JP2005328277A - Signal processor and method, recording medium, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily correct colors of an inputted image signal. <P>SOLUTION: The distance calculation section 21a of a uv gain correction coefficient calculation section 21 calculates the distance between an inputted uv signal and the center position of an area as the object of color correction in a mode set by a uv gain correction coefficient calculating method setting section 28. A correction coefficient calculation section 21b calculates a uv gain correction coefficient according to the found distance. A luminance gain correction coefficient calculation section 22 calculates a luminance gain correction coefficient in a mode set by a coefficient calculating method setting section 29. A u-direction correction quantity calculation section 23 and a v-directional correction quantity calculation section 24 calculate a correction quantity for the uv signal by a calculating method set by a direction correction quantity calculating method setting section 30. Adders 26 and 25 add the correction quantities supplied from the u-direction correction quantity calculation section 23 and v-direction correction quantity calculation section 24 to make corrections. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a signal processing apparatus and method, a recording medium, and a program, and more particularly to a signal processing apparatus and method, a recording medium, and a program that can easily perform color correction on an input image signal.

  Conventionally, in a video camera, the contrast (brightness difference) and sharpness (brightness of the boundary) of an image captured by an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor) are improved. As a method, a contrast enhancement method by gradation conversion and a high frequency component enhancement method for enhancing the contrast of a high frequency component in an image are considered.

  As a contrast enhancement method, tone curve adjustment for converting each pixel level of an image with a function having a predetermined input / output relationship (hereinafter referred to as a level conversion function), or frequency distribution of pixel levels A method called histogram equalization has been proposed in which the level conversion function is adaptively changed according to the above.

  As a high frequency component enhancement method, a method called an unsharp mask that performs edge enhancement that extracts edges from an image and emphasizes the extracted edges has been proposed.

  However, in contrast enhancement methods, in addition to the problem that the contrast can be improved only in a part of the luminance range in the entire dynamic range (difference between the maximum level and the minimum level) of the image, in addition, in the case of tone curve adjustment However, there is a problem that the contrast is lowered in the brightest and darkest parts of the image, and in the case of histogram equalization, in the vicinity of the luminance region where the frequency distribution is small. Further, in the high frequency component enhancement method, only the contrast of the high frequency component of the image is enhanced, thereby causing a problem that the vicinity of the edge of the image is unnaturally enhanced and the image quality is deteriorated.

  Therefore, conventionally, an image signal processing device configured as shown in FIG. 1 is used to amplify a portion other than the edge by amplifying a portion other than the edge while preserving an edge having a sharp change in pixel value. There is a method for emphasizing other parts (for example, Patent Document 1).

In the image signal processing apparatus shown in FIG. 1, the input image signal (pixel value) is input to the ε filter 1 and the subtraction unit 2. The ε filter 1 has an edge larger than a predetermined threshold ε ₁ , for example, an edge as shown in FIG. 2B when an image signal slightly fluctuating across a steep edge as shown in FIG. 2A is input. Is converted into an extracted image signal and output to the subtracting unit 2 and the adding unit 4.

Specific processing of the ε filter 1 will be described with reference to FIGS. 3 and 4. The ε filter 1 sequentially determines each pixel of the input image as the target pixel C, and, as shown in FIG. 3, a plurality of neighboring pixels (in this case, four pixels L2) that are continuous in the horizontal direction with the target pixel C as the center. , L1, R1, R2), and the pixel values of the target pixel C and the plurality of neighboring pixels are set to tap coefficients (eg, {1, 2, 3, 2, 1}) to obtain a conversion result C ′ corresponding to the target pixel C.
C ′ = (1 · L2 + 2 · L1 + 3 · C + 2 · R1 + 1 · R2) / 9
... (1)

However, as shown in FIG. 4, for a neighboring pixel (a neighboring pixel R2 in the case of FIG. 4) whose difference from the pixel value of the target pixel C is larger than a predetermined threshold ε ₁ , the pixel value of the target pixel C is changed. Replace it with something to calculate. That is, in the case of FIG. 4, the following equation (2) is calculated.
C ′ = (1 · L2 + 2 · L1 + 3 · C + 2 · R1 + 1 · C) / 9
... (2)

  The image signal smoothed by the ε filter 1 is also referred to as a structural component of the image signal.

  Returning to FIG. The subtracting unit 2 subtracts the image signal input from the ε filter 1 from the image signal input from the previous stage (the same as the input to the ε filter 1), thereby slightly changing the components other than the structural components of the image signal. The extracted image signal is extracted and output to the amplifying unit 3. The amplification unit 3 amplifies the output of the subtraction unit 2 and outputs the amplified output to the addition unit 4. Note that the component of the image signal that slightly varies other than the structural component is also referred to as an amplitude component of the image signal. The adder 4 adds the image signal in which a part other than the structural component output from the amplifier 3 is amplified and the structural component of the image signal input from the ε filter 1. This addition result is an image signal in which a portion other than the edge is amplified while a steep edge is held.

JP 2001-298621 A

  However, in the above method, the yuv signal (y signal: luminance signal, u signal: (RY) color difference signal), v signal: (BY) color difference signal (where R and B are the three primary color signals of light, respectively) In the case of an image signal consisting of Red and Blue signals)), the signal that can be easily adjusted is only for the y signal, and the adjustment of the uv signal, that is, so-called color correction cannot be easily performed. There was a problem that complicated processing was involved.

  The present invention has been made in view of such circumstances, and in particular, makes it possible to easily perform color correction on an input image signal.

  The first signal processing apparatus of the present invention includes a distance calculation unit that calculates a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space, and a distance calculation unit. Based on the calculated distance, the uv signal correction coefficient calculating means for calculating the correction coefficient of the uv signal, and at least using the uv signal correction coefficient calculated by the uv signal correction coefficient calculating means, the correction amount of the uv signal is calculated. Uv signal correction amount calculation means for calculating, and correction means for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation means.

  The value calculated as the distance between the position in the uv signal of the image signal in the uv space and the position corresponding to the predetermined color in the uv space includes the position in the uv space in the uv signal of the image signal and the uv space. The square root of the sum of the squares of the differences of the u and v components from the position corresponding to the predetermined color in the image, the position in the uv space in the uv signal of the image signal, and the position corresponding to the predetermined color in the uv space The sum of the absolute difference of each of the u and v components, or the u component of the position in the uv space and the position corresponding to a predetermined color in the uv space or v component of the uv signal of the image signal The larger of them can be included.

  The square root of the sum of the squares of the difference between the u component and the v component of the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space, the uv space in the uv signal of the image signal The sum of the absolute differences of the u and v components between the position in the uv space and the position corresponding to the predetermined color in the uv space, or the position in the uv space in the uv signal of the image signal and the predetermined in the uv space The position corresponding to the color of the u component or the v component, whichever is larger, the position in the uv space in the uv signal of the image signal, and the position corresponding to the predetermined color in the uv space A distance setting means for setting the distance of the image signal may be further provided, and the distance calculation means includes the distance set by the distance setting means as the position in the uv space of the uv signal of the image signal and the distance in the uv space. The distance from the position corresponding to the predetermined color It can be made to be calculated.

  A first signal processing method of the present invention includes a distance calculation step of calculating a distance between a position in the uv space in the uv signal of the image signal and a position corresponding to a predetermined color in the uv space, Based on the distance calculated in the process, the uv signal correction coefficient calculation step for calculating the correction coefficient of the uv signal and at least the uv signal correction coefficient calculated in the processing of the uv signal correction coefficient calculation step And a correction step of correcting the uv signal of the image signal based on the uv correction amount calculated in the process of the uv correction amount calculation step. .

  The first recording medium program of the present invention includes a distance calculation control step for controlling calculation of a distance between a position in the uv space in the uv signal of the image signal and a position corresponding to a predetermined color in the uv space; The uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal based on the distance calculated by the distance calculation control step process, and the uv signal calculated by at least the process of the uv signal correction coefficient calculation control step Uv signal correction amount calculation control step for controlling the calculation of the correction amount of the uv signal using the correction coefficient, and the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. And a correction control step for controlling the correction.

  A first program of the present invention includes a distance calculation control step for controlling calculation of a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space, and distance calculation control Uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal based on the distance calculated in the processing of the step, and at least the correction coefficient of the uv signal calculated by the processing of the uv signal correction coefficient calculation control step The uv signal correction amount calculation control step for controlling the calculation of the uv signal correction amount, and the uv correction amount of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. A process including a correction control step for controlling is executed.

  The second signal processing apparatus of the present invention includes a uv signal correction coefficient calculation unit that calculates a correction coefficient of the uv signal based on the y signal of the image signal, and at least the uv signal calculated by the uv signal correction coefficient calculation unit. Uv signal correction amount calculation means for calculating the correction amount of the uv signal using the correction coefficient, and correction means for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation means. It is characterized by providing.

  The uv signal correction coefficient calculation means can calculate the correction coefficient of the uv signal by a function using the y signal of the image signal as an argument.

  A function setting means for setting any one of the plurality of functions may be further provided, and the uv signal correction coefficient calculation means may calculate a correction coefficient for the uv signal according to the function set by the function setting means. It can be calculated.

  Nonlinear smoothing means for nonlinearly smoothing the y signal of the image signal can be further provided, and the uv signal correction coefficient calculating means converts the y signal of the image signal nonlinearly smoothed by the nonlinear smoothing means. Based on this, the correction coefficient of the uv signal can be calculated.

  According to the second signal processing method of the present invention, the uv signal correction coefficient calculation step for calculating the correction coefficient of the uv signal based on the y signal of the image signal, and the uv calculated by at least the processing of the uv signal correction coefficient calculation step. Using the signal correction coefficient, the uv signal correction amount calculation step for calculating the correction amount of the uv signal and the uv correction amount calculated in the processing of the uv correction amount calculation step correct the uv signal of the image signal. And a correction step.

  The program of the second recording medium of the present invention includes a uv signal correction coefficient calculation control step for controlling calculation of a uv signal correction coefficient based on the y signal of the image signal, and a process of at least the uv signal correction coefficient calculation control step. Based on the uv correction amount calculated in the processing of the uv signal correction amount calculation control step and the uv correction amount calculation control step for controlling the calculation of the correction amount of the uv signal using the correction factor of the uv signal calculated in And a correction control step for controlling correction of the uv signal of the image signal.

