Hair color treatment method

Abstract

To provide a hair color processing method capable of making a desirable image regardless of a hair color by processing an image while considering a hair color after processing.SOLUTION: A hair color processing method for coloring a hair region showing a hair color on an image includes: a designated color receiving step (step S102) of receiving designation of a designated color to be colored with respect to the hair region; and an image processing step of synthesizing the designated color designated in the designated color receiving step with a ground color as a color of the hair region on the image. In the image processing step, a synthetic ratio of the designated color with respect to the ground color is changed in accordance with the hue of the designated color.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hair color processing method, a hair color processing device, and a hair color processing program. [Background technology]

[0002] Currently, many applications for processing photographed facial images are in practical use. Publicly known examples of such applications are described, for example, in Patent Document 1 and Non-Patent Document 1. The image print creation device described in Patent Document 1 allows a user to input makeup, and creates makeup image data corresponding to the makeup input using a predetermined image processing method. The device then combines the photographed image data and the makeup image data to create composite image data. In addition, the application disclosed in Non-Patent Document 1 allows users to select a desired hair color using an icon displayed on the screen of a terminal device, and color at least a portion of the hair of a person's image displayed on the screen with the selected color.

[0003] Such image processing devices and applications can create processed images by processing an image into a desired hair color and can be used for simulations to determine the hair color when actually dyeing hair, etc. Furthermore, such image processing devices and applications can create processed images with various hair colors without actually dyeing hair, and provide them to SNS (Social Networking Service) and the like. Whether it's a hair color simulation or creating a social media image, the edited image must give a favorable impression to others. "Pleasant" here means that people who see the edited image do not find it unnatural or strange, but rather find it beautiful. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-69404 [Non-patent literature]

[0005] [Non-Patent Document 1] Erinacchi, July 27, 2018, "Change your color contact lenses and hair color! Selfie camera app summary, try out any color you like for free,"<https: / / apptopi.jp / 2018 / 07 / 27 / haircolor-colorcontact-app / > , accessed March 28, 2019 Summary of the Invention [Problem to be solved by the invention]

[0006] Mammals possess only melanocytes, which produce melanin, as pigment cells. Most melanocytes are found in the epidermis, where melanin synthesis occurs in specific intracellular organelles called melanosomes. Once melanin is fully deposited, melanosomes are transported to keratinocytes, determining the color of skin and hair. Melanin pigments are divided into eumelanin (black to dark brown) and pheomelanin (reddish brown to yellow). The body hair of Asians, including Japanese, is produced by eumelanin, while the body hair of Northern Europeans is produced by pheomelanin (Noriko Oshima, 2003, "Mechanisms for Chromatophores and Their Motility Control in Teleost Fish," Comparative Physiology and Biochemistry, 2003, Vol. 20, No. 3, pp. 131-139). This suggests that humans are more sensitive to hair colors that cannot be expressed by the aforementioned melanin pigments than to colors such as black or reddish brown, and are able to notice even slight discoloration. However, the above-mentioned Patent Document 1 and Non-Patent Document 1 make no mention of taking into account post-processing hair color when processing an image. Therefore, when a processed image is created using the image print creation device described in Patent Document 1 or the application described in Non-Patent Document 1, depending on the hair color, the processed image may look unnatural and may impair the beauty of the image. The present invention has been made in consideration of the above points, and relates to a hair color processing method, a hair color processing device, and a hair color processing program that can process an image taking into account the hair color after processing and create a desirable image regardless of the hair color. [Means for solving the problem]

[0007] The hair color processing method of the present invention is a hair color processing method for coloring a hair region in an image that indicates hair, and includes a color specification receiving step for receiving a specification of a specified color to be colored in the hair region, and a synthesis step for combining the specified color specified in the color specification receiving step with a base color that is the color of the hair region in the image, and in the synthesis step, the synthesis ratio of the specified color with respect to the base color is changed depending on the hue of the specified color. [Effects of the Invention]

