JPH11284867A - Image processing device - Google Patents

Abstract

(57) [Problem] To provide an image processing apparatus capable of extracting color information embedded in a monochrome image output and obtaining a color copy output. An RG of an image input from an image reading device is provided.
An image processing device that performs RGB / KCMY conversion based on a B signal and outputs a KCMY signal to a color output device. When a monochrome image document in which color information is embedded as an image pattern is read, an RGB input signal is output. The luminance / hue separation means 11 for separating a single-color luminance signal having a predetermined bit length into a plurality of upper bits and a plurality of lower bits and outputting each of the plurality of bits as a luminance signal and a hue signal.
And a mapping table 12 for converting a hue signal into a value indicating a designated color in a color coordinate space and outputting the converted value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to an image processing apparatus capable of outputting a color image from read image information when color information is embedded in a color image output.

[0002]

2. Description of the Related Art Generally, even if a document is a color image,
When distributing the manuscript to a large number of people at a meeting, etc., or when sending the manuscript to many people by direct mail, etc., copy and output it with a monochrome copying machine that can copy quickly and inexpensively. Often done. The black-and-white copy output described above does not pose a serious problem to the recipient of the black-and-white copy output in the case of a document mainly composed of text or a document in which the content is not so important. However, if the color of the manuscript is important to the recipient of the black-and-white copy output, the recipient should ask the distributor to distribute (send) the color copy output copied again by a color copying machine or the like to himself / herself. Need to be required. In addition, the distributor usually cannot recognize which of the recipients needs the color copy output, since it largely depends on their needs and feelings. Therefore, the distributor uniformly distributes and sends the black-and-white copy output. For the reasons described above, those who receive a black and white copy output in spite of the need for a color copy output often have to request the color copy output from the distributor each time. In order to solve the problem, for example, by expressing the color of the original with a hatch pattern of different black and white on the copy output, it is possible to make the recipient recognize the color difference even in the black and white copy output. Monochrome copiers are known. That is, even if a color image is once copied in black and white, a hatch pattern is provided in the black and white image on the black and white copy paper so as to determine whether the image is a color image or a black and white image. In addition, the present inventor has proposed in an application prior to the present application an image processing apparatus that performs color copying and output by embedding color information in a document image as information that is difficult to be discerned by human eyes into a monochrome image or the like.

[0003]

However, in the above-described hatch pattern, although a portion where the color is different can be recognized, what kind of visual effect can be obtained depending on the actual color image and the combination of colors. I didn't know about it. In addition, the present inventor has already proposed an image forming apparatus that outputs a black-and-white copy image in which color information is embedded, but obtains a color copy image from a black-and-white copy image in which an image pattern of color image information is embedded. The means are not specifically described. The present invention has been made to solve the conventional problems as described above, and when a color image original is copied in black and white, the color information portion and the monochrome information portion in the black and white image on the black and white copy are compared. It is an object of the present invention to provide an image processing apparatus capable of reproducing a color image by identifying a color information portion and a black and white information portion from a black and white image when represented by an identifiable image pattern. I do.

[0004]

