JP5318587B2 - Gradation creating method, program and apparatus - Google Patents

Description

  The present invention relates to a method, a program, and an apparatus for creating a gradation in a drawing process using a computer.

  When an image being drawn is colored on a computer, in addition to the coloring by a certain color, a coloring using a gradation in which the color moves from one color to another, or the shade of the same color changes is required. Creating this gradation is a laborious operation for the operator.

  A gradation in an image being drawn using a computer is usually created using a software tool called “brush” (see, for example, Non-Patent Document 1). Working with brushes requires advanced skills and experience because subtle blurring is required. Therefore, it is not only a difficult task for general users, but also a time-consuming and time-consuming task for professional operators.

  In particular, in the process of creating manga or illustration, coloring using gradation is required when expressing rounded objects such as human limbs, shadows caused by light on buildings, and expressing eyes. Non-Patent Document 1 describes linear gradation (gradation in which the color moves in a specific direction) and circular gradation (around the point where the color is located) as gradations that can be used for shading and three-dimensional expression. (Gradient that moves while).

“Introduction to Clarice Draw” by Keiko Isa, BN Corporation, April 25, 1996, p200, 201, 278

  Thus, there is a need for a software tool that can be used to perform work efficiently in the image coloring process using gradation.

In order to solve the above problems, a method for creating a color gradation based on the color characteristics of a selected baseline within a closed region surrounded by two or more baselines each having color characteristics according to the present invention,
Determining the shortest distance from the selected baseline for each pixel in the closed region;
Determining an intermediate color characteristic at each pixel based on a distance function, the shortest distance, and a baseline color characteristic.

In order to solve the above problem, a color gradation creation method for a closed region surrounded by a baseline according to the present invention is as follows.
A boundary pixel extraction step for extracting boundary pixels in the baseline that are in contact with a closed region surrounded by two or more baselines each having a color characteristic, based on the baseline data stored in the storage means;
Based on the color characteristic of the boundary pixel extracted in the boundary pixel extraction step, a color characteristic to be used for creating a color gradation in the closed region is determined by the calculation means, or a use to be used by an operator A color characteristic determination step for accepting color characteristic determination by an input device;
A coordinate value storing step of storing the coordinate value of the boundary pixel having the use color characteristic in a storage unit;
A distance determining step for determining, for each used color characteristic, the shortest distance between a certain target pixel in the closed region and the determined boundary pixel having the used color characteristic by using the stored coordinate value of the boundary pixel;
Substituting the value of the shortest distance determined for each of the used color characteristics into a given function, and determining an intermediate color characteristic by the computing means;
Repeating the distance determining step and the intermediate color characteristic determining step for all or selected pixels in the closed region.

In order to solve the above problem, a color gradation creation method for a closed region surrounded by a baseline according to the present invention is as follows.
A temporary image creating step of creating a temporary image by a computing means by painting a closed region surrounded by two or more baselines each having color characteristics with a certain color;
A boundary pixel extracting step of extracting the boundary pixels in the base line in contact with the processing target area, which is a painted area in the temporary image creating step, by the calculation unit based on the data of the base line stored in the storage unit;
Based on the color characteristic of the boundary pixel extracted in the boundary pixel extraction step, a color characteristic to be used for creating a color gradation in the processing target area is determined by the calculation means or should be used by an operator A used color characteristic determining step for accepting a used color characteristic determination by an input device;
A coordinate value storing step of storing the coordinate value of the boundary pixel having the use color characteristic in a storage unit;
A distance determining step for determining, for each used color characteristic, a shortest distance between a certain target pixel in the processing target area and the determined boundary pixel having the used color characteristic using the stored coordinate value of the boundary pixel;
An intermediate color characteristic determining step of substituting the value of the shortest distance obtained for each of the used color characteristics into a given function to determine an intermediate color characteristic by the computing means;
Repeating the distance determining step and the intermediate color characteristic determining step for all pixels in the processing target region.