[0008] The present invention can provide a hair color processing method, a hair color processing device, and a hair color processing program that can process an image taking into account the hair color after processing and create a desirable image regardless of the hair color. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a flowchart illustrating an image processing method according to an embodiment of the present invention. [Figure 2] FIG. 2 is a functional block diagram of a hair color processing device that executes the hair color processing method shown in the flowchart of FIG. [Figure 3] 3 is a diagram for explaining a reception unit shown in FIG. 2. FIG. [Figure 4] 10A and 10B are diagrams for explaining a method for determining a color synthesis ratio according to the hue of a specified color. [Figure 5] 10A and 10B are diagrams for explaining the relationship between the hue of a specified color and a minimum blending ratio; [Figure 6] 10A to 10E are diagrams showing the relationship between the hue of a specified color and the minimum blending ratio for a plurality of combinations of saturation and lightness. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described below with reference to the drawings. Note that the drawings of the present embodiment are intended to explain the technical concept, configuration, and operation of the present invention, and are not intended to specifically limit the configuration. [Hair color treatment method] FIG. 1 is a flowchart illustrating a hair color processing method according to this embodiment. This embodiment is a hair color processing method for coloring an area in an image that indicates hair. Here, an image refers to data (hereinafter also referred to as "image data") that combines pixel values ​​that indicate the density of the image with the position coordinates of these pixel values. The output destination of the image data may be a paper medium or a display screen. When an image is composed of multiple color components, pixel values ​​are determined for each color component.

[0011] Hair includes head hair (hereinafter simply referred to as "hair") and body hair. Hair is not limited to human hair, but also includes animal body hair and feathers. The above-mentioned region is specified by the region's longitudinal length and the length in the direction perpendicular to this longitudinal direction (hereinafter also referred to as "width"). The region's width can be specified, for example, by selecting at least one from a plurality of pre-set widths. The region's length is determined based on a line specified on the image. The region refers to a closed region determined by such width and length. In this embodiment, such a region is the target of coloring, and therefore this region will hereinafter be referred to as a "coloring region." However, this embodiment is not limited to a configuration in which the width of the coloring region is set in advance. For example, the width of the coloring region may be determined by detecting the pressure applied to an image displayed on a display screen using a known technology and determining the width in proportion to the magnitude of the pressure. Furthermore, in this embodiment, when a line is specified by touching the image with a finger, a pen, or the like, the width of the coloring region may be determined as the width of the contacted image, or the width of the contacted image plus or minus a predetermined length.

[0012] Furthermore, in this embodiment, it is also possible to specify the length of the coloring region by points. When specifying the length of the coloring region by points, the start point and end point of the coloring region may be specified, or multiple points spaced apart from each other along the flow of the hair may be specified. The designated color is a color designated by an operator who changes the hair color using the hair color processing method. The designated color may be a color arbitrarily designated by the operator, or may be a color designated from a plurality of preset colors. Under the above conditions, this embodiment describes a hair color processing method, a hair color processing device, and a hair color processing program using an example in which a person's hair color is the target of processing, the length of the coloring area is specified by moving a pen while it is in contact with the image, and the width of the coloring area is selected from a plurality of preset widths.

[0013] 1, the hair color processing method of this embodiment includes an image capturing step (step S101) of capturing an image to be processed, a color designation receiving step (step S102) of receiving a designation of a designated color to be applied to the hair region, and a compositing step (steps S104, S105) of combining the designated color designated in the color designation receiving step with a base color, which is the color of the hair region in the image. The compositing step changes the composition ratio of the designated color to the base color depending on the hue of the designated color.

[0014] In the above, "hair region" refers to the region in the image that shows hair, and in this embodiment, refers to the region that shows head hair. "Coloring" refers to combining a specified color with a base color (base color), and combining refers to the process of using image processing to change the pixels of the base color to a color (confirmed color) that is intermediate between the base color and the specified color. "Combining ratio" indicates the ratio of the specified color to the confirmed color.

[0015] The image capturing step is a step of capturing an image of a subject whose hair color is to be processed. The color designation receiving step is a step of receiving an input of a designated color designated by an operator who operates the hair color processing device. The combining process includes a color combining ratio setting process (step S104) and an image processing process (step S105). After step S105 is completed, the combining process determines whether or not to perform processing using a color other than the designated color accepted in step S102 (step S106). If the hair color is to be processed using another color (step S106: Yes), the designated color is accepted again in step S102. The color combination ratio setting step in step S104 is performed by the operator operating the reception unit 10. The hair color processing device 1 executes the subsequent combination process of the designated color according to the set color combination ratio.