According to a first aspect of the present invention, there is provided an image processing apparatus, comprising: an image processing unit configured to generate an RGB / K image based on an RGB signal of an image input from an image reading apparatus;
An image processing device that performs CMY conversion and outputs a KCMY signal to a color output device. When reading a monochrome image document in which color information is embedded as an image pattern, a monochrome image having a predetermined bit length in the RGB input signal is read. A luminance / hue separation unit that separates the luminance signal into a plurality of upper bits and a plurality of lower bits, and outputs each of the plurality of bits as a luminance signal and a hue signal; And a mapping table for converting the value into a value indicating the value and outputting the converted value. An image processing apparatus according to a second aspect of the present invention is an image processing apparatus that performs RGB / KCMY conversion based on an RGB signal of an image input from an image reading device and outputs a KCMY signal to a color output device. When reading a black-and-white image original in which information is embedded as an image pattern, a luminance separating means for outputting a single-color luminance signal of a predetermined bit length in the RGB input signal, and outputting the luminance signal as a density signal by delaying the luminance signal Delay storage means, a pattern extraction means for extracting an area modulation pattern by filtering the luminance signal and outputting a pattern value, and a mapping for converting the pattern value into a value indicating a designated color in a color coordinate space and outputting the converted value. And a table. An image processing apparatus according to a third aspect of the present invention is an image processing apparatus that performs RGB / KCMY conversion based on an RGB signal of an image input from an image reading device and outputs a KCMY signal to a color output device. When reading a black-and-white image original in which information is embedded as an image pattern, a luminance separating unit that outputs a single-color luminance signal of a predetermined bit length in the RGB input signal, and an area modulation pattern by filtering the luminance signal. First pattern extracting means for extracting and outputting a first pattern value for a hue signal; a first mapping table for converting the first pattern value into a value indicating a designated color in a color coordinate space and outputting the value; A second pattern extracting means for extracting an area modulation pattern by filtering the luminance signal and outputting a second pattern value for the luminance signal; And having a second mapping table for converting the over emissions value to the value of the luminance signal. According to another aspect of the present invention, there is provided an image processing apparatus for RGB of an image input from an image reading apparatus.
An image processing apparatus that performs RGB / KCMY conversion based on a signal and outputs a KCMY signal to a color output device, wherein a luminance signal is printed by a first color of KCMY,
When a two-color image original on which a hue signal is printed in the second color of KCMY is read, the RGB input signal is separated into the first color hue signal and the second color hue signal and output. A first hue separation unit that converts the hue signal of the first color into a luminance signal and outputs the luminance signal;
Second conversion means for converting a color hue signal into a value indicating a designated color in a color coordinate space and outputting the converted value.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on illustrated embodiments. FIG. 1 is a block diagram showing an overall configuration in which an image processing apparatus according to the present invention is used. As shown in FIG. 1, an image processing apparatus 2 according to the present invention is connected to a scanner 1 and a printer 3. The scanner 1 is an image reading device that reads image data from a black-and-white image document in which color information is embedded as an image pattern and outputs RGB signals, and in the present invention, a black-and-white image or KCMY
Images of two colors of the signals are read and RGB signals are output. More specifically, the original to be read by the scanner 1 is a monochrome copy of a color image original by a special copying machine. This copying machine uses a color information image pattern in a color image and a monochrome image. By making the pattern different from the pattern so that the scanner can identify it, a color image pattern is extracted from a monochrome image so that a color image can be reproduced.

[0006] The image processing device 2 converts the input RGB signals into KCMY signals and outputs them. In the present invention,
From a part or all of the input RGB signals obtained by reading a monochrome image or a two-color image of the KCMY signal,
The embedded luminance signal and hue signal are extracted, and a KCMY signal is generated and output based on the luminance signal and the hue signal.
The printer 3 is a color image output device that outputs a color image based on the input KCMY signal. FIG. 2 is a block diagram showing a first embodiment of a signal extraction part in the image processing apparatus. The signal extraction part of FIG. 2 includes a luminance / hue separation unit 11 and a hue signal mapping table 12. For example, when reading a monochrome print having an 8-bit density by the scanner 1 having an 8-bit resolution, an 8-bit RGB signal is output from the scanner 1. The 8-bit data is stored in 7a, 6b, 5c, 4d,
The data is composed of 3e, 2f, 1g, and 0h. In this case, since the read image is a black-and-white image, the luminance / hue separation section 11 receives the G signal (8 bits) of the RGB signals and outputs the upper 4 bits and lower 4 bits of the 8-bit luminance signal. Output the bits separated. The upper 4 bits are used as a luminance signal, and the lower 4 bits are used as a hue signal. That is, data of 7a, 6b, 5c, and 4d in the 8-bit data is used as a luminance signal, and data of 3e, 2f, 1g, and 0h are used as hue signals. The lower 4 bits of the hue signal are input to the hue signal mapping table 12, converted into a value indicating the designated color in the color coordinate space, and output. For example, the hue signal mapping table 12 converts the lower 4 bits to red if the lower 4 bits are signals of 0 to 3 and converts the lower 4 bits to yellow if the lower 4 bits are signals of 4 to 7, and 8 to 11
Is a table that converts the signal to green if it is a signal of, and converts it to blue if it is a signal of 12 to 15. A KCMY signal is generated and output based on the color signal obtained by converting the upper 4 bits of the luminance signal and the lower 4 bits of the hue signal in the above table.

