JPH07288703A - Color picture output device - Google Patents

Abstract

PURPOSE:To provide output pictures provided with accurate colors at all times without being influenced by the secular change and individual difference of a scanner and a printer at the time of color conversion. CONSTITUTION:This device is provided with a scanner input conversion table 3 for converting RGB signals inputted from a color scanner 1 to R'G'B' signals independent of the scanner and a first color conversion part 2 provided with a masking function for converting the R'G'B' signals to Y'M'C'K' signals. A second color conversion part 4 uses a printer output conversion table 5 and converts the Y'M'C'K' signals into YMCK signals independent of the printer, that is, not influenced by the output characteristics of the printer at the time of picture output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image output device such as a color printer or a color facsimile, and more particularly to a chromaticity calibration function (hereinafter referred to as a calibration function) for preventing color misregistration during color conversion. The present invention relates to a color image output device.

[0002]

2. Description of the Related Art Conventionally, in a color image output device such as a color printer, RGB (red, green, blue) read by a color image scanner (color image reading device) in a color conversion unit inside the color image output device. The input color space represented by the image signal is divided into a plurality of color spaces, and a plurality of color conversion information located at the vertices are selected,
A YMCK for recording (yellow, magenta,
Cyan, black) signals were being converted.

[0003]

However, in the conventional example as described above, there is no function for preventing color misregistration at the time of conversion into YMCK signals. There is a drawback in that the aging of the apparatus and individual differences occur, and a change in tint due to color mixture deterioration of color materials such as toner and ink, that is, a change in color reproducibility in an output image occurs. .
For example