WO2016080011A1 - Color attribute display device, method, and program for digital image and image processing apparatus - Google Patents

Abstract

[Problem] Although color attributes of an image are represented by a histogram of R, G, B in photo-retouching software, considerable experience and proficiency are needed to understand a relationship with an actual image. [Solution] All pixels of image data are classified into 256 luminance gradation levels, and pixels belonging to an n-th gradation level (n=0 to 255) are mapped to a right-angled isosceles triangle-shaped pseudo xy chromaticity diagram. The mapped pixels (MPs) are projected by mapping from within the pseudo xy chromaticity diagram into an equilateral triangle, and then from within the equilateral triangle to the circumcircle of the equilateral triangle to thereby obtain an n-th gradation-level gradation-level-based chromaticity circle 30(n) in which the MPs are distributed. A chromaticity circle and a color space front view are displayed on the basis of cylindrical HSV color space data created by gradation-level-based chromaticity circles 30(n) corresponding to 256 gradation levels. Operation tools such as a cursor are also displayed thereon. The pixels of the image data and the MPs of the HSV color space data are associated with each other, and the movement of the MPs by the operation tool and the like are reflected in color attributes of an image.

Description

Digital image color attribute display apparatus, method and program, and image processing apparatus

When a digital image taken with a digital camera or the like is retouched with a computer, a display (numerical value or histogram) relating to the color attribute of the image is referred to. In the present invention, the color attribute is converted into a cylindrical HSV color space. The present invention relates to an apparatus, a method, a program, and an image processing apparatus using the color attribute display device.

Conventionally, with regard to image processing techniques for digital images, various proposals have been made with the spread of digital cameras, and a large number of photo retouching software has been available for use.
This kind of software is generally capable of changing three color attributes of a digital image, that is, hue, saturation, and brightness, and each element is operated using a GUI (Graphical User Interface). It is like that.

Therefore, while the user recognizes the color attribute information of the change target image on the GUI display screen, each value of hue, saturation, and brightness is changed by moving the slider bar or inputting a numerical value. In general, a histogram is used as a means for visually expressing information relating to the three elements of the color attribute.
Here, as the histogram, the horizontal axis represents 0 to 255 gradations from the left, the vertical axis represents the number of pixels, and luminance, RGB (average of R, G, B) and R / G / B individual distribution states are shown. In general, a display that is sequentially switched and a display in which the distribution states of R / G / B are superimposed are displayed.

Further, the GUI disclosed in the following Patent Documents 1 to 3 proposes a method that does not use a slider bar.
Specifically, Patent Document 1 displays a color map of the L * a * b * color system and specifies a color before and after correction and a color range affected by the correction. Patent Document 3 displays a chromaticity diagram (hue / saturation plan view, brightness plan view) as a method of executing a hue adjustment and a saturation adjustment by displaying a ring and operating a rotating ring or a saturation increase / decrease button. In addition, a method for performing hue adjustment and saturation adjustment by moving an operation color object displayed thereon is disclosed.

In addition, in order to check the degree of reflection on the digital image due to the change of the color attribute, the image data before the change is stored, and each image before and after the change can be switched and displayed. A method of displaying the images side by side is employed, and a dedicated color palette is displayed on the GUI display screen for the case where the user changes a specific color in the image to be changed to a favorite color. Some are prepared and selected.

JP 2000-13628 A JP 2004-72168 A Japanese Patent No. 4,677,323 JP-A-2-51979

By the way, in image processing typified by photo retouching software, it is possible to easily confirm the tendency of the color attribute of the digital image to be changed, and based on this, the hue is adjusted so that the digital image is in a desired display state. It is desirable that the saturation and brightness can be freely changed by a simple operation.

However, as described above, histograms are widely used as means for expressing the color attributes of digital images, and the actual situation is that the method is used in many photo retouching software.
In Patent Documents 1 to 3, the display / confirmation of the color attribute of the digital image itself is not particularly mentioned.
In Patent Document 4, “frequency distribution of image data (L: lightness, H: hue, S: saturation) and statistical data (average value, mode, maximum value, minimum value, etc.) are obtained and displayed”. However, the specific disclosure is not made, and the display of “frequency distribution” is merely a display like a histogram.

On the other hand, for users such as photo retouching software, in order to be able to accurately perform the color attribute changing operation while understanding the relationship between the color attribute of the digital image represented by the histogram and the hue of the actual digital image, Experience and skill are required, and a new approach to this issue has long been eagerly desired.

Therefore, the present invention provides a color attribute display device, method and program for displaying the color attributes of all the pixels of the digital image so that the user can intuitively and accurately recognize them by simple data processing. The present invention was created for the purpose of providing an image processing apparatus capable of changing a digital image by directly changing the display contents.

The first invention in the present application is a first storage means for storing digital image data, and all the pixels of the digital image data in the first storage means have N gradations (N is an integer of 16 or more) based on a luminance value. Of the three colors for the total value of the light intensity of R (red), G (green), and B (blue) for each pixel, the pixel sorting means for sorting and the gradation pixel groups sorted by the pixel sorting means By calculating the ratio of each light intensity value relating to any one of the two colors and mapping the two ratios onto the coordinates of the pseudo xy chromaticity diagram which is an orthogonal coordinate with the vertical axis and the horizontal axis, A first data creating means for creating first stage data in which chromaticity information of a pixel group belonging to the gradation is mapped as a pixel in an isosceles right triangle having sides corresponding to two orthogonal sides; Each first stage for N gradations created by the data creation means For the floor data, a pixel related to chromaticity information mapped in the right-angled isosceles triangle (hereinafter referred to as “mapping pixel”) is projected into the regular triangle by mapping, and each of the three vertices of the regular triangle corresponds to the luminance. It corresponds to a clear color or pure color of R, G, B in gradation, and each of the three sides corresponds to a clear color or pure color by mixing two colors of R, G, B in the luminance gradation, And a second data creation means for creating second stage data corresponding to an achromatic color at the brightness gradation, and each second stage data for N gradations created by the second data creation means. The mapping pixels in the equilateral triangle are projected into a circle by mapping, and the positions of every 120 ° in the central angle on the circumference of the circle are respectively R, G, B clear colors or It corresponds to pure color, and each other section of the circumference Gradation-specific chromaticity circle data corresponding to a clear color or a pure color by mixing two colors of R, G, and B in the gradation and whose center position corresponds to an achromatic color in the luminance gradation. HSV color in which mapping pixels are three-dimensionally distributed in a cylindrical color space, with third data creation means to be created and gradation-specific chromaticity circle data for N gradations created by the third data creation means. Second storage means for storing as spatial data; and display data creation means for creating display data of chromaticity circles when the HSV color space is viewed from the cylinder axis direction based on the HSV color space data of the second storage means; And a display control means for displaying the chromaticity circle on a display based on the display data created by the display data creation means.

In the first aspect of the invention, the display data creating means is configured to make the HSV color space in a direction perpendicular to the cylinder axis together with the display data of the chromaticity circle based on the HSV color space data of the second storage means. Display data of the front view seen from below (hereinafter referred to as “color space front view”) may be created, and the display control means may display the color space front view together with the chromaticity circle on the display. .

According to a second aspect of the present invention, there is provided a digital image color attribute display method corresponding to the first aspect, wherein a first step of storing digital image data in a first storage means, and the first step The second step of classifying all the pixels of the digital image data stored in the first storage means into N gradations based on the luminance value, and each tone pixel group classified in the second step The ratio of each light intensity value for any two of the three colors to the total value of the light intensity of R, G, and B is obtained for each, and the two ratios are expressed in orthogonal coordinates with the vertical axis and the horizontal axis. By mapping on the coordinates of a certain pseudo xy chromaticity diagram, the chromaticity information of the pixel group belonging to the gradation is mapped as a pixel in an isosceles right triangle with the sides corresponding to each ratio as two orthogonal sides. Third step to create first stage data And mapping each mapping pixel in the right-angled isosceles triangle into an equilateral triangle by mapping for each of the first step data for N tones created in the third step, and the three vertices of the equilateral triangle are respectively Corresponds to the clear color or pure color of R, G, B at the luminance gradation, and the three sides correspond to the clear color or pure color by mixing two colors of R, G, B at the luminance gradation, respectively. And the fourth step of creating the second stage data corresponding to the achromatic color at the brightness gradation and the second stage data for the N gradations created in the fourth step, The mapping pixels in the equilateral triangle are projected into a circle by mapping, and the positions of every 120 ° in the central angle on the circumference of the circle are respectively R, G, B clear color or pure color at the luminance gradation. The other sections of the circumference are R, G, A fifth step of creating tone-specific chromaticity circle data corresponding to a clear color or a pure color by mixing two colors of B and having a center position of the circle corresponding to an achromatic color in the luminance gradation; Sixth tone-specific chromaticity circle data for N tones created in the fifth step is stored in the second storage means as HSV color space data in which mapping pixels are three-dimensionally distributed in a cylindrical color space. And a seventh step of creating display data of a chromaticity circle when the HSV color space is viewed from the cylinder axis direction based on the HSV color space data stored in the second storage means in the sixth step. And an eighth step of displaying the chromaticity circle on a display based on the display data created in the seventh step.

