JP2879006B2 - Color data converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing specific processing on a color image, and more particularly, to an apparatus for applying a special effect (posterization effect) to an image by reducing the gradation of a natural image, and a color image. And a device for extracting a specific region.

[0002]

[Prior art]

(First Prior Art) First, as a first prior art, a method of implementing a special effect by reducing the number of gradations of color components in image processing, a so-called posterization effect, will be described with reference to the drawings.

[0003] In so-called posterization, the original natural image is represented by a small number of colors such as those used in poster designs by reducing the tone components of a natural image having multiple tones to a specified number of tones. Refers to image processing for converting to an image. The number that can be taken as the value of each component that constitutes a color is called the number of gradations, and the number that can be taken as the type of color expressed as a combination of the components is called the number of colors.

[0004] Designers who produce advertisement images and the like have created a work that they imagine by applying various special effects including a posterization effect to a natural image as a material. Among these special effects, the posterization effect is widely used in various situations as a means to easily and effectively generate images represented by a small number of colors, such as cell images used for animation, from material images. I have.

FIG. 7 is a block diagram showing the configuration of a conventional color data converter for posterization.
Each of the three-dimensional value components (here, R, G, and B components) constituting the pixels of the input image is converted into an independent signal conversion unit 701.
The gradation is reduced by ７０ 703 and output. FIG.
FIG. 4 is a diagram for explaining an operation of signal conversion in the signal conversion units 701 to 703. For example, if the number of gradations on the output side is 2, as shown in FIG.
The multi-gradation input signal is converted into two-gradation values by the signal converters 701 to 703. Similarly, when the number of gradations on the output side is 3
In this case, as shown in FIG. 8B, the multi-tone input signal is converted into three-tone values by the signal converters 701 to 703.

Here, the value constituting the pixel of the input image is 3
Since each component has two-dimensional components, it is painted in eight colors (2 to the third power) when each component is expressed in two tones, and in 27 colors (3 to the third power) when expressed in three tones. An output image will be obtained. An output when each component of a three-dimensional value constituting a pixel of an input image is R, G, and B (each component has a value of 0 to 255), and each component is expressed in two tones and three tones. Tables 1 and 2 below show examples of combinations of colors that can be separately applied to images.

[0007]

[Table 1]

[0008]

[Table 2]

FIG. 9 shows an example of color space division when each component is expressed in three gradations. FIG. 9 shows a sectional view in which the B component in the divided color space is constant, that is, only the RG plane.
It is dimensionally divided. As described above, in the first prior art, the color space is fixedly divided, and the colors of the input pixels belonging to the same divided area are changed to the same color representing the area, thereby obtaining the color of the input pixels. The number is decreasing.

In the above description, each component of a pixel is represented by a value based on (R, G, B). However, as a three-dimensional value component used for posterization in the conventional method, a television video signal is used. (Y, Cb, Cr) used for the processing of (i), and (L ^* , a ^* , b ^* ) defined in the uniform perceived color space used for a print image or the like. (Second Prior Art) Next, as a second prior art, a method for selecting an area using color information in image processing will be described with reference to the drawings.

In a series of image processing, selection of an area is called generation of mask data in still image processing and generation of a key signal in moving image processing. In the subsequent processing, a specific area is separated from other areas. This is an essential step for independent processing. Each of the mask data and the key signal is represented by a one-dimensional binary value (maximum value / minimum value) having a maximum value in a selected portion and a minimum value in an unselected portion, and is a signal of an image to be processed. This is a kind of image data having a format according to.

Here, a case will be described in which a signal for selecting only a monochrome background region, that is, a so-called key signal, is generated from a television image of a person or the like by using color information in the image. In an actual video production site, the generation of this key signal is frequently performed as a process preceding the chroma key synthesis used for replacing only the background portion of the captured video with another video.

FIG. 10 is a block diagram showing a configuration of a conventional color data converter for generating a key signal. The three-dimensional signal components constituting the pixels of the input video are represented by Y, Cb, and Cr.
Then, the Cb and Cr signals, which are the color difference components of the original signal, are converted into the chroma component C (Chrom
a), is converted into a hue component H (HueAngle).
The three components Y, C, and H are converted into selection signals key-y to key-h in selection signal generation units 1002 to 1004 corresponding to each component, and then combined in a multiplication unit 1005, and finally the key signal key Is output as

FIG. 11 is a diagram for explaining the operation of the selection signal generators 1002 to 1004 in FIG. 10 and shows the input / output relationship of signals. This relationship is a rectangular graph defined by a selection center value (CenterValue) and a selection width (Width) preset for each component. Therefore, the Y, C, and H components of the input signal are:
Conversion is performed in accordance with the graph shown in FIG. 11, and the selection signals (key-y, key
-c, key-h).