  The second program of the present invention is calculated by the processing of the uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal based on the y signal of the image signal, and at least the processing of the uv signal correction coefficient calculation control step. Uv signal correction amount calculation control step for controlling the calculation of the correction amount of the uv signal using the correction coefficient of the uv signal, and the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. And a correction control step for controlling correction of the uv signal.

  According to a third signal processing apparatus of the present invention, a uv signal correction coefficient calculating unit that calculates a correction coefficient of a uv signal of an image signal based on the image signal, and a correction of the uv signal calculated by the uv signal correction coefficient calculating unit Based on the coefficient, the uv signal correction amount calculation means for calculating the correction amount of the uv signal of the image signal to be corrected in the predetermined correction direction in the uv space, and only the correction amount of the uv signal calculated by the uv correction amount calculation means And correction means for correcting the uv signal of the image signal in a predetermined correction direction in the uv space.

  In the correction direction of the predetermined uv space, the direction to the position in the uv space in the uv signal of the image signal as seen from the position of the origin in the uv space, the position in the uv space as seen from the position of the origin in the uv space. To include either the direction to the position corresponding to the predetermined color or the direction to the position corresponding to the target color in the uv space as seen from the position in the uv space of the uv signal of the image signal can do.

  The direction to the position in the uv space in the uv signal of the image signal as viewed from the position of the origin in the uv space, the direction to the position corresponding to a predetermined color in the uv space from the position of the origin in the uv space Or, in the uv space that corrects the uv signal of the image signal, either the direction to the position corresponding to the target color in the uv space as seen from the position in the uv space of the uv signal of the image signal Correction direction setting means for setting as a predetermined correction direction can be further provided.

  According to a third signal processing method of the present invention, a uv signal correction coefficient calculation step for calculating a correction coefficient of the uv signal of the image signal based on the image signal, and a uv signal calculated by the processing of the uv signal correction coefficient calculation step Uv signal correction amount calculation step for calculating the correction amount of the uv signal of the image signal, which is corrected in a predetermined correction direction in the uv space based on the correction coefficient of uv, and uv calculated by the processing of the uv correction amount calculation step And a correction step of correcting the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the signal.

  The third recording medium program of the present invention includes a uv signal correction coefficient calculation control step for controlling calculation of a uv signal correction coefficient of an image signal based on the image signal, and a process of a uv signal correction coefficient calculation control step. A uv signal correction amount calculation control step for controlling calculation of the correction amount of the uv signal of the image signal, which is corrected in a predetermined correction direction in the uv space based on the calculated correction coefficient of the uv signal, and a uv correction amount calculation And a correction control step for controlling the correction of the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated in the control step process.

  The third program of the present invention is calculated based on the image signal in the process of the uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal of the image signal and the process of the uv signal correction coefficient calculation control step. a uv signal correction amount calculation control step for controlling calculation of a correction amount of the uv signal of the image signal, which is corrected in a predetermined correction direction in the uv space based on the correction coefficient of the uv signal, and a uv correction amount calculation control step A correction control step for controlling correction of the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated in the process is executed.

  The fourth signal processing apparatus of the present invention includes a distance calculation unit that calculates a distance between a position in the uv space in the uv signal of the image signal and a position corresponding to a predetermined color in the uv space, and a distance calculation unit. Based on the calculated distance, a first uv signal correction coefficient calculating means for calculating a first correction coefficient of the uv signal, and a second correction coefficient of the uv signal based on the y signal of the image signal. A second uv signal correction coefficient calculating means; at least a first correction coefficient of the uv signal calculated by the first uv signal correction coefficient calculating means; and a uv signal calculated by the second uv signal correction coefficient calculating means. The uv signal correction amount calculating means for calculating the correction amount of the uv signal of the image signal to be corrected in the predetermined correction direction in the uv space, and the uv correction amount calculating means. The uv signal of the image signal in the predetermined correction direction in the uv space by the correction amount of the uv signal And correction means for correcting the signal.

  In the first signal processing apparatus and method and program of the present invention, the distance between the position in the uv space of the uv signal of the image signal and the position corresponding to a predetermined color in the uv space is calculated and calculated. The correction factor of the uv signal is calculated based on the calculated distance, the correction amount of the uv signal is calculated using at least the calculated correction factor of the uv signal, and the image signal is calculated based on the calculated uv correction amount. The uv signal is corrected.

  In the second signal processing apparatus and method and the program of the present invention, a correction coefficient of the uv signal is calculated based on the y signal of the image signal, and at least the uv signal is calculated using the calculated correction coefficient of the uv signal. The correction amount is calculated, and the uv signal of the image signal is corrected based on the calculated uv correction amount.

  In the third signal processing apparatus and method and program of the present invention, the correction coefficient of the uv signal of the image signal is calculated based on the image signal, and the uv space is calculated based on the calculated correction coefficient of the uv signal. The correction amount of the uv signal of the image signal to be corrected in the predetermined correction direction is calculated, and the uv signal of the image signal is corrected in the predetermined correction direction in the uv space by the calculated correction amount of the uv signal.

  In the fourth signal processing device of the present invention, the distance between the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space is calculated, and based on the calculated distance. A first correction factor of the uv signal is calculated, a second correction factor of the uv signal is calculated based on the y signal of the image signal, and at least calculated with the first correction factor of the calculated uv signal The correction amount of the uv signal of the image signal to be corrected in the predetermined correction direction in the uv space is calculated using the second correction coefficient of the uv signal, and the calculated correction amount of the uv signal is calculated in the uv space. The uv signal of the image signal is corrected in the predetermined correction direction.

  The signal processing apparatus of the present invention may be an independent apparatus or a block that performs signal processing.

  According to the present invention, it is possible to easily perform color correction on an input image signal.

  Embodiments of the present invention will be described below. The correspondence relationship between the invention described in this specification and the embodiments of the invention is exemplified as follows. This description is intended to confirm that the embodiments supporting the invention described in this specification are described in this specification. Therefore, although there is an embodiment which is described in the embodiment of the invention but is not described here as corresponding to the invention, it means that the embodiment is not It does not mean that it does not correspond to the invention. Conversely, even if an embodiment is described herein as corresponding to an invention, that means that the embodiment does not correspond to an invention other than the invention. Absent.

  Further, this description does not mean all the inventions described in this specification. In other words, this description is for the invention described in the present specification, which is not claimed in this application, that is, for the invention that will be applied for in the future or that will appear and be added by amendment. It does not deny existence.

  That is, the first signal processing apparatus of the present invention is a distance calculation means (for example, a diagram) for calculating the distance between the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space. 5 distance calculation unit 21a), uv signal correction coefficient calculation means (for example, correction coefficient calculation unit 21b in FIG. 5) for calculating a correction coefficient of the uv signal based on the distance calculated by the distance calculation means, The uv signal correction amount calculation means (for example, the u direction correction amount calculation unit 23 in FIG. 5, the v direction correction) calculates the correction amount of the uv signal using the correction coefficient of the uv signal calculated by the uv signal correction coefficient calculation means. And a correction unit (for example, adders 25 and 26 in FIG. 5) for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation unit. Features.

  The square root of the sum of the squares of the difference between the u component and the v component of the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space, the uv space in the uv signal of the image signal The sum of the absolute differences of the u and v components between the position in the uv space and the position corresponding to the predetermined color in the uv space, or the position in the uv space in the uv signal of the image signal and the predetermined in the uv space The position corresponding to the color of the u component or the v component, whichever is larger, the position in the uv space in the uv signal of the image signal, and the position corresponding to the predetermined color in the uv space The distance setting means (for example, the uv gain correction coefficient calculation method setting section 28 in FIG. 5) can be further provided as the distance, and the distance calculation means includes the distance set by the distance setting means, In the uv space in the uv signal of the image signal And location, can be adapted to calculate as the distance between the position corresponding to a predetermined color in uv space.

  In the first signal processing method of the present invention, a distance calculation step for calculating a distance between a position in the uv space in the uv signal of the image signal and a position corresponding to a predetermined color in the uv space (for example, FIG. 18). Steps S83, S85, and S86 of the flowchart) and a uv signal correction coefficient calculation step for calculating a correction coefficient of the uv signal based on the distance calculated in the distance calculation step (for example, the step of the flowchart of FIG. 18). Uv signal correction amount calculating step (for example, calculating the correction amount of the uv signal using the correction coefficient of the uv signal calculated at least in the processing of the uv signal correction coefficient calculating step) (for example, the processing of S88, S90, S92, S93) 27, the processing in steps S133, S135, and S136 in the flowchart of FIG. 27 and the uv correction amount calculated in the uv correction amount calculation step processing. And a correction step for correcting the uv signal of the signal (for example, the process of step S35 in the flowchart of FIG. 12).

  The second signal processing apparatus of the present invention includes a uv signal correction coefficient calculation unit (for example, a luminance gain correction coefficient calculation unit 22 in FIG. 5) that calculates a correction coefficient of the uv signal based on the y signal of the image signal, Uv signal correction amount calculation means for calculating the correction amount of the uv signal using at least the correction coefficient of the uv signal calculated by the uv signal correction coefficient calculation means (for example, the u direction correction amount calculation unit 23, v direction in FIG. 5). A correction amount calculation unit 24) and correction means (for example, adders 25 and 26 in FIG. 5) for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation means. It is characterized by.

  Function setting means for setting any one of the plurality of functions (for example, the uv gain correction coefficient calculation method setting unit 28 in FIG. 5) can be further provided, and the uv signal correction coefficient calculation means includes: The correction coefficient of the uv signal can be calculated by a function set by the function setting means and using the y signal of the image signal as an argument.

  Nonlinear smoothing means (for example, the adders 25 and 26 in FIG. 5) for nonlinearly smoothing the y signal of the image signal can be further provided, and the uv signal correction coefficient calculating means includes nonlinear smoothing means. Thus, the correction coefficient of the uv signal can be calculated based on the y signal of the image signal that has been nonlinearly smoothed.