[0016] [Hair color treatment device] Figures 2 and 3 are diagrams for explaining the hair color processing device 1 that executes the hair color processing method shown in the flowchart of Figure 1. Figure 2 is a functional block diagram of the hair color processing device 1. Figure 3 is a diagram for explaining the receiving unit 10 shown in Figure 2. The hair color processing device 1 shown in Fig. 2 is a hair color processing device that colors a hair region that indicates hair in an image. The hair color processing device 1 includes a reception unit 10, which is a color specification reception unit that receives a specification of a specified color to be used in the hair region, and a synthesis unit 20 that combines the specified color specified in the reception unit 10 with a base color, which is the color of the hair region in the image. The synthesis unit 20 changes the synthesis ratio of the specified color to the base color depending on the hue of the specified color. To perform this processing, the synthesis unit 20 includes a color synthesis ratio setting unit 21, a hair strand extraction unit 22, and an image processing unit 23. The image 12 colored by the combining unit 20 is displayed on the display screen 30 of the reception unit 10.

[0017] [Hair color processing program] The composition unit 20 is a hair color processing program executed by the hair color processing device that applies a specified color to a hair region in an image. The composition unit 20 causes the computer to realize a composition function that combines the specified color with the base color in the image 12, and at this time, processes the composition ratio of the specified color to the base color to change depending on the hue of the specified color. Here, the computer may be any computing device that includes a CPU (Central Processing Unit), a memory used for CPU computing, an interface used for data input and output, and executes a hair color processing program. For example, it is possible to use a general-purpose personal computer as the computer and install an image processing program together with the synthesis unit 20 in the personal computer to configure an integrated hair color processing device 1. In this embodiment, a tablet terminal used as the reception unit 10 is used as the computer. The above configuration will be explained below in order.

[0018] (Reception Department) The reception unit 10 executes the color designation reception step (step S102) and the coloring region designation reception step (step S103) of FIG. 3, the reception unit 10 of this embodiment is configured as a tablet terminal device having a display screen 30. The display screen 30 displays an image 12 and accepts input of a designation of a coloring area on the image 12 based on the range of the touch pen 3 that is in contact with the display screen 30. The reception unit 10 also has a hair color selection panel 13 that accepts designation of a designated color to be colored to the hair, a coloring selection panel 14 that accepts selection of a coloring state, and an operation panel 15 that accepts selection of a coloring operation.

[0019] The hair color selection panel 13 includes a plurality of selection buttons 131, each of which is assigned a color such as natural pink (NP) or bleached (BLEACH). These selection buttons 131 are all buttons for specifying a designated color to be combined with the hair portion of the image 12. The hair color selection panel 13 may be a touch panel, and the selection buttons 131 may be icons displayed on the touch panel. In this embodiment, the hair color selection panel 13 may also be a touch pad. The operator selects from the selection buttons 131 the selection button 131 that corresponds to the desired designated color.

[0020] The receiving unit 10 may receive the color to be used for coloring (combining) hair by the color name, such as red or blue. The receiving unit 10 may also receive the designated color by information identifying the hair dye. The information identifying the hair dye may be, for example, a name such as "dark brown" or "snow white" that is added to the product name of the hair dye to represent the color. In this embodiment, the selection button 131 may be displayed in the designated color. In this way, the operator can intuitively select the designated color by looking at the selection button 131.

[0021] The coloring selection panel 14 includes a plurality of selection buttons 141 for accepting selection of the line width, degree of blurring, and color density (saturation) when performing coloring. The selection buttons 141 are used to select narrow, medium, or wide line widths. The selection buttons 141 are also used to select hard, medium, or soft blur strength, and weak, medium, or strong color strength. In this embodiment, the blur strength is basically determined according to the line width. The selection buttons 141 for the blur strength are used to further fine-tune the blur strength determined according to the line width. By providing the selection buttons 141, this embodiment can further adjust the blur strength, which is roughly determined according to the line width, to a state that is more preferable to an individual's sensibility.

[0022] (colored area) The coloring area is accepted by two points on the image 12 and the width (line width) of a line that starts and ends at these two points. The line width is the width of the coloring area selected at one time with the touch pen 3. That is, in this embodiment, the operator is encouraged to specify the coloring area by moving the touch pen 3 as if drawing a line. At this time, the coloring area has one of the following widths selected with the selection button 141: thin, medium, or thick, and is specified as an area having the length from the start point to the end point of the line that follows the path of the touch pen 3.

