 0.34, ymin = 0.286, ymax = 0.346) in the xy chromaticity diagram as a target area 111, which is slightly smaller than the center of gravity of the target area 111. An x, y value (x = 0.291, y = 0.301) close to B (blue) is designated as the destination point 121.

  Correspondingly, the microcomputer 27 sets the x and y values (xmin = 0.28, xmax = 0.34, ymin = 0.286, ymax = 0.346) of the two symmetry angles of the target area 111 and the target x = 0.291, objective y = 0.301 is set, and the D coefficient value is obtained from objective x = 0.291 and objective y = 0.301 of the objective point 121. The matrix generation unit 22 generates a 3 × 3 matrix based on the D coefficient value, and the matrix calculation unit 23 performs color conversion on the target region 111 using the 3 × 3 matrix.

  Thereby, for example, since the target area 111 is converted into the target point 121, white can be mainly changed to a bluish color.

  The 3 × 3 matrix generated by the matrix generation unit 22 is also obtained based on the region value k in the target region 111 calculated by the region value calculation unit 21 for the input image signal. Yes. Therefore, discontinuity between the colors of the target region 111 to be color-converted and other regions is suppressed.

  Next, the user indicates an area (xmin = 0.14, xmax = 0.4, ymin = 0.41, ymax = 0.65) mainly representing yellow to green in the xy chromaticity diagram as the target area 112, and the center of gravity of the target area 112 An x, y value (x = 0.21, y = 0.65) closer to G (green) than that is indicated as the destination point 122.

  Correspondingly, the microcomputer 27 sets the x and y values (xmin = 0.14, xmax = 0.4, ymin = 0.41, ymax = 0.65) of the two symmetry angles of the target region 112 and the target x = 0.21, objective y = 0.65 is set, and the D coefficient value is obtained from objective x = 0.21 of objective point 122, objective y = 0.65. Then, the matrix generation unit 22 generates a 3 × 3 matrix based on the D coefficient values, and the matrix calculation unit 23 performs color conversion on the target region 112 using the 3 × 3 matrix.

  Thereby, for example, since the target area 112 is converted into the target point 122, it is possible to mainly change the green color from yellow to pure green.

  The 3 × 3 matrix generated by the matrix generation unit 22 is also obtained based on the region value k in the target region 112 calculated by the region value calculation unit 21 for the input image signal. Yes. Therefore, discontinuity between the colors of the target region 112 to be color-converted and other regions is suppressed.

  Similarly, in the xy chromaticity diagram, an area (xmin = 0.14, xmax = 0.262, ymin = 0.082, ymax = 0.230) mainly representing light blue to blue in the xy chromaticity diagram is designated as the target area 113, An x, y value (x = 0.191, y = 0.148) closer to B (blue) than the center of gravity is designated as the target point 123.

  Correspondingly, the microcomputer 27 sets the x and y values (xmin = 0.14, xmax = 0.262, ymin = 0.082, ymax = 0.230) of the two symmetry angles of the target region 113 and the target x = 0.191 and objective y = 0.148 are set, and the D coefficient value is obtained from objective x = 0.191 and objective y = 0.148 of the objective point 123. Then, the matrix generation unit 22 generates a 3 × 3 matrix based on the D coefficient value, and the matrix calculation unit 23 performs color conversion on the target region 113 using the 3 × 3 matrix.

  Thereby, for example, since the target area 113 is converted into the target point 123, it is possible to change the light blue mainly from pure blue to pure blue.

  The 3 × 3 matrix generated by the matrix generation unit 22 is also obtained based on the region value k in the target region 113 calculated for the input image signal by the region value calculation unit 21. Yes. Therefore, it is possible to suppress discontinuity in the colors of the target region 113 to be color-converted and other regions.

  Finally, the user designates a region (xmin = 0.535, xmax = 0.672, ymin = 0.281, ymax = 0.371) mainly representing light red to red in the xy chromaticity diagram as the target region 114. An x, y value (x = 0.635, y = 0.33) closer to R (red) than the center of gravity is designated as the destination point 124.

  Correspondingly, the microcomputer 27 sets the x and y values (xmin = 0.535, xmax = 0.672, ymin = 0.281, ymax = 0.371) of the two symmetry angles of the target region 114 and the target x = 0.635, the objective y = 0.33 is set, and the D coefficient value is obtained from the objective x = 0.635 of the objective point 124 and the objective y = 0.33. Then, the matrix generation unit 22 generates a 3 × 3 matrix based on the D coefficient value, and the matrix calculation unit 23 performs color conversion on the target region 114 using the 3 × 3 matrix.

  Thereby, for example, since the target area 114 is converted into the target point 124, the red color can be changed from pure red to pure red.

  The 3 × 3 matrix generated by the matrix generation unit 22 is also obtained based on the region value k in the target region 114 calculated by the region value calculation unit 21 for the input image signal. Yes. Therefore, it is possible to suppress discontinuity between the colors of the target region 114 to be color-converted and other regions.

  In the example of FIG. 6, the example of color conversion for each target area has been described in order. However, the color conversion of the plurality of target areas is actually performed simultaneously on the input image signals.

  By the way, in the above description, it has been described that the D coefficient value is obtained from the purpose x and the purpose y of the desired color. However, in practice, the expressions (24) to ( In (26) and (36) to (38), transmission γ (gamma) is not taken into consideration, and coefficient calculation for linear GBR is performed.