In order to solve the above problems, a computer program for creating a color gradation for a closed region surrounded by a base line according to the present invention,
Image reading means for reading an image into the storage means;
A boundary that extracts boundary pixels in the base line that touch a closed region surrounded by two or more base lines each having color characteristics in the image, and extracts and stores the boundary pixels in the storage unit based on the baseline data stored in the storage unit Pixel extraction means;
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the closed region are determined, or the operator inputs the color characteristics to be used Use color characteristic determining means for receiving and storing in the storage means,
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value of the boundary pixel, the distance determination unit determines the shortest distance between a certain target pixel in the closed region and the boundary pixel having the determined use color characteristic for each use color characteristic and stores the distance in the storage unit. Means,
Substituting the value of the shortest distance obtained for each of the used color characteristics into a given function to determine an intermediate color characteristic, and an intermediate color characteristic determining means for storing the color characteristic of the target pixel in a storage means; Make it a computer.

In order to solve the above problems, a computer program for creating a color gradation for a closed region surrounded by a base line according to the present invention,
Image reading means for reading an image into the storage means;
A temporary image creating means for creating a temporary image by painting a closed region surrounded by two or more baselines each having color characteristics in the image with a certain color, and storing the temporary image in the storage means;
Boundary pixel extraction for extracting boundary pixels in the base line in contact with the processing target area, which is a region painted by the temporary image creating unit, based on the baseline data stored in the storage unit and storing it in the storage unit Means,
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the processing target area are determined, or the color characteristics to be used by the operator are determined. Use color characteristic determining means for receiving an input and storing it in the storage means;
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Distance determining means for determining, for each used color characteristic, a shortest distance between a certain target pixel in the processing target area and a boundary pixel having the determined used color characteristic for each used color characteristic using the stored coordinate value; ,
Substituting the value of the shortest distance obtained for each of the used color characteristics into a given function to determine an intermediate color characteristic, and an intermediate color characteristic determining means for storing the color characteristic of the target pixel in a storage means; Make it a computer.

In order to solve the above problems, an apparatus for creating a color gradation for a closed region surrounded by a base line according to the present invention is as follows.
Image reading means for reading an image into the storage means;
A boundary that extracts boundary pixels in the base line that touch a closed region surrounded by two or more base lines each having color characteristics in the image, and extracts and stores the boundary pixels in the storage unit based on the baseline data stored in the storage unit Pixel extraction means;
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the closed region are determined, or the operator inputs the color characteristics to be used Use color characteristic determining means for receiving and storing in the storage means,
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value of the boundary pixel, the distance determination unit determines the shortest distance between a certain target pixel in the closed region and the boundary pixel having the determined use color characteristic for each use color characteristic and stores the distance in the storage unit. Means,
Substituting the value of the shortest distance obtained for each of the used color characteristics into a given function to determine an intermediate color characteristic, and an intermediate color characteristic determining means for storing the color characteristic of the target pixel in a storage means; Prepare.

In order to solve the above problems, an apparatus for creating a color gradation for a closed region surrounded by a base line according to the present invention is as follows.
Image reading means for reading an image into the storage means;
A temporary image creating means for creating a temporary image by painting a closed region surrounded by two or more baselines each having color characteristics in the image with a certain color, and storing the temporary image in the storage means;
Boundary pixel extraction for extracting boundary pixels in the base line in contact with the processing target area, which is a region painted by the temporary image creating unit, based on the baseline data stored in the storage unit and storing it in the storage unit Means,
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the processing target area are determined, or the color characteristics to be used by the operator are determined. Use color characteristic determining means for receiving an input and storing it in the storage means;
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Distance determining means for determining, for each used color characteristic, a shortest distance between a certain target pixel in the processing target area and a boundary pixel having the determined used color characteristic for each used color characteristic using the stored coordinate value; ,
Substituting the value of the shortest distance obtained for each of the used color characteristics into a given function to determine an intermediate color characteristic, and an intermediate color characteristic determining means for storing the color characteristic of the target pixel in a storage means; Prepare.

  In this specification and the claims of this application, “color” includes both chromatic and achromatic colors, and “color characteristics” means coordinate values in a color space for expressing the colors. For example, the color characteristic in the RGB color space means the lightness of the three primary colors of red, green, and blue. This lightness can be converted into luminance at the time of color output by a computer device by performing gamma correction. The color characteristics in the HSV color space mean hue, saturation, and brightness. Here, the hue, saturation, and lightness conform to the commonly used definition of chromaticity, and the hue means a color aspect such as red, yellow, green, and blue. Saturation means the vividness of a color (a measure representing how much white is mixed in a certain color). Furthermore, the brightness means the brightness of the color.