A selection signal for each component is multiplied by a multiplication unit 1005
Are ANDed and output as a key signal (Key). 12A is a selection signal (Key-c) of the C component, FIG. 12B is a selection signal (Key-h) of the H component, and FIG.
Shows the distribution of the key signal (Key) after synthesis in each CbCr input color difference plane. FIG. 12A to FIG.
2 (c) shows a cross-sectional view in which the Y component in the divided color space is constant, that is, only the CbCr input color difference plane, but actually, the specific area of the specific YCbCr space is 3
Dimensionally selected.

Thus, according to the second prior art,
A key signal is generated based on a selection center value and a selection width preset for each color component.

[0017]

However, in the method of implementing the posterization effect according to the first prior art, the method of dividing the gradation and the color arrangement of the image after the effect has been implemented are the three-dimensional values constituting the pixels. It is uniquely determined by the component and the designated number of gradations. That is, when the input signal is reduced to two gradations, the input signal is only fixedly divided into two as shown in FIG. 8A, and when the input signal is reduced to three gradations, similarly, FIG. As shown in (1), only three fixed divisions are made, and these division methods are determined uniformly regardless of the image to be implemented. For this reason, there is a problem that an optimal posterization effect cannot be performed according to the content and type of the image.

The color scheme is also fixed to the combinations shown in Tables 1 and 2. For example, in the case of three gradations, as shown in FIG. Only the representative colors are painted separately, and there is no room for reflecting the intention of the worker. Further, in the generation of a key signal using color information according to the second conventional technique, a three-dimensional signal constituting a pixel of an input video is independently converted into a selection signal for each component and then synthesized as a key signal. Therefore, there is a problem that the shape in the color space of the region selected as the key signal is limited to a certain shape.

For example, in the signal conversion as shown in FIG. 10, the color area finally selected has a fan shape as shown in FIG. In this case, the distribution in the color space of the color area to be selected in the input image to be actually processed has a distorted shape like the shaded area in FIG. In this case, it is no longer possible to cut out such a color region.

Further, in order to cut out a region in a color space in which a color to be selected as a region is distributed, an operator needs to specify a selection center value and a selection width shown in FIG. 11 for all components of a three-dimensional signal. However, when the color to be cut out is distributed in a direction inclined with respect to the defined axis of any component of the three-dimensional signal, it is difficult to cut out that region accurately. Also, the task of designating the selection center value and the selection width of the cutout region to be input itself depends on the skill of the operator, and a method that can easily obtain the optimum value is desired.

Accordingly, the present invention is to solve the above-mentioned conventional problems, and to provide a color data which can implement a posterization effect using an arbitrary number of colors or a color arrangement by free color division by a simple operation. It is an object to provide a conversion device. Further, the present invention provides a color data conversion device which can generate a selection signal by cutting out an optimal area by a free shape with a simple operation in a color space in which each component of an input signal is defined. Also aim.

[0022]

In order to solve this problem, a first color data conversion device according to the present invention is a device for reducing the number of colors of an input color image. Input specified value recording means for recording a color serving as a reference for dividing the area into input designated values, and an output designated value for recording a color associated with each input designated value as an output designated value An input unit that, when color data is given, calculates and compares a distance in a three-dimensional color space between the color and each input designated value recorded in the input designated value recording unit and minimizes the distance. It is provided with input designated value specifying means for specifying a specified value, and output means for reading and outputting an output specified value corresponding to the specified input specified value from the output specified value recording means.

A second color data conversion device according to the present invention is a device for determining whether or not the color of each pixel of an input color image belongs to a color of a predetermined selected area. Input designated value recording means for recording, as an input designated value, a color serving as a reference for dividing a color space into a predetermined area; and determining whether an area corresponding to the input designated value is included in the selected area. Output designation value recording means for recording a value to be represented as an output designation value; and, when color data is given, a distance between the color and each input designation value recorded in the input designation value recording means in a three-dimensional color space. An input specification value specifying unit that specifies an input specification value whose distance is minimum by calculating and comparing, and an output specification value corresponding to the specified input specification value is read from the output specification value recording unit and output. Output hand Characterized in that it comprises and.