In the second aspect of the invention, in the seventh step, the display data of the color space front view is generated together with the display data of the chromaticity circle based on the HSV color space data of the second storage means. In the eighth step, the color space front view may be displayed on the display together with the chromaticity circle.

The third invention of the present application relates to a digital image color attribute display program for causing a computer to execute each step of the color attribute display method.

Thus, in the digital image color attribute display device, method and program of the present invention, HSV color space data in which all the pixels of the digital image data are three-dimensionally mapped into the cylindrical color space as pixels for color attribute display. And the chromaticity circle is displayed based on the HSV color space data, or the chromaticity circle and the color space front view are displayed.

The HSV color space data is created by the following procedure.
(1) All pixels of digital image data are sorted into N pixel groups for each luminance gradation.
(2) For each classified pixel group, mapping is performed on a pseudo xy chromaticity diagram having an isosceles right triangle. That is, the respective light intensity ratios for two colors of R, G, and B in each pixel are obtained, and the x-axis (horizontal axis) and y-axis (vertical axis) of the pseudo xy chromaticity diagram which is an orthogonal coordinate. ) In a range of 0 to 100%, pixels representing chromaticity are distributed in a right triangle having isosceles in the x-axis direction and the y-axis direction. This is the first stage data and is created for N gradations.
(3) The mapping data in the pseudo xy chromaticity diagram (isosceles right triangle) which is the first stage data is projected into the regular triangle by mapping to create the second stage data. In this case, the simplest method is to perform projection into an equilateral triangle formed by deformation by tilting the y-axis of the pseudo xy chromaticity diagram by 30 ° toward the x-axis. Then, the second stage data is created for N gradations.
(4) The mapping pixels within the equilateral triangle, which is the second stage data, are projected into a circle by mapping to create tone-specific chromaticity circle data. As the mapping in this case, the simplest method is to perform projection from an equilateral triangle onto its circumscribed circle. The tone-specific chromaticity circle data is created for N gradations.

By the way, in the pseudo xy chromaticity diagram, the light intensity ratio of one color other than the two colors selected with the x axis and the y axis as the axes of the light intensity ratio is naturally from 100% to the light intensity ratio of the two colors. Therefore, the three vertices of the right-angled isosceles triangle of the first stage data and the regular triangle of the second stage data pass through the central angle of 120 ° in the circle of the chromaticity circle data by gradation. Three points on the circumference correspond to R, G, and B clear colors or pure colors at the luminance gradation, respectively.
Further, the points on each side in the right-angled isosceles triangle of the first stage data and the equilateral triangle of the second stage data and the section on the circumference other than the three points in the gradation-specific chromaticity circle data are respectively the brightness gradation. It corresponds to a clear color or a pure color by mixing two colors of R, G and B.
Further, the center positions of the centroids in the isosceles right triangle (pseudo xy chromaticity diagram) of the first stage data and the regular triangle of the second stage data and the center position of the circle of the chromaticity circle data by gradation are respectively the values in the luminance gradation. Corresponds to coloring.

Therefore, by stacking tone gradation data for gradations corresponding to N gradations, cylindrical HSV color space data in which all pixels of the digital image data are mapped as pixels for color attribute display is configured. The hue (Hue) changes along the circumferential direction of the cylinder, the saturation (Saturation) increases according to the separation distance from the cylinder axis, and the lightness (Value) becomes N gradations in the direction of the cylinder axis. It has a configuration.

Next, a fourth invention of the present application includes the digital image color attribute display device according to the first invention, wherein the display control means of the device displays the chromaticity circle on a display, and the first An image processing apparatus for displaying an image of digital image data stored in a storage unit on the display, wherein the image processing apparatus can move in a circumferential direction along an outer periphery of the chromaticity circle displayed by the color attribute display apparatus. Concentric with the cursor, the first cursor and the center of the chromaticity circle, the radius line rotating with the movement of the first cursor, the second cursor movable on the radius line, and the chromaticity circle An operation tool display means for displaying a circular line passing through the second cursor, an operation input means capable of independently moving the first cursor and the second cursor, and the operation input means. According to the rotation of the radial line accompanying the movement of the first cursor, the mapping pixel of the HSV color space stored in the second storage means of the color attribute display device is moved or deleted in the circumferential direction, Further, the mapping pixel in the HSV color space is moved or deleted in the radial direction according to the increase / decrease of the radius of the circular line accompanying the movement of the second cursor by the operation input means, and the moved mapping pixel is moved to The color space data changing means for changing to the color attribute value and the pixel of the digital image data in the first storage means corresponding to the mapping pixel to be changed (moved or deleted) by the color space data changing means are the same. And display pixel data changing means for changing the color attribute.

In the image processing apparatus according to the fourth aspect of the present invention, the initial display position of the first cursor in the chromaticity circle is divided into M equal parts around the central axis of the HSV color space. M is an integer greater than or equal to 16), and is set to the outer peripheral position of the largest number of the mapping pixels included therein, and the initial display position of the second cursor in the chromaticity circle is A function of setting a position on the radius line corresponding to an average value of saturation values of all pixels of the digital image data stored in the first storage unit of the color attribute display device may be provided. desirable.

A fifth invention of the present application comprises the digital image color attribute display device according to the second invention, wherein the display control means of the device displays the chromaticity circle and the color space front view on a display, An image processing apparatus for displaying an image of digital image data stored in the first storage means on the display, and movable in a circumferential direction along an outer periphery of the chromaticity circle displayed by the color attribute display apparatus A first cursor, a radius line connecting the first cursor and the center of the chromaticity circle and rotating as the first cursor moves, a second cursor movable on the radius line, the chromaticity circle, An operation tool display means for displaying a concentric circle passing through the second cursor and a third cursor movable in a direction parallel to the cylinder axis of the HSV color space in the color space front view; car And the operation input means capable of independently moving the second cursor and the third cursor, and the color according to the rotation of the radius line accompanying the movement of the first cursor by the operation input means. The mapping pixel of the HSV color space stored in the second storage unit of the attribute display device is moved or deleted in the circumferential direction, and the radius of the circle is increased or decreased with the movement of the second cursor by the operation input unit. The HSV color space mapping pixel is moved or erased in the radial direction in response to the movement of the third cursor by the operation input means, and the HSV color space mapping pixel is parallel to the cylinder axis. Color space data changing means for moving or erasing the mapping pixel and changing the moved mapping pixel to a destination color attribute value; Display pixel data changing means for performing the same color attribute changing process on the pixels of the digital image data in the first storage means corresponding to the mapping pixels to be changed (moved or deleted) by the data changing means; It is characterized by that.

In the image processing apparatus according to the fifth aspect of the present invention, the initial display position of the first cursor in the chromaticity circle is divided into M equal parts around the central axis of the HSV color space. M is an integer greater than or equal to 16), and is set to the outer peripheral position of the largest number of the mapping pixels included therein, and the initial display position of the second cursor in the chromaticity circle is Set on a radius line at a position corresponding to the average value of the saturation values of all the pixels of the digital image data stored in the first storage means of the color attribute display device, and the color space front view A function of setting the initial display position of the third cursor to the gradation position corresponding to the maximum number of mapping pixels among the gradation-specific chromaticity circles for N gradations created by the color attribute display device Keep Theft is desirable.

As described above, the image processing apparatus of the present invention includes the color attribute display apparatus of the present invention, and a chromaticity circle (fourth and fifth inventions) in which mapping pixels corresponding to all the pixels of the digital image are distributed. ) And a color space front view (only the fifth aspect of the invention) are displayed on the display, and the color attributes (hue / saturation / lightness) of the image are presented to the user in an easily understandable manner.
In addition, the mapping pixels can be moved by displaying operation tools on the chromaticity circle and the color space front view and operating them with an operation input means such as a mouse.
Here, the first cursor and the radius line, which are operation tools, are used for changing the hue, the second cursor and the circle are used for changing the saturation, and the third cursor is used for changing the brightness. While looking at the distribution state of the mapping pixel in the degree circle and the color space front view, that is, confirming the tendency of the hue, saturation, and brightness of all the pixels of the image from the three-dimensional distribution state The distribution state can be changed directly.
Then, the mapping pixel of the chromaticity circle and the color space front view changes to the color attribute given at the movement destination position with the movement, and the mapping pixel is associated with the pixel of the digital image data in the first storage means. Thus, the pixel of the digital image data is also changed to the color attribute at the movement destination position of the mapping pixel.