  According to the present invention, it is possible to provide an efficient gradation creation method and a computer program and apparatus for executing the method. With this method, computer program, or apparatus, gradation can be created more easily than in the past.

It is a top view which shows an example of the image used as the object which produces a gradation. It is a flowchart which shows an example of the process sequence of the method which concerns on this invention. It is a top view which shows a mode that the starting point A was defined. It is a top view which shows an example of a temporary image. It is a top view which shows an example of the boundary pixel extracted from the temporary image. It is a top view which shows an example of the distance of a certain pixel of a temporary image, and the extracted boundary pixel. It is a figure which shows an example of the screen which sets the mixing ratio of a color characteristic. It is a top view which shows an example of the image in which the gradation was created. (A) It is a top view which shows an example of another image used as the object which produces a gradation. (B) It is a top view which shows an example of the gradation image produced by making black into the object of gradation. (C) It is a top view which shows an example of the gradation image produced by replacing black with yellow. (D) It is a top view which shows an example of the gradation image produced without making black the object of gradation and designating the use color characteristic. (A) It is a top view which shows an example of another image used as the object which produces a gradation. (B) It is a top view which shows an example of the gradation image produced by making transparency into the object of gradation. (C) It is a top view which shows an example of the gradation image produced by replacing transparency with blue. (D) It is a top view which shows an example of the gradation image produced without making transparent the object of gradation and designating the use color characteristic. (A) It is a top view which shows an example of a layer. (B) It is a top view which shows another example of a layer. (C) It is a top view which shows an example of the image which overlap | superposed the layer shown in FIG. 11 (A), and the layer shown in FIG.11 (B). (D) It is a top view which shows an example of the image which produced the gradation in the image shown in FIG.11 (C). (A) It is a top view which shows an example of another image used as the object which produces a gradation. (B) It is a top view which shows an example of the image which the user added the base line to the image shown to FIG. 12 (A). (C) It is a top view which shows an example of the image which produced the gradation in the image shown in FIG.12 (B). FIG. 12 is a block diagram of a computer system 1300 that executes a computer program according to the present invention. It is a flowchart which shows an example of the process sequence of the computer program which concerns on this invention.

  Next, one mode for carrying out the gradation creating method according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an original image 100 for which gradation is to be created. The original image 100 includes, for example, a red base line 110, a blue base line 120, and a green base line 130. Further, the original image 100 includes a closed region 140 surrounded by the base lines 110, 120, and 130. Here, it is assumed that one base line has one color characteristic. Different baselines can have different color characteristics, but there is no change in color characteristics within each baseline.

  Hereinafter, a procedure for creating a gradation in the closed region 140 of FIG. 1 will be described.

  FIG. 2 is a flowchart showing an example of the processing procedure of the gradation creating method according to the present invention. Starting from step S201, a point (pixel) in the closed region 140 is defined as a start pixel in step S202. The start pixel may be determined by a pen touch or the like using an image display device (display) capable of inputting by a tablet or a pen, and may be any pixel in the closed region 140. The starting pixel A thus determined is shown in FIG. The starting pixel is not necessarily determined, but is arbitrary.

  In step S203, starting from the start pixel A, a result of filling the closed region 140 with black, for example, is created as a temporary image. A temporary image 400 created in this way is shown in FIG. The area filled in black is indicated by reference numeral 150. The area 150 is hereinafter referred to as a “processing target area”. If a closed area has already been specified at the time of starting the operation in step 201, the specified closed area is directly set as the area 150, or the area is copied (transferred) and the copy is set as the area 150. Step S202 can be omitted.

  As a method for filling the inside of the closed region 140, for example, an existing seed fill algorithm (an algorithm for filling the inside of the closed region using one point inside the closed region as a starting point) can be used. A scanline seed fill algorithm (an algorithm that requires less storage capacity than the seed fill algorithm), which is an improved version of this seed fill algorithm, can also be used suitably.

  In step S204, pixels (boundary pixels) in contact with the processing target area 150 are extracted from the baseline. Among the extracted boundary pixels, the boundary pixel constituting the red base line 110 is indicated by reference numeral 115 in FIG. Similarly, among the extracted boundary pixels, a boundary pixel constituting the blue base line 120 is denoted by reference numeral 125, and a boundary pixel constituting the green base line 130 is denoted by reference numeral 135. In FIG. 5, the processing target area 150 is shown in white (no hatching) for easy understanding of the drawing.