  The second signal processing method of the present invention is a uv signal correction coefficient calculation step for calculating a correction coefficient of the uv signal based on the y signal of the image signal (for example, the processing of steps S112, S114, and S115 in the flowchart of FIG. 23). ) And at least the uv signal correction coefficient calculated in the process of the uv signal correction coefficient calculation step, the uv signal correction amount calculation step (for example, step S133 in the flowchart of FIG. 27) calculates the correction amount of the uv signal. S135 and S136), and a correction step for correcting the uv signal of the image signal based on the uv correction amount calculated in the uv correction amount calculation step (for example, the process in step S35 in the flowchart of FIG. 12), It is characterized by including.

  The third signal processing apparatus of the present invention is a uv signal correction coefficient calculation unit (for example, the correction coefficient calculation unit 21b in FIG. 5 or the luminance gain) that calculates the correction coefficient of the uv signal of the image signal based on the image signal. Based on the correction coefficient of the uv signal calculated by the correction coefficient calculation unit 22) and the uv signal correction coefficient calculation means, uv for calculating the correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space. The signal correction amount calculation means (for example, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 in FIG. 5) and the uv signal correction amount calculated by the uv correction amount calculation means are predetermined in the uv space. And correction means (for example, adders 25 and 26 in FIG. 5) for correcting the uv signal of the image signal in the correction direction.

  The direction to the position in the uv space in the uv signal of the image signal as viewed from the position of the origin in the uv space, the direction to the position corresponding to a predetermined color in the uv space from the position of the origin in the uv space Or, in the uv space that corrects the uv signal of the image signal, either the direction to the position corresponding to the target color in the uv space as seen from the position in the uv space of the uv signal of the image signal Correction direction setting means (for example, a direction correction amount calculation method setting unit 30 in FIG. 5) for setting as a predetermined correction direction can be further provided.

  In the third signal processing method of the present invention, a uv signal correction coefficient calculation step (for example, steps S88, S90, S92, and S93 in the flowchart of FIG. 18) for calculating a correction coefficient of the uv signal of the image signal based on the image signal. And a uv signal for calculating a correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space based on the correction coefficient of the uv signal calculated in the process of the uv signal correction coefficient calculation step. In the predetermined correction direction in the uv space, only the correction amount of the uv signal calculated by the correction amount calculation step (for example, the processing of steps S133, S135, and S136 in the flowchart of FIG. 27) and the uv correction amount calculation step. And a correction step of correcting the uv signal of the image signal (for example, the process of step S35 in the flowchart of FIG. 12).

  The fourth signal processing apparatus of the present invention is a distance calculation means for calculating the distance between the position in the uv space of the uv signal of the image signal and the position corresponding to a predetermined color in the uv space (for example, FIG. 5). Based on the distance calculation unit 21a) and the distance calculated by the distance calculation unit, the first uv signal correction coefficient calculation unit (for example, the correction coefficient calculation unit 21b of FIG. 5) that calculates the first correction coefficient of the uv signal. ), A second uv signal correction coefficient calculation unit (for example, the luminance gain correction coefficient calculation unit 22 in FIG. 5) that calculates a second correction coefficient of the uv signal based on the y signal of the image signal, and at least a first Uv space using the first correction coefficient of the uv signal calculated by the one uv signal correction coefficient calculation means and the second correction coefficient of the uv signal calculated by the second uv signal correction coefficient calculation means. The amount of correction of the uv signal of the image signal is corrected in the predetermined correction direction. The uv signal is calculated by the uv signal correction amount calculated by the uv signal correction amount calculation means (for example, the u direction correction amount calculation unit 23 and the v direction correction amount calculation unit 24 in FIG. 5) and the uv correction amount calculation means. And correction means (for example, adders 25 and 26 in FIG. 5) for correcting the uv signal of the image signal in a predetermined correction direction.

  Since the correspondence relationship regarding the invention of the recording medium and the program is the same as that of the signal processing method, the description thereof is omitted.

  FIG. 5 is a diagram showing a configuration of an embodiment of the color correction processing apparatus 11 to which the present invention is applied.

  The color correction processing device 11 converts the image signal composed of the yuv signal into an RGB signal (Red Green Blue) and corrects and outputs the color so that Green is displayed more clearly. In the following description, the process for correcting the color of Green more clearly is particularly referred to as a green enhancement process.

Based on the calculation method set by the uv gain correction coefficient calculation method setting unit 28, the uv gain correction coefficient calculation unit 21 calculates uv based on the u signal u _in and the v signal v _in of the input image signals. The gain correction coefficient is calculated, and the calculation result is output to the luminance gain correction coefficient calculation unit 22. More specifically, the distance calculation unit 21a of the uv gain correction coefficient calculation unit 21 obtains the position (u _in , v _in ) of the input u signal u _in and v signal v _{in in} the uv space, and in the uv space. , The distance r ₁ from the position (u _cent , v _cent ) corresponding to Green of the RGB signal is obtained, and the information is supplied to the correction coefficient calculation unit 21b. The correction coefficient calculation unit 21b obtains a uv gain correction coefficient G _uv necessary for the green enhancement process according to the distance information supplied from the distance calculation unit 21a, and supplies it to the luminance gain correction coefficient calculation unit 22.

The luminance gain correction coefficient calculation unit 22 is a y signal (of the yuv signal) subjected to nonlinear smoothing processing by the nonlinear smoothing processing unit 27 based on the calculation method set by the luminance gain correction coefficient calculation method setting unit 29. Luminance signal) A coefficient necessary for green enhancement processing corresponding to y _in is obtained, multiplied by the uv gain correction coefficient G _uv supplied from the uv gain correction coefficient calculation unit 21, and corrected in the u direction as the luminance gain correction coefficient G _y. The amount is supplied to the amount calculator 23 and the v direction correction amount calculator 24.

Based on the calculation method set by the direction correction amount calculation method setting unit 30, the u direction correction amount calculation unit 23 calculates the green color from the luminance gain correction coefficient G _y supplied from the luminance gain correction coefficient calculation unit 22 and the u signal. A correction amount u _c in the u direction in the uv space necessary for the enhancement processing is calculated and output to the adder 26.

v direction correction amount calculating unit 24 based on the calculation method set by the direction correction amount calculating method setting unit 30, from the brightness gain correction coefficient G _y and v signal supplied from the brightness gain correction coefficient calculating section 22, green A correction amount v _c in the v direction in the uv space necessary for the enhancement processing is calculated and output to the adder 25.

The adder 25 and 26, the v direction correction amount v _c supplied from the v direction correction amount calculating unit 24 and the u direction correction amount calculating unit 23, respectively and the u-direction correction quantity u _c, input v signal v _in And the u signal u _in are added to each other, and the corrected v signal v _out and u signal u _out are output to a downstream device (not shown).

  The non-linear smoothing processing unit 27 performs non-linear smoothing processing on the y signal that is an input luminance signal, supplies the y signal to the luminance gain correction coefficient calculation unit 22, and outputs it to a subsequent device (not shown). Details of the nonlinear smoothing processing unit 27 will be described later with reference to FIG.

The uv gain correction coefficient calculation method setting unit 28 is input by the user operating an unillustrated input device or the like. The calculation method and initial values necessary for calculating the uv gain correction coefficient in the uv gain correction coefficient calculation unit 21 Remember. More specifically, the uv gain correction coefficient calculation method setting unit 28 determines the center position (u _cent , v) of the region corresponding to Green of the RGB signal (hereinafter also referred to as Green region) in the uv space that is the correction amount region. _cent ), Green region radius r ₀ , reference constant G ₀ used to calculate the uv gain correction coefficient, distance calculation mode mode-r, and uv gain correction coefficient calculation mode mode-g These set values are stored and supplied to the uv gain correction coefficient calculation unit 21 as necessary.

Distance calculation mode mode-r, when finding the u signal u _in a v signal v _in input, the center position of the Green region of RGB signals in the uv space (u _cent, v _cent) the distance r ₁ between the This mode sets the calculation method. More specifically, the distance calculation mode mode-r can set any of mode-r = 1 to 3, and the set value is stored. The distance between the input u signal u _in and v signal v _{in in} each mode of mode-r = mode 1 to 3 and the center position (u _cent , v _cent ) of the _green region of the RGB signal in the uv space. Details of the calculation method will be described later.

The uv gain correction coefficient calculation mode mode-g is the relationship between the input u signal u _in and v signal v _in and the center position (u _cent , v _cent ) of the region corresponding to Green of the RGB signal in the uv space. than the distance r ₁ is a mode for setting a method of calculating the brightness gain correction coefficient G _y. More specifically, the uv gain correction coefficient calculation mode mode-g can be set to any of mode-g = mode 1 to 3, and the set value is stored. The distance r between the input u signal u _in and v signal v _{in in} each mode of mode-g = 1 to 3 and the center position (u _cent , v _cent ) of the _green region of the RGB signal in the uv space. _The method for calculating the luminance gain correction coefficient G _uv from ₁ will be described in detail later.

The luminance gain correction coefficient calculation method setting unit 29 executes a process of setting the luminance gain correction coefficient calculation mode mode-y that sets the calculation method of the luminance gain correction coefficient G _y based on the input y signal y _in. At the same time, the set luminance gain correction coefficient calculation mode mode-y is stored and supplied to the luminance gain correction coefficient calculation unit 22 as necessary. More specifically, the luminance gain correction coefficient calculation mode mode-y can set any of mode-y = 1 to 3, and the set value is stored. The method of calculating the luminance gain correction coefficient G _y from the input y signal y _{in in} each mode of mode-y = mode 1 to 3 will be described in detail later.

The direction correction amount calculation method setting unit 30 is based on the luminance gain correction coefficient G _y and is calculated in the u direction correction amount calculation unit 23 and the v direction correction amount calculation unit 24 in the uv space necessary for green enhancement processing. Direction correction amount calculation mode mode-d for setting the calculation method of the correction amount v _{c in the} v direction and the correction amount u _{c in} the u direction, and the target position (u ₂ , v ₂₎ consisting of the target value of the uv signal ) Is set, and the set value is stored. More specifically, the direction correction amount calculation mode mode-d can be set to any of mode-d = mode 1 to 3, and the set value is stored. The calculation method of the correction amount v _c in the v direction and the correction amount u _{c in} the u direction in the uv space necessary for the green enhancement processing in each mode of mode-d = 1 to 3 will be described in detail later. .