Further, these apparatuses are provided with a graphical user interface unit for determining an input designated value and an output designated value in accordance with an instruction of an operator and recording them in the input designated value recording means and the output designated value recording means. You can also.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a color data converter according to the present invention will be described below with reference to the drawings. (First Embodiment) The first embodiment relates to a case where a posterization effect is applied to an input image according to the present invention.

FIG. 1 is a block diagram showing a configuration of a color data conversion device according to the present embodiment. This apparatus includes a designated value recording unit 101, a distance comparison unit 102, and an output designated value selection unit 103. The designated value recording unit 101 stores a value determined in advance according to the contents of the posterization effect to be performed, and further includes an input designated value recording unit 101a and an output designated value recording unit 101b.

The input designated value recording unit 101a records a plurality of input designated values, that is, color components for determining the area division of the color space, which are representative of each area. The unit 101b records the same number of output designated values as the input designated values, that is, the components of the color that is ultimately desired to be obtained by the posterization effect and corresponding to each input designated value.

Table 3 shows the designated input values and designated output values stored in the designated input value recording unit 101a and designated designated output value recording unit 101b.

[0029]

[Table 3]

For ease of explanation, the designated input value and the designated output value are matched. It is assumed that data in the input signal system and the output signal system are defined in the L ^* a ^* b ^* color space. That is, each pixel constituting the image has a three-dimensional value corresponding to each component of L ^* , a ^* , and b ^* . The distance comparing unit 102 determines which region the input color data belongs to,
The output designation value selection unit 103 outputs the color data after the number of gradations has been reduced.

The components 101 to 103 of the present apparatus
Is realized by a program executed under a general-purpose CPU. The operation of the present device configured as described above will be described. First, the three-dimensional signals that make up the image are:
An input value is input to the distance comparison unit 102 for each basic unit (pixel in this case) that forms a color. Distance comparison unit 102
Calculates the Euclidean distance ΔE (= √L ^{* 2} + a ^{* 2} + b ^{* 2} ) in the three-dimensional color space between the input value and all the input specification values recorded in the input specification value recording unit 101a.
By sequentially comparing the values, the input designated value that minimizes the distance to the pixel is determined, and the output designated value selection unit 1
Notify 03.

The specified output value selection unit 103 receiving the notification
Reads out the output designated value corresponding to the input designated value from the output designated value recording unit 101b and outputs it as the output value corresponding to the input value. FIG. 2 is a diagram showing a state of division of a color space in which an input signal system is defined, where a ^* b where L ^* is constant.
^{* It} is a sectional view in a plane. The white circles in the figure correspond to the input designated values and the output designated values in Table 3. This figure shows that when an input value belonging to a divided area surrounded by a boundary line is given to the present apparatus, an output value corresponding to a white circle in the area is output. The division diagram of the space by such a method is generally called Voronoi Diagrams.

As described above, the input value having 256 gradations for each component is converted into an output value having the shortest distance in the color space by the present apparatus, that is, one of the six colors. Has been converted to And the six colors are
This is an output designation value created in advance by the operator. Therefore, the present apparatus makes it possible to implement the posterization effect by a method of dividing the color space according to the number of colors that the operator wants to obtain and the content of the image to be processed.

In the present apparatus, the color for dividing the area (designated input value) and the converted color of the input value belonging to the area (designated output value) are the same in the same color space. Component, but is not limited to this. By setting the input specified value and the output specified value to different values or to values defined in different color spaces, it is possible to freely set the color scheme of the image obtained after the implementation of the posterization effect, The color space in which the output image is defined can also be freely selected according to the requirements of the system.

In this embodiment, for convenience of display in FIG. 2, the input designation value and the output designation value in Table 3 use a value in which L ^* is constant, and in FIG. 2, L ^* is constant. Although the cross section is displayed, it is generally possible to freely set both the input designation value and the output designation value in the three-dimensional L ^* a ^* b ^* color space. It becomes dimensional.

In this embodiment, the color space in which the input signal system is defined is the L ^* a ^* b ^* color space.
B, YCbCr, YUV, YIQ, CMY, CMYK,
Other color spaces generally used for image processing, such as L ^* u ^* v ^* , HSV, and HLS, may be used, or a color space uniquely defined according to a processed image may be used. The same effect can be obtained in any of the color spaces.