  That is, in the case of the D coefficient value obtained from the desired x and y of the desired color, after the conversion from Yo, CBo, CRo to Yn, CBn, CRn in the matrix calculation unit 23, and further in the RGB conversion unit 24 It is desirable that the image signal is linear GBR when converted to GBR. However, in practice, as described above with reference to FIG. 3, the input image signal is subjected to γ correction on the transmission side, so for example, Yn, CBn, CRn is converted to GBR, In the system that is configured to be linear for the first time when actually displayed on the display device 3, inconsistency occurs.

  In actual processing, if the D coefficients α, β, and γ for the desired color purpose x and purpose y are calculated by hardware, the circuit scale becomes enormous and the operation speed may not be in time. .

  Therefore, in the television receiver 1 of FIG. 2, predetermined areas are set on the chromaticity diagram in advance, and predetermined D coefficients α, β, γ are stored in the microcomputer 27 for the four corners, and the user The purpose x and purpose y of the desired color are specified only within the range of the predetermined area, and the D coefficients α, β, and γ are determined by linear interpolation for the purpose x and the purpose y in the predetermined area. Make it asking.

  That is, in the television receiver 1, since eight target areas can be set, a predetermined area is set in advance for each of the eight target areas. Although described in detail later, the user can specify the size and position of the target area. Therefore, the predetermined area is set to be slightly larger so as to include a target area of a size that the user would desire as a color conversion target. In other words, the predetermined area is a maximum value area that the target area can take.

  The microcomputer 27 calculates and stores predetermined D coefficients α, β, γ for the four corners of the predetermined area for each of the predetermined areas. The predetermined D coefficient value setting process by the microcomputer 27 will be described with reference to the flowchart of FIG.

  This process is a process performed by the microcomputer 27 based on a predetermined program recorded in a built-in memory, and this process is a process that does not need to be executed on an image signal in real time.

  In step S11, the microcomputer 27 sets the D coefficient α at one of the four corners and the x and y values (for example, x-1, y-1 in FIG. , Referred to as angle y). Since the D coefficient α corresponds to the gain setting of the Y signal, it is directly given at this time.

  In step S12, the microcomputer 27 uses the angle x and the angle y to obtain the D coefficients β and γ according to the equations (25) and (26) or the equations (37) and (38).

  In step S13, the microcomputer 27 obtains Yn, CBn, and CRn according to equation (27) using the D coefficient α defined in step S11 and the D coefficients β and γ obtained in step S12. For Yo at this time, a luminance value assumed in advance by the designer is used as a representative value. For this reason, there is a slight error with respect to the actual input Y signal, but this error is not a practical problem when viewed from the user.

  In step S14, the microcomputer 27 obtains xn, yn in Yn, CBn, CRn obtained in step S13 by using equations (3) to (10).

  That is, the microcomputer 27 first obtains GBR from Yn, CBn, and CRn according to Equation (3) or Equation (4), and performs linear γ correction on GBR according to Equation (5) or Equation (6). Then, the microcomputer 27 converts the signals Gγ, Bγ, and Rγ after linear γ correction into X, Y, and Z signals according to Equation (7) or Equation (8), and Equations (9) and (10). Thus, Yxy is obtained from the signals converted into X, Y, and Z. Thereby, xn, yn in Yn, CBn, CRn obtained in step S13 is obtained.

  In step S15, the microcomputer 27 determines whether or not xn, yn obtained in step S14 matches the angles x and y defined in step S11. In the first time, since the D coefficients β and γ are obtained without considering the transmission γ, and an error is caused thereby, it is determined in step S15 that xn and yn do not match the angles x and y, The process proceeds to step S16.

  In step S16, the microcomputer 27 virtually shifts the corner x and the corner y to the corner xv and the corner yv. Then, after step S16, the process returns to step S12, and the processes after step S12 are executed for the corner x and the corner y that are virtually shifted in step S16.

  When the processes in steps S12 to S15 are repeated several times, xn and yn obtained in step S14 become substantially equal to the angles x and y. If it is determined in step S15 that xn, yn matches the angle x, angle y, the process proceeds to step S17, and the microcomputer 27 determines that D is determined to match the angle x, angle y. Coefficients α, β, and γ are set as D coefficient values for the corners and stored in the built-in memory.

  In step S18, the microcomputer 27 determines whether or not the D coefficients α, β, and γ for all four corners of the predetermined area are stored in the built-in memory, and the D coefficients for all four corners of the predetermined area. If it is determined that α, β, and γ are not yet stored, the process returns to step S11 and the subsequent processing is repeated for the next of the four corners.

  If it is determined in step S18 that the D coefficients α, β, γ for all four corners of the predetermined area are stored in the built-in memory, the specified D coefficient value setting process is terminated.

  As described above, the prescribed D coefficient values of the four corners in the eight predetermined areas are obtained and stored in the microcomputer 27 in advance.

  FIG. 8 is a diagram for explaining in detail the linear interpolation of the square prescribed D coefficient values.

  In the example of FIG. 8, the four xy chromaticity values are (x-1, y-1), (x-2, y-1), (x-1, y-2), and (x, respectively). -2, y-2) is shown. For example, the microcomputer 27 includes (x-1, y-1), (x-2, y-1), (x-1 , y-2), and (x-2, y-2) as the default D coefficient values β of four angles, β1, β2, β3, and β4, respectively, are as described above with reference to FIG. Sought and stored.

  In this case, the D coefficient value βset of the purpose x and the purpose y instructed by the user is obtained as follows. First, a and b are obtained by the following equations (39) and (40) according to how far the object x is from x-1 and x-2 in the predetermined region 151. Here, x1 represents the distance from the object x to x-1, and x2 represents the distance from the object x to x-2.

  Then, the D coefficient value βset is obtained by the following equation (41) according to how far the object y is from y-1 and y-2 of the predetermined region 151. Here, y1 represents the distance from the target y to y-1, and y2 represents the distance from the target y to y-2.