[0023] Furthermore, operation panel 15 accepts instructions for operations such as undoing (UNDO) and redoing (REDO). Operation panel 15 is provided with touch buttons with operation names such as "UNDO" written on them, and by touching the desired operation name, an operation related to coloring image 12 displayed on display screen 30 can be input. The reception unit 10, which is a tablet terminal device, may have a camera function and display an image 12 including a face photographed by the operator on the display screen 30, or may read and display an image 12 stored in a memory (not shown). Furthermore, the reception unit 10 may have a communication function and acquire an image via an internet line and display it on the display screen 30. The operator operates the hair color selection panel 13 and the coloring selection panel 14 to combine a specified color with the coloring area of ​​the image displayed on the display screen 30.

[0024] (Synthesis ratio selection section) The color combination ratio setting unit 21 executes the step of setting the color combination ratio in FIG. 1 (step S104). When the specified color is blended with the base color, the resulting hair color is a final color that includes both the base color and the specified color. The color blending ratio is an index that indicates the proportion of the specified color in the final color. The process of determining the final color from the base color and the specified color is performed, for example, by a process called alpha blending. The final color is calculated using the following formula (1). In formula (1), the base color, specified color, and final color are all represented by hexadecimal WEB color codes. α in formula (1) is a coefficient that determines the color blending ratio. In this embodiment, the value of α in formula (1) is changed according to the hue of the specified color to create a desirable image. Final color = background color + (specified color - background color) × (α / 255) Formula (1)

[0025] FIG. 4 is a diagram illustrating a method for determining a color combination ratio according to the hue of a specified color. In this embodiment, a tablet terminal device functioning as the reception unit 10 is installed with a color combination ratio determination application. The application is then launched to display a color combination ratio determination screen 4. The color combination ratio determination screen 4 is a screen for performing processing to combine the specified color with the hair region of the image 12 displayed on the display screen 30 and set the colored region to a final color. This processing is performed by determining the final color from the base color and the specified color and replacing the pixels in the hair region with pixels of the final color.

[0026] The color blending ratio determination screen 4 includes a color confirmation screen 413, a color adjustment screen 41, an α value determination screen 43, and a save screen 45. The color confirmation screen 413 is a screen on which the operator of the hair color processing device 1 visually confirms the designated color. The color adjustment screen 41 is a screen on which the operator independently determines the H (hue), S (saturation), V (value), R (Red), G (Green), B (Blue), and L (luminance) of the designated color by operating the slider buttons 412. Each item can be changed not only by operating the slider buttons 412 but also by operating the scroll bar 414 to change the number displayed in the small window 411. The operator adjusts the designated color to be blended into the hair region of the image 12 using the color adjustment screen 41. The designated color is displayed on the color confirmation screen 413 during the adjustment process, and the operator can further adjust the designated color while viewing the displayed designated color. When the adjustment operation is completed, the designated color is finalized.

[0027] The α value determination screen 43 is a screen for determining the α value (Apply) of the color synthesis intensity. The operator determines such a value by operating the slider button 432. In addition to the slider button 432, each value can also be determined by operating the scroll bar 433 to change the number displayed on the α value determination screen 43. When a coloring area is designated in the image 12, the designated color determined on the color adjustment screen 41 is combined with the coloring area at a color combination ratio (α value) corresponding to the designated color. Note that in this embodiment, after combining the designated colors, the operator may be able to change the color combination ratio while visually checking the image 12.

[0028] The save screen 45 allows the settings determined on the color adjustment screen 41 and the alpha value determination screen 43 to be saved in a folder with a palette name. The save screen 45 displays a close button 46, a new save button 47, and an overwrite save button 48. However, this embodiment is not limited to displaying the color combination ratio determination screen 4 using the reception unit 10, and the color combination ratio determination screen 4 may be displayed by a personal computer other than the hair color processing device 1, and the designated color may be set and saved on the color adjustment screen 41. At this time, the saved settings are read into the reception unit 10 via an external memory or a network. In this way, it becomes possible to read out and use a designated color set by a person other than the operator of the hair color processing device 1, without having to set the designated color every time color synthesis is performed.

[0029] Next, a method for setting a color combination ratio according to a hue will be described. In this embodiment, a method for setting a color combination ratio by the color combination ratio setting unit 21 of the hair color processing device 1 will be described, but the color combination ratio may be set by another computer or the like. Furthermore, the color combination ratio does not necessarily have to be set by a computer, but may be set by, for example, an evaluator performing a sensory evaluation while viewing multiple images or hairs with different color combination ratios. Furthermore, the color combination ratio may be set each time color combination is performed, or a preset color combination ratio may be stored in association with a specified color and read out when color combination is performed.