In this embodiment, the distance comparison unit 10
Although the Euclidean distance ΔE in the L ^* a ^* b ^* color space is used as the distance in the color space compared in 2, the value of the square of the Euclidean distance may be used. When the Euclidean distance is used, any color space can be used as the definition of the input signal system.On the other hand, when the value of the square of the Euclidean distance is used, the process of finding the square root in the distance calculation is unnecessary. Therefore, the processing cost can be significantly reduced. Since the distance comparison unit 102 determines only the magnitude of the distance, no difference occurs in the processing result due to the use of the squared value of the Euclidean distance.

Also, in the present embodiment, the input designated value and the output designated value are recorded in separate locations in the designated value recording unit 101, but the corresponding input designated value and output designated value are the same. In addition, when the condition of being defined in the same color space is maintained, the input designated value and the output designated value may be integrated without being recorded separately. In this case, the same effect as in the present embodiment can be obtained while reducing the storage capacity required for the designated value recording unit 101 by half.

Although the present apparatus is realized as software operating inside the computer apparatus, all or a part of a series of operations may be implemented by hardware designed for exclusive use or general purpose use. . In that case, it is possible to perform faster and more comfortable processing according to the performance of the hardware used. (Second Embodiment) The second embodiment relates to a case where a key signal is generated and a case where a posterization effect is applied to an input image using a graphical user interface.

FIG. 3 is a block diagram showing the configuration of the color data conversion device according to this embodiment. The apparatus includes a designated value determining unit 304, a designated value recording unit 301, a distance comparing unit 30
2. It is composed of an output designation value selection unit 303. This apparatus is different from the apparatus according to the first embodiment in that the designated value determination unit 304
Is added. Therefore, the designated value determining unit 304
The following description focuses on differences from the apparatus of the first embodiment.

The designated value determining unit 304 is a man-machine interface for determining a designated value to be recorded in the designated value recording unit 301 based on an instruction from an operator, and is an input / output device such as a mouse and a CRT in a general computer system. And its control program. <Case of Generating Region Selection Signal> An operation of the device configured as described above to generate a region selection signal using color information of an input image will be described. Here, the input signal system is a moving image signal of a standard television image defined in the YCbCr color space, and the output signal system is an area selection signal called a key signal, which is represented by one-dimensional binary.

The designated value determining unit 304 selects an input designated value corresponding to a color to be set in the selected area or outside the selected area based on an instruction from the operator, and selects whether each input designated value is set in the selected area. A plurality of sets of output designation values indicating whether the area is outside the area are determined. Here, the designated input value is a three-dimensional value composed of the same Y, Cb, and Cr components as the values of the input signal system. On the other hand, unlike the first embodiment, the output designated value is a value represented by a one-dimensional binary value (maximum value / minimum value), and the color corresponding to the corresponding input designated value is within the selected area. In this case, the value is the maximum value, and when the value is outside the selected area, the value is the minimum value.

The set of the input designated value and the output designated value decided by the designated value decision unit 304 is stored in the designated value recording unit 3 respectively.
01 are recorded in the input designated value recording unit 301a and the output designated value recording unit 301b. Table 4 below shows an example of respective values when seven sets of input designated values and output designated values are determined.

[0044]

[Table 4]

Next, when a three-dimensional signal constituting an image is input as an input value to the distance comparison unit 302, the apparatus generates an area selection signal corresponding to the input value. The operation of the output designated value selection unit 303 is basically the same as in the first embodiment. However, since the area selection signal output by the output designated value selection unit 303 is one of the values recorded in the output designated value recording unit 301b, the area selection signal is a one-dimensional binary (0/255). 1
Is different from the embodiment.

FIG. 4 shows an example of color space division in key signal generation signal conversion in this embodiment. Here, a white circle in the figure indicates an input designated value whose corresponding output designated value is the maximum value (255), and a black circle indicates an input designated value whose corresponding output designated value is the minimum value (0). I have. As can be seen from FIG. 4, according to the present apparatus, a signal having a maximum value when the input designated value closest to the input value is within the selected area and a minimum value when being outside the selected area is a key signal. Will be output as

Further, even when the distribution of the color to be selected in the input image has a distorted shape as shown by the hatched area in FIG. Since a desired color can be arbitrarily designated as an input designation value, an accurate region can be cut out by performing color space division by a Voronoi diagram.