In the image processing apparatus of the present invention, it is also possible to set the initial position of each cursor based on statistical information. For the user, the distribution state of mapping pixels in the chromaticity circle and the color space front view In addition, it is possible to provide meaningful information that serves as a guide for changing the color attribute of the image.

According to the digital image color attribute display apparatus, method and program of the present invention, the color attribute of all the pixels of the digital image is converted into a cylindrical HSV color space in which mapping pixels are three-dimensionally distributed by simple data processing ( Chromaticity circle or color space front view), and allows the user to more intuitively grasp the color attribute information of the image that is the premise of the image processing operation.
The image processing device of the present invention uses the color attribute display device, displays the chromaticity circle and the color space front view, and displays an operation tool such as a cursor on them. The color attribute of the image can be changed by directly applying various changing operations to the distribution state of the mapping pixel, thereby realizing a better GUI for image processing.

It is a block diagram which shows the structural example of the image processing apparatus which concerns on embodiment of this invention. FIG. 6 is an image processing screen provided as a GUI in the image processing apparatus, where (A) shows a display state before reading the processing target image data, and (B) shows a display state after reading the processing target image data. Note that an image before processing and an image after processing are displayed in the display areas of the original image and the changed image in FIG. It is a figure which shows the relationship between the chromaticity circle by gradation which distributed the mapping pixel for a color attribute display, and cylindrical HSV color space. It is a figure which shows the process of producing the color circle by gradation which distributed the mapping pixel for a color attribute display. FIG. 5B shows a mapping regarding the position of the mapping pixel when the pseudo xy chromaticity diagram (A) of the right isosceles triangle is transformed into the equilateral triangle (B) in the process of creating the chromaticity circle by gradation shown in FIG. It is a figure for explaining how to obtain the coefficients m1, m2, m3 applied in. FIG. 5B is a diagram for explaining a mapping regarding the position of a mapping pixel when the regular triangle of FIG. 5A (B) is changed to a circumscribed circle in the process of creating tone-specific chromaticity circles shown in FIG. 4. It is explanatory drawing regarding the hue and saturation of the chromaticity circle according to gradation. It is a flowchart which shows the basic operation | movement procedure of an image processing apparatus. It is a flowchart which shows the initial display procedure of each operation tool with respect to the chromaticity circle and color space front view of the image processing screen. It is a figure explaining operation | movement of each operation tool in a chromaticity circle and a color space front view. It is explanatory drawing in the case of changing the hue of the whole image by operation of the 1st cursor in a chromaticity circle. It is explanatory drawing in the case of selectively changing the one part hue contained in the image by operation of the 1st cursor in a chromaticity circle. It is explanatory drawing in the case of changing the saturation of the whole image by operation of the 2nd cursor in a chromaticity circle. Explanatory drawing when selecting a part of the hue included in the image by operating the first cursor in the chromaticity circle and changing the saturation of the hue range centered on that hue by operating the second cursor It is. It is explanatory drawing in the case of changing the brightness of the whole screen by operation of the 3rd cursor in a color space front view. It is explanatory drawing in the case of selecting the one part hue contained in the image by operation of the 1st cursor in a chromaticity circle, and changing the lightness of the hue by operation of the 3rd cursor in color space front view. . It is explanatory drawing in the case of changing the contrast of an image by operation of the 3rd cursor in a color space front view. It is explanatory drawing in the case of emphasizing the specific hue range contained in the image by operation of the 1st cursor in a chromaticity circle. It is explanatory drawing in the case of emphasizing the specific saturation range contained in the image by operation of the 2nd cursor in a chromaticity circle. It is explanatory drawing in the case of performing the brightness process of special images, such as halation, by operation of the 3rd cursor in a color space front view. It is explanatory drawing in the case of erasing the specific hue range included in the image by the operation of the first cursor in the chromaticity circle. It is explanatory drawing at the time of erasing the specific saturation range contained in the image by operation of the 2nd cursor in a chromaticity circle. It is explanatory drawing at the time of erasing the specific luminance range contained in the image by operation of the 3rd cursor in a color space front view.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
First, FIG. 1 shows a configuration example of an image processing apparatus according to the embodiment, and generally a desktop or notebook personal computer is used.

In the image processing apparatus of FIG. 1, 1 is a central processing unit (CPU), 2 is a program for executing image display and image processing control, a main memory in which image data is expanded, and 3 is an image processing program ( A hard disk (HDD) that stores various application programs including a retouch application), image data, and the like, 4 is a disk drive that reads / writes image data and the like by accessing a disk 4a such as a DVD, and 5 is a LAN, WWW, or the like A network I / F (Interface) for loading image data and the like stored in an accessible recording device on an external network, and an input I / F 6 for inputting input operation signals of the mouse 6a and the keyboard 6b into the system F and 7 are video signals such as image data, which are displayed on the LCD panel. Video I / F, 8 to be output to the spray 7a is sound I / F for outputting an audio signal to the speaker 8a, each module is connected as shown to the system bus 9.
The entire system is controlled by the CPU 1 based on the system control program of the HDD 3. The application program is developed by the CPU 1 in the main memory 2 based on input operation signals from the mouse 6 a and the keyboard 6 b. Execute.
The image processing apparatus may further be provided with an I / F for capturing image data from an external storage medium such as a USB memory or various memory cards.

In this image processing apparatus, when there is an operation signal related to the execution instruction of the image processing program by the mouse 6a or the keyboard 6b, the CPU 1 reads the image processing program of the HDD 3 into the main memory 2 and executes it, and the image processing screen as a GUI Is displayed on the display 7a, and image data to be processed is selected from the HDD 3, the disk 4a, the LAN, or the like by operating the mouse 6a or the keyboard 6b.
When the selection signal is input, the CPU 1 that receives the selection signal reads the selected image data into the main memory 2.

Here, FIG. 2A shows an image processing screen 10 that is initially displayed after the image processing program is started.
In the same screen 10, the lower right half of the menu bar 11 corresponds to the color attribute display area of the digital image, and a chromaticity circle 12 and a front view of a cylindrical HSV color space with the axial direction as the vertical direction. A color space front view 13 viewed from the side is displayed vertically.
In the lower left half of the menu bar 11, an unprocessed image (original image) display region 14 and a processed image (changed image) display region 15 are provided above and below.
In the color attribute display area, a hue processing mode / saturation processing mode selection unit 16a is located diagonally to the upper left of the chromaticity circle 12, and a lightness processing mode selection unit 16b is located in the upper left of the color space front view 13. The user can select one of the processing modes of hue / saturation / lightness when performing an image processing operation to be described later by turning ON / OFF the radio button of each selection unit 16a, 16b. Can be selected.

On the other hand, FIG. 2B shows the image processing screen 10 after image data is captured by the file menu of the menu bar 11 and a predetermined procedure of the image processing program is executed.
The read image data is developed in the main memory 2, and the image is displayed in the display area 14 of the original image, and all pixels of the image data are analyzed to obtain chromaticity circles as pixels for color attribute display. 12 and the color space front view 13 are mapped.
Further, on the chromaticity circle 12 and the color space front view 13, a first cursor 17, a radius line 18, a second cursor 19, a circle line 20, and a third cursor 21 which are operation tools used for image processing operations described later. A level line 22 is also displayed.

By the way, the cylindrical HSV color space is a basic color space for drawing the chromaticity circle 12 and the color space front view 13 in the color attribute display area, and the hue value changes in the circumferential direction of the cylinder. Consists of a coordinate system related to the color attribute that the saturation value increases according to the distance from the center (clear or pure color at the outermost periphery, the central axis is achromatic), and the luminance increases from 0 to 255 tones from the bottom surface to the top surface. It has been done.
Therefore, as shown in FIG. 3, the columnar HSV color space can be configured by stacking tone-dependent chromaticity circles 30 (n) [n = 0 to 255] related to each luminance in the axial direction. The degree circle 30 (n) is obtained by two-dimensionally mapping each pixel belonging to the nth luminance gradation in the image data based on the hue value and the saturation value.