The target position (u ₂ , v ₂ ) consisting of the target value of the uv signal is the position _in the uv space of the input u signal u _in and v signal v _in when calculating the uv correction amount (u _in , v _in ) is information for indicating a correction direction in the uv space. The method of calculating the correction amount v _c in the v direction and the correction amount u _{c in} the u direction in the uv space using the target position (u ₂ , v ₂ ) will be described in detail later.

  Next, a detailed configuration of the nonlinear smoothing processing unit 27 will be described with reference to FIG.

The non-linear filter 51 of the non-linear smoothing processing unit 27 holds a steep edge whose size is larger than the threshold ε ₁ among the fluctuations of the pixels constituting the input y signal y _in, and a portion other than the edge the smoothed outputs the image signal y _F smoothed to the mixing unit 52.

The mixing ratio detection unit 53 calculates the mixing ratio based on a minute change among the fluctuations of the pixels constituting the input image signal y _in and supplies it to the mixing unit 52.

The mixing unit 52 mixes the smoothed image signal y _F and the unsmoothed input image signal y _in based on the mixing ratio supplied from the mixing ratio detection unit 53, and performs nonlinear smoothing. _Is output as a processed image signal y _out .

An LPF (Low Pass Filter) 61 of the non-linear filter 51 is based on a control signal supplied from the control signal generator 62, and a horizontal processing direction component pixel that is two pixels adjacent to the left and right in the horizontal direction. using the pixel values, to smooth the pixel of interest, and outputs the image signal y _F smoothed to the mixing unit 52. The control signal generator 62 calculates an absolute difference between pixel values of the target pixel and the horizontal processing direction component pixel, generates a control signal for controlling the LPF 61 based on the calculation result, and supplies the control signal to the LPF 61. As the nonlinear filter 51, for example, the above-described conventional ε filter 1 may be used.

  Next, the uv gain correction coefficient calculation method setting process will be described with reference to the flowchart of FIG.

  In step S1, the uv gain correction coefficient calculation method setting unit 28 determines whether or not an input unit (not shown) has been operated to instruct setting of the uv gain correction coefficient calculation method. The process is repeated until setting is instructed. For example, when setting of the uv gain correction coefficient calculation method is instructed, the process proceeds to step S2.

In step S2, the uv gain correction coefficient calculation method setting unit 28 sets the center position (u _cent , v _cent ) of the correction region, the radius r ₀ , the reference constant G ₀ , the distance calculation mode mode-r, and the uv gain correction amount. Display the calculation mode mode-g setting screen.

  In step S3, the uv gain correction coefficient calculation method setting unit 28 determines whether or not an input unit (not shown) has been operated to make a setting, and repeats the process until the setting is made. If it is determined that the setting has been made, the process proceeds to step S4.

In step S4, the uv gain correction coefficient calculation method setting unit 28 operates an input unit (not shown) to set the center position (u _cent , v _cent ), radius r ₀ , reference constant G ₀ , The distance calculation mode mode-r and the uv gain correction coefficient calculation mode mode-g are stored, the process returns to step S1, and the subsequent processes are repeated.

  With the above processing, the uv gain correction coefficient calculation method is set.

Here, the center position (u _cent , v _cent ) and the radius r ₀ will be described.

The uv signal in the region corresponding to Green of the RGB signal is a region where both the u signal and the v signal in the uv space are negative. The green enhancement process is a process of correcting the color of the uv signal in the region corresponding to Green of the RGB signal in the uv space, for example, as shown in FIG. More specifically, the green enhancement process is a process of correcting the uv signal to (u _out , v _out ) by moving the input uv signal (u _in , v _in ) in the direction of the arrow in the figure. . That is, in the uv space, when the origin is the uv space, the color is determined by the angle formed by the coordinates indicating the uv signal with respect to the origin. Furthermore, since the origin is white, the color becomes clear (a clear color) according to the distance from the origin. That is, as shown in FIG. 8, the green enhancement process is a process of correcting the position of the input uv signal in the uv space so as to be away from the origin while maintaining the angle formed with the origin within a predetermined range. It can be said that there is.

However, since green enhancement processing is intended here, it is assumed that the green enhancement processing is performed on the uv signal whose input signal is Green of the RGB signal. That is, it is necessary to set an area in the uv space corresponding to the input signal Green of the RGB signal. Therefore, in the green enhancement processing of the present invention, as shown in FIG. 9, an area (area indicated by a circle in the figure) having a predetermined distance r ₀ from the center position (u _cent , v _cent ) is an input signal. Is defined as a region in the uv space corresponding to Green of the RGB signal for. That is, the green enhancement process is performed only when the uv signal is in this region.

The reference constant G ₀ is a constant used for calculating the uv gain correction coefficient G _uv . Any one of modes 1 to 3 can be set for the distance calculation mode mode-r and the uv gain correction coefficient calculation mode mode-g. The details of the calculation method corresponding to each setting mode will be described later.

  Next, the luminance gain correction coefficient calculation method setting process will be described with reference to the flowchart of FIG.

  In step S11, the luminance gain correction coefficient calculation method setting unit 29 determines whether or not the setting of the luminance gain correction coefficient calculation method is instructed by operating an input unit (not shown). The process is repeated until setting is instructed. For example, when setting of the luminance gain correction coefficient calculation method is instructed, the process proceeds to step S12.

  In step S12, the luminance gain correction coefficient calculation method setting unit 29 displays a setting screen for the luminance gain correction amount calculation mode mode-y.

  In step S13, the luminance gain correction coefficient calculation method setting unit 29 determines whether or not an input unit (not shown) has been operated to make a setting, and repeats the process until the setting is made. If it is determined that the setting has been made, the process proceeds to step S14.

  In step S14, the luminance gain correction coefficient calculation method setting unit 29 operates the input unit (not shown) to store the set luminance gain correction amount calculation mode mode-y, and the process returns to step S11. The subsequent processing is repeated.

  With the above processing, the luminance gain correction coefficient calculation method is set. Note that any one of modes 1 to 3 can be set for the luminance gain correction amount calculation mode mode-y. Details of the calculation method corresponding to each setting mode will be described later.

  Next, the direction correction amount calculation method setting process will be described with reference to the flowchart of FIG.

  In step S21, the direction correction amount calculation method setting unit 30 determines whether or not an input unit (not shown) is operated to instruct setting of the direction correction amount calculation method, and the setting of the direction correction amount calculation method is instructed. The process is repeated until For example, when setting of the direction correction amount calculation method is instructed, the process proceeds to step S22.

In step S22, the direction correction amount calculation method setting unit 30 displays a setting screen for the direction correction amount calculation mode mode-d and, if necessary, the coordinates (u ₂ , v ₂ ) indicating the correction target position.

  In step S23, the direction correction amount calculation method setting unit 30 determines whether or not an input unit (not shown) has been operated to make a setting, and repeats the process until the setting is made. If it is determined that the setting has been made, the process proceeds to step S24.

In step S24, the direction correction amount calculation method setting unit 30 operates the input unit (not shown) to set the direction correction amount calculation mode mode-d, and coordinates (u ₂ , v ₂ ) are stored, and the processing returns to step S 21, and the subsequent processing is repeated.

With the above processing, the direction correction amount calculation method is set. Note that any one of modes 1 to 3 can be set for the direction correction amount calculation mode mode-d. Further, the coordinates (u ₂ , v ₂ ) indicating the correction target position are moved toward the correction target position when the uv signal that is the input signal is subjected to the green enhancement processing in the direction correction amount calculation mode mode-d. Used when calculating the correction amount. Details of the calculation method corresponding to each setting mode will be described later.

  Next, color correction processing will be described with reference to the flowchart of FIG.

In step S31, the non-linear smoothing processing unit 27 executes non-linear smoothing processing on the y signal y _in which is an input luminance signal.

  Here, with reference to the flowchart of FIG. 13, the nonlinear smoothing process by the nonlinear smoothing process part 27 is demonstrated.

  In step S41, the control signal generator 62 of the nonlinear filter 51 calculates the absolute difference between the luminance signal of the target pixel and the luminance signal (luminance value) between the horizontal processing direction component pixels. That is, for example, in the case of FIG. 3, the control signal generation unit 62 calculates the absolute difference in luminance value between the target pixel C and the horizontal processing direction component pixels L2, L1, R1, and R2, which are neighboring pixels adjacent in the horizontal direction. The values | C-L2 |, | C-L1 |, | C-R1 |, and | C-R2 | are calculated.

In step S42, the low-pass filter 61 compares each difference absolute value calculated by the control signal generating unit 62 with a predetermined threshold value ε _2, and nonlinearly applies to the input luminance signal y _in corresponding to the comparison result. Apply filtering processing. More specifically, the low-pass filter 61 corresponds to the target pixel C by performing weighted averaging of the luminance values of the target pixel C and the horizontal processing direction component pixel using a tap coefficient, for example, as in Expression (1). the conversion result C 'to be output to the mixing unit 52 as a smoothed image signal y _F. However, for the horizontal processing direction component pixels whose difference absolute value from the pixel value of the target pixel C is larger than the predetermined threshold value ε ₂ , the luminance value is replaced with the pixel value of the target pixel C and weighted averaging is performed. (For example, calculation is performed as shown in Expression (2)).

  In step S43, a minute edge determination process is executed to determine whether a minute edge exists.

  Here, the minute edge determination processing will be described with reference to the flowchart of FIG.

In step S61, the mixture ratio detection unit 53 calculates a difference absolute value of the luminance value between the target pixel and each horizontal processing direction component pixel, and all the difference absolute values are smaller than the threshold value ε ₃ (<< ε ₂ ). It is determined whether or not it is small. Then, the mixture ratio detection unit 53 determines whether or not a minute edge exists based on the determination result.

That is, for example, as illustrated in FIG. 3, the mixture ratio detection unit 53 determines the absolute value of the difference in luminance value between the target pixel C and the horizontal processing direction component pixels L2, L1, R1, and R2 adjacent in the horizontal direction. Is calculated, and it is determined whether or not each absolute difference value is smaller than the threshold value ε ₃ . When the mixture ratio detection unit 53 determines that the absolute values of all the differences are all smaller than the threshold value ε ₃ , the change between the neighboring pixels and the target pixel is small, and thus the process proceeds to step S64 and the vicinity of the target pixel is reached. Determines that a minute edge does not exist.