  In this embodiment, the boundary pixel extracted in step S204 is also a pixel constituting the base line 110, 120, or 130.

  In step S205, among the boundary pixels extracted in step S204, the most frequently used color characteristic is defined as a first used color characteristic, and the second most common color characteristic is defined as a second used color characteristic. In FIG. 5, since the number of blue boundary pixels 125 is the largest, followed by the number of red boundary pixels 115, the first used color characteristic is determined to be blue, and the second used color characteristic is determined to be red. In this example, the green boundary pixel 135 having the smallest number of pixels is not taken into consideration, and a gradation is created using only the first use color characteristic (blue) and the second use color characteristic (red). That is, the computing means counts the number of pixels for each color characteristic, the color characteristic having the largest number of pixels is defined as the first used color characteristic, and the color characteristic having the second largest number of pixels is defined as the second used color characteristic. It is determined and stored in the storage means. The color characteristics used may be determined based on the rule of adopting the color characteristic with the largest number of pixels and the color characteristic with the second largest number of pixels, or separately from the number of pixels for each color characteristic, The operator can input blue and red as the first and second use color characteristics using the input device, respectively, and save the result in the storage means. In the case of input by an operator, the first and second used color characteristics can be freely determined as red and green, or blue and white, respectively, regardless of the number of pixels for each color characteristic. Also, depending on the operator's input, both the first and second used color characteristics can be determined to be red. In this case, it is uniformly painted in red and no gradation is created.

  In step S206, each coordinate value of the boundary pixel 125 of the first use color characteristic (blue) is stored in the storage unit as a first table. As an example, the X coordinate value and the Y coordinate value of the boundary pixel can be stored as a table. Similarly, each coordinate value of the boundary pixel 115 of the second use color characteristic (red) is stored in the storage unit as a second table.

  In step S207, a certain pixel in the processing target area 150 is selected and set as a pixel B (target pixel). The shortest distance between this pixel B and the first use color characteristic (blue) boundary pixel 125 is d1. Furthermore, the shortest distance between the pixel B and the boundary pixel 115 having the second use color characteristic (red) is defined as d2. FIG. 6 shows pixels B and d1 and d2.

  In step S208, a ratio for mixing the first use color characteristic (blue) and the second use color characteristic (red) is determined according to the two distances d1 and d2 obtained in step S207. Based on the ratio, a mixing ratio of the first used color characteristic and the second used color characteristic is determined. The mixed color characteristic (intermediate color characteristic) obtained by this mixing ratio is defined as the color characteristic of the pixel B.

  Details of the conversion from d1 and d2 to the mixing ratio of the color characteristics can be set by the user. FIG. 7 shows an example of setting when the first use color characteristic (blue) is darker than the second use color characteristic (red). The horizontal axis of the graph of FIG. 7 is d1 / (d1 + d2) (0 or more and 1 or less), and the vertical axis is the ratio (unit: percent) of the second used color characteristic to the entire color characteristic. Point P is a point with coordinates (0, 0), and point S is a point with coordinates (1, 100). Points Q and R are points arbitrarily set by the user by operating input means such as a mouse. Curve C is a Bezier curve obtained from points P, Q, R, and S. Curve C is also called a tone curve. That is, using the tone curve C, the color characteristic mixing ratio can be obtained from d1 and d2. Various functions can be used here, and although they are arbitrary, a Bezier function is generally preferable. In addition to Bezier functions, non-continuous functions and partially linear functions can be used to achieve various gradation effects. It is preferable to prepare several different functions so that the operator can select the function to be used.

In FIG. 7, in order to make it a black and white drawing, it is expressed only by shading.
The brightness of each of red, green, and blue, or a representation of them as a unit, can be expressed as a function. Note that the brightness can be converted to luminance at the time of color output by a computer device by performing gamma correction. Alternatively, each of hue, saturation, and lightness, or a function in the HSV color space that expresses them as a unit can be used.

  In FIG. 7, the user can set two points, point Q and point R, but the number of points and the coordinates of the points can be arbitrarily set by the user. Depending on the setting, it may be a discontinuous curve or a line including both a linear part and a non-linear part. By doing so, it is also possible to create a gradation in which color characteristics change drastically, which is often used in animation.