Here, a method of creating the tone-specific chromaticity circle 30 (n) will be described with reference to FIG.
First, all the pixels of the image data are sorted into pixel groups for each luminance gradation.
In the pseudo xy chromaticity diagram of FIG. 4A, the R ratio (0 to 100%), which is the ratio of the light intensity of R to the total value of the light intensity of R, G, B on the x axis, is plotted on the y axis. FIG. 4 is a chromaticity diagram of xy orthogonal coordinates taking a G ratio (0 to 100%), which is a ratio of a G light intensity to a total value of R, G, and B light intensity.
Then, an R ratio and a G ratio are obtained for the pixel group belonging to the nth luminance gradation, and are mapped as color attribute display pixels on the pseudo xy chromaticity diagram based on each ratio.
In the following, this pixel for color attribute display is referred to as “mapping pixel” and is represented as “MP” in the drawing.

Therefore, in FIG. 4A, the mapping pixels are distributed in the pseudo xy chromaticity diagram of a right isosceles triangle. Next, as shown in FIG. The vertical axis (G ratio) of the degree diagram is tilted 30 ° toward the horizontal axis (R ratio), and the right angled isosceles triangle is transformed into an equilateral triangle.
In that case, the mapping pixel is arranged in the equilateral triangle based on the mapping of the right isosceles triangle into the equilateral triangle, and the ratio (%) of the light intensity with respect to R, G, B at each vertex is (100, 0). , 0), (0,100,0), (0,0,100) are clear colors or pure colors, and each three sides are clear colors or pure colors by mixing two colors of R, G, and B. At the center of gravity, the color is achromatic (100, 100, 100).

Next, as shown in FIG. 4 (C), assuming a circumscribed circle of the equilateral triangle, each side of the equilateral triangle is bulged outward and deformed to become an arc of the circumscribed circle. Then, a tone-specific chromaticity circle 30 (n) shown in FIG.
In this case, the mapping pixel is arranged in the circumscribed circle based on the mapping projected from the equilateral triangle into the circumscribed circle. Specifically, the mapping pixel is a deformed portion of a bulge shape. Each vertex of the equilateral triangle is a point on the circumference every 120 ° as a central angle and becomes a clear color or pure color regarding R, G, B, and other sections on the circumference are R , G, and B become a clear color or a pure color by mixing two colors, and the center of gravity of the regular triangle becomes the center of the circle and becomes an achromatic color.
The tone-dependent chromaticity circle 30 (n) has the property that the hue changes to RGB in the circumferential direction of the circle, and the saturation increases as the distance from the center of the circle increases. The mapping pixels are distributed based on the chromaticity condition.

5A and 5B are mappings of mapping pixel positions that provide chromaticity information between the stages of the pseudo xy chromaticity diagram, the regular triangle, and the gradation-specific chromaticity circle 30 (n) shown in FIG. It is explanatory drawing which shows whether it is correspondence of. However, the necessary mathematical expressions are described as (1) to (17) in the figure.

(A) in FIG. 5A is a pseudo xy chromaticity diagram that is a right-angled isosceles triangle represented by XY coordinates, with the X axis corresponding to the R ratio (%) and the Y axis corresponding to the G ratio (%). is doing.
First, in the figure, the coordinates of the center of gravity of a right-angled isosceles triangle are given as (xc, yc) = (100/3, 100/3) as shown in the equation (1), but the center of gravity (xc, yc) and each A right isosceles triangle is divided into three regions <M1>, <M2>, and <M3> as shown in the figure by line segments connecting the vertices.
Here, if the coordinates of an arbitrary mapping pixel in the region <M3> are (x, y), the coordinate passes through the center of gravity (xc, yc) and is parallel to one side of the right-angled isosceles triangle surrounding the region <M3>. The length of the perpendicular drawn from the position (x, y) of the mapping pixel with respect to the straight line is given by Equation (2).
Further, the length of a perpendicular line drawn from the center of gravity (xc, yc) to one side of a right isosceles triangle surrounding the region <M3> is given by Equation (3).
Then, the coefficient m3 corresponding to each mapping pixel in the region <M3> is given by Expression (4) that is the ratio of Expression (2) to Expression (3).
Further, the same idea as described above is applied to any mapping pixel [coordinate (x, y)] in the region <M1> and the region <M2>, and each of the regions <M1> and <M2> Coefficients m1 and m2 corresponding to the mapping pixel are given by equations (5) and (6).
The obtained coefficients m1, m2, and m3 are linear functions of x, y, and (x + y), respectively, but are transformed from a regular triangle described later to a tone-specific chromaticity circle 30 (n) (FIG. 5B). ).

Next, as shown in FIG. 5A (B), when the pseudo xy chromaticity diagram on the XY coordinates is transformed into an equilateral triangle, a point (x, y) at an arbitrary position in the pseudo xy chromaticity diagram is obtained. By the mathematical expression (7) using the mapping, the point (x1, y1) on the equilateral triangle given by the mathematical expression (8) is obtained.
Further, the centroid (xc, yc) of the right isosceles triangle in the pseudo xy chromaticity diagram is the centroid (xg, yg) = (50, 50 / √3) shown in the formula (9) even in the equilateral triangle.

Then, the origin of the XY coordinates in (A) and (B) of FIG. 5A is moved to the center of the equilateral triangle given by the coordinate value of Equation (9), and the center of gravity is moved as shown in FIG. 5B. Considering the Xs-Ys coordinate as the origin, the point (x1, y1) at an arbitrary position on the XY coordinate corresponds to the point (x2, y2) given by the equations (10) and (11). Become.
The circumscribed circle of the regular triangle is the contour of the tone-dependent chromaticity circle 30 (n), and the radius R of the chromaticity circle 30 (n) is given by the value of Equation (12).

Next, the transformation from the regular triangle on the Xs-Ys coordinate to the tone-specific chromaticity circle 30 (n), as shown in FIG. 5B, the regular triangle is represented by a line segment connecting the center of gravity of the regular triangle and each vertex. The area of each isosceles triangle (the angle formed by the isosceles is 120 °) in the case of being divided into three equal parts is 120 ° center angle including each isosceles triangle in the tone-specific chromaticity circle 30 (n) which is a circumscribed circle. It is none other than expanding to each sector area.
Here, the expansion from the isosceles triangle area to the fan-shaped area is, for example, the point (x2, y2) at an arbitrary position in the upper right isosceles triangle in FIG. x2 and y2) between the origin and the point (x2, y2) depending on the expansion rate k3 when it is assumed that the distance S from the origin of the intersection of the straight line connecting to the side of the equilateral triangle extends to the radius R of the circumscribed circle This means that the distance V extends to become the distance between the origin and the point (x3, y3) on the straight line.

Therefore, the expansion rate k3 is given by the equation (13) [k3 = R / S], but the coefficient m3 = (2) / (3) of the equation (4) obtained in (A) of FIG. Since the relationship is not deviated from the relationship of (line segment qc) / (line segment pc) in the figure due to the general relationship, it is given as V / S shown in equation (14). After erasing, the expansion rate k3 can be calculated by equation (13a).
The coordinates of the point (x3, y3) are obtained as x3 = k3 * x2 and y3 = k3 * y2 as shown in the equations (16) and (17).
In this case, m3 is obtained in advance as Equation (4), R is obtained from Equation (12), and V is obtained from Equation (15). Therefore, the coordinates of the point (x3, y3) are coordinates (x2, y2) as variables. And (x2, y2) can also be easily obtained from (x, y) via Equation (8) and Equations (10), (11). Data processing for generating tone-specific chromaticity circles 30 (n) from the chromaticity diagram can be executed at high speed.

In the above description, the mapping pixel in the upper right isosceles triangle in FIG. 5B [corresponding to the region <M3> in (A) of FIG. 5A] has been described. However, in the upper left and lower isosceles triangles [FIG. For the mapping pixel (x2 ′, y2 ′) at an arbitrary position in the region <M1> and the region <M2> in (A) of 5A], the same idea is applied to the gradation circle 30 (n ) Corresponding position (x3 ′, y3 ′).
When obtaining the expansion ratios k1 and k2 used for the mapping pixels (x2 ′, y2 ′) in the region <M1> and the region <M2>, m1 in the above formulas (5) and (6) is used. , M2 applies.

Note that, as described above, mj (j = 1, 2, 3) is obtained in advance at the stage of the pseudo xy chromaticity diagram [(A) of FIG. 5A] as a method of obtaining the expansion rate k j (j = 1, 2, 3). In FIG. 5B, the intersection coordinates between the straight line connecting the origin and the mapping pixel position (x2, y2) and the equilateral triangle are calculated, S is calculated, and this is substituted into equation (13). Although geometrically, it can be said that it is rather a general method, there is a drawback that the calculation becomes very complicated and the efficiency of data processing decreases.

Thus, pixels mapped based on the R ratio (%) and the G ratio (%) with respect to the pseudo xy chromaticity diagram of the right isosceles triangle have the pseudo xy chromaticity diagram as an equilateral triangle and the equilateral triangle. At each stage of transformation from tone to tone-specific chromaticity circle 30 (n), coordinates are obtained based on the mapping corresponding to the change in planar shape, and tone-specific chromaticity circle 30 (n The distribution of mapping pixels to) is realized.