  In the example of FIG. 8, the case of obtaining the D coefficient value βset has been described. However, since the D coefficient values αset and γset are obtained in the same manner, the description thereof will be omitted because it is repeated.

  As described above, predetermined areas are set in advance on the xy chromaticity diagram, and the predetermined D coefficients α, β, γ are stored in the microcomputer 27 for the four corners. The purpose x and purpose y of the desired color are specified only in the range, and the D coefficients α, β, and γ are obtained by linear interpolation for the purpose x and purpose y in the predetermined area. Thereby, it is possible to suppress the occurrence of inconsistency due to the transmission γ of the image signal, and it is possible to reduce the calculation burden for obtaining the D coefficient value.

  FIG. 9 shows an example of a screen displayed on the display device 3.

  In the example of FIG. 9, the screen of the display device 3 has an image 181 corresponding to an image signal (main line image signal) input to the television receiver 1 and a right side of the image 181 so as to transmit the image 181. It is composed of a user interface image 182 arranged below.

  That is, the user interface image 182 corresponds to the user interface image signals Gg, Bg, and Rg generated by the graphic generation unit 28 based on the information from the microcomputer 27. By superimposing the signals Gg, Bg, and Rg on the main line image signal, a screen on which the image 182 for user interface is superimposed on the image 181 is displayed on the display device 3.

  The user interface image 182 may be superimposed and displayed by α blending or the like so as to allow the image 181 to pass through. Alternatively, the user interface image 182 may be completely switched from the image 181 corresponding to the main line image signal. Only the image 182 for use can be displayed on the display device 3.

  On the display device 3, a triangular chromaticity diagram 201 corresponding to the maximum color region 101 of the xy chromaticity diagram of FIG. 6 is displayed as an image 182 for the user interface. For the target areas 211 to 214 of four colors, W (white), G (green), B (blue), and R (red), and the target areas 211 to 214, the user can specify The target points 221 to 224 indicating the positions of the target x and the target y after the desired color conversion are displayed.

  For convenience of explanation, the triangular chromaticity diagram 201 shows only a frame, but actually, the triangular chromaticity diagram 201 can be displayed in a gradation that connects the respective colors in succession. Further, in each of the target areas 211 to 214, corresponding codes W, G, B, and R are shown so that the colors (white, green, blue, and red) corresponding to the respective target areas can be seen. For example, each of the target areas 211 to 214 can be displayed with a corresponding color.

  For example, the user first operates the remote controller 2 in order to generally select the color to be converted, so that the four colors W (white), G (green), B (blue), One area is selected from the R (red) target areas 211 to 214, and the position and size of each of the selected target areas 211 to 214 are input to the television receiver 1.

  In the example of FIG. 9, only four color target areas are shown. However, in the television receiver 1, in actuality, eight color target areas can be set. The user can select eight target areas. Further, in the user interface image 182 of FIG. 9, the target region 212 and the target point 222 are conspicuous with bold lines when the G (green) target region 212 is selected by the user's operation of the remote controller 2. It is shown.

  Next, the user operates the remote controller 2 to move the target point in the selected target area (for example, the target point 222 in the G (green) target area 212) up, down, left, and right within the target area. The color direction desired after color conversion can be input to the television receiver 1.

  In response to this, the television receiver 1 sets the purpose x and the purpose y corresponding to the target point 222, and obtains the D coefficient value corresponding to the purpose x and the purpose y.

  As a result, the 3 × 3 matrix is changed based on the obtained D coefficient value, and the input image signal is color-converted by performing an arithmetic operation on the changed 3 × 3 matrix. The color of the image 181 is also changed in conjunction with the movement of the target point 222 of the image 182 displayed on the device 3.

  With reference to FIG. 10, the user interface image 182 of FIG. 9 will be described in more detail.

  In the example of FIG. 10, the display area is 200 dots vertically (dots) and 200 dots horizontally (dots), the horizontal axis corresponds to x of chromaticity, and the vertical axis corresponds to y of chromaticity. The image 182 is shown. Further, by setting the range of x and y to 0 to 1, respectively, the resolution of 1 dot is 0.005. Thereby, it is possible to facilitate the correspondence between the hardware for setting xmin, xmax, ymin, and ymax of the target area and the image display. Note that the resolution of 0.005 has the advantage that it is close to the detection limit where the color appears to change.

  The triangular chromaticity diagram 201 in the user interface image 182 can be easily drawn because x, y chromaticity values in pure G, B, and R are predetermined in the xy chromaticity diagram. For example, x and y in NTSC employing the ITU-BT601 system are expressed by the following equation (42).

  X and y in the HDTV adopting the ITU-BT709 system are expressed by the following equation (43).

  Therefore, the triangular chromaticity diagram 201 can be displayed by connecting the coordinates (x, y values) of these three points (pure G, B, and R). This is performed by the microcomputer 27 based on a predetermined program stored in a built-in memory. The drawing data of the triangular chromaticity diagram 201 is supplied to the graphic generation unit 28.

  Here, the user interface image 182 in FIG. 10 includes a triangular chromaticity diagram 201 in FIG. 9 and four colors W (white), G (green), B (blue), and R that can be designated by the user. In addition to (red) target areas 211 to 214 and the converted target x and target y 221 to 224 desired by the user, corresponding to each target area 211 to 214, a little smaller than each target area 211 to 214 Larger maximum value areas 251 to 254 are indicated by dotted lines.

  The maximum value areas 251 to 254 are predetermined areas set in advance when the predetermined D coefficient values are stored in advance. As described above with reference to FIG. Predefined D coefficients α, β, and γ are stored for each of the four corners of the value areas 251 to 254.