  In step S209, it is determined whether or not there is a pixel for which color characteristics are not defined (coloring processing is not performed) among the pixels in the processing target area 150. If there is an uncolored pixel, the processes of steps S207 and S208 are performed for that pixel. As a result, all the pixels in the processing target area 150 can be colored. An image 800 obtained in this way is shown in FIG. As shown in the figure, a gradation is created by the first use color characteristic (blue in this example) and the second use color characteristic (red in this example). Finally, the procedure ends at step S210.

  The procedure of the method according to the present embodiment is as described above. In the above example, the gradation is created using the two used color characteristics of blue and red. However, the gradation can be created in the same manner when the used color characteristics are three or more.

  A modification of the above procedure will be described below. First, FIG. 9A is an image 900 that includes a black baseline 910 and a red baseline 920. FIG. 9B shows a state in which gradation is created for this image 900 using black as a gradation target. That is, gradation is created by setting the first and second use color characteristics to black and red, respectively. The color continuously transitions from black on the base line 910 to red on the base line 920. On the other hand, FIG. 9C shows a state where gradation is created by replacing black with yellow, for example. In this case, a gradation is created by setting the first and second use color characteristics to yellow and red, respectively, according to an operator input. As a result, in FIG. 9C, the black base line 910 remains as it is, and yellow and red make the gradation closer to the black base line 910 and closer to yellow, and then transition to red toward the base line 920. Has been. FIG. 9D shows a result in a case where the operator instructs that black is not a gradation target, and the operator does not specify a use color characteristic for the base line 910. That is, no gradation is created, and the area surrounded by the base lines 910 and 920 is uniformly painted in red.

  Further modifications of the above procedure will be described below. First, FIG. 10A is an image 1000 that includes a green region 1010 and a red baseline 1020. That is, the green region 1010 of the image 1000 does not seem to be partially surrounded by the base line, but is surrounded by the base line that is transparent (there is no color and the image of the lower layer can be seen through). As shown in FIG. FIG. 10B shows a state in which the operator determines the first and second use color characteristics as transparent and red for the image 1000 and creates a gradation. On the other hand, FIG. 10C shows a state in which the gradation is created by setting the first and second use color characteristics as blue and red by the operator without setting transparency as a gradation target. In this case, a gradation is created by considering that a blue base line exists at a boundary without the base line 1020 among the boundaries of the region 1010. In FIG. 10C, a gradation is created that becomes closer to blue as the first used color characteristic as the distance from the red base line 1020 increases. Note that FIG. 10D shows a state where transparency is not targeted for gradation and the operator does not specify the color characteristics to be used. That is, no gradation is created, and the area indicated by reference numeral 1010 is uniformly painted in red.

  Next, an application example of the gradation creating method according to the present invention will be described. First, FIG. 11A shows a layer L1 including a red base line 1110. FIG. 11B shows a layer L2 that includes a green baseline 1120 and a blue baseline 1130. FIG. 11C shows a state in which the layers L1 and L2 are overlapped. A region surrounded by the base lines 1110, 1120, and 1130 is indicated by reference numeral 1140. For this region 1140, the first base color characteristic is green as the color of the base line 1120, and the blue base color is the second use color characteristic as the color of the base line 1130, using the gradation creation method according to the present invention. The resulting gradation is shown in FIG. 11D. An area where gradation is created is indicated by reference numeral 1150. In this way, a gradation can be created for an image obtained by overlaying a plurality of layers.

  Another application example will be described. First, FIG. 12A shows a part of a human leg drawn by a base line 1270 and a base line 1280, which is cut out by an area 1200 set. A gradation is created only within the area 1200. On the other hand, FIG. 12B shows a state in which the user has added the base lines 1210, 1220, 1230, 1240, 1250, and 1260. These baselines create five regions, regions 1291, 1292, 1293, 1294, and 1295. These baselines are all skin color but have different brightness. An image obtained from these baselines using the gradation creating method according to the present invention is shown in FIG. 12C. That is, the method according to the present invention is applied to each of the five areas 1291 to 1295. Unlike the conventional gradation creation using a brush, the gradation can be created simply by adding several baselines having different color characteristics, so that the labor of the work can be greatly reduced.

  Next, one form of a computer program for creating gradation according to the present invention will be described with reference to the drawings.