FIG. 3 is a block diagram showing a second embodiment of the signal extraction portion in the image processing apparatus. The signal extraction part of FIG. 3 includes a luminance separation unit 21 and a pattern extraction unit 2
2, a hue signal mapping table 23 and a delay memory 24. The input signal from the scanner 1 is an 8-bit G signal similar to the case of FIG. FIG.
In the case of, the 8-bit luminance signal is output from the luminance separation unit 21 without being separated. The 8-bit luminance signal is input in parallel to the delay memory 24 together with the pattern extraction unit 22. The pattern extraction unit 22 performs a filtering process and an area modulation pattern extraction on the input 8-bit luminance signal. For example, an area modulation pattern of a high frequency component is extracted through a filter that passes only a high frequency component. Incidentally, the normal area modulation pattern is a method of expressing the density by the presence or absence of a plurality of dots.
When the density of one pixel is represented by a dot, "None" or "None"
Represents a “light” density, “absence” and “presence” represent a “normal” density, and “presence” and “presence” represent a “dark” density. In the present invention, using this information, for example, In the case of the two-dot information in the above example, "absence" and "absence" represent "red",
“No” and “Yes” represent “green”, and “Yes” and “Yes” are used as hue information indicating “Yellow”. Then, a predetermined value extracted from the area modulation pattern is output by allocating the hue information to, for example, a 4 × 4 dot matrix pattern. The predetermined value is input to the hue signal mapping table 23, and the same processing as in the hue signal mapping table 12 of FIG. 2 is performed to output a color signal. On the other hand, the 8-bit luminance signal input to the delay memory 24 is output to the outside in synchronization with the output of the hue signal mapping table 23.

FIG. 4 is a block diagram showing a third embodiment of the signal extraction portion in the image processing apparatus. 4 includes a luminance separation unit 31, a first pattern extraction unit 32, a hue signal mapping table 33, a second pattern extraction unit 34, and a luminance signal mapping table 3.
5. In the embodiment of FIG. 4, a second pattern extracting unit 34 and a luminance signal mapping table 35 are provided in place of the delay memory 24 of FIG.
Therefore, the configuration and operation of the luminance separating unit 31, the first pattern extracting unit 32, and the hue signal mapping table 33 in FIG. The configuration and operation are almost the same. In the case of FIG. 4 as well, the 8-bit luminance signal is output from the luminance separating unit 31 without being separated. The 8-bit luminance signal is input to the second pattern extraction unit 34 in parallel with the first pattern extraction unit 32. The first pattern extraction unit 32 performs a filtering process and an area modulation pattern extraction on the input 8-bit luminance signal. For example, an area modulation pattern of a high frequency component is extracted through a filter that passes only a high frequency component. Then, by assigning the hue information obtained from the area modulation pattern to, for example, an 8 × 8 dot matrix pattern, a predetermined value extracted from the area modulation pattern is output. The predetermined value is input to the hue signal mapping table 33, and the same processing as in the hue signal mapping table 12 of FIG. 2 is performed to output a color signal. On the other hand, the second pattern extraction unit 34 also performs filter processing and area modulation pattern extraction on the input 8-bit luminance signal. Then, by assigning the hue information obtained from the area modulation pattern to, for example, a matrix pattern different from the first pattern extraction unit 32, for example, a 4 × 4 dot matrix pattern, A predetermined value extracted from the area modulation pattern is output. The predetermined value is input to the luminance signal mapping table 35, and a luminance signal is output. First
As the combination of the matrix patterns in the pattern extraction unit 32 and the second pattern extraction unit 34, since the luminance signal is more sensitive to normal human eyes, the first pattern extraction that outputs the luminance signal The smaller matrix is assigned to the unit 32.

FIG. 5 is a block diagram showing a fourth embodiment of the signal extraction portion in the image processing apparatus. 5 includes a hue separation unit 41 and a first conversion processing unit 42.
And a second conversion processing unit 43. Also in this case, the data is 8-bit data.
The read image is a two-color image of KCMY (for example, M
And the image on the printed matter printed with K)
All of the signals (8 bits) are input, and two-color signals of the 8-bit KCMY are separated again from the input signals and output. For example, assuming that the M signal and the K signal are output signals, the K signal represents a luminance signal, and the M signal represents a hue signal. The K signal is output to the first conversion processing unit 4
When the signal is input to 2, the signal is converted into a luminance signal and output to the subsequent stage. When the M signal is input to the second conversion processing unit 43, it is converted into a hue signal and output to the subsequent stage, and finally the hue signal mapping tables 12, 23, and 33 shown in FIGS. Is output. A KCMY signal is finally generated and output from the luminance signal and the color signal obtained by converting the hue signal.