  The maximum value areas 251 to 254 are not actually displayed as the user interface image 182, but for example, when the user selects the G (green) target area 212, the maximum value areas 251 to 254 are displayed in the maximum value area 252. However, it is set internally so that the position and size of the target area 212 cannot be indicated. Therefore, even if an attempt is made to specify the position and size of the target area 212 outside the maximum value area 252, the position and size of the target area 212 are not set as instructed. Will remain.

  On the other hand, if the user selects the G (green) target area 212, the position and size of the target area 212 and the target area 212A can be freely set within the maximum value area 252, for example. It is possible to indicate.

  For example, as a result of instructing the position and size by the user, the microcomputer 27 sets xmin, xmax, ymin, ymax of the target area 212, and the area corresponding to the set xmin, xmax, ymin, ymax is rectangular. The drawing data of the target area 212 to be enclosed or filled with is generated, and the generated drawing data of the target area 212 and the set xmin, xmax, ymin, ymax are supplied to the graphic generation unit 28.

  The graphic generation unit 28 arranges the drawing data of the target area 212 at the positions of xmin, xmax, ymin, and ymax set by the microcomputer 27 on the drawing data of the triangular chromaticity diagram 201, and is used for the user interface. Image signals Gg, Bg, and Rg are generated and supplied to the graphic superimposing unit 25.

  The graphic superimposing unit 25 superimposes the input image signals Gn, Bn, Rn and the image signals Gg, Bg, Rg from the graphic generating unit 28, and displays a screen corresponding to the superimposed image signals Gm, Bm, Rm, It is displayed on the display device 3. As a result, a screen in which the image 182 for user interface is superimposed on the image 181 as shown in FIG. 9 is displayed on the display device 3.

  Next, the user moves the target point 222 in the G (green) target area 212 indicating the position and size in the target area 212 up, down, left, and right, so that the desired color direction after color conversion is obtained. And the degree of conversion can be input to the television receiver 1.

  That is, in the case of the target area 212, the user can convert the desired target point after conversion so that the x and y values of the center of gravity of the target area 212 become the x and y values of the target point 222 as indicated by the dotted arrows. 222 is moved, and the color direction and the degree of conversion desired after color conversion are input to the television receiver 1.

  For example, when the position and size of the G (green) target area 212A are instructed and the G (green) target area 212A is set, the user can set the target point in the G (green) target area 212A. By moving 222A up, down, left, and right within the target area 212A, the color direction and the degree of conversion desired after color conversion can be input to the television receiver 1.

  In this case, when the objective point 222A is input to the microcomputer 27, the microcomputer 27 sets the objective x and objective y corresponding to the objective point 222A, and sets the objective x and objective y and the objective point 222A. Is supplied to the graphic generation unit 28.

  In response to this, the graphic generation unit 28 arranges the drawing data of the target area 212A at the positions of xmin, xmax, ymin, ymax set by the microcomputer 27 on the drawing data of the triangular chromaticity diagram 201. Then, image signals Gg, Bg, Rg in which the drawing data of the target point 222A are arranged at the set positions of the target x and the target y are generated and supplied to the graphic superimposing unit 25.

  At this time, the microcomputer 27 sets the D coefficients αset, βset, and γset for the set objective x and objective y at the four corners of the maximum value areas 251 to 254 as described above with reference to FIG. The predetermined D coefficients α, β, and γ are used to obtain the values by linear interpolation, and the D coefficients αset, βset, and γset are supplied to the matrix generator 22.

  The matrix generation unit 22 generates a 3 × 3 matrix based on the D coefficients αset, βset, and γset obtained according to the purpose x and the purpose y, and supplies the generated matrix to the matrix calculation unit 23. Color conversion of the image signal using the 3 × 3 matrix is performed, and the image signal subjected to the color conversion is supplied to the graphic superimposing unit 25 via the RGB conversion unit 24.

  Then, the graphic superimposing unit 25 displays the image signals Gg, Bg, Rg for displaying the user interface image 182 from the graphic generating unit 28, and the color-converted image signals Gn, Bn, Rg from the matrix calculating unit 23. Rn is superimposed and a screen corresponding to the superimposed image signals Gm, Bm, Rm is displayed on the display device 3.

  As a result, the user interface image 182 in which the target point 222A is moved and displayed is color-converted in accordance with the movement of the target point 222A (that is, the x and y values of the center of gravity of the target region 212A are The x and y values other than the center of gravity of the target area 212A are superimposed on the image 181 so that the x and y values become the x and y values. Is displayed on the display device 3.

  As described above, since the display device 3 represents the x, y chromaticity diagram and displays the triangular chromaticity diagram 201 in which the target area and the target point are arranged, the user is displayed on the display device 3. While viewing an image (that is, displayed based on the characteristics of the display device), it is possible to intuitively instruct a color to be changed, and a color conversion operation can be easily performed.

  Thereby, an arbitrary color of the image signal can be converted into a desired arbitrary color according to the characteristics of the display device and the user's preference.

  Next, processing of the television receiver 1 executed in response to the user's operation of the remote controller 2 will be described with reference to the flowchart of FIG.

  In the television receiver 1, for example, xmin, xmax, ymin, ymax of each target area set as an initial value or instructed by the previous user, each target x, target y, and each target x , The D coefficient value obtained according to the purpose y is used, color conversion is performed as will be described later with reference to FIG. 12, and an image corresponding to the color-converted image signal is displayed on the display device 3. ing.