As a result, the light intensity ratio (%) of R, B, and G in the gradation tone chromaticity circle 30 (n) of the nth gradation (n = 0 to 255) shown in FIG. 3 and FIG. ) Changes with the tendency shown in FIG. 6 according to the position in the circle, the hue changes to RGB with a central angle of 120 ° in the circumferential direction of the circle, and the saturation changes to the color. The chromaticity coordinate system changes so that the center of the degree circle (R = n, G = n, B = n) is 0 (%) and the outermost circumference is 100 (%).
As described above, as a property of the tone-specific chromaticity circle 30 (n), the center of the circle is a mixture of three colors of R, G, and B and is achromatic, and the outermost circumference of the circle has only one color or Since it is a mixture of two colors, it corresponds to a clear color or a pure color, and hues (a and b in the figure) at symmetrical positions with respect to the center of the chromaticity circle have a complementary color relationship.

Next, the operation procedure of the image processing apparatus (FIG. 1) according to the embodiment will be described based on the flowchart of FIG.
First, when the image processing program is activated by operating the mouse 6a or the keyboard 6b, the image processing screen data prepared by the program is read out to the video I / F 7, as shown in FIG. An initial screen 10 for image processing is displayed (S1).
When an instruction to select and import image data to be processed is given from the file menu in the menu bar 11, the image is received from the HDD 3, the disk 4a, the recording device on the external network, or the like that is the storage destination of the selected image data. Data is read and stored in the main memory 2 (S2, S3).
The stored image data is read out to the video I / F 7 and displayed in the display area 14 of the original image on the image processing screen 10 (S4).

Next, all the pixels of the image data in the main memory 2 are analyzed, and each pixel is assigned to a luminance gradation of 0 to 255 based on the luminance value (S5).
Then, data of the chromaticity circle 30 (n) for each gradation is created for each luminance gradation by the method described in detail with reference to FIGS. 4, 5A, and 5B.
That is, the light intensity of R, G, B of each pixel belonging to the nth gradation is analyzed, and the ratio of the R and G light intensity to the total value of each R, G, B light intensity (R ratio, G Ratio), and mapping as a pixel for color attribute display on the pseudo xy chromaticity diagram based on the R ratio and G ratio of each pixel, and from the pseudo xy chromaticity diagram (right isosceles triangle) to an equilateral triangle, Further, projection is performed in order from an equilateral triangle to a circle (circumscribed circle), and in each process, mapping pixel positions are associated based on the mapping corresponding to the shape change, and the nth gradation level is obtained. Data of the tonal chromaticity circle 30 (n) is created (S6, S7).
This procedure is executed for each pixel belonging to each luminance gradation from 0 to 255, and data of 256 sets of chromaticity circles 30 (n) by gradation is saved in the main memory 2 (S6 to S9 → S8). .

In this way, when data of tone-specific chromaticity circles 30 (n) [n = 0 to 255] is saved, a cylindrical HSV color space corresponding to a configuration in which these tone-specific chromaticity circles are stacked. Data (see FIG. 3) has been created (S10).
Then, based on the fact that this cylindrical HSV color space data represents the distribution state of hue, saturation, and luminance of the image by mapping pixels, a chromaticity circle 12 when the HSV color space is viewed from the upper side in the axial direction. Display data of the color space front view 13 viewed from the direction perpendicular to the axial direction is generated and displayed in the color attribute display area of the display 7a as shown in FIG. 2B (S11).

In this embodiment, as an operation tool used for various image processing, as shown in FIG. 2B, the first cursor 17, the first cursor 17, and the chromaticity circle 12 are applied to the chromaticity circle 12. A radius line 18 connecting the centers, a second cursor 19 above the radius line 18 and a circle line 20 passing through the second cursor 19 concentrically with the chromaticity circle 12 are displayed. Displays the third cursor 21 and the level line 22 corresponding to the tone-specific chromaticity circle 30 (n) at the same gradation position (S12).
Here, the first cursor 17 and the radius line 18 are used for changing the hue, the second cursor 19 and the circular line 20 are used for changing the saturation, and the third cursor 21 and the level line 22 are used for changing the brightness. is there.

However, in this embodiment, the initial display positions of these operation tools 17, 18, 19, 20, 21, and 22 are given a certain significance.
FIG. 8 details step S12 of FIG. 7, and is a flowchart showing an initial display procedure of each operation tool.
In the procedure, first, three numerical values are obtained as follows.
(1) The distance from the central axis of the columnar HSV space is obtained for all mapping pixels of the columnar HSV color space data obtained in step S10 of FIG. 7, and the average value Dave of these distances is obtained (S21). .
(2) The circumference of the central axis in the columnar HSV space is equally divided into 32 (center angle = 11.25 °), and the number of pixels Nc (i) [i = 0 to 32] belonging to each divided section is obtained ( S22).
(3) The number of pixels Nv (n) [n = 0 to 255] belonging to each gradation tone chromaticity circle 30 (n) for the luminance gradation of 0 to 255 is obtained (S23).

Then, the first cursor 17 is displayed with the outer side of the chromaticity circle 12 at the position where the straight line that bisects the central angle of the divided space where Nc (i) is maximum and the outermost circumference of the chromaticity circle intersect as the initial position. In addition, a radius line 18 connecting the center of the chromaticity circle 12 and the first cursor 17 is displayed (S24).
Further, the circle line 20 is displayed at the position of the radius Dave from the center of the chromaticity circle 12, and the second cursor 19 is displayed at the intersection of the radius line 18 and the circle line 20 (S25, S26).
Further, the tone-specific chromaticity circle 30 that is on a line parallel to the cylinder axis from the position of the second cursor 19 of the chromaticity circle 12 toward the color space front view 13 and has the maximum number of pixels Nv (n). The third cursor 21 is displayed at a position corresponding to (n), and the level line 22 is displayed at a position corresponding to the tone-specific chromaticity circle 30 (n) (S27, S28).

Thus, by setting the initial display positions of the cursors 17, 19, 21 and the radius line 18, the circle line 20, and the level line 22, the chromaticity circle 12 and the mapping pixels displayed in the color space front view 13 are displayed. In addition to the color attribute distribution state, the highest hue in the image, the average saturation of the entire image, and the luminance gradation of the largest number of pixels can be confirmed at the same time, and the subsequent operation tools 17, 18, 19, 20, 21, 22 can be This can be used as a guide for changing the color attribute of the used digital image.

Returning to the flowchart of FIG. 7, when the operation tools 17, 18, 19, 20, 21 and 22 are displayed, the chromaticity circle 12 and the color space are displayed together with the digital image in the display area 14 of the original image to be changed. While looking at the distribution state of the mapping pixel in the front view 13, after setting each processing mode of hue / saturation / lightness with the radio buttons 16a, 16b, the mouse 6a is used to right-click / left-click the button or the keyboard 6b. While selecting detailed processing contents using function keys or the like, the digital image color attribute changing operation is performed by dragging and dropping the cursors 17, 19, and 21 (S13).

Then, when a color attribute change operation is performed in the chromaticity circle 12 or the color space front view 13, movement or deletion is changed for the mapping pixels of the HSV color space data in the main memory 2, and the chromaticity circle 12 or The change is reflected in the display of the mapping pixel in the color space front view 13 (S13).
Further, when each mapping pixel in the chromaticity circle 12 or the color space front view 13 is associated with each pixel of the digital image data developed in the main memory 2, the color attribute of the mapping pixel is changed. The change is reflected in the corresponding pixel on the image data side, the digital image data after the change is separately stored in the main memory 2 and read out to the video I / F 7, and the image is displayed in the display area of the change image. 15 (S13, S14).

Next, FIG. 9 shows the basic operation of the mouse 6a and the operation tools 17, 18, 19, when setting the hue / saturation / lightness processing modes and performing the color attribute changing operation in step S13 of FIG. It is a figure explaining the relationship with the operation | movement of 20,21,22.
The first cursor 17 can move on the trajectory along the outer periphery of the chromaticity circle 12. In the hue processing mode, the first cursor 17 can be moved to a free position on the trajectory by rotating the wheel of the mouse 6a. In order to change the hue, the mouse 6a is moved by dragging and dropping the trajectory.
The radius line 18 always rotates with the movement of the first cursor, and becomes a guideline for changing the mapping pixel when changing the hue of the image, and is particularly useful when changing a part of the hue in the image. It is.