Although FIG. 4 shows a cross section of the color space for convenience of display as in the case of FIG. 2, it is actually three-dimensionally divided. <Case of Applying Posterization Effect> Next, the operation of the apparatus when the posterization effect is applied to an input image by the present apparatus will be described.

Note that this case is different from the case of the above-described area selection signal generation in that the output designated value recorded in the output designated value recording unit 301b is not a one-dimensional component but a three-dimensional component. Designated value determination unit 30 for determining a value
Since the operation is No. 4, the description will be focused on these contents.
Also, the input signal system and the output signal system are both moving image signals of a standard television image defined in the YCbCr color space.

According to an instruction from the operator, the designated value determining unit 304 determines an input designated value corresponding to a plurality of colors to be representative colors for applying the posterizing effect, and what color the colors in the vicinity of each representative color are. Are determined, and a set of output designated values indicating whether the input designated value
And the output designated value recording unit 301b. The distance comparison unit 302 and the designated output value selection unit 303 operate in the same manner as in the first embodiment. That is, when an input value forming an input image is given, the distance comparison unit 302 determines an input designated value that is closest to the input value, and the output designated value selection unit 303 outputs an output value corresponding to the input designated value. Output specified value as output value. Thus, the number of colors of the input image is
The number of colors is reduced to the number of colors equal to the number of input designated values recorded in the input designated value recording unit 301a.
A posterization effect image according to the color scheme recorded in 1b is obtained.

Here, since the operation of the designated value determination unit 304 is characteristic, this operation will be described in more detail with reference to the drawings. Note that, as described above, the designated value determining unit 304 mainly provides the function of the man-machine interface.
This function will be described from the viewpoint of how the operation of the operator is performed by the function provided by the fourth function.

FIG. 5 shows an example of a user interface provided to the operator by the designated value determination unit 304, that is, an example of screen display on a display device provided in the present apparatus. This screen display includes an input / output image display unit 501, an input / output designated value set display unit 502, an output designated value change unit 503, and a plurality of operation buttons.
FIG. 6A is a flowchart showing the operation of the designated value determining unit 304, and FIG. 6B is a flowchart showing the flow of operation by the worker.

First, when the worker instructs to start posterization (step S601b), the input / output image display unit 501 displays an input image obtained by being distributed from the input signal (step S601a). The operator specifies a pixel in the input image using a mouse provided in the apparatus (step S602b).

The designated pixel color is registered in the input designated value recording unit 301a and the output designated value recording unit 301b as the first set of the input designated value and the output designated value, respectively. The value is displayed on the value set display unit 502 (step S602a). If the designated value recording unit 301 is created by setting the designated input value and designated output value to the same color, it is not necessary to change the designated output value, and the operator must subsequently designate another pixel. To register the second and subsequent pairs of input designated values and output designated values (step S602).
b, S602a).

The registered plural sets of input designated values and output designated values are arranged on the same child window of the input / output designated value set display section 502. When the number increases, it is not displayed on the child window at the same time, but it can be scrolled and displayed by operating a scroll bar arranged on the side of the child window. on the other hand,
When the designated value recording unit 301 is created using different colors for the designated input value and the designated output value, it is necessary to change the designated output value.

For this purpose, the operator first selects a set to be changed from the set of input designated values and output designated values arranged in the same child window of the input / output designated value set display section 502 with a mouse. . Then, the selected set is changed to a display different from the other sets, and at the same time, the three components of the specified output value are displayed on the three sliders of the specified output value changing unit 503.

The operator can change the current output designated value to a desired value by operating each slider with the mouse (step S603b). The changed output specification value is
This is always reflected on the display of the corresponding output designated value on the input / output designated value set display section 502 (step S603a). In this way, when the registration of the set of the input designated value and the output designated value required for the desired posterization effect processing is completed, the operator:
The execution of the posterization effect process is instructed by the corresponding operation button (step S604b). Then, the display of the input / output image display unit 501 is switched from the input image up to that time to the output image with the effect applied (step S6).
04a). Here, if the output image is an image intended by the operator, this operation ends.