[0030] The color blending ratio setting unit 21 determines the blending ratio based on the minimum blending ratio, which is the minimum blending ratio at which the designated color is visually recognized when the designated color is blended with the base color. For this processing, the color blending ratio setting step of this embodiment includes a blending ratio designation receiving step that receives designation of the color blending ratio of the designated color. The blending ratio specification receiving step determines a minimum blending ratio for each hue of the specified color. To determine the minimum blending ratio, the operator sets multiple specified colors by changing the hue of the specified color on the color adjustment screen 41. The operator also adjusts the α value for each hue of the specified color by, for example, operating the slider button 432 on the α value determination screen 43. The α value can be adjusted, for example, by operating the slider button 432 to set the α value to its maximum value and then gradually decreasing the α value while viewing the colored area of ​​the image 12. The blending ratio specification receiving step adjusts the α value for the image 12 displayed on the display screen 30. The α value can be adjusted, for example, by first setting the α value of the specified color to its maximum value and then gradually decreasing the α value. At this time, the operator inputs the timing at which the coloring of the specified color is visually recognized while viewing the colored area of ​​the image 12 into the color blending ratio setting unit 21. This operation allows the α value at the boundary where the specified color changes from visible to invisible on the image 12 to be determined. In this embodiment, the α value at the boundary is determined as the minimum blending ratio. The determined minimum blending ratio is stored in the color blending ratio setting unit 21 and is used thereafter when blending designated colors.

[0031] Figure 5 illustrates the relationship between the hue of a specified color and the minimum blending ratio. The vertical axis of Figure 5 represents the minimum blending ratio, and the horizontal axis represents the angle when the hue is represented on a color wheel. In Figure 5, the different plots represent different base colors (0T, 6-7T, 7-9T, 15T). The base colors were determined based on the Coloring Level Scale (Utility Model Registration No. 3082344) provided by the NPO Japan Hair Color Association. Of the 0T, 6-7T, 7-9T, and 15T, 0T represents black, followed by 6-7T, 7-9T, and 15T, which are progressively lighter in color. The circle plot indicates a 0T base color. The square plot indicates a 6-7T base color, the triangle plot indicates a 7-9T base color, and the cross plot indicates a 15T base color. The minimum blending ratios shown in Fig. 5 are relative values ​​normalized with the smallest value among the minimum blending ratios for each hue being 1. The hue on the horizontal axis is when S (saturation) is 50 and V (lightness) is 70.

[0032] According to Figure 5, it can be seen that the minimum blending ratio reaches a minimum value (bottom) when the hue is approximately 130-140 and when the hue is approximately 300. It can also be seen that the minimum blending ratio peaks when the hue is 40 and 225. This tendency is seen regardless of the base color. Hues with small minimum blending ratios can be seen by humans even if the color blending ratio is relatively small. When hair is dyed with a color of such a hue, it is more noticeable than when other colors are dyed, and is likely to give others a sense of incongruity. Furthermore, hues with large minimum blending ratios cannot be seen by others unless the color blending ratio is large, making it difficult to achieve the desired hair dyeing effect.

[0033] Taking the above points into consideration, in the color combination ratio setting step, the combination unit 20 sets a smaller combination ratio as the minimum combination ratio shown in Fig. 5 becomes smaller. That is, in this embodiment, the curve shown in Fig. 5 (minimum combination ratio curve) is stored in the image processing unit 23, and the designated color is combined with the base color at a color combination ratio based on the minimum combination ratio corresponding to the hue of the designated color designated by the operator.

[0034] Furthermore, the blending unit 20 may unify the minimum blending ratio and the blending ratio difference regardless of the hue of the specified color in the above setting. That is, the "color blending ratio based on the minimum blending ratio" may be, for example, a value obtained by adding a constant blending ratio to the minimum blending ratio regardless of the hue. Such a blending ratio can be calculated by shifting the minimum blending ratio shown in FIG. 5 upward by a constant color blending ratio regardless of the hue. This processing is based on the results of experiments conducted by the inventors, which showed that a preferable image can be obtained by blending using a color blending ratio in which the minimum blending ratio is increased by a constant value regardless of the hue of the specified color. Furthermore, by doing so, the smaller the minimum blending ratio, the smaller the color blending ratio of the specified color blended by the image processing unit 23 can be.