  For example, the user operates the remote controller 2 to instruct the television receiver 1 in the color conversion mode. When the microcomputer 27 receives an instruction signal corresponding to a user operation via the light receiving unit 26, the microcomputer 27 causes the display device 3 to display the triangular chromaticity diagram 201 of FIG. 9 in step S31.

  That is, the microcomputer 27 draws the triangular chromaticity diagram 201, for example, xmin, xmax, ymin, ymax of each target area set as an initial value or instructed by the previous user and their drawing. The data, each object x and object y corresponding to each target area, and their drawing data are supplied to the graphic generation unit 28.

  Based on information from the microcomputer 27, the graphic generation unit 28 displays image signals Gg, Gg, for displaying a user interface image 182 in which each target area and each target point are arranged on the triangular chromaticity diagram 201. Bg and Rg are generated, and the generated image signals Gg, Bg and Rg are supplied to the graphic superimposing unit 25. The graphic superimposing unit 25 superimposes the image signals Gg, Bg, Rg from the graphic generating unit 28 on the main line image signals Gn, Bn, Rn, and displays a screen corresponding to the superimposed image signals Gm, Bm, Rm. It is displayed on the device 3.

  As a result, a screen as shown in FIG. 9 is displayed on the display device 3.

  In step S32, the microcomputer 27 determines whether or not a color to be changed has been selected. For example, when the user selects the G (green) target region 212 by operating the remote controller 2 while viewing the screen displayed on the display device 3 in order to select the color to be changed, the micro The computer 27 determines that the color to be changed has been selected, and the process proceeds to step S33.

  In step S <b> 33, the microcomputer 27 highlights the target area 212 selected by the user and the target point 222 displayed on the display device 3 with a thick frame.

  That is, the microcomputer 27 draws the target area 212 and its target point 222 selected by the user with a thick frame, supplies the drawing data to the graphic generation unit 28, and the graphic generation unit 28 draws the drawing data. Is used to generate image signals Gg, Bg, and Rg and display them on the display device 3 via the graphic superimposing unit 25.

  Thereby, on the triangular chromaticity diagram 201 of the display device 3, the target area 212 and its destination point 222, which are the colors selected by the user, are highlighted with a thick frame.

  In step S34, the microcomputer 27 determines whether the selected color range is instructed. For example, the user operates the remote controller 2 to instruct the position and size (within the maximum value area 252) of the selected target area 212. In this case, the microcomputer 27 determines in step S34 that the selected color range has been instructed, and the process proceeds to step S35.

  In step S35, the microcomputer 27 sets xmin, xmax, ymin, ymax of the target area 212. Then, the microcomputer 27 supplies xmin, xmax, ymin, ymax of the set target area 212 to the area value calculation unit 21 and also sets the target area 212 corresponding to the set xmin, xmax, ymin, ymax. Generate drawing data.

  In step S <b> 36, the microcomputer 27 supplies the generated drawing data of the target area 212 and xmin, xmax, ymin, ymax of the set target area 212 to the graphic generation unit 28 and displays them on the display device 3. The size and position of the target area 212 are moved, enlarged, or reduced.

  That is, the graphic generation unit 28 generates image signals Gg, Bg, and Rg using information (x, y values and drawing data) from the microcomputer 27, and sends it to the display device 3 via the graphic superimposition unit 25. Display.

  Thereby, on the triangular chromaticity diagram 201 of the display device 3, the size and position of the target area 212, which is the color selected by the user, are displayed by being moved, enlarged, or reduced.

  In step S37, the microcomputer 27 determines whether or not the target point of the selected target area has been moved. For example, the user operates the remote controller 2 to move the target point 222 in the selected target area 212 up and down, left and right within the target area 212, so that the color direction and color desired after color conversion are obtained. The degree of conversion is instructed to the television receiver 1.

  In response to this, in step S37, the microcomputer 27 determines that the target point of the selected target area has been moved, and the process proceeds to step S38.

  In step S <b> 38, the microcomputer 27 sets the purpose x and the purpose y of the target point 222, and supplies the set purpose x and purpose y to the graphic generation unit 28. The graphic generation unit 28 generates image signals Gg, Bg, Rg in which drawing data of the target point 222 is arranged at the set positions of the target x and the target y, and supplies them to the graphic superimposing unit 25.

  In step S <b> 39, the microcomputer 27 calculates D coefficient values for the set objective x and objective y and supplies them to the matrix generation unit 22. Specifically, as described above with reference to FIG. 8, the microcomputer 27 sets the D coefficients αset, βset, and γset for the set purpose x and purpose y to the default D of the four corners of the maximum value region 252. Using the coefficients α, β, and γ, linear interpolation is used, and the obtained D coefficients αset, βset, and γset for the purpose x and purpose y are supplied to the matrix generation unit 22.

  Based on the D coefficients αset, βset, γset and the region value k, the matrix generation unit 22 generates a 3 × 3 matrix in step S67 of FIG. 12 to be described later, and color conversion is performed using the generated matrix. The image signal thus obtained is supplied to the graphic superimposing unit 25 via the RGB conversion unit 24.

  Accordingly, in step S40, the graphic superimposing unit 25 displays the image signals Gg, Bg, Rg for displaying the user interface image 182 from the graphic generating unit 28 and the color-converted image signals from the matrix calculating unit 23. Gn, Bn, Rn are superimposed and the screen corresponding to the superimposed image signals Gm, Bm, Rm is displayed on the display device 3 so that the display device 3 moves together with the chromaticity diagram in which the target point has been moved. A color-converted image is displayed according to the target point.

  That is, in step S40, a screen is displayed in which the user interface image 182 with the destination point 222 moved on the triangular chromaticity diagram 201 is superimposed on the image 181 that has been color-converted in accordance with the movement of the destination point 222. Displayed on device 3.