When the parameter is changed and further repeated, the operator performs the following operation in order to add and change a set of an input designated value and an output designated value. First, the worker
By switching an image to be displayed on the input / output image display unit 501 to an input image or an output image by a corresponding operation button, a pixel is designated on the image by using a mouse, and a set of an input designated value and an output value is set. Register a new one. If a pixel is specified from the input image, the specified pixel value is registered as both the input specified value and the output specified value, while if a pixel is specified from the output image, the specified pixel value is output As the designated value, the pixel value at the same position in the input image is registered as the input designated value.

In order to delete the already registered pair of the input designated value and the output designated value, or to return the output designated value to be changed to the same color as the input designated value, the corresponding operation button must be operated. Performed by In this way, the worker
It is possible to add or change a desired set of input designation value and output designation value. As is apparent from the above description, since the designated value determination unit 304 of the present apparatus has the above-described function of the graphical user interface, the operator can easily operate the color space and sufficiently reflect his / her intention. Can be implemented by the posterization effect processing. That is, since the input designated value and the output designated value can be determined by the operation on the same window, the necessary parameters can be effectively designated by the unified operation.

Further, since the input image and the output image can be alternately displayed on the same window and displayed, it is easy to confirm the change of the input / output image. In addition, in the case of specifying a set of an input designated value and an output designated value by pixel designation, when designation is performed on an input image, the registered input designated value and output designated value have the same color. If this is done, the input specified value and the output specified value will be different and will reflect the previous processing, so that the colors that you do not want to change too much due to the posterization effect will be specified in the input image In addition, it is possible to fine-tune the effected image and specify the color to be emphasized in the output image, making it easier to determine the input and output specified values reflecting the intention of the worker. Becomes

Further, since the set of the designated input value and the designated output value is scrolled and displayed on the same child window, the display device can be displayed even when a large number of designated pairs of the designated input value and the designated output value are registered. Subsequent operations can be performed without being limited by the area or the like. Further, since the output designated value changing unit 503 is provided for changing only the output designated value of the selected set among the set of the input designated value and the output designated value arranged in the same child window, the output A sufficient area can be used for the arrangement of the designated value changing unit 503, and a display that is easy to operate can be provided.

Further, by using the present apparatus for generating an area selection signal, regardless of the three-dimensional distribution of the color to be selected in the color space, the color to be set in the area and the color to be set outside the area can be input. Designated value determining unit 30 according to image
By simply designating a plurality of items by using 4, it is possible to cut out an optimal area with a free shape according to the input image, regardless of the skill of the operator.

Since the color data converter of the present embodiment is realized by using a computer and signal processing hardware controlled by a software program, it is possible to perform signal processing on a moving image signal in real time. In addition, since the processing on the still image signal is performed at a higher speed, processing that does not cause the operator to feel stress can be performed.

Although the color data conversion device according to the present embodiment is realized by a computer device and signal processing hardware controlled by a software program, there are cases where real-time processing of a moving image is unnecessary. In the case where very high-speed processing is not required, or in a case where a sufficient processing speed can be obtained in a computer device even without signal processing hardware, the present invention may be realized as a computer device and a software program. In this case, it is possible to obtain an effect that the cost of realization is low and the system can be easily improved.

Also, in this embodiment, the input signal
The defined color space is YCbCr color space,
B, YUV, YIQ, CMY, CMYK, L^*a^*b^*,
L^*u ^*v^*, HSV, HLS, etc.
Other color spaces may be used, and depending on the processed image.
A color space uniquely defined by the user may be used. Any color sky
The same effect can be obtained even when a gap is used.

Further, the display of the input image and the output image in the input / output image display unit 501 described in this embodiment is performed alternately in the same child window, but the child window is divided into a plurality of windows and displayed simultaneously. In this case, the input image and the output image can be compared at the same time, so that the specification of the set of the specified values becomes simpler. Although the output designated value changing unit 503 described in the present embodiment changes the output specified value by operating the slider, the output specified value is changed by selecting from a color sample display (not shown), inputting a numerical value, or a combination thereof. In this case, more flexible and simple changes can be made according to the purpose. For example, use a slider to specify the color of the sky, specify a color for cosmetics such as lipstick using selections from color samples corresponding to product samples, and specify a color for characters imposed on the image. Can be flexibly used, for example, using a numerical value determined in advance in consideration of the characteristics of the display device.