  FIG. 13 shows a computer system 1300 that executes a computer program according to the present invention. As illustrated in FIG. 13, the computer system 1300 includes a calculation unit 1301, an input unit 1305 such as a mouse or a keyboard, a display unit 1310 such as a display, and a storage unit 1315 such as a memory. The computer system 1300 includes an image reading unit 1320 that reads an image for which gradation is to be created into a storage unit, a start pixel determining unit 1330, a temporary image creating unit 1340, a boundary pixel extracting unit 1350, and a used color characteristic. It further includes a determination unit 1360, a coordinate value storage unit 1370, a distance determination unit 1380, an intermediate color characteristic determination unit 1385, and an achromatic color pixel presence determination unit 1390.

  FIG. 14 shows a flowchart of processing of a computer program for gradation creation according to the present invention. First, starting from step S1401, in step S1402, the image reading unit 1320 reads the image 100 shown in FIG.

  In step S <b> 1403, the start pixel determination unit 1330 determines a certain point (pixel) in the closed region 140 as a start pixel and stores it in the storage unit 1315. The start pixel may be determined by an operator by touching the pen or the like, and may be any pixel in the closed region 140. The starting pixel A thus determined is shown in FIG. The determination of the start pixel is not necessarily required, but is arbitrary.

  In step S <b> 1404, the temporary image creating unit 1340 starts from the start pixel A and stores the result of filling the closed region 140 in black, for example, in the storage unit 1315 as a temporary image. Even when the start pixel is not specified, if the closed region is specified, the filling can be started from an arbitrary point in the closed region. A temporary image 400 created in this way is shown in FIG. The area filled in black is indicated by reference numeral 150. As described above, the region 150 is also referred to as a “processing target region”.

  In step S <b> 1405, the boundary pixel extraction unit 1350 extracts pixels (boundary pixels) in contact with the processing target area 150 from the base line and stores them in the storage unit 1315. Among the extracted boundary pixels, the boundary pixel constituting the red base line 110 is indicated by reference numeral 115 in FIG. Similarly, among the extracted boundary pixels, a boundary pixel constituting the blue base line 120 is denoted by reference numeral 125, and a boundary pixel constituting the green base line 130 is denoted by reference numeral 135. In FIG. 5, the processing target area 150 is shown in white (no hatching) for easy understanding of the drawing.

  In this embodiment, the boundary pixel extracted in step S1405 is also a pixel constituting the baseline 110, 120, or 130.

  In step S1406, the used color characteristic determination unit 1360 determines that the most existing color characteristic among the boundary pixels extracted in step S1405 is the first used color characteristic, and sets the next most existing color characteristic to the second color characteristic. The color characteristics are determined and stored in the storage unit 1315. In FIG. 5, since the number of blue boundary pixels 125 is the largest, followed by the number of red boundary pixels 115, the first used color characteristic is determined to be blue, and the second used color characteristic is determined to be red. In this example, the green boundary pixel 135 having the smallest number of pixels is not taken into consideration, and a gradation is created using only the first use color characteristic (blue) and the second use color characteristic (red). That is, the used color characteristic determining unit 1360 counts the number of pixels for each color characteristic, determines the color characteristic having the largest number of pixels as the first used color characteristic, and determines the color characteristic having the second largest number of pixels as the second color characteristic. The color characteristics are determined and stored in the storage unit 1315. The color characteristics used may be determined based on the rule of adopting the color characteristic with the largest number of pixels and the color characteristic with the second largest number of pixels, or separately from the number of pixels for each color characteristic, The operator can input the first and second use color characteristics as blue and red using the input unit 1305 and store the result in the storage unit 1315. In the case of input by an operator, the first and second used color characteristics can be freely determined as red and green, or blue and white, respectively, regardless of the number of pixels for each color characteristic. Also, depending on the operator's input, both the first and second used color characteristics can be determined to be red. In this case, it is uniformly painted in red and no gradation is created.

  In step S1407, the coordinate value storage unit 1370 stores the coordinate values of the boundary pixels 125 of the first color characteristic (blue) in the storage unit 1315 as a first table. As an example, the X coordinate value and the Y coordinate value of the boundary pixel can be stored as a table. Similarly, each coordinate value of the boundary pixel 115 of the second color characteristic (red) is stored in the storage unit 1315 as a second table.

