JPH06121159A - Color image processor - Google Patents

Abstract

PURPOSE:To reduce a color correcting operation by an operator and to provide high quality color output by performing color conversion for which the memorized colors of a human being are considered. CONSTITUTION:Image data inputted from an input part 1 are converted from RGB data to the data of brightness, saturation and hue space in a color conversion part 2 and the color correction of the memorized colors such as skin color, blue and green, etc., is performed in a memorized color correction part 3. The data color-corrected at the memorized color correction part 3 are converted to YMC data and the RGB data in the color conversion part of a display/output part 5 and outputted by a printer and a display, etc. Since the memorized color correction part 3 is provided and the color correction of the memorized colors is performed, the color correction for approaching to the memorized colors of the human performed by the operator in the past can be automatically performed and the color correcting operation by the operator can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image processing apparatus for processing images such as color photographs in the fields of printing, newspapers, design and the like. In recent years, with the demand for colorization of printed matter, development of a system for handling a color image using a computer has been advanced. In a color image processing system, a color photograph or the like is input from a camera or an image scanner and output to an output device. At this time, looking at the display color of the display and the printing color of the printer, it is to some extent faithful to the original color, but colors such as human skin color and green of forest are colors that humans remember (hereinafter referred to as memory colors). Can be different from. In color printing, color reproduction that is faithful to the original is not always good, and it is necessary to make the image look beautiful to the human eye.

[0002]

2. Description of the Related Art FIG. 6 is a diagram showing a conventional color image system. In FIG.
Reference numeral 2 is an image scanner that reads an image from a document 11, 13 is image data read by the image scanner 12, 14 is a color conversion unit that converts the image data 13 into RGB, and 15 is a display that displays a color image,
Reference numeral 16 is a color conversion unit for converting the image data 13 into YMC (yellow, magenta, cyan) suitable for printing, 17 is a printer for printing a color image, and 18 is a printer 1.
7 shows a printed matter printed out by 7.

In the color image system shown in FIG.
The color image data 13 of the original 11 read by the image scanner 12 is converted into RGB in the color conversion unit 14 and displayed on the display 15, and converted into YMC in the color conversion unit 16 and printed out by the printer 17. . As a color conversion method in the color conversion units 14 and 16, conventionally, color conversion by masking has been used. As the masking, there are the following primary masking, two-step masking and secondary masking depending on the order of the correction term.

[0004]

[Equation 1]

In the conversion here, the conversion coefficient is obtained in consideration of the distortion of the input or output device so that the color faithful to the original is reproduced. For example, a standard color chart is input from the image scanner 12 shown in FIG. 6, this is displayed on the display 15, and the display color is measured by a colorimeter. On the other hand, the original color of the input color chart is also measured by a colorimeter, a conversion coefficient that matches these values is obtained, and masking correction is performed before displaying on the display 15.

In this case, since color conversion is performed for the purpose of reproducing a color faithful to the original color, there is no problem when comparing the output color and the original color, but it is unnatural to human eyes. Often reflected. In particular, memory colors (colors that humans have in their memories) are unnatural. Therefore, in the past, when performing color printing, the operator "makes the skin more pink" and "makes the sky more vivid blue".
The color correction was done.

[0007]

As described above, in the prior art, color correction has been conventionally performed by the operator so that the memorized color does not become unnatural. In the color correction, the operator has to directly change a plurality of dials to adjust the print color, and this work is limited to a specific expert.

The present invention has been made in order to improve the above-mentioned problems of the prior art, and by performing color conversion in consideration of human memory colors, the color correction work of the operator can be reduced, and a higher level of operation can be achieved. An object of the present invention is to provide a color image processing device capable of obtaining a high quality color output.

[0009]

FIG. 1 is a basic configuration diagram of the present invention. In FIG. 1, reference numeral 1 is an input unit composed of a scanner for reading a color image original and outputting RGB data, and 2 is an input. A color conversion unit that performs coordinate conversion of the image data into brightness, saturation, and hue, 3 is a memory color correction unit that performs color correction in consideration of human memory colors such as skin color, sky blue, and green, and 4 is a memory color correction unit 3 Image data 5 obtained by the above is a display / output unit for color-converting the image data 4 and outputting the color data to a printer or a display.

In order to solve the above problems, the invention of claim 1 of the present invention is, as shown in FIG. 1, a data input section 1 for inputting color image data in a color image processing apparatus.
A color conversion unit 2 that performs coordinate conversion of the image data input from the data input unit 1 into lightness, saturation, and hue in consideration of device distortion; and skin color of the image data converted by the color conversion unit 2. Provided with a memory color correction unit 3 for performing color correction in consideration of human memory colors such as sky blue and green, and a display / output unit 5 for displaying and printing the image data 5 corrected by the memory color correction unit 3. Is.

According to a second aspect of the present invention, in the first aspect of the invention, the memory color correction unit 3 sets an area determined to be a human memory color in the image data represented by the lightness, the saturation, and the hue. The color correction is performed by extracting and determining the presence or absence of the memory color correction based on the area area.

[0012]

According to the first aspect of the present invention, in the color image processing apparatus, the color conversion unit 2 for coordinate-converting the image data input from the data input unit 1 into lightness, saturation and hue.
Since the image data converted by the color conversion unit 2 is provided with the memory color correction unit 3 that performs color correction in consideration of human memory colors such as flesh color, sky blue, and green, human operators conventionally used The color correction to bring the color closer to the memory color can be automatically performed, and the color correction work of the operator can be reduced.

According to the second aspect of the present invention, the memory color correction unit 3 extracts a region determined to be a human memory color from the image data represented by the lightness, the saturation and the hue, and the region is extracted. Since the presence or absence of the memory color correction is determined based on the area and the color correction is performed, it is possible to improve the processing speed without performing the color correction even for a small area having a small influence.