On the other hand, in step S61, among the calculated absolute difference value, if it is determined that even one has a threshold epsilon ₃ or more of, the process proceeds to step S62, the mix rate detector 53, one of the left and right of the pixel of interest absolute difference value of the luminance values between the target pixel and the horizontal processing direction component pixels on the side is smaller than all the threshold epsilon _3, and the difference absolute value between the pixel of interest and the horizontal processing direction component pixels of the left and right on the other side of the pixel of interest Are equal to or greater than the threshold value ε ₃ , and it is determined whether or not the positive and negative of the difference between the luminance values of the horizontal processing direction component pixels on the left and right sides of the target pixel and the target pixel match.

That is, the horizontal processing direction component pixels on the left and right sides of the target pixel C are, for example, the pixels L2 and L1 in FIG. 3, and the horizontal processing direction component pixels on the left and right sides of the target pixel C are the pixels in FIG. In the case of R2 and R1, the mixture ratio detection unit 53 has all the absolute differences between the horizontal processing direction component pixels on the left and right sides of the target pixel C and the target pixel C smaller than the threshold ε ₃ , and the target pixel a is C in the horizontal processing direction component pixels R1 of the right and left on the other side, R2 the difference absolute value between the target pixel C are all threshold epsilon ₃ or more and the horizontal processing direction component pixels of the left and right on the other side of the pixel of interest C It is determined whether or not the difference between the luminance values of R1 and R2 and the target pixel C is the same.

  For example, when it is determined that the above condition is satisfied, in step S63, the mixture ratio detection unit 53 determines that a minute edge exists in the vicinity of the target pixel.

  On the other hand, when it is determined in step S62 that the above condition is not satisfied, in step S64, the mixture ratio detection unit 53 determines that there is no minute edge in the vicinity of the target pixel.

For example, if the relationship between the target pixel C and the horizontal processing direction component pixels L2, L1, R1, and R2 is as shown in FIG. 15, the difference absolute value | L2− between the target pixel C and the left horizontal processing direction component pixels L2 and L1. C |, | L1-C | is smaller than the threshold epsilon _3, and the difference absolute value of the horizontal processing of the target pixel C and the right direction component pixels R1, R2 | R1-C | , | R2-C | is threshold epsilon _At least ₃ and the signs of the differences (R1-C) and (R2-C) of the target pixel C and the right horizontal processing direction component pixels R1, R2 match (both are positive in this case). It is determined that a minute edge exists in the vicinity of the pixel C.

Further, for example, when the relationship between the target pixel C and the horizontal processing direction component pixels L2, L1, R1, and R2 is as shown in FIG. 16, the absolute difference between the target pixel C and the left horizontal processing direction component pixels L2 and L1 | L2-C |, | L1- C | is smaller than the threshold epsilon _3, and the difference absolute value of the horizontal processing of the target pixel C and the right direction component pixels R1, R2 | R1-C | , | R2-C | is Although not less than the threshold ε ₃ , the signs of the differences (R1−C) and (R2−C) between the target pixel C and the right horizontal processing direction component pixels R1 and R2 do not match (in this case, positive and negative respectively). Therefore, it is determined that there is no minute edge in the vicinity of the target pixel C.

Further, for example, when the relationship between the target pixel C and the horizontal processing direction component pixels L2, L1, R1, and R2 is as shown in FIG. Are not all smaller than the threshold value ε ₃ , it is determined that no minute edge exists in the vicinity of the target pixel C.

  In this way, after determining whether or not a minute edge exists in the vicinity of the target pixel, the process returns to step S44 in FIG.

When the process of step S43 ends, in step S44, the mixture ratio detection unit 53 determines whether or not the determination result of the minute edge determination process in step S43 is “a minute edge exists in the vicinity of the target pixel C”. Determine. For example, when the determination result by the minute edge determination process is “a minute edge exists in the vicinity of the target pixel C”, in step S45, the mixture ratio detection unit 53 performs the luminance signal subjected to the non-linear filtering process in the horizontal direction. Mix rate Mr- _H , which is a mixing ratio of y _F and input luminance signal y _in , is output to mixing unit 52 as maximum mix rate Mr- _{H max} . The maximum mix rate Mr _{-H max} is the maximum value of the mix rate Mr _-H , that is, the maximum value and minimum value of the luminance value (minimum value and maximum value of the dynamic range of the luminance value that can be expressed by one pixel). Difference absolute value.

In step S <b> 46, the mixing unit 52 receives the input luminance signal y _in and the luminance signal y _F subjected to nonlinear smoothing processing by the nonlinear filter 51 based on the mix rate Mr _−H supplied from the mixing ratio detection unit 53. _Are output as a non-linearly smoothed luminance signal y _out . More specifically, the mixing unit 52 calculates the following expression (3) and synthesizes the input luminance signal y _in and the luminance signal y _F nonlinearly smoothed by the non-linear filter.

y _out = y _in × Mr _−H / Mr _{−H max} + y _F × (1−Mr _−H / Mr _{−H max} )
... (3)
Here, Mr _-H is the Mix rate, and Mr _{-H max} is the maximum value of the Mix rate Mr _-H , that is, the absolute value of the difference between the maximum value and the minimum value of the luminance value (luminance that can be expressed by one pixel) The absolute value of the difference between the minimum value and the maximum value of the dynamic range of the value).

As shown in the equation (3), if the mix rate Mr _−H is large, the weight of the luminance signal y _F processed by the non-linear filter 51 becomes small, and the weight of the input unprocessed image signal y _in becomes small. growing. Conversely, the smaller the Mix rate Mr _-H, i.e., as the difference absolute value of the luminance values between pixels adjacent in the horizontal direction is small, the weight of the luminance signal y _F processed by a nonlinear filter is increased, the input The weight of the unprocessed luminance signal y _in is reduced.

Accordingly, when a minute edge is detected, the mix rate Mr _−H becomes the maximum mix rate Mr _{−H max} , so that the substantially inputted luminance signal y _in is output as it is.

On the other hand, when it is determined in step S44 that “a minute edge does not exist”, in step S47, the mixture ratio detection unit 53 determines the absolute value of the difference in luminance value between the target pixel and each horizontal processing direction component pixel, respectively. The maximum value of the calculated absolute differences is calculated as the mixing rate Mr- _H , which is the mixing ratio, and is output to the mixing unit 52. The process proceeds to step S46.

That is, in the case of FIG. 3, the mixture ratio detection unit 53 determines the absolute value difference | C−L2 |, | C−L1 of the luminance value between the target pixel C and each of the horizontal processing direction component pixels L2, L1, R1, and R2. |, | C−R1 |, | C−R2 | are calculated, and the maximum value among the calculated absolute values of the differences is obtained as a mix rate Mr _−H that is a mixing ratio, and is output to the mixing unit 52.

That is, when there is no minute edge, the luminance signal y _F subjected to nonlinear filtering and the input luminance signal y according to the maximum absolute value of the difference in luminance value between the target pixel and each horizontal processing direction component pixel _in is mixed to generate a luminance signal y _{out that} has been subjected to nonlinear smoothing processing. If there is a minute edge, the input luminance signal y _in is output as it is.

As a result, in the non-linear smoother 32, since minute edge is to be detected the threshold epsilon ₃ as a reference, portions fine edge exists, as well as such is not performed the non-linear smoother, Even for the part where the edge does not exist, since the luminance signal y _F subjected to the nonlinear smoothing process according to the magnitude of the difference absolute value and the input luminance signal y _in are mixed, in particular, It is possible to suppress a situation in which image quality is significantly deteriorated with a simple pattern image or the like composed of minute edges.

  Now, the description returns to the flowchart of FIG.

In step S <b> 32, the uv gain correction coefficient calculation unit 21 executes a uv gain correction coefficient calculation process, calculates the uv gain correction coefficient G _uv , and supplies it to the luminance gain correction coefficient calculation unit 22.

  Here, the uv gain correction coefficient calculation processing will be described with reference to the flowchart of FIG.

In step S81, the distance calculation unit 21a acquires information (u _in , v _in ) of the input uv signal.

  In step S82, the distance calculation unit 21a inquires of the uv gain correction coefficient calculation method setting unit 28 and determines whether or not the distance calculation mode mode-r is mode1. For example, when it is determined that the distance calculation mode mode-r is mode 1, the process proceeds to step S83.

In step S83, the distance calculation unit 21a inquires of the uv gain correction coefficient calculation method setting unit 28, and reads the information of the following formula (4) as the center position (u _cent , v _cent ) and the calculation method. Furthermore, the distance calculation unit 21a calculates the read equation (4), and calculates the calculation result as the center of the region corresponding to the input u signal u _in and v signal v _in and the RGB signal Green in the uv space. The distance r ₁ to the position (u _cent , v _cent ) is supplied to the correction coefficient calculator 21b.

r ₁ = ((u _in −u _cent ) ² + (v _in −v _cent ) ² ) ^1/2
... (4)

  In step S82, for example, when it is determined that the distance calculation mode mode-r is not mode1, the process proceeds to step S84, and the distance calculation unit 21a inquires the uv gain correction coefficient calculation method setting unit 28 to determine the distance calculation mode mode. Determine whether -r is mode2. In step S84, for example, when it is determined that the distance calculation mode mode-r is mode2, the process proceeds to step S85.

In step S85, the distance calculation unit 21a inquires of the uv gain correction coefficient calculation method setting unit 28, and reads the information of the following formula (5) as the center position (u _cent , v _cent ) and the calculation method. Further, the distance calculation unit 21a calculates the read equation (5), and calculates the calculation result as the center of the region corresponding to the input u signal u _in and v signal v _in and the RGB signal Green in the uv space. The distance r ₁ to the position (u _cent , v _cent ) is supplied to the correction coefficient calculator 21b.

r ₁ = | u _in −u _cent | + | v _in −v _cent |
... (5)

In step S84, for example, when it is determined that the distance calculation mode mode-r is not mode2, that is, when the distance calculation mode mode-r is not mode1 or mode2, the mode is mode3, and the process proceeds to step S86. The distance calculation unit 21a inquires of the uv gain correction coefficient calculation method setting unit 28 and reads the information of the following formula (6) as the center position (u _cent , v _cent ) and the calculation method. Furthermore, the distance calculation unit 21a calculates the read equation (6), and calculates the calculation result as the center of the region corresponding to the input u signal u _in and v signal v _in and the RGB signal Green in the uv space. The distance r ₁ to the position (u _cent , v _cent ) is supplied to the correction coefficient calculator 21b.

r ₁ = max {(u _in −u _cent ), (v _in −v _cent )}
... (6)

  Here, max (A, B) indicates that the maximum value of A and B is selected.

That is, corresponding to whether the distance calculation mode mode-r is mode 1 to 3, as shown in FIG. 19, the input u signal u _in and v signal v _in, and the RGB signal in the uv space The calculation method of the distance r _{1 from} the center position (u _cent , v _cent ) of the region corresponding to Green is switched to any one of the equations (4) to (6). As a result, the distance calculation method can have a degree of freedom.

In step S87, the correction coefficient calculation unit 21b inquires of the uv gain correction coefficient calculation method setting unit 28, reads the radius r _{0 of the} Green region, and calculates the radius r ₁ obtained by the process of steps S83, S85, or S86. It is determined whether or not the radius r ₁ is smaller than the radius r ₀ . In step S87, for example, when it is determined that the radius r ₁ is not smaller than the radius r ₀ , the process proceeds to step S88, and the correction coefficient calculation unit 21b sets the uv gain correction coefficient G _uv to 0 and corrects the luminance gain. It outputs to the coefficient calculation part 22. In other words, the fact that the radius r ₁ is not smaller than the radius r ₀ means that the input uv signal is outside the Green region in the uv space, and is not a signal subject to green enhancement processing. Therefore, the uv gain correction coefficient G _uv is set to 0 in order to make the correction amount substantially zero.

In step S87, for example, when it is determined that the radius r ₁ is smaller than the radius r ₀ , that is, when it is determined that the uv signal is the target of the green enhancement process, the process proceeds to step S89.

  In step S89, the correction coefficient calculation unit 21b determines whether or not the uv gain correction coefficient calculation mode mode-g is mode1. For example, when it is determined that the uv gain correction coefficient calculation mode mode-g is mode1, the process proceeds to step S90.

In step S90, the correction coefficient calculation unit 21b inquires of the uv gain correction coefficient calculation method setting unit 28 as a correction coefficient calculation method when the reference constant G ₀ and the uv gain correction coefficient calculation mode mode-g are mode1. The following equation (7) is read out. Then, the correction coefficient calculating unit 21b according to the distance r _1, read calculates the equation (7) to the brightness gain correction coefficient calculating section 22 as uv gain correction coefficient G _uv.

G _uv = G ₀
... (7)

That is, when the uv gain correction coefficient calculation mode mode-g is mode1, the correction coefficient calculation unit 21b sets the uv gain correction coefficient G _uv as the reference constant G ₀ regardless of the distance r ₁ as shown in FIG. Seek to be constant.

  In step S89, for example, when it is determined that the uv gain correction coefficient calculation mode mode-g is not mode1, the process proceeds to step S91, and the correction coefficient calculation unit 21b sets the uv gain correction coefficient calculation mode mode-g to mode2. It is determined whether or not. For example, when it is determined that the uv gain correction coefficient calculation mode mode-g is mode2, the process proceeds to step S92.

In step S92, the correction coefficient calculation unit 21b inquires of the uv gain correction coefficient calculation method setting unit 28 as a correction coefficient calculation method when the reference constant G ₀ and the uv gain correction coefficient calculation mode mode-g are mode2. The following equation (8) is read out. Then, the correction coefficient calculating unit 21b according to the distance r _1, read calculates the equation (8) to the brightness gain correction coefficient calculating section 22 as uv gain correction coefficient G _uv.

G _uv = G ₀ × (1-r ₁ / r ₀ )
... (8)

That is, when the uv gain correction coefficient calculation mode mode-g is mode2, the correction coefficient calculation unit 21b obtains a uv gain correction coefficient G _uv that decreases in proportion to the distance r ₁ as shown in FIG.

In step S91, for example, when it is determined that the uv gain correction coefficient calculation mode mode-g is not mode2, that is, when the uv gain correction coefficient calculation mode mode-g is neither mode1 nor mode2, it is mode3. Therefore, the process proceeds to step S93, and the correction coefficient calculation 21b inquires of the uv gain correction coefficient calculation method setting unit 28, inquires of the uv gain correction coefficient calculation method setting unit 28, and determines the reference constant G ₀ and the uv gain correction coefficient. As a correction coefficient calculation method when the calculation mode mode-g is mode 3, the following equation (9) is read. Then, the correction coefficient calculating unit 21b according to the distance r _1, read calculates the equation (9) to the brightness gain correction coefficient calculating section 22 as uv gain correction coefficient G _uv.

G _uv = G ₀ × (1- (r ₁ / r ₀ ) ² )
... (9)

That is, when the uv gain correction coefficient calculation mode mode-g is mode 3, the correction coefficient calculation unit 21b decreases the uv gain correction coefficient G, which decreases in proportion to (r ₁ / r ₀ ) ² as shown in FIG. _Ask for _uv .

By switching the uv gain correction coefficient calculation mode mode-g through the above processing, the uv gain correction coefficient G _uv can be obtained by various kinds of calculation methods. In the above description, the distance calculation mode “mode-r” and the uv gain correction coefficient calculation mode “mode-g” have been described as being able to set modes 1 to 3, respectively. You may do it.

  Here, it returns to the flowchart of FIG.

  In step S32, the uv gain correction coefficient calculation process is executed. When the uv gain correction coefficient is calculated, the process proceeds to step S33, and the luminance gain correction coefficient calculation unit 22 executes the luminance gain correction coefficient calculation process. Then, the luminance gain correction coefficient Gy is calculated and output to the u direction correction amount calculator 23 and the v direction correction amount calculator 24.

  Here, the luminance gain correction coefficient calculation processing will be described with reference to the flowchart of FIG.

  In step S111, the luminance gain correction coefficient calculation unit 22 inquires of the luminance gain correction coefficient calculation method setting unit 29 and determines whether or not the luminance gain correction coefficient calculation mode mode-y is mode1. For example, when it is determined that the luminance gain correction coefficient calculation mode mode-y is mode1, the process proceeds to step S112.

In step S112, the luminance gain correction coefficient calculation unit 22 inquires of the luminance gain correction coefficient calculation method setting unit 29, and uses the following formula as a luminance gain correction coefficient calculation method when the luminance gain correction coefficient calculation mode mode-y is mode1. Read (10). Then, the luminance gain correction coefficient calculation unit 22 reads out based on the luminance signal y supplied from the nonlinear smoothing processing unit 27 and the uv gain correction coefficient G _uv supplied from the uv gain correction coefficient calculation unit 21. It calculates the equation (10), u direction correction amount calculating section 23 as the brightness gain correction coefficient G _y, and, v and outputs a direction correction amount calculation unit 24.

G _y = G _uv × f ₀ (y)
f ₀ (y) = y / y _max
(10)

Here, y _max is the maximum luminance value. That is, when the luminance gain correction coefficient calculation mode mode-y is mode 1, the luminance gain correction coefficient calculation unit 22 makes the luminance gain correction coefficient G _y proportional to the luminance value y as shown in FIG. calculate.

  If it is determined in step S111 that the luminance gain correction coefficient calculation mode mode-y is not mode1, the process proceeds to step S113, and the luminance gain correction coefficient calculation mode 22 is mode2. It is determined whether or not. For example, when it is determined that the luminance gain correction coefficient calculation mode mode-y is mode2, the process proceeds to step S114.

In step S114, the luminance gain correction coefficient calculation unit 22 inquires of the luminance gain correction coefficient calculation method setting unit 29, and uses the following formula as a luminance gain correction coefficient calculation method when the luminance gain correction coefficient calculation mode mode-y is mode2. Read (11). Then, the luminance gain correction coefficient calculation unit 22 reads out based on the luminance signal y supplied from the nonlinear smoothing processing unit 27 and the uv gain correction coefficient G _uv supplied from the uv gain correction coefficient calculation unit 21. It calculates the equation (11), u direction correction amount calculating section 23 as the brightness gain correction coefficient G _y, and, v and outputs a direction correction amount calculation unit 24.

G _y = G _uv × f ₁ (y)
f ₁ (y) = (y / y _max ) ²
(11)

That is, when the brightness gain correction coefficient calculation mode mode-y is mode2, brightness gain correction coefficient calculating section 22, as shown in Figure 25, the proportional brightness gain correction coefficient G _y are relative to the square of the luminance value y Calculate as you want.

In step S113, for example, when it is determined that the luminance gain correction coefficient calculation mode mode-y is not mode2, that is, when the luminance gain correction coefficient calculation mode mode-y is neither mode1 nor mode2, it is mode3. Therefore, the process proceeds to step S115, and the luminance gain correction coefficient calculation unit 22 inquires of the luminance gain correction coefficient calculation method setting unit 29 as a luminance gain correction coefficient calculation method when the luminance gain correction coefficient calculation mode mode-y is mode3. The following equation (12) is read out. Then, the luminance gain correction coefficient calculation unit 22 reads out based on the luminance signal y supplied from the nonlinear smoothing processing unit 27 and the uv gain correction coefficient G _uv supplied from the uv gain correction coefficient calculation unit 21. It calculates the equation (12), u direction correction amount calculating section 23 as the brightness gain correction coefficient G _y, and, v and outputs a direction correction amount calculation unit 24.

G _y = G _uv × f ₂ (y)
f ₂ (y) = (y / y _max ) ^1/2
(12)

That is, when the luminance gain correction coefficient calculation mode mode-y is mode 3, the luminance gain correction coefficient calculation unit 22 determines that the luminance gain correction coefficient G _y is 1/2 of the luminance value y as shown in FIG. To be proportional.

Further, as shown in the above equations (10) to (12), the luminance gain correction coefficient includes the uv gain correction coefficient G _uv , and the luminance gain correction coefficient G _y is strictly Can be said to be a coefficient including both luminance gain correction and uv gain correction. Therefore, when only the uv gain correction coefficient is used, it can be realized by setting f _n (y) to 1. Further, when it is desired that the luminance gain correction coefficient does not include an element of the uv gain correction coefficient, it can be realized by setting the uv gain correction coefficient G _uv to 1.

By the above processing, by switching the brightness gain correction coefficient calculation mode mode-y, it is possible to obtain the luminance gain correction coefficient G _y in various types of calculation method. In the above description, the luminance gain correction coefficient calculation mode mode-y has been described for the case where modes 1 to 3 can be set, but a mode number greater than that may be set. However, the function f _n (y) needs to be a function that monotonously increases with a change in the luminance value y.

  Now, the description returns to the flowchart of FIG.

In step S33, when the luminance gain correction coefficient calculation process is executed and the luminance gain correction coefficient _Gy is calculated, the process proceeds to step S34, where the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 Each direction correction amount calculation process is executed.

  Here, the direction correction amount calculation processing will be described with reference to the flowchart of FIG.

In step S131, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 each acquire information (u _in , v _in ) of the input uv signal.

  In step S132, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 make an inquiry to the direction correction amount calculation method setting unit 30, respectively, and whether or not the direction correction amount calculation mode mode-d is mode1. Determine whether. For example, when it is determined that the direction correction amount calculation mode mode-d is mode1, the process proceeds to step S133.

In step S133, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 make an inquiry to the direction correction amount calculation method setting unit 30, respectively, and the direction correction amount calculation mode mode-d is mode 1. As a direction correction amount calculation method, the following equation (13) is read, and equation (13) is calculated based on the luminance gain correction coefficient _Gy and the input u signal u _in and v signal v _in (u direction). The correction amount calculator 23 calculates the upper equation of the equation (13), and the v-direction correction amount calculator 24 calculates the lower equation of the equation (13)), and the correction amount u _c of the u signal that is the operation result , And the correction amount v _c of the v signal is supplied to the adders 26 and 25, respectively.

u _c = G _y × u _in
v _c = G _y × v _in
... (13)

  In step S132, for example, when it is determined that the direction correction amount calculation mode mode-r is not mode1, the process proceeds to step S134, where the u direction correction amount calculation unit 23 and the v direction correction amount calculation unit 24 The correction amount calculation method setting unit 30 is inquired to determine whether or not the direction correction amount calculation mode mode-d is mode2. In step S134, for example, when it is determined that the direction correction amount calculation mode mode-d is mode2, the process proceeds to step S135.

In step S135, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 make an inquiry to the direction correction amount calculation method setting unit 30, respectively, and the direction correction amount calculation mode mode-d is mode2. As a direction correction amount calculation method, the following equation (14) is read out, and based on the u signal u _cent and the v signal v _{cent at} the center position of the region corresponding to the luminance gain correction coefficient G _y and Green, the equation (14) (The u-direction correction amount calculation unit 23 calculates the upper expression of the equation (14) and the v-direction correction amount calculation unit 24 calculates the lower expression of the equation (14)), and u A signal correction amount u _c and a v signal correction amount v _c are supplied to adders 26 and 25, respectively.

u _c = G _y × u _cent
v _c = G _y × v _cent
(14)

In step S134, for example, when it is determined that the direction correction amount calculation mode mode-d is not mode2, that is, when the direction correction amount calculation mode mode-d is neither mode1 nor mode2, it is mode3. In step S136, the u-direction correction amount calculation unit 23 and the v-direction correction amount calculation unit 24 make inquiries to the direction correction amount calculation method setting unit 30, respectively, and the direction correction amount calculation mode mode-d is mode3. As a method of calculating the amount of direction correction, the equation (15) is read, and the equation (15) is calculated based on the luminance gain correction coefficient G _y and the input u signal u _in and v signal v _in (u direction correction). The amount calculation unit 23 calculates the upper expression of the equation (15), and the v-direction correction amount calculation unit 24 calculates the lower expression of the equation (15)), and the u signal correction amount u _c , which is the operation result, and, v signal correction amount v _c adders 26,2 Supplied to.

u _c = G _y × (u ₂ −u _in )
v _c = G _y × (v ₂ −v _in )
(15)

  Now, the description returns to the flowchart of FIG.

In step S35, the adders 26 and 25 respectively calculate the u signal correction amount u _c and the v signal correction amount v _c supplied from the u direction correction amount calculation unit 23 and the v direction correction amount calculation unit 24, respectively. Are added to the input u signal and v signal, and u signal u _out and v signal v _out obtained by correcting the u signal and v signal are output.

For example, if the direction correction amount calculation mode mode-d is mode1, the u signal u _out and the v signal v corrected from the calculation result of the equation (13) as indicated by the following equation (16): _out is output.

u _out = u _in + u _c = u _in + G _y × u _in
v _out = v _in + v _c = v _in + G _y × v _in
... (16)

As a result, when the direction correction amount calculation mode mode-d is mode1, as shown in FIG. 28, the input uv signals (u _in , v _in ) and (u ′ _in , v ′ _in ) are , Corrected to (u _out , v _out ) and (u ′ _out , v ′ _out ), respectively, and output. That is, _in the direction on a straight line connecting the input uv signals (u _in , v _in ) and (u ' _in , v' _in ) with the origin of the uv space, and from the input uv signal , It is corrected to a position in the uv space that is G _y times the distance between the input uv signal and the origin. Therefore, color correction can be performed while maintaining the relationship between the input uv signal and the uv space.

For example, when the direction correction amount calculation mode mode-d is mode2, the corrected u signal u _out and the v signal v as shown in the following expression (17) are calculated from the calculation result of the expression (14). _out is output.

u _out = u _in + u _c = u _in + G _y × u _cent
v _out = v _in + v _c = v _in + G _y × v _cent
... (17)

As a result, when the direction correction amount calculation mode mode-d is mode 2, as shown in FIG. 29, the input uv signals (u _in , v _in ) and (u ′ _in , v ′ _in ) are , Corrected to (u _out , v _out ) and (u ′ _out , v ′ _out ), respectively, and output. That is, from the viewpoint of (u _in , v _in ) and (u ' _in , v' _in ) that are input uv signals, _in the direction connecting the origin of uv space and the center position (u _cent , v _cent ) of the Green region and, viewed from the input uv signal is corrected to the position of the G _y times the uv space distance of the input uv signals and the origin. Therefore, it is possible to correct the input uv signal so as to maintain the relationship between the origin of the uv space and the center position of the Green region.

Further, for example, when the direction correction amount calculation mode mode-d is mode 3, the corrected u signal u _out and the v signal v as shown in the following expression (18) are calculated from the calculation result of the expression (15). _out is output.

u _out = u _in + u _c = u _in + G _y × (u ₂ −u _in )
v _out = v _in + v _c = v _in + G _y × (v ₂ −v _in )
... (18)

As a result, when the direction correction amount calculation mode mode-d is mode 3, as shown in FIG. 30, the input uv signals (u _in , v _in ) and (u ′ _in , v ′ _in ) are , Corrected to (u _out , v _out ) and (u ′ _out , v ′ _out ), respectively, and output. That is, in view of the input uv signals (u _in , v _in ) and (u ' _in , v' _in ), the direction is connected to the target position (u ₂ , v ₂ ) in the uv space, and viewed from the uv signal is corrected to the position of the G _y times the uv space distance of the input uv signals and the origin. Therefore, it is possible to perform color correction so as to approach the target color.

  In the color correction processing apparatus 11 described above, an example of performing green enhancement processing has been described. However, not only color correction for sharpening Green but also other colors are corrected by a similar method. Can be. However, when the RGB signal is expressed as a yuv signal, since the weight of the luminance value y is large in Green, it is considered that color correction considering the luminance value y has the greatest effect in the green enhancement processing. .

  In the above, the Green region, that is, the region for setting the uv signal to be subjected to color correction is a circular position within the range of the center position and a predetermined distance from the center position. Although the case of setting has been described, the shape may be a shape other than a circle, for example, a polygon.

  As described above, the distance calculation mode, the uv gain correction coefficient calculation mode, the luminance gain correction coefficient calculation mode, and the direction correction amount calculation mode can be changed and set for various directions in the uv space. Color correction can be performed easily.

  The series of processes described above can be executed by hardware, but can also be executed by software. When a series of processes is executed by software, a program constituting the software may execute various functions by installing a computer incorporated in dedicated hardware or various programs. For example, it is installed from a recording medium in a general-purpose personal computer or the like.

  FIG. 31 shows a configuration of an embodiment of a personal computer when the electrical internal configuration of the color correction processing apparatus 11 of FIG. 5 is realized by software. The CPU 101 of the personal computer controls the overall operation of the personal computer. Further, when an instruction is input from the input unit 106 such as a keyboard or a mouse from the user via the bus 104 and the input / output interface 105, the CPU 101 is stored in a ROM (Read Only Memory) 102 correspondingly. Run the program. Alternatively, the CPU 101 reads a program read from the magnetic disk 121, the optical disk 122, the magneto-optical disk 123, or the semiconductor memory 124 connected to the drive 110 and installed in the storage unit 108 into a RAM (Random Access Memory) 103. To load and execute. Thereby, the function of the color correction processing apparatus 11 in FIG. 5 described above is realized by software. Further, the CPU 101 controls the communication unit 109 to communicate with the outside and exchange data.

  As shown in FIG. 31, the recording medium on which the program is recorded is distributed to provide the program to the user separately from the computer, and a magnetic disk 121 (including a flexible disk) on which the program is recorded, By a package medium composed of an optical disk 122 (including compact disc-read only memory (CD-ROM), DVD (digital versatile disk)), a magneto-optical disk 123 (including MD (mini-disc)), or a semiconductor memory 124 In addition to being configured, it is configured by a ROM 102 on which a program is recorded and a hard disk included in the storage unit 108 provided to the user in a state of being preinstalled in a computer.

  In this specification, the step of describing the program recorded on the recording medium is not limited to the processing performed in time series in the order described, but of course, it is not necessarily performed in time series. Or the process performed separately is included.

It is a block diagram which shows the structural example of the image signal processing apparatus which emphasizes parts other than an edge in the state which preserve | saved the steep edge in an image. It is a figure which shows the image signal input into the epsilon filter of FIG. 1, and the output image signal. It is a figure which shows an example of the tap used with the epsilon filter of FIG. It is a figure for demonstrating operation | movement of the epsilon filter of FIG. It is a block diagram which shows the structure of one Embodiment of the color correction processing apparatus to which this invention is applied. It is a block diagram which shows the structure of the nonlinear smoothing process part of FIG. It is a flowchart explaining the uv gain correction coefficient calculation method setting process. It is a figure explaining the uv gain correction coefficient calculation method setting process. It is a figure explaining the uv gain correction coefficient calculation method setting process. It is a flowchart explaining a luminance gain correction coefficient calculation method setting process. It is a flowchart explaining a direction correction amount calculation method setting process. It is a flowchart explaining a color correction process. It is a flowchart explaining the nonlinear smoothing process of FIG. It is a flowchart explaining the minute edge determination process of FIG. It is a figure explaining the minute edge determination processing of FIG. It is a figure explaining the minute edge determination processing of FIG. It is a figure explaining the minute edge determination processing of FIG. It is a flowchart explaining the uv gain correction coefficient calculation process of FIG. It is a figure explaining the uv gain correction coefficient calculation process of FIG. It is a figure explaining the uv gain correction coefficient calculation process of FIG. It is a figure explaining the uv gain correction coefficient calculation process of FIG. It is a figure explaining the uv gain correction coefficient calculation process of FIG. It is a flowchart explaining the brightness | luminance gain correction coefficient calculation process of FIG. It is a figure explaining the brightness | luminance gain correction coefficient calculation process of FIG. It is a figure explaining the brightness | luminance gain correction coefficient calculation process of FIG. It is a figure explaining the brightness | luminance gain correction coefficient calculation process of FIG. It is a flowchart explaining the direction correction amount calculation process of FIG. It is a figure explaining the direction correction amount calculation process of FIG. It is a figure explaining the direction correction amount calculation process of FIG. It is a figure explaining the direction correction amount calculation process of FIG. It is a figure explaining a recording medium.

Explanation of symbols

  11 color correction processing device, 21 uv gain correction coefficient calculation unit, 21a distance calculation unit, 21b correction coefficient calculation unit, 22 luminance gain correction coefficient calculation unit, 23 u direction correction amount calculation unit, 24 v direction correction amount calculation unit, 25 , 26 adder, 27 nonlinear smoothing processing unit, 28 uv gain correction coefficient calculation method setting unit, 29 luminance gain correction coefficient calculation method setting unit, 30 direction correction amount calculation method setting unit

Claims (20)

In a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
A distance calculating means for calculating a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space;
Uv signal correction coefficient calculation means for calculating a correction coefficient of the uv signal based on the distance calculated by the distance calculation means;
Uv signal correction amount calculating means for calculating a correction amount of the uv signal using at least the correction coefficient of the uv signal calculated by the uv signal correction coefficient calculating means;
A signal processing apparatus comprising: correction means for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation means. The value calculated as the distance between the position in the uv space of the uv signal of the image signal and the position corresponding to the predetermined color in the uv space is:
The square root of the sum of the squares of the differences between the u component and the v component of the position of the image signal in the uv space and the position corresponding to the predetermined color in the uv space,
The sum of absolute differences of the u component and the v component of the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space,
Alternatively, the larger one of the u component and the v component of the position in the uv space and the position corresponding to the predetermined color in the uv space in the uv signal of the image signal is included. Item 2. The signal processing device according to Item 1. The square root of the sum of the squares of the differences between the u component and the v component of the position of the image signal in the uv space and the position corresponding to the predetermined color in the uv space,
The sum of absolute differences of the u component and the v component of the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space,
Alternatively, the larger of the u component or the v component of the position in the uv space in the uv signal of the image signal and the position corresponding to the predetermined color in the uv space, whichever is larger of the image signal a distance setting means for setting as a distance between a position in the uv space in the uv signal and a position corresponding to a predetermined color in the uv space;
The distance calculation means calculates the distance set by the distance setting means as a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space. The signal processing apparatus according to claim 2. In a signal processing method of a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
A distance calculating step of calculating a distance between a position in the uv space in the uv signal of the image signal and a position corresponding to a predetermined color in the uv space;
A uv signal correction coefficient calculation step for calculating a correction coefficient of the uv signal based on the distance calculated in the processing of the distance calculation step;
A uv signal correction amount calculation step of calculating a correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation step;
And a correction step of correcting the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation step. In a recording medium on which a program for controlling a signal processing device for correcting a predetermined color of an image signal composed of a yuv signal is recorded,
A distance calculation control step for controlling calculation of a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space;
A uv signal correction coefficient calculation control step for controlling calculation of a correction coefficient of the uv signal based on the distance calculated in the processing of the distance calculation control step;
Uv signal correction amount calculation control step for controlling calculation of the correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step;
And a correction control step for controlling correction of the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. Recording media. A computer that controls a signal processing device that corrects a predetermined color of an image signal composed of a yuv signal,
A distance calculation control step for controlling calculation of a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space;
A uv signal correction coefficient calculation control step for controlling calculation of a correction coefficient of the uv signal based on the distance calculated in the processing of the distance calculation control step;
Uv signal correction amount calculation control step for controlling calculation of the correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step;
And a correction control step for controlling correction of the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. In a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
Uv signal correction coefficient calculation means for calculating a correction coefficient of the uv signal based on the y signal of the image signal;
Uv signal correction amount calculating means for calculating a correction amount of the uv signal using at least the correction coefficient of the uv signal calculated by the uv signal correction coefficient calculating means;
A signal processing apparatus comprising: correction means for correcting the uv signal of the image signal based on the uv correction amount calculated by the uv correction amount calculation means. The signal processing apparatus according to claim 7, wherein the uv signal correction coefficient calculation unit calculates a correction coefficient of the uv signal by using a function having the y signal of the image signal as an argument. A function setting means for setting any one of the plurality of functions;
The signal processing apparatus according to claim 8, wherein the uv signal correction coefficient calculation unit calculates a correction coefficient of the uv signal by using a function having an argument set by the function setting unit. Further comprising non-linear smoothing means for non-linear smoothing the y signal of the image signal,
The signal according to claim 7, wherein the uv signal correction coefficient calculation unit calculates a correction coefficient of the uv signal based on a y signal of the image signal that has been nonlinearly smoothed by the nonlinear smoothing unit. Processing equipment. In a signal processing method of a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
Uv signal correction coefficient calculation step for calculating a correction coefficient of the uv signal based on the y signal of the image signal;
A uv signal correction amount calculation step of calculating a correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation step;
And a correction step of correcting the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation step. In a recording medium on which a program for controlling a signal processing device for correcting a predetermined color of an image signal composed of a yuv signal is recorded,
Uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal based on the y signal of the image signal;
Uv signal correction amount calculation control step for controlling calculation of the correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step;
And a correction control step for controlling correction of the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. Recording media. A computer that controls a signal processing device that corrects a predetermined color of an image signal composed of a yuv signal,
Uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal based on the y signal of the image signal;
Uv signal correction amount calculation control step for controlling calculation of the correction amount of the uv signal using at least the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step;
And a correction control step for controlling correction of the uv signal of the image signal based on the uv correction amount calculated in the processing of the uv correction amount calculation control step. In a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
Uv signal correction coefficient calculation means for calculating a correction coefficient of the uv signal of the image signal based on the image signal;
Uv signal correction amount calculation for calculating a correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space based on the correction coefficient of the uv signal calculated by the uv signal correction coefficient calculation means. Means,
A signal processing apparatus comprising: correction means for correcting the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated by the uv correction amount calculation means. The predetermined correction direction in the uv space is
From the position of the origin in the uv space, the direction to the position in the uv space in the uv signal of the image signal,
A direction to a position corresponding to a predetermined color in the uv space as seen from the position of the origin in the uv space;
Alternatively, when viewed from a position in the uv space in the uv signal of the image signal, the direction includes any direction to a position corresponding to a target color in the uv space. Signal processing equipment. From the position of the origin in the uv space, the direction to the position in the uv space in the uv signal of the image signal,
A direction to a position corresponding to a predetermined color in the uv space as seen from the position of the origin in the uv space;
Alternatively, as viewed from the position in the uv space of the uv signal of the image signal, the direction to the position corresponding to the target color in the uv space The signal processing apparatus according to claim 15, further comprising correction direction setting means for setting as a predetermined correction direction in the space. In a signal processing method of a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
Uv signal correction coefficient calculation step of calculating a correction coefficient of the uv signal of the image signal based on the image signal;
Uv signal correction for calculating a correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space based on the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation step. A quantity calculation step;
And a correction step of correcting the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated in the processing of the uv correction amount calculation step. Method. In a recording medium on which a program for controlling a signal processing device for correcting a predetermined color of an image signal composed of a yuv signal is recorded,
Uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal of the image signal based on the image signal;
Based on the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step, the calculation of the correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space is controlled. uv signal correction amount calculation control step;
A correction control step for controlling correction of the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated by the processing of the uv correction amount calculation control step. A recording medium on which a computer-readable program is recorded. A computer that controls a signal processing device that corrects a predetermined color of an image signal composed of a yuv signal,
Uv signal correction coefficient calculation control step for controlling the calculation of the correction coefficient of the uv signal of the image signal based on the image signal;
Based on the correction coefficient of the uv signal calculated in the processing of the uv signal correction coefficient calculation control step, the calculation of the correction amount of the uv signal of the image signal to be corrected in a predetermined correction direction in the uv space is controlled. uv signal correction amount calculation control step;
A correction control step for controlling correction of the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated in the processing of the uv correction amount calculation control step. A program characterized by letting In a signal processing device for correcting a predetermined color of an image signal composed of yuv signals,
A distance calculating means for calculating a distance between a position in the uv space of the uv signal of the image signal and a position corresponding to a predetermined color in the uv space;
First uv signal correction coefficient calculation means for calculating a first correction coefficient of the uv signal based on the distance calculated by the distance calculation means;
Second uv signal correction coefficient calculation means for calculating a second correction coefficient of the uv signal based on the y signal of the image signal;
At least a first correction coefficient of the uv signal calculated by the first uv signal correction coefficient calculating means, and a second correction coefficient of the uv signal calculated by the second uv signal correction coefficient calculating means. Uv signal correction amount calculating means for calculating a correction amount of the uv signal of the image signal, which is corrected in a predetermined correction direction in the uv space,
A signal processing apparatus comprising: correction means for correcting the uv signal of the image signal in a predetermined correction direction in the uv space by the correction amount of the uv signal calculated by the uv correction amount calculation means.

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