  If it is determined in step S32 that the color to be changed is not selected, if it is determined in step S34 that the range of the selected color is not indicated, or if the selected object is selected in step S37 If it is determined that the target point of the region has not been moved, the process proceeds to step S41, and the microcomputer 27 determines whether or not a predetermined time has elapsed.

  That is, when a predetermined time has elapsed since the last user operation was input via the remote controller 2, the microcomputer 27 ends the color conversion mode and ends this process.

  If it is determined that the predetermined time has not yet elapsed since the user's operation was last input, the process returns to step S32 and the subsequent processes are repeated.

  As described above, since the triangular chromaticity diagram 201 in which the target area and the target point are arranged is displayed on the display device 3 in the color conversion using the x, y chromaticity values, the television receiver 1, it is easy to achieve consistency between the color conversion process and the drawing process. In addition, the user can intuitively instruct the color to be changed while viewing the triangular chromaticity diagram displayed according to the characteristics of the display device, so that the color conversion operation can be easily performed.

  Therefore, in the television receiver 1, an arbitrary color of the image signal can be converted into a desired arbitrary color according to the characteristics of the display device and the user's preference.

  Next, color conversion processing of the television receiver 1 will be described with reference to the flowchart of FIG. In other words, this color conversion processing is performed in real time using the target region and the purpose x and purpose y set by the processing of FIG. 11 and the D coefficient value obtained according to the purpose x and purpose y. It is.

  The image signals (Y color difference signals) Yo, CBo, and CRo are input to the region value calculation unit 21 and the matrix calculation unit 23.

  In step S61, the GBR conversion unit 41 of the region value calculation unit 21 converts the Y color difference signals Yo, CBo, CRo of the input pixels into G, B, R signals. The signal converted into GBR is supplied to the linear γ correction unit 42.

  In step S62, the linear γ correction unit 42 normalizes the G, B, and R signals from the GBR conversion unit 41 by 1, and approximates the normalized G, B, and R signals to γ, thereby linear γ Correction is performed, and the signals Gγ, Bγ, and Rγ after the linear γ correction are supplied to the XYZ conversion unit 43.

  In step S63, the XYZ conversion unit 43 converts the signal converted to Gγ, Bγ, Rγ from the linear γ correction unit 42 into an X, Y, Z signal, and converts the converted X, Y, Z signal to xy This is supplied to the conversion unit 44.

  In step S <b> 64, the xy conversion unit 44 obtains Yxy from the signal converted into X, Y, and Z, and supplies the obtained x and y to the area selection unit 51.

  Here, for example, when an initial value is set, the microcomputer 27 supplies xmin, xmax, ymin, ymax of each target region of the initial value to the area selection unit 51 and the selector 52 in advance, Furthermore, in step S36 of FIG. 11, every time xmin, xmax, ymin, ymax of each target area is set, the set xmin, xmax, ymin, ymax of each target area is changed to the area selector 51 and the selector 52. To supply.

  In step S65, the area selection unit 51 selects the area number n (0 ≦ n ≦ 7) of the target region including x and y from the xy conversion unit 44, and selects the selected area number n with the selector 52 and the selector 71, selector 72, distance calculation unit 73, and matrix generation unit 22. In step S65, when x and y from the xy conversion unit 44 are not included in any target region, n = 8 is selected.

  In step S66, the normalization unit 53 and the region value calculation unit 46 obtain the region value k.

  That is, the selector 52 supplies the selected ymin to the calculator 61-2 and the calculator 62-2, and supplies the selected ymax only to the calculator 62-2. The arithmetic units 61-1 and 62-1 and the division unit 63-1 calculate where the input x is from xmin to xmax, normalize, and use the normalized xnor of the region value calculation unit 46. It supplies to the distance calculation part 73. The calculators 61-2 and 62-2 and the division unit 63-2 calculate and normalize the y value where y is input from ymin to ymax, as in the case of x. The normalized ynor is supplied to the distance calculation unit 73 of the region value calculation unit 46.

  The distance calculation unit 73 calculates how close xnor and ynor from the normalization unit 53 are to the center of the target region corresponding to the area number n, sets the value as VOL, and supplies the VOL to the multiplier 74. . The multiplier 74 multiplies the VOL obtained by the distance calculation unit 73 by the gain coefficient of the target area supplied by the microcomputer 27 and selected by the selector 71, and sets the VOL multiplied by the gain coefficient to the limiter 75. To supply. The limiter 75 limits the VOL from the multiplier 74 with the limiter value of the target area supplied by the microcomputer 27 and selected by the selector 72, and generates a matrix with the VOL limited by the limiter value as the area value k. Supplied to the unit 22.

  In step S67, the matrix generation unit 22 determines 3 × 3 according to the region value k from the limiter 75, the area number n from the area selection unit 51, and the D coefficients αset, βset, and γset from the microcomputer 27. Generate a matrix of

  That is, in addition to the region value k from the limiter 75 and the area number n from the area selection unit 51, the matrix generation unit 22 is supplied with D coefficients αset, βset, and γset for each target region.

  Depending on the user's operation, the D coefficient value obtained in advance according to the initial purpose x and purpose y is supplied to the target area for which purpose x and purpose y are not yet set. However, in step S37 of FIG. 11 described above, the microcomputer 27 sets the purpose x and the purpose y corresponding to the selected target area, and in step S38, it is obtained according to the set purpose x and the purpose y. Each time, the D coefficients αset, βset, and γset of the selected target region are supplied.

  The matrix generation unit 22 processes the equation (29) based on the region value k from the limiter 75 and the D coefficients αset, βset, and γset corresponding to the area number n from the area selection unit 51 to obtain 3 × 3 And the generated 3 × 3 matrix is supplied to the matrix calculation unit 23.