Further, the designated value determining unit 304 described in the present embodiment is used for applying the posterization effect, but the display of the output designated value in the input / output designated value set display unit 502 indicates the inside and outside of the area. The display is changed to a display, and the inside and outside of the area can be designated by the output designated value change unit 503, and the display of the output image on the input / output image display unit 501 is a monochrome image showing the area itself. The generation of the area selection signal may be performed. In this case, it is easier to specify the color desired to be set in the area and the color set to be set outside the area, and it becomes easier to cut out the optimum area with a free shape according to the input image.

[0068]

As is apparent from the above description, the color data conversion device according to the present invention uses input designated value recording means for recording input designated values and color data associated with each input designated value. An output designated value recording means recorded as an output designated value, and an input designated value which minimizes a distance in a three-dimensional color space between a given color and each input designated value recorded in the input designated value recording means. An input designated value specifying unit to be specified and an output unit to output an output specified value corresponding to the specified input specified value are provided.

As a result, the color of each pixel constituting the color image is converted into the output designated value corresponding to the input designated value having the shortest distance in the color space. It is reduced to a number equal to the number of pairs of value and output specification value. That is, the area division for reducing the number of colors is not a uniform method by division for each axis of the color space,
Since the determination is made based on “the closest color (input designated color)”, it is easy to implement the posterization effect that sufficiently reflects the intention of the worker.

Color for area division (input designation color)
And the final output color (designated output color) are registered independently, so that it is possible to determine the area division for posterization and the output color independently, and flexible posterization using an arbitrary color scheme Implementation of the effect is realized. The input designated value and the output designated value may be the same value, and the input designated value recording means may also have the function of the output designated value recording means. As a result, these recording means can be integrated, and the storage capacity can be saved.

The output designation value may be a value (region selection signal) indicating whether or not a region in a corresponding color space belongs to a predetermined selection region, instead of a color to be output. Accordingly, based on the cutout based on the distance in the color space between the given color and the input designated value, that is, based on the cutout based on the arbitrary shape, instead of the cutout based on the uniform shape by dividing the color space for each axis. An area selection signal is output.

Also, the input designated value specifying means may calculate and compare not the Euclidean distance but the square of the Euclidean distance as the distance. This eliminates the need for the process of finding the square root in the distance calculation, thereby reducing the processing cost and increasing the processing speed. Further, the color data conversion device according to the present invention further comprises a graphical user for determining an input designated value and an output designated value in accordance with an instruction of an operator and recording them in the input designated value recording means and the output designated value recording means. An interface unit may be provided.

As a result, the operator can arbitrarily set and change the input designation value serving as a reference for area division and the output designation value serving as a final output by a simple operation, which is the object of processing. Various posterizations and selection signals can be generated according to the content and type of the color image. Further, the graphical user interface unit displays the input image and the output image simultaneously or alternately on a display device, and when a pixel on the input image is designated, the color of the pixel is designated as an input designated value and an output designated value. When a pixel on the output image is designated, the color of that pixel can be determined as the output designated value, and the color of the pixel at the same position in the corresponding input image can be decided as the input designated value.

In this way, a method of designating colors that are not to be changed so much by the posterization effect is performed on the input image, and fine adjustment of the effect-completed image and designation of colors to be emphasized are performed on the output image. Therefore, efficient work without waste reflecting the previous specification can be performed. In addition, the graphical user interface unit can arrange a plurality of pairs of the determined input designated value and the determined output designated value on the same window and display them on the display device.

As a result, the operator can easily confirm the set of the input designated value and the output designated value which have already been determined, thereby avoiding erroneous operations such as duplicate designation. Also, when one of those sets is selected by the operator, the graphical user interface unit operates a slider to change the component corresponding to each axis of the color space, selects by a color sample, and inputs a numerical value. Thus, a change in the output designated value of the set can be accepted.

As a result, the operator can flexibly and easily specify the intended output designation value by a natural operation, so that the operation of generating a desired posterization or selection signal can be completed in a shorter time. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a color data conversion device according to a first embodiment of the present invention.

FIG. 2 is an a ^* b ^* plan view showing division of a color space by the device.

FIG. 3 is a block diagram illustrating a configuration of a color data conversion device according to a second embodiment of the present invention.

FIG. 4 is an a ^* b ^* plan view showing division of a color space by the device.

FIG. 5 is a graphical user interface provided by a designated value determining unit 304 of the device.

FIG. 6A is a flowchart illustrating an operation procedure of a designated value determination unit 304 of the device. FIG. 6B is a flowchart showing a flow in a case where an operator operates using the apparatus.