[0014]

FIG. 2 is a diagram showing the overall construction of an embodiment of the present invention. In FIG. 2, reference numeral 21 denotes an input unit composed of an image scanner or the like for reading an image from a document, and 22.
Is a color conversion unit that converts the RGB data input from the input unit 21 into lightness, saturation, and hue space coordinates in consideration of distortion of the input / output device. The lightness, the saturation, and the hue space coordinates are, for example, Munsell space (HVC), L *, a *, b * which is a uniform color space, or L *, u *, v *.
However, the Munsell space (HVC) is used in this embodiment.
An example using will be described. Here, in HVC, H represents hue (hue), V represents value (lightness), and C represents chroma (saturation).

Reference numeral 23 is a flesh color, a sky color, which is a human memory color, from the data HVC converted into lightness, saturation, and hue space coordinates.
A memory color correction unit that extracts memory colors such as green and performs color correction,
24 is a data base for storing the image data of the lightness, saturation, and hue space coordinates H'V'C 'corrected by the memory color correction unit 23; 25 is the lightness of the image data stored in the data base 24; Saturation and hue space coordinates H'V'C '
To YMC data, 26 is a color conversion unit that converts the lightness, saturation, and hue space coordinates H'V'C 'of image data into RGB data, and 27 is the image data converted into YMC data. An output unit such as a printer for outputting, 28 is R
The output unit is a CRT display or the like that outputs the image data converted into GB data.

In the figure, the image data input from the input unit 21 is converted into HVC data by the color conversion unit 22, and the memory color correction unit 22 corrects the color of the memory color. The presence / absence of color correction in the memory color correction unit 22 can be instructed by the operator. The H′V′C ′ data color-corrected by the memory color correction unit 22 is stored in the data base 24, converted into YMC data and RGB data by the color conversion units 25 and 26, and output by the output unit 27,
At 28, it is output by a printer, a display, or the like.

FIG. 3 is a diagram showing an embodiment of the memory color correction section 24 of FIG. 2, in which 31, 31 and 33 are data sections, and FIG.
32 is a memory color correction unit, 32a is a memory color extraction unit, 32b is a region determination unit, and 32c is a memory color change unit. Figure 4
FIG. 4 is a diagram showing a process in the memory color correction unit in FIG. 3, and the memory color correction process in this embodiment will be described with reference to FIGS. 3 and 4.

The HVC data output from the data section 31 is given to the memory color extraction section 32a of the memory color correction section 32 in FIG. 3, and here, for the image data HVC, each preset memory color, for example, skin color It is determined whether or not it is within the range of the area, the sky blue area, and the leaf color area, and if it belongs to this area, it is extracted as a memory color (see 41 in FIG. 4).

With respect to the memory color extracted by the memory color extracting section, the area determining section 32b calculates the ratio of the area area of the memory color to the entire image area, for example, the ratio α of the skin color area area (see 42 in FIG. 4). When α is equal to or larger than a certain threshold, the memory color changing unit 32c changes the HVC data of the memory color. That is, as shown at 43 in FIG. 4, the HVC value corrected for the memory color is obtained by multiplying the HVC value by the predetermined constants a, b, and c, and the data section 33 is obtained.
Is output to.

The memory color correction is performed, for example, in the Munsell hue and saturation shown in FIG. 5 by changing the data in the flesh color area to color data shifted from yellow to red, or by changing the data in the sky blue area. Change to color data in the direction of increasing brightness (brightness) and brightness. Obtain these correction values in advance by collecting data such as questionnaire surveys,
Color correction is performed to a more preferable memory color.

In the above embodiment, an example using the Munsell space (HVC) has been described, but L *, a *, b *, or L *, u *, v, which are uniform color spaces.
The same can be done by using *.

[0022]

As is apparent from the above description,
In the present invention, the input image data is converted into spatial coordinates of lightness, saturation, and hue, and color correction considering human memory colors such as skin color, sky blue, and green is performed in lightness, saturation, and hue space. Since the color correction is performed, the operator may correct the color that cannot be corrected by the color correction.

Therefore, the color correction work conventionally performed by the operator can be reduced, and a higher quality color output can be obtained.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of the present invention.

FIG. 2 is a diagram showing an overall configuration of an embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a memory color correction unit.

FIG. 4 is a diagram illustrating a process in a memory color correction unit.

FIG. 5 is a diagram showing memory color correction in Munsell space.

FIG. 6 is a diagram showing a conventional image processing system.

[Explanation of symbols]

 1, 21 Input unit 2, 22, 25, 26 Color conversion unit 3, 23, 32 Memory color correction unit 4 Display / output unit 24 Data base 27, 28 Output unit 32a Memory color extraction unit 32b Region determination unit 32c Memory color Change part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location G09G 5/36 8121-5G H04N 1/46 9068-5C

Claims (2)

[Claims] 1. A data input unit (1) for inputting color image data, and a color for coordinate-converting the image data input from the data input unit (1) into lightness, saturation, and hue in consideration of device distortion. The conversion unit (2) and the image data converted by the color conversion unit (2) are corrected by the memory color correction unit (3) and the memory color correction unit (3) that perform color correction considering human memory colors. A color image processing device comprising a display / output unit (5) for displaying and printing the image data (4) that has been recorded. 2. A memory color correction unit (3) extracts a region determined to be a human memory color from image data represented by lightness, saturation, and hue, and the presence or absence of memory color correction based on the region area. The color image processing apparatus according to claim 1, wherein the color image processing apparatus determines the color difference and performs color correction.