  In step S <b> 68, the matrix calculation unit 23 performs arithmetic operation on Yo, CBo, CRo of the input image signal (pixel) and the 3 × 3 matrix from the matrix generation unit 22, so that the pixel after color conversion is calculated. Y color difference signals (Yn, CBn, CRn) are obtained, and the obtained Yn, CBn, CRn are output to the RGB converter 24.

  In step S69, the RGB conversion unit 24 performs matrix conversion of Yn, CBn, and CRn from the matrix calculation unit 23 into G, B, and R. In step S70, the RGB conversion unit 24 outputs the converted G, B, and R signals to the graphic superimposing unit 25, and the color conversion process is ended.

  Correspondingly, in the color conversion mode, the graphic superimposing unit 25 displays image signals Gg, Bg, Rg for displaying the user interface image 182 from the graphic generating unit 28 in step S40 of FIG. Then, the color-converted image signals Gn, Bn, Rn from the matrix calculation unit 23 are superimposed, and a screen corresponding to the superimposed image signals Gm, Bm, Rm is displayed on the display device 3.

  If not in the color conversion mode, the graphic superimposing unit 25 causes the display device 3 to display a screen corresponding to the color-converted image signals Gn, Bn, Rn from the matrix calculation unit 23.

  As described above, the matrix generated based on the D coefficients α, β, and γ that become the user's purpose x and purpose y after the conversion (that is, the xy chromaticity is used at the time of color conversion, and the x and y values are Since the color conversion is performed using a matrix that moves in an arbitrary direction, as described above with reference to FIG. 1, the color that could conventionally be moved only in a specific one-axis direction as indicated by arrows A <b> 1 and A <b> 2. Can be moved in any direction, and the color of white that could not be changed conventionally can be changed to reddish white or bluish white.

  FIG. 13 is a diagram for explaining the color movement by the color conversion of the present invention on the general xy chromaticity diagram described above with reference to FIG.

  Conventionally, red could only be changed in one direction of yellow. However, according to the present invention, for an arbitrary orange O, for example, yellow as shown in the order of arrows O1 to O6. The color can be changed in each direction such as pure orange, pure red, magenta, muddy orange, yellowish green.

  Also, for example, for any magenta M, the color changes in various directions such as magenta, pure red, pure magenta, pure blue, cyan, etc., as shown in the order of arrows M1 to M6. Can be made.

  Further, for example, for white W, the colors can be changed in various directions such as yellow, red, magenta, blue, cyan, and green, as shown in order by arrows W1 to W6.

  In addition, since the color conversion of the present invention is performed not only according to the D coefficients α, β, γ, but also according to the region value k indicating how far away from the center of the target region, No color conversion is performed, and for the pixels in the target region, color conversion is performed such that the larger the pixel is in the center of the target region and the smaller the pixel is in the region, the smaller the pixel is.

  As a result, the target area is color-converted so that the user's purpose is x and y while maintaining the continuity between the color in the target area where color conversion is performed and the color outside the target area where color conversion is not performed. be able to. That is, an arbitrary color that the user wants to convert can be converted to an arbitrary color desired by the user.

  In the above description, the case where the user desires the purpose x and the purpose y has been described. However, the manufacturer who adjusts at the manufacturer sets the hue while viewing the image displayed on the display device 3 and the triangular chromaticity diagram. Even in this case, the color conversion can be adjusted in the same manner.

  In the above description, the television receiver including the tuner and the display has been described. However, the present invention is not limited to the television receiver, and displays an image corresponding to an input image signal. In addition, any apparatus that performs color conversion can be applied to, for example, an image processing apparatus.

  The series of processes described above can be executed by hardware or can be executed by software. From the viewpoint of processing speed, only the process of obtaining the D coefficient value by the microcomputer 27 is performed by software, and the process of obtaining the area value performed by the area value calculation unit 21 and the matrix generation unit 22 are performed. It is most preferable that the matrix generation process and the matrix calculation process performed by the matrix calculation unit 23 be performed by hardware.

  When a series of processing is executed by software, a program constituting the software executes various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a program recording medium in a general-purpose personal computer or the like.

  FIG. 14 is a block diagram showing an example of the configuration of a personal computer 301 that executes the above-described series of processing by a program. A CPU (Central Processing Unit) 311 executes various processes according to a program stored in a ROM (Read Only Memory) 312 or a storage unit 318. A RAM (Random Access Memory) 313 appropriately stores programs executed by the CPU 311 and data. The CPU 311, ROM 312, and RAM 313 are connected to each other via a bus 314.

  An input / output interface 315 is also connected to the CPU 311 via the bus 314. The input / output interface 315 is connected to an input unit 316 including a keyboard, a mouse, and a microphone, and an output unit 317 including a display and a speaker. The CPU 311 executes various processes in response to commands input from the input unit 316. Then, the CPU 311 outputs the processing result to the output unit 317.

  A storage unit 318 connected to the input / output interface 315 includes, for example, a hard disk, and stores programs executed by the CPU 311 and various data. The communication unit 319 communicates with an external device via a network such as the Internet or a local area network.

  A program may be acquired via the communication unit 319 and stored in the storage unit 318.

  The drive 320 connected to the input / output interface 315 drives a removable medium 321 such as a magnetic disk, an optical disk, a magneto-optical disk, or a semiconductor memory, and drives programs and data recorded there. Get etc. The acquired program and data are transferred to and stored in the storage unit 318 as necessary.