The second cursor 19 can move on the radius line 18, and can be moved to a free position on the radius line 18 by rotating the wheel of the mouse 6a in the saturation processing mode. When the saturation change is executed, the mouse 6a is moved by dragging and dropping on the radius line 18.
The circle line 20 is a circle that is concentric with the chromaticity circle 12 and always passes through the second cursor 19, and the radius thereof increases or decreases when the second cursor 19 moves on the radius line 18. When changing the saturation of the image, it becomes a guideline for changing the mapping pixel, and is particularly useful when changing the saturation of a part of the image.

The third cursor 21 can move on a straight line 31 parallel to the axis in the color space front view 13 through the position of the second cursor 19 on the chromaticity circle 12 side. In the lightness processing mode, the mouse 6a can be rotated to a free gradation position on the trajectory by rotating the wheel. When changing the lightness of the image, the mouse 6a is dragged and dropped on the straight line 31. To move.
The level line 22 corresponds to the tone-specific chromaticity circle 30 (n) where the third cursor 21 is located. When the brightness of the image is changed, the level line 22 is an indication of the change to the mapping pixel. This is useful when changing the brightness of the part.

Hereinafter, various color attribute changing operations on the chromaticity circle 12 and the color space front view 13 executed in step S13 of FIG.
<Hue change processing of entire image>
As shown in FIG. 10A, in the hue processing mode setting state, the first cursor 17 at an arbitrary position on the outer periphery of the chromaticity circle 12 is right-clicked with the mouse 6a, and the outer periphery of the chromaticity circle 12 is displayed. When dragging and dropping along the line, as shown in FIG. 10B, all the mapping pixels of the HSV color space data move the cylinder axis of the HSV color space by the rotation angle of the radius line 18 accompanying the movement of the first cursor 17. It can be rotated to the center.
Accordingly, in the chromaticity circle 12, all mapping pixels are changed from the hue at the position before the rotation to the hue at the position after the rotation, and the hue of all the pixels on the image data side is also changed accordingly.

<Selective hue change processing of image>
First, in the setting state of the hue processing mode, by operating the wheel of the mouse 6a and moving the first cursor 17 along the outer periphery of the chromaticity circle 12, the change destination hue side in the hue range where the radius line 18 is to be changed. Located on the opposite boundary.
Then, as shown in FIG. 11A, when the first cursor 17 is left-clicked with the mouse 6a in the hue processing mode and dragged and dropped along the outer periphery of the chromaticity circle 12, (B) of FIG. ), Each mapping pixel of the HSV color space data included in the rotation angle range (hue range to be changed) of the radius line 18 accompanying the movement of the first cursor 17 is the rotation angle amount about the cylinder axis. Can only be rotated.
Therefore, the mapping pixels included in the range in the chromaticity circle 12 are changed from the hue before rotation to the hue after rotation, and the hue of the pixels on the image data side corresponding to these mapping pixels is also changed.
For the color weak, there are many cases where the image appears more clearly by changing the hue, and this hue range changing process is effective in that sense.

<Saturation change processing of entire image>
As shown in FIG. 12A, in the saturation processing mode setting state, the second cursor 19 at an arbitrary position on the radius line 18 is right-clicked with the mouse 6a and the radius line 18 is moved outward. When dragging and dropping, as shown in FIG. 12B, all the mapping pixels of the HSV color space data are moved in such a manner as to spread around the cylinder axis toward the outer peripheral side. However, it does not move outward from the position of the outer peripheral surface of the cylinder.
Therefore, in the chromaticity circle 12, all the mapping pixels are changed from the saturation before the movement to the saturation after the movement, and the saturation of all the pixels of the image data is also changed accordingly. That is, the vividness of the image on the entire screen increases.
Note that when the second cursor 19 on the radius line 18 is dragged and dropped inward, all the mapping pixels of the HSV color space data move in a manner concentrating toward the cylinder axis side, and as a result, the screen is changed. The vividness of the entire image is reduced.

<Saturation change processing for selected hue in image>
First, in the setting state of the hue processing mode, the radius line 18 is positioned at the center of the hue range to be changed by operating the wheel of the mouse 6a and moving the first cursor 17 along the outer periphery of the chromaticity circle 12. .
Then, as shown in FIG. 13A, when the mode is switched to the saturation processing mode, the second cursor 19 is left-clicked with the mouse 6a and dragged and dropped on the radial line 18 in the inner direction, the ( As shown in B), the mapping pixel moves in a manner in which the entire HSV color space data is compressed from the cylindrical space to an elliptical columnar space having the radius line 18 as the short axis. It is possible to selectively reduce the saturation of the mapping pixel in the hue range centering on.
As a result, the saturation of pixels in the hue range in the image data can be selectively reduced, and the saturation of a specific hue range in the image can be reduced without greatly changing the overall balance. it can.
This image processing is effective, for example, when it is easy to see an image taken under sunset or tungsten light.
In FIG. 13A, when the second cursor 19 on the radial line 18 is dragged and dropped in the outward direction, the saturation of a specific hue range can be increased contrary to the above.

<Brightness change processing for entire image>
As shown in FIG. 14A, in the lightness processing mode setting state, the third cursor 21 at an arbitrary position on the straight line 31 in the color space front view 13 is right-clicked with the mouse 6a and the straight line 31 is clicked. When moving in the direction of ΔV by ΔV, as shown in FIG. 14B, all mapping pixels of the HSV color space data also move in the moving direction of the third cursor 21 by ΔV. However, the mapping pixel does not move beyond the upper surface (255th gradation) and the bottom surface (0th gradation) of the cylinder, each of which is the limit of the movement range.
Therefore, if the third cursor 21 is moved upward / downward, the luminance of all the mapping pixels is increased / decreased by the luminance gradation corresponding to the movement distance ΔV, and the luminance gradation of all the pixels of the image data is correspondingly increased. Since it is changed to be higher / lower, the brightness of the entire image can be changed.

<Lightness change processing for the selected hue in the image>
First, in the setting state of the hue processing mode, the radius line 18 is positioned at the center of the hue range to be changed by operating the wheel of the mouse 6a and moving the first cursor 17 along the outer periphery of the chromaticity circle 12. .
Next, after pressing the function key Fn of the keyboard 6b, an angle is input with the numeric keypad to select a hue range, and when the function key Fn is pressed again, the selected hue range is masked with light white.
Then, as shown in FIG. 15A, the mode is switched to the brightness processing mode, and the third cursor 21 at an arbitrary position on the straight line 31 is left-clicked with the mouse 6a to move on the straight line 3 by ΔV. As shown in FIG. 15B, only the mapping pixels included in the color space below the selected hue range (the hatched range in the chromaticity circle 12 in the figure) move the third cursor 21. Move in the direction by ΔV.
Accordingly, if the third cursor 21 is moved upward / downward, the luminance of the mapping pixel within a certain hue range is increased / decreased by the luminance gradation corresponding to the moving distance ΔV, and the image data corresponding to the above-described image data is correspondingly increased. The luminance gradation of the pixels within the hue range is also changed to be higher / lower.
That is, the luminance of pixels in a specific hue range in the image can be selectively changed.

<Image contrast change processing>
First, in the lightness processing mode setting state, the third cursor 21 is moved to a predetermined luminance gradation position on the straight line 31 by operating the wheel of the mouse 6a.
Then, as shown in FIG. 16A, while maintaining the brightness processing mode, the third cursor 21 is right-clicked with the mouse 6a while pressing the function key Fn of the keyboard 6b in the setting state of the brightness processing mode. As shown in FIG. 16B, when the pixel 31 is moved by ΔB gradation, the luminance of the mapping pixel belonging to the tone-specific chromaticity circle having the gradation higher than the gradation at the movement start position is set to ΔB gradation. On the contrary, the luminance of the mapping pixel belonging to the tone-specific chromaticity circle of the gradation lower than the gradation of the movement start position is decreased by ΔB gradation.
Therefore, among the mapping pixels, the pixel belonging to the higher luminance side than the luminance gradation at the movement start position of the third cursor 21 belongs to the higher luminance and the lower luminance side due to the movement of the third cursor 21 under the above conditions. Since the luminance of the object is lower and the luminance gradation of the pixel of the image data is correspondingly changed correspondingly, the changing process for increasing the contrast can be performed.
Note that the effect of changing the contrast differs depending on the position at which the third cursor 21 is first moved by the wheel operation of the mouse 6a.