[0035] Furthermore, this embodiment is not limited to the above aspect. For example, in this embodiment, in the color combination ratio setting process, the ratio of the color combination ratio to the minimum combination ratio may be unified regardless of the hue of the specified color. Such processing is realized, for example, by multiplying the minimum combination ratio by a predetermined coefficient that is independent of the hue to determine the color combination ratio. However, this embodiment is not limited to the above, and the coefficient by which the minimum combination ratio is multiplied may be different depending on the hue. Furthermore, in this embodiment, the coefficient by which the minimum combination ratio is multiplied may be adjusted depending on the degree of blurring of the specified color and the size and shape of the colored area.

[0036] Hues 130-140 indicate green or greenish colors. Hue 300 indicates purple or purpleish colors. Hue 40 indicates red or redish colors, and hue 225 indicates blue or blueish colors. For this reason, the hair color processing device 1 of this embodiment, in the image processing unit 23, sets a smaller blending ratio when the hue of the specified color is green than when the hue of the specified color is red. As explained above, this corresponds to the fact that people have a high sensitivity to detecting green hair colors, which are not produced by eumelanin or pheomelanin, and feel a sense of discomfort, while their detection sensitivity decreases to red and black-like blue colors, which are produced by pheomelanin.

[0037] Next, in the image processing step of step S105, hair bundle extraction unit 22 detects consecutive pixels of image 12 in the coloring area and performs processing to detect the flow of hair bundles (hair bundles) from the consecutive pixels. Image processing unit 23 processes the image so as to color image 12 based on the processing results of color synthesis ratio setting unit 21 and hair bundle extraction unit 22 (step S105). At this time, image processing unit 23 synthesizes a specified color into the coloring area along the extracted hair bundles. Here, "along the hair strand" refers to arranging pixels of the determined color more densely around the hair strand and its periphery than outside it when coloring the colored area with a gradated determined color. By performing this process, the present embodiment can create an image 12 that gives the impression that dye has been applied along the actual hair. [Example]

[0038] FIGS. 6(a) through 6(e) are diagrams illustrating examples of the above-described embodiment, showing the relationship between the hue of a specified color and the minimum blending ratio for multiple combinations of saturation and lightness. The vertical axis of FIG. 6 indicates the minimum blending ratio, and the horizontal axis indicates the angle when the hue is represented on a hue wheel. The different plots indicate different base colors (0T, 6-7T, 7-9T, 15T), with the circle plot indicating a black base color. The base colors indicated by the plots become progressively brighter in the order of square, triangle, and cross. The minimum blending ratios shown in FIG. 6 are relative values ​​normalized with the smallest value of the minimum blending ratios for each hue being 1. FIG. 6(a) shows an example where the saturation (S) is 50 and the lightness (V) is 100. Figure 6(b) shows an example where saturation (S) is 30 and lightness (V) is 70, Figure 6(c) shows an example where saturation (S) is 50 and lightness (V) is 70, Figure 6(d) shows an example where saturation (S) is 70 and lightness (V) is 70, Figure 6(d) shows an example where saturation (S) is 70 and lightness (V) is 70, and Figure 6(e) shows an example where saturation (S) is 50 and lightness (V) is 40.

[0039] As shown in Figures 6(a) to 6(e), the inventor's experiments have shown that the minimum blending ratio curve has two peaks and two bottoms, with the peaks appearing in reddish and bluish colors, and the two bottoms appearing in greenish and purple colors, regardless of the lightness and saturation of the specified color. 6(a) to 6(e) show that the above tendency is constant regardless of the base color and does not change significantly depending on the lightness or saturation. Furthermore, as shown in Fig. 6(b) and Fig. 6(e), when a relatively dark designated color with low lightness or saturation is used, the minimum blending ratio for red becomes large, especially when the base color is black, making it difficult to see the coloring on the hair. Also, as shown in Figure 6(d), when the lightness and saturation of the specified color are high, the peaks of the minimum blending ratios of red and blue become slightly higher, making it difficult to visually recognize the coloring on the hair. Furthermore, Figures 6(b), 6(c), and 6(d) show that the minimum blending ratio of red to be blended with a black background color decreases as the saturation increases, under conditions where the lightness of the specified color is constant. [Explanation of symbols]

[0040] 1. Hair color treatment device 3. Touch pen 4. Color composition ratio setting screen 10. Reception 12···Images 13. Hair color selection panel 14. Color selection panel 15. Operation panel 20. Synthesis section 21. Color composition ratio setting section 22 Hair bundle extraction unit 23. Image Processing Department 30···Display screen 41...Color adjustment screen 43. Alpha value determination screen 45...Save screen 46··· button 47···New save button 48···Save button 131, 141... selection button 411, 431... Small window 412, 432...Slider buttons 413...Color confirmation screen 414, 433...Scroll bar