[0010]

As described above, according to the present invention, hue information can be extracted from a luminance signal obtained by reading a monochrome print by using pattern extraction or a mapping table, and the amount of information contained in the luminance signal can be reduced. Can be increased. Also, in a two-color print, a luminance signal and a multi-color hue signal can be included in each hue signal.
In other words, when a color image original is copied in black and white, if the color information portion and the black and white information portion in the black and white image on the black and white copy are represented by an identifiable image pattern, the color information portion is extracted from the monochrome image. A color image can be reproduced by discriminating the monochrome information portion.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration in which an image processing apparatus according to the present invention is used.

FIG. 2 is a block diagram showing a first embodiment of a signal extraction part in the image processing apparatus.

FIG. 3 is a block diagram showing a second embodiment of a signal extraction part in the image processing apparatus.

FIG. 4 is a block diagram showing a third embodiment of a signal extraction part in the image processing apparatus.

FIG. 5 is a block diagram showing a fourth embodiment of a signal extraction part in the image processing apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... scanner, 2 ... image processing part, 3 ... printer, 11 ... brightness / hue separation part, 12, 23, 33
... Hue signal mapping table, 21, 31 ...
Brightness separation unit, 22 ... pattern extraction unit, 24 ... delay memory, 32 ... first pattern extraction unit, 34 ...
Second pattern extraction unit, 35: luminance signal mapping table, 41: hue separation unit, 42: first conversion processing unit, 43: second conversion processing unit

Claims (4)

[Claims] An RG of an image input from an image reading device.
An image processing apparatus for performing RGB / KCMY conversion based on a B signal and outputting a KCMY signal to a color output device, wherein when reading a black-and-white image original in which color information is embedded as an image pattern, the RGB input signal A luminance / hue separation unit that separates a single-color luminance signal having a predetermined bit length into a plurality of upper bits and a plurality of lower bits, and outputs each of the plurality of bits as a luminance signal and a hue signal; An image processing apparatus comprising: a mapping table that converts a value indicating a designated color in a color coordinate space and outputs the converted value. 2. The RG of an image input from an image reading device.
An image processing apparatus for performing RGB / KCMY conversion based on a B signal and outputting a KCMY signal to a color output device, wherein when reading a black-and-white image original in which color information is embedded as an image pattern, the RGB input signal A luminance separating means for outputting a monochromatic luminance signal having a predetermined bit length therein;
Delay storage means for delaying the luminance signal and outputting it as a density signal; pattern extraction means for extracting an area modulation pattern by filtering the luminance signal to output a pattern value; and specifying the pattern value in a color coordinate space. An image processing device comprising: a mapping table that converts a value into a value indicating a color and outputs the converted value. 3. An RG of an image input from an image reading device.
An image processing apparatus for performing RGB / KCMY conversion based on a B signal and outputting a KCMY signal to a color output device, wherein when reading a black-and-white image original in which color information is embedded as an image pattern, the RGB input signal A luminance separating means for outputting a monochromatic luminance signal having a predetermined bit length therein;
A first step of extracting an area modulation pattern by filtering the luminance signal and outputting a first pattern value for a hue signal;
Pattern extracting means, a first mapping table for converting the first pattern value into a value indicating a designated color in a color coordinate space and outputting the value, and extracting a luminance signal by extracting an area modulation pattern by filtering the luminance signal. Image processing apparatus, comprising: a second pattern extracting means for outputting a second pattern value for use in the image processing apparatus; and a second mapping table for converting the second pattern value into a luminance signal value and outputting the luminance signal value. . 4. An RG of an image input from an image reading device.
An image processing device that performs RGB / KCMY conversion based on a B signal and outputs a KCMY signal to a color output device, wherein a luminance signal is printed by a first color of KCMY,
When a two-color image original on which a hue signal is printed in the second color of KCMY is read, the RGB input signal is separated into the first color hue signal and the second color hue signal and output. A first hue separation unit that converts the hue signal of the first color into a luminance signal and outputs the luminance signal;
An image processing apparatus comprising: a second conversion unit that converts a color hue signal into a value indicating a designated color in a color coordinate space and outputs the converted value.