  In step S1408, the distance determination unit 1380 selects a certain pixel in the processing target area 150 and sets it as a pixel B (target pixel). The shortest distance between this pixel B and the first use color characteristic (blue) boundary pixel 125 is d1. Furthermore, the shortest distance between the pixel B and the boundary pixel 115 of the second color characteristic (red) is d2. FIG. 6 shows pixels B and d1 and d2.

  In step S1409, the intermediate color characteristic determining unit 1385 calculates the first use color characteristic (blue) and the second use color characteristic (red) according to the two distances d1 and d2 obtained in step S1408. The mixing ratio is determined and stored in the storage unit 1315. Thereafter, the intermediate color characteristic determining unit 1385 determines a mixing ratio of the first color characteristic and the second color characteristic based on the ratio, and stores it in the storage unit 1315. Further, the intermediate color characteristic determining unit 1385 determines the mixed color characteristic (intermediate color characteristic) obtained by this mixing ratio as the color characteristic of the pixel B, and stores the result in the storage unit 1315.

  The conversion from d1 and d2 to the color characteristic mixture ratio is as described in the embodiment of the gradation creation method.

  In step S <b> 1410, the achromatic color pixel presence determination unit 1390 determines whether there is a pixel for which color characteristics have not been determined (color processing has not been performed) among the pixels in the processing target area 150. If there is a pixel that is not colored, the processes of steps S1408 and S1409 are performed for the pixel. As a result, all the pixels in the processing target area 150 can be colored. An image 800 obtained in this way is shown in FIG. As shown in the figure, a gradation is created by the first use color characteristic (blue in this example) and the second use color characteristic (red in this example). Finally, the procedure ends at step S1411.

  The processing procedure of the computer program according to the present embodiment is as described above. In the above example, the gradation is created using the two used color characteristics of blue and red. However, the gradation can be created in the same manner when the used color characteristics are three or more.

  According to the method according to the present invention and the computer program according to the present invention, gradation can be created more easily than in the past. For example, it is possible to efficiently create a shadow of a human skin or a shadow generated by light hitting a building.

100, 900, 1000 Original image 400 Temporary image 800 Image in which gradation is created 1300 Computer system 1305 Input means 1310 Display means 1315 Storage means 1320 Image reading means 1330 Start pixel determining means 1340 Temporary image creating means 1350 Boundary pixel extracting means 1360 Used color characteristic determining means 1370 Coordinate value storing means 1380 Distance determining means 1385 Intermediate color characteristic determining means 1390 Achromatic pixel presence determining means L1, L2 layers

Claims (6)