Claims

1. 1. A hair color treatment method for coloring a hair area in an image that indicates hair, comprising: a color designation receiving step of receiving a designation of a designated color to be colored to the hair region; a combining step of combining the designated color designated in the color designation receiving step with a base color that is the color of the hair region in the image, In the combining step, a combining ratio of the designated color to the base color is determined in accordance with the hue of the designated color based on a minimum combining ratio at which the designated color is visually recognized when combined with the base color and which is stored in a computer, such that the smaller the minimum combining ratio, the smaller the combining ratio becomes.

2. 1. A hair color treatment method for coloring a hair area in an image that indicates hair, comprising: a color designation receiving step of receiving a designation of a designated color to be colored to the hair region; a combining step of combining the designated color designated in the color designation receiving step with a base color that is the color of the hair region in the image, In the combining step, a combining ratio of the designated color to the base color is determined in accordance with the hue of the designated color based on a minimum combining ratio at which the designated color is visually recognized when combined with the base color and is stored in a computer, so that a difference between the minimum combining ratio and the combining ratio is uniform regardless of the hue of the designated color.

3. 1. A hair color treatment method for coloring a hair area in an image that indicates hair, comprising: a color designation receiving step of receiving a designation of a designated color to be colored to the hair region; a combining step of combining the designated color designated in the color designation receiving step with a base color that is the color of the hair region in the image, In the combining step, a combining ratio of the designated color to the base color is determined in accordance with the hue of the designated color based on a minimum combining ratio at which the designated color is visually recognized when the designated color is combined with the base color and is stored in a computer, so that the ratio between the minimum combining ratio and the combining ratio is uniform regardless of the hue of the designated color.

4. The hair color processing method according to claim 1 , wherein in the combining step, the combining ratio is set smaller when the hue of the specified color is green than when the hue of the specified color is red.

5. The hair color processing method according to claim 1 , wherein the color specification receiving step receives the specification of the specified color based on information specifying a hair dye used to color the hair.

6. 1. A hair color processing device for coloring a hair area in an image that indicates hair, comprising: a color designation receiving unit that receives designation of a designated color to be colored to the hair region; a combining unit that combines the designated color designated by the color designation receiving unit with a background color that is the color of the hair region in the image, the combining unit determines a combining ratio of the designated color to the base color according to a hue of the designated color based on a minimum combining ratio at which the designated color is visually recognized when the designated color is combined with the base color and is stored in the hair color processing device, such that the smaller the minimum combining ratio, the smaller the combining ratio becomes.

7. 1. A hair color processing device for coloring a hair area in an image that indicates hair, comprising: a color designation receiving unit that receives designation of a designated color to be colored to the hair region; a combining unit that combines the designated color designated by the color designation receiving unit with a background color that is the color of the hair region in the image, the combining unit determines a combining ratio of the designated color to the base color in accordance with the hue of the designated color, based on a minimum combining ratio that is the minimum combining ratio at which the designated color is visible when the designated color is combined with the base color and is stored in the hair color processing device, so as to unify a difference between the minimum combining ratio and the combining ratio, regardless of the hue of the designated color.

8. 1. A hair color processing program for coloring a hair region in an image that indicates hair, comprising: On the computer, a synthesis function for synthesizing the designated color to be applied to the hair region with a base color, which is the color of the hair region in the image; The hair color processing program, wherein the blending function determines a blending ratio of the designated color to the base color according to the hue of the designated color based on a minimum blending ratio stored in a computer, which is the minimum blending ratio at which the designated color is visible when blended with the base color, so that the blending ratio decreases as the minimum blending ratio decreases.

9. 1. A hair color processing program for coloring a hair region in an image that indicates hair, comprising: On the computer, a synthesis function for synthesizing the designated color to be applied to the hair region with a base color, which is the color of the hair region in the image; The hair color processing program, wherein the blending function determines a blending ratio of the designated color to the base color according to the hue of the designated color so as to unify the difference between the minimum blending ratio and the blending ratio, regardless of the hue of the designated color, based on a minimum blending ratio stored in a computer, which is the minimum blending ratio at which the designated color is visible when the designated color is blended with the base color.

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