FIG. 7 is a block diagram showing a configuration of a conventional posterization color data conversion device.

FIG. 8A is a diagram showing a relationship between input and output signals when the input signal is reduced to two gradations by the same device. FIG. 8B is a diagram showing a relationship between input and output signals when the input signal is reduced to three gradations by the same device.

FIG. 9 is an RG plan view showing division of a color space by the device.

FIG. 10 is a block diagram showing a configuration of a conventional color data conversion device for generating a key signal.

FIG. 11 shows selection signal generation units 1002 to 1004 of the device.
It is a figure for explaining the operation in.

FIG. 12A is a diagram illustrating a distribution of a selection signal (Key-c) of a C component in a CbCr input color difference plane in the device. FIG. 12B is a diagram showing the distribution of the selection signal (Key-h) of the H component in the CbCr input color difference plane in the device. FIG. 12C shows a distribution of a key signal (Key) after synthesis in the same device on a CbCr input color difference plane.

FIG. 13 is a diagram showing a distribution of key signals in a CbCr input color difference plane when a color area to be selected has an irregular shape.

[Explanation of symbols]

 101, 301 Designated value recording unit 101a, 301a Input designated value recording unit 101b, 301b Output designated value recording unit 102, 302 Distance comparison unit 103, 303 Output designated value selection unit 304 Designated value determination unit 501 Input / output image display unit 502 Input Output specified value group display section 503 Output specified value change section

Claims (11)

(57) [Claims] 1. A color data conversion device for converting color data of pixels constituting a color image, which serves as a reference for dividing a three-dimensional color space used for specifying the color into a predetermined area. An input designated value recording means for recording a color (input designated value); and an output for recording a value (output designated value) finally associated with each of the input designated values and desired to be output. Given designated value recording means, and given color data of pixels constituting the color image, calculate a distance in a three-dimensional color space between the color and each designated input value recorded in the designated designated value recording means. Input specified value specifying means for specifying an input specified value whose distance is minimized by comparing the output specified value corresponding to the input specified value specified by the input specified value specifying means; Color data conversion apparatus characterized by and output means for outputting the read out stage. 2. The color data conversion device according to claim 1, wherein said input designated value specifying means calculates and compares the square of a Euclidean distance as said distance. 3. The color data conversion device according to claim 2, wherein the specified output value is a value indicating whether or not an area corresponding to the specified output value is included in a predetermined selected area. 4. The color data conversion device according to claim 2, wherein the specified output value is a value representing a color desired to be obtained after conversion for a color belonging to an area corresponding to the specified output value. 5. The color data conversion device according to claim 4, wherein said output designated value corresponding to said input designated value is the same value. 6. The color data converter further comprises a designated value determining means for determining an input designated value and an output designated value in accordance with an instruction of an operator, and recording these in the input designated value recording means and the output designated value recording means. The color data conversion device according to claim 3, wherein the color data conversion device is provided. 7. A display device, an input unit for receiving an instruction from an operator, and a window and an operation panel arranged on the window are displayed on the display device. 7. The color data conversion device according to claim 6, further comprising a graphical user interface unit that controls the unit to determine the input designated value and the output designated value. 8. The input / output image display for simultaneously or alternately displaying an input image to be processed and an output image obtained from the output means in correspondence with the input image on the display device. When a pixel on the input image is designated by the input unit, the color of the pixel as an input designated value and an output designated value,
A determination unit that determines a color of the pixel as an output designation value when a pixel on the output image is designated, and a color of a pixel at the same position in the corresponding input image as an input designation value. Item 7. A color data conversion device according to Item 7. 9. The graphical user interface unit further comprises an input / output designated value set display unit for arranging a plurality of determined input designated value and output designated value sets on the same window and displaying them on the display device. 9. The color data conversion device according to claim 8, wherein: 10. The graphical user interface unit further comprises: when any one of the sets displayed by the input / output designated value set display unit is selected by the input unit,
10. The color data conversion device according to claim 9, further comprising an output designated value change unit that receives the set of output designated values as a change target. 11. The output designated value changing unit displays a slider for changing a component corresponding to each axis of the three-dimensional color space, performs an operation by the input unit, displays a color sample, and selects by the input unit. 11. The color data conversion device according to claim 10, wherein the output designation value is changed by inputting a numerical value by the input unit and a combination thereof.