A boundary pixel extraction step for extracting boundary pixels in the baseline that are in contact with a closed region surrounded by two or more baselines each having a color characteristic, based on the baseline data stored in the storage means;
Based on the color characteristic of the boundary pixel extracted in the boundary pixel extraction step, a color characteristic to be used for creating a color gradation in the closed region is determined by the calculation means, or a use to be used by an operator A color characteristic determination step for accepting color characteristic determination by an input device;
A coordinate value storing step of storing the coordinate value of the boundary pixel having the use color characteristic in a storage unit;
A distance determining step of obtaining a shortest distance between pixels between a certain target pixel in the closed region and the determined boundary pixel having the used color characteristic for each used color characteristic by using the stored coordinate value of the boundary pixel. When,
Substituting the value of the shortest distance between pixels determined for each of the used color characteristics into a Bezier function, and determining an intermediate color characteristic by the calculation means;
A method of creating a color gradation for a closed region surrounded by a base line, comprising: repeating the distance determining step and the intermediate color characteristic determining step for all or selected pixels in the closed region. A temporary image creating step of creating a temporary image by a computing means by painting a closed region surrounded by two or more baselines each having color characteristics with a certain color;
A boundary pixel extracting step of extracting the boundary pixels in the base line in contact with the processing target area, which is a painted area in the temporary image creating step, by the calculation unit based on the data of the base line stored in the storage unit;
Based on the color characteristic of the boundary pixel extracted in the boundary pixel extraction step, a color characteristic to be used for creating a color gradation in the processing target area is determined by the calculation means or should be used by an operator A used color characteristic determining step for accepting a used color characteristic determination by an input device;
A coordinate value storing step of storing the coordinate value of the boundary pixel having the use color characteristic in a storage unit;
A distance determination step for determining, for each used color characteristic, a shortest distance between pixels between a certain target pixel in the processing target area and the boundary pixel having the determined used color characteristic, using the stored coordinate values of the boundary pixel;
An intermediate color characteristic determining step of substituting the value of the shortest distance between pixels determined for each of the used color characteristics into a Bezier function and determining an intermediate color characteristic by the calculation means;
A color gradation creating method for a closed region surrounded by a base line, comprising: repeating the distance determining step and the intermediate color characteristic determining step for all pixels in the processing target region. Image reading means for reading an image into the storage means;
A boundary that extracts boundary pixels in the base line that touch a closed region surrounded by two or more base lines each having color characteristics in the image, and extracts and stores the boundary pixels in the storage unit based on the baseline data stored in the storage unit Pixel extraction means;
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the closed region are determined, or the operator inputs the color characteristics to be used Use color characteristic determining means for receiving and storing in the storage means,
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value of the boundary pixel, the shortest distance between pixels between a certain target pixel in the closed region and the boundary pixel having the determined use color characteristic is obtained for each use color characteristic and stored in the storage unit. A distance determining means;
An intermediate color characteristic determining unit that determines an intermediate color characteristic by substituting the value of the shortest distance between pixels obtained for each of the used color characteristics into a Bezier function, and stores the color characteristic of the target pixel in a storage unit; A computer program for creating a color gradation for a closed area surrounded by a base line. Image reading means for reading an image into the storage means;
A temporary image creating means for creating a temporary image by painting a closed region surrounded by two or more baselines each having color characteristics in the image with a certain color, and storing the temporary image in the storage means;
Boundary pixel extraction for extracting boundary pixels in the base line in contact with the processing target area, which is a region painted by the temporary image creating unit, based on the baseline data stored in the storage unit and storing it in the storage unit Means,
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the processing target area are determined, or the color characteristics to be used by the operator are determined. Use color characteristic determining means for receiving an input and storing it in the storage means;
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value, determining the distance between the target pixel in the processing target area and the boundary pixel having the determined used color characteristic for each used color characteristic and storing the distance in the storage unit Means,
An intermediate color characteristic determining unit that determines an intermediate color characteristic by substituting the value of the shortest distance between pixels obtained for each of the used color characteristics into a Bezier function, and stores the color characteristic of the target pixel in a storage unit; A computer program for creating a color gradation for a closed area surrounded by a base line. Image reading means for reading an image into the storage means;
A boundary that extracts boundary pixels in the base line that touch a closed region surrounded by two or more base lines each having color characteristics in the image, and extracts and stores the boundary pixels in the storage unit based on the baseline data stored in the storage unit Pixel extraction means;
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the closed region are determined, or the operator inputs the color characteristics to be used Use color characteristic determining means for receiving and storing in the storage means,
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value of the boundary pixel, the shortest distance between pixels between a certain target pixel in the closed region and the boundary pixel having the determined use color characteristic is obtained for each use color characteristic and stored in the storage unit. A distance determining means;
An intermediate color characteristic determining unit that determines an intermediate color characteristic by substituting the value of the shortest distance between pixels obtained for each of the used color characteristics into a Bezier function, and stores the color characteristic of the target pixel in a storage unit; A device for creating a color gradation for a closed region surrounded by a baseline. Image reading means for reading an image into the storage means;
A temporary image creating means for creating a temporary image by painting a closed region surrounded by two or more baselines each having color characteristics in the image with a certain color, and storing the temporary image in the storage means;
Boundary pixel extraction for extracting boundary pixels in the base line in contact with the processing target area, which is a region painted by the temporary image creating unit, based on the baseline data stored in the storage unit and storing it in the storage unit Means,
Based on the color characteristics of the boundary pixels extracted by the boundary pixel extraction means, the color characteristics to be used for creating a color gradation in the processing target area are determined, or the color characteristics to be used by the operator are determined. Use color characteristic determining means for receiving an input and storing it in the storage means;
Coordinate value storage means for storing the coordinate values of the boundary pixels having the use color characteristics in the storage means;
Using the stored coordinate value, determining the distance between the target pixel in the processing target area and the boundary pixel having the determined used color characteristic for each used color characteristic and storing the distance in the storage unit Means,
An intermediate color characteristic determining unit that determines an intermediate color characteristic by substituting the value of the shortest distance between pixels obtained for each of the used color characteristics into a Bezier function, and stores the color characteristic of the target pixel in a storage unit; A device for creating a color gradation for a closed region surrounded by a baseline.