  As shown in FIG. 14, a program recording medium that stores a program that is installed in a computer and can be executed by the computer includes a magnetic disk (including a flexible disk), an optical disk (CD-ROM (Compact Disc-Read Only). Memory, DVD (Digital Versatile Disc), a magneto-optical disk, a removable medium 321 which is a package medium made of a semiconductor memory, a ROM 312 in which a program is temporarily or permanently stored, or a storage unit 318 It is comprised by the hard disk etc. which comprise. The program is stored in the program recording medium using a wired or wireless communication medium such as a local area network, the Internet, or digital satellite broadcasting via a communication unit 319 that is an interface such as a router or a modem as necessary. Done.

  In the present specification, the step of describing the program stored in the program recording medium is not limited to the processing performed in time series in the order described, but is not necessarily performed in time series. Or the process performed separately is also included.

  Further, in this specification, the system represents the entire apparatus constituted by a plurality of apparatuses.

It is a figure explaining the conventional color conversion. It is a block diagram which shows the structure of one Embodiment of the television receiver to which this invention is applied. It is a block diagram which shows the structural example of the area | region value calculating part of FIG. It is a figure which shows an area | region value notionally. It is a figure explaining the 3 * 3 matrix which the matrix production | generation part of FIG. 2 produces | generates. It is a figure which shows the example of the color conversion of this invention. FIG. 3 is a flowchart for explaining processing for setting a default D coefficient value of the television receiver of FIG. 2. FIG. It is a figure explaining linear interpolation of a predetermined D coefficient value. It is a figure which shows the example of the screen displayed on the display device of FIG. FIG. 10 is a diagram illustrating in detail an image for the user interface in FIG. 9. 3 is a flowchart for explaining processing of the television receiver in FIG. 2. 3 is a flowchart illustrating an example of color conversion processing of the television receiver in FIG. 2. It is a figure explaining the color conversion by the television receiver of FIG. It is a block diagram which shows the structural example of the personal computer to which this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Television receiver, 2 Remote controller, 3 Display device, 21 Area value calculating part, 22 Matrix generation part, 23 Matrix calculating part, 24 RGB conversion part, 25 Graphic superimposition part, 26 Light receiving part, 27 Microcomputer, 28 Graphics Generating unit, 41 RGB converting unit, 42 linear gamma correcting unit, 43 XYZ converting unit, 44 xy converting unit, 45 target region detecting unit, 46 region value calculating unit, 51 area selecting unit, 52 selector, 53 normalizing unit, 71 , 72 selector, 73 distance calculator, 74 multiplier, 75 limiter, 181 image, 182 user interface image, 201 triangular chromaticity diagram, 211 to 214 target area, 221 to 224 destination point

Claims (8)

In a color conversion device that performs color conversion of an input image signal,
An area value calculation means for normalizing an area value representing a distance from the center in a target area for color conversion on the xy chromaticity diagram with respect to the xy chromaticity value of the image signal;
Coefficient value calculation means for obtaining a coefficient value so that the luminance value after color conversion and the xy chromaticity value become a value desired by the user when the region value for the xy chromaticity value of the image signal is 1.
Matrix generating means for generating a 3 × 3 matrix based on the coefficient value obtained by the coefficient value calculating means and the area value obtained by the area value calculating means;
A color conversion apparatus comprising: color conversion means for performing color conversion of the image signal using the 3 × 3 matrix generated by the matrix generation means. The color conversion apparatus according to claim 1, wherein the region value is a value that decreases as the distance from the center of the target region increases. The coefficient value calculating means obtains and stores the coefficient values at four corners of a predetermined area on the xy chromaticity diagram, and the coefficient value of the luminance value after the color conversion and the xy chromaticity value are The color conversion apparatus according to claim 1, wherein the color conversion apparatus is obtained by linear interpolation using the coefficient values at four corners. The image signal corresponding to the triangular chromaticity diagram having x as the horizontal axis and y as the vertical axis and the xy chromaticity values corresponding to saturated G, B, and R as vertices is color-converted by the color conversion means. The color conversion apparatus according to claim 1, further comprising a display control unit that superimposes the image signal and displays a screen corresponding to the superimposed image signal. In response to the user's operation, the position of the user's desired xy chromaticity value when the region value is 1 with respect to the target region and the xy chromaticity value of the image signal is displayed on the triangular chromaticity diagram. An image generation means for generating an image signal for display;
The display control unit superimposes the image signal generated by the image generation unit on the image signal subjected to color conversion by the color conversion unit, and displays a screen corresponding to the superimposed image signal. The color conversion apparatus according to claim 4. In a color conversion method of a color conversion device that performs color conversion of an input image signal,
For the xy chromaticity value of the image signal, obtain a normalized region value representing the distance from the center in the target region of color conversion on the xy chromaticity diagram,
When the region value with respect to the xy chromaticity value of the image signal is 1, a coefficient value is obtained so that the luminance value after color conversion and the xy chromaticity value become values desired by the user,
Based on the obtained coefficient value and the obtained region value, a 3 × 3 matrix is generated,
A color conversion method including a step of performing color conversion of the image signal using the generated 3 × 3 matrix. A program for causing a computer to perform color conversion of an input image signal,
For the xy chromaticity value of the image signal, obtain a normalized region value representing the distance from the center in the target region of color conversion on the xy chromaticity diagram,
When the region value with respect to the xy chromaticity value of the image signal is 1, a coefficient value is obtained so that the luminance value after color conversion and the xy chromaticity value become values desired by the user,
Based on the obtained coefficient value and the obtained region value, a 3 × 3 matrix is generated,
A program including a step of performing color conversion of the image signal using the generated 3 × 3 matrix.   A recording medium on which the program according to claim 7 is recorded.

Images