<Enhancement of selected hue in image>
First, in the setting state of the hue processing mode, the first cursor 17 is moved along the outer periphery of the chromaticity circle 12 by operating the wheel of the mouse 6a, so that the radial line 18 is positioned on the side of the hue range to be emphasized. Let
Then, as shown in FIG. 17A, in the hue processing mode, the first cursor 17 is left-clicked with the mouse 6a and dragged along the outer periphery of the chromaticity circle 12 while pressing the function key F1 of the keyboard 6b. When the & drop is performed, the mapping pixels included in the lower color space of the sector (hatched area) formed on the chromaticity circle 12 within the rotation range of the radius line 18 accompanying the movement are left as they are, as shown in FIG. As shown in (B), mapping pixels in another color space are replenished into the color space from the circumferential direction.
That is, the distribution state of the mapping pixels in the other color spaces is expanded uniformly in the circumferential direction, and the mapping pixels are moved from the circumferential direction into the lower color space of the sector shape.
Therefore, the number of mapping pixels having a hue defined in the HSV color space on the lower side of the sector increases, and the corresponding number of pixels of the image data has the hue, thereby enhancing the hue in the image. Can be processed.

<Enhancement of selected saturation range in image>
First, with the saturation processing mode set, the wheel of the mouse 6a is operated to position the second cursor 19 inside the saturation range (hatched annular region) to be emphasized on the radius line 18.
Then, as shown in FIG. 18A, in the saturation processing mode, the second cursor 19 is left-clicked with the mouse 6a while pressing the function key F1 of the keyboard 6b, and the saturation range is set on the radius line 18. When dragging and dropping to the outside, the mapping pixels included in the color space below the hatched annular region are left as they are, and the mapping pixels in the other color spaces have the radius as shown in FIG. It is replenished into the color space from the direction.
That is, the distribution state of the mapping pixels in other color spaces (inside and outside of the shaded annular region) is uniformly expanded in the radial direction, and the mapping pixels are radially entered into the color space below the shaded annular region. Move from.
Therefore, the number of mapping pixels having the saturation defined in the color space below the shaded annular area increases, and correspondingly, the number of pixels of the image data having the saturation increases. The saturation range can be emphasized.

<Brightness change processing for special images>
When there is a very strong light source such as the sun entering the image, so-called halation occurs and the periphery of the light source part becomes a white and blurred image.
Looking at the distribution state of the mapping pixels in the color space front view 13, as shown in FIG. 19A, a state in which many mapping pixels are concentrated in the vicinity of the highest gradation (shaded portion) and the vicinity thereof. As can be confirmed.
In that case, after the third cursor 21 is moved to the lower side of the concentrated portion of the mapping pixels by operating the wheel of the mouse 6a as shown in FIG. While holding down the function key F1 of the keyboard 6b, the third cursor 21 is left-clicked with the mouse 6a and dragged and dropped near the highest gradation.
Then, the mapping pixels near the highest luminance gradation are almost unchanged, and as shown in FIG. 19B, the mapping pixels distributed in the gradation slightly below are sent to the vicinity of the highest gradation. The mapping pixel belonging to the lower gradation moves to the lower side.
Due to the processing on the mapping pixel in the color space front view 13, the pixel in the portion where halation occurs in the image data moves to the highest gradation side, and the image is visually reduced in halation.

<Process for selectively removing a certain range of hues from an image>
First, in the setting state of the hue processing mode, by operating the wheel of the mouse 6a to move the first cursor 17 along the outer periphery of the chromaticity circle 12, the radius line 18 is moved to the side of the hue range where the hue line is desired to disappear. Position.
Then, as shown in FIG. 20A, in the hue processing mode, the first cursor 17 is left-clicked with the mouse 6a while pressing the function key F2 of the keyboard 6b, and the radius line 18 indicates the hue range to be erased. Drag and drop along the outer periphery of the chromaticity circle 12 to rotate.
Then, as shown in FIG. 20B, the mapping pixel included in the color space below the sector (hatched area) through which the radius line 18 passes in the chromaticity circle 12 has the sector central radius line. Each of them moves in the circumferential direction in a manner separated as a boundary, and as a result, there is no mapping pixel in the lower color space of the fan shape, and all the mapping pixels are in a more dense positional relationship in the circumferential direction. Become.
Corresponding to this operation processing, the pixels of the hue belonging to the fan-shaped range in the image data become hue values at new movement positions in the chromaticity circles 31 (n) for each hierarchy, and in the image, the fan-shaped pixels Therefore, there is no pixel having a hue value within the range of.

<Process for selectively erasing a certain saturation range from an image>
First, in the saturation processing mode setting state, by operating the wheel of the mouse 6a to move the second cursor 19 along the radius line 18, the saturation range (annular range) to be lost in the chromaticity circle 12 is set. )
Then, as shown in FIG. 21A, in the saturation processing mode, the second cursor 19 is left-clicked with the mouse 6a while pressing the function key F2 of the keyboard 6b, and the ring-shaped range on the radius line 18 is displayed. Drag and drop outside the box.
Then, as shown in FIG. 21B, the mapping pixels included in the color space below the ring-shaped range (shaded area) are inward and outward with a circle passing through the center of the ring-shaped range as a boundary. Each moves in a radial direction in a divided manner.
As a result, there are no mapping pixels in the lower color space of the ring-shaped range, and all the mapping pixels are in a distribution state with a closer positional relationship in the radial direction.
Corresponding to this operation processing, the saturation pixel belonging to the ring-shaped range in the image data becomes the saturation value at the new movement position, and the image has the saturation value included in the ring-shaped range. There will be no pixels.
The second cursor 19 is positioned outside the ring-shaped range by operating the wheel of the mouse 6a, and the second cursor 19 is left-clicked with the mouse 6a and dragged inside the ring-shaped range while pressing the function key F2. Even in the case of & drop, the same function / effect may be obtained.

<Process for selectively erasing a certain luminance range from an image>
First, in the setting state of the brightness processing mode, the third cursor 21 is moved in the direction of the straight line 31 by operating the wheel of the mouse 6a, so that it is positioned below the luminance range to be lost in the color space front view 13. .
Then, as shown in FIG. 22A, in the lightness processing mode, while holding down the function key F2 of the keyboard 6b, the third cursor 21 is left-clicked with the mouse 6a and dragged to the upper side of the luminance range to be lost. Drop it.
Then, the mapping pixels included in the luminance range in the HSV color space move in the vertical direction in such a manner that the mapping pixels are divided into upper and lower sides with the central level of the luminance range as a boundary. And all the mapping pixels are distributed more densely in the vertical direction.
Corresponding to this operation processing, pixels belonging to the luminance range in the image data become luminance values at the new movement position, and no pixel having a luminance value included in the luminance range exists from the image. .
Note that the third cursor 21 is positioned above the luminance range by operating the wheel of the mouse 6a, and left-clicked with the mouse 6a while pressing the function key F2 and dragged and dropped to the lower side of the luminance range. Similar functions and effects may be obtained.

The above-mentioned “process for selectively erasing the hue range / saturation range / luminance range from the image” is a process for changing the image, but the erasure position of the color attribute is reduced by reducing the disappearance range of the color attribute. If it is provided, confidential information such as copyright information can be added to the image data without substantially affecting the image.

In the above embodiment, the case where the chromaticity circle 12 and the spatial front view 13 are displayed based on the HSV color space data and the image processing is executed has been described. However, when only the hue and saturation are changed, Alternatively, only the chromaticity circle 12 and the operation tools 17, 18, 19, and 20 related thereto may be displayed.
Further, even when performing a lightness changing operation, a method of displaying the chromaticity circle 12 of this embodiment in combination with the conventional lightness changing slider bar may be used, but in this method, the selected hue range is used. It is impossible to change the brightness of pixels belonging to the saturation range.

The present invention can be applied to an image processing apparatus and photo retouching software that change the hue, saturation, and brightness of a digital image using a GUI.

1 ... CPU, 2 ... main memory, 3 ... hard disk, 4 ... disk drive, 4a ... disk, 5 ... network I / F, 6 ... input I / F, 6a ... mouse, 6b ... keyboard, 7 ... video I / F , 8 ... Sound I / F, 8a ... Speaker, 9 ... System bus, 10 ... Initial screen for image processing, 11 ... Menu bar, 12 ... Chromaticity circle, 13 ... Color space front view, 15 ... Display of original image Area, 15 ... display area of the changed image, 16a ... selection section for each processing mode of hue / saturation, 16b ... selection section for lightness processing mode, 17 ... first cursor, 18 ... radius line, 19 ... second cursor, 20 ... circle line, 21 ... third cursor, 22 ... level line, 30 (n) ... tone-specific chromaticity circle, 31 ... straight line, MP ... mapping pixel.

Claims (9)

First storage means for storing digital image data;
Pixel sorting means for sorting all the pixels of the digital image data in the first storage means into N gradations (N is an integer of 16 or more) based on the luminance value;
For each gradation pixel group sorted by the pixel sorting means, each pixel is associated with any two of the three colors for the total light intensity of R (red), G (green), and B (blue). The ratio of each light intensity value is obtained, and the two ratios are mapped onto the coordinates of the pseudo xy chromaticity diagram, which is an orthogonal coordinate with the vertical axis and the horizontal axis, so that the side corresponding to each ratio is orthogonally divided. First data creation means for creating first stage data in which chromaticity information of a pixel group belonging to the gradation is mapped as a pixel in a right isosceles triangle as a side;
For each of the first gradation data for N gradations created by the first data creation means, a pixel related to chromaticity information (hereinafter referred to as “mapping pixel”) mapped in the right isosceles triangle is mapped. Projecting into an equilateral triangle, the three vertices of the equilateral triangle correspond to R, G, and B clear colors or pure colors at the luminance gradation, and the three sides are respectively R, G, B at the luminance gradation. Second data creation means for creating second-stage data corresponding to a clear color or a pure color by mixing two colors of G and B and having a gravity center position corresponding to an achromatic color at the luminance gradation;
For each second stage data for N gradations created by the second data creation means, the mapping pixels in the equilateral triangle are projected into a circle by mapping, and the central angle at the circumference of the circle is 120 °. Each position corresponds to a clear color or pure color of R, G, B at the luminance gradation, and the other sections of the circumference are mixed with two colors of R, G, B at the luminance gradation, respectively. A third data creating means for creating tone-specific chromaticity circle data corresponding to a clear color or a pure color according to, and the center position of the circle corresponding to an achromatic color in the luminance gradation;
Second storage means for storing gradation-specific chromaticity circle data for N gradations created by the third data creation means as HSV color space data in which mapping pixels are three-dimensionally distributed in a cylindrical color space; ,
Display data creation means for creating display data of chromaticity circles when the HSV color space is viewed from the cylinder axis direction based on the HSV color space data of the second storage means;
A digital image color attribute display device comprising: display control means for displaying the chromaticity circle on a display based on display data created by the display data creating means. The display data creating means is a view of the HSV color space viewed from the direction perpendicular to the cylinder axis together with the display data of the chromaticity circle based on the HSV color space data of the second storage means (hereinafter referred to as “color space”). 2. The digital image color attribute display device according to claim 1, wherein display data of “front view” is created, and the display control unit displays the chromaticity circle and the color space front view on a display. A color attribute display method for a digital image performed by a computer,
A first step of storing digital image data in a first storage means;
A second step of classifying all pixels of the digital image data stored in the first storage means in the first step into N gradations (N is an integer of 16 or more) based on a luminance value;
For each tone pixel group sorted in the second step, the ratio of each light intensity value for any two of the three colors to the total light intensity of R, G, B for each pixel is obtained. By mapping the two ratios onto the coordinates of the pseudo xy chromaticity diagram, which is an orthogonal coordinate with the vertical axis and the horizontal axis, the inside of a right isosceles triangle with the sides corresponding to each ratio as two orthogonal sides A third step of creating first stage data in which chromaticity information of a pixel group belonging to the gradation is mapped as a pixel;
For each of the first-stage data for N tones created in the third step, the mapping pixels in the right-angled isosceles triangle are projected into an equilateral triangle by mapping, and the three vertices of the equilateral triangle each have the corresponding luminance. It corresponds to a clear color or pure color of R, G, B in gradation, and each of the three sides corresponds to a clear color or pure color by mixing two colors of R, G, B in the luminance gradation, A fourth step of creating second stage data in which the position of the center of gravity corresponds to an achromatic color at the luminance gradation;
For each of the second-stage data for N gradations created in the fourth step, the mapping pixels in the equilateral triangle are projected into a circle by mapping, and the central angle on the circumference of the circle is set every 120 °. Each position corresponds to a clear color or a pure color of R, G, B at the brightness gradation, and the other sections of the circumference are each a clear color by mixing two colors of R, G, B at the brightness gradation. A fifth step of creating tone-specific chromaticity circle data corresponding to a color or a pure color and having a center position of the circle corresponding to an achromatic color in the luminance gradation;
Sixth tone-specific chromaticity circle data for N tones created in the fifth step is stored in the second storage means as HSV color space data in which mapping pixels are three-dimensionally distributed in a cylindrical color space. And the steps
Based on the HSV color space data stored in the second storage means in the sixth step, a seventh step of creating display data of a chromaticity circle when the HSV color space is viewed from the cylinder axis direction;
A digital image color attribute display method comprising: an eighth step of displaying the chromaticity circle on a display based on the display data created in the seventh step. In the seventh step, display data of a color space front view is created together with the display data of the chromaticity circle based on the HSV color space data of the second storage means, and in the eighth step, the color data 4. The digital image color attribute display method according to claim 3, wherein the color space front view is displayed on a display together with a degree circle. A digital image color attribute display program which causes a computer to execute each step of the digital image color attribute display method according to claim 3 or 4. The digital image color attribute display device according to claim 1, wherein the display control unit of the device displays the chromaticity circle on a display, and the digital image data stored in the first storage unit is also the image. An image processing apparatus to be displayed on a display,
A first cursor that is movable in the circumferential direction along the outer periphery of the chromaticity circle displayed by the color attribute display device, connects the first cursor and the center of the chromaticity circle, and moves with the movement of the first cursor. An operating tool display means for displaying a rotating radius line, a second cursor movable on the radius line, and a circular line concentric with the chromaticity circle and passing through the second cursor;
Operation input means capable of independently moving the first cursor and the second cursor;
The mapping pixels in the HSV color space stored in the second storage unit of the color attribute display device in the circumferential direction are rotated according to the rotation of the radial line accompanying the movement of the first cursor by the operation input unit. The mapping pixel moved or erased in the radial direction is moved or erased in accordance with the increase or decrease of the radius of the circular line accompanying the movement of the second cursor by the operation input means. For the pixel, color space data changing means for changing to the destination color attribute value,
Display pixel data changing means for performing the same color attribute changing process on the pixels of the digital image data in the first storage means corresponding to the mapping pixels to be changed (moved or deleted) by the color space data changing means; An image processing apparatus comprising: The operation tool display means is configured to divide the initial display position of the first cursor in the chromaticity circle into M equal parts (M is an integer of 16 or more) around the HSV color space, The maximum number of mapping pixels contained therein is set to the outer peripheral position, and the initial display position of the second cursor in the chromaticity circle is on the radius line and is the first position of the color attribute display device. The image processing apparatus according to claim 6, wherein the position is set to a position corresponding to an average value of saturation values of all pixels of the digital image data stored in the one storage unit. 3. A digital image color attribute display device according to claim 2, wherein the display control means of the device displays the chromaticity circle and the color space front view on a display, and the digital data stored in the first storage means. An image processing apparatus for displaying an image of image data on the display,
A first cursor that is movable in the circumferential direction along the outer periphery of the chromaticity circle displayed by the color attribute display device, connects the first cursor and the center of the chromaticity circle, and moves with the movement of the first cursor. A rotating radius line, a second cursor movable on the radius line, a circular line concentric with the chromaticity circle and passing through the second cursor, and a cylinder axis related to the HSV color space in the color space front view An operation tool display means for displaying a third cursor movable in a parallel direction;
Operation input means capable of independently moving the first cursor, the second cursor, and the third cursor;
The mapping pixels in the HSV color space stored in the second storage unit of the color attribute display device in the circumferential direction are rotated according to the rotation of the radial line accompanying the movement of the first cursor by the operation input unit. The HSV color space mapping pixel is moved or erased in the radial direction in accordance with the increase or decrease of the radius of the circular line accompanying the movement of the second cursor by the operation input means, and the operation input means According to the movement of the third cursor by the color space data, the mapping pixel in the HSV color space is moved or deleted in the direction parallel to the cylinder axis, and the moved mapping pixel is changed to the destination color attribute value. Change means,
Display pixel data changing means for performing the same color attribute changing process on the pixels of the digital image data in the first storage means corresponding to the mapping pixels to be changed (moved or deleted) by the color space data changing means; An image processing apparatus comprising: The operation tool display means is configured to divide the initial display position of the first cursor in the chromaticity circle into M equal parts (M is an integer of 16 or more) around the HSV color space, It is set to the outer peripheral position of the largest number of mapping pixels included therein, and the initial display position of the second cursor in the chromaticity circle is on the radius line and is the first of the color attribute display device. The color attribute display device sets the initial display position of the third cursor in the color space front view to a position corresponding to the average value of the saturation values of all the pixels of the digital image data stored in the storage means 9. The image processing apparatus according to claim 8, wherein the gradation position is set to a gradation position corresponding to a maximum number of mapping pixels among gradation gradation-specific chromaticity circles for N gradations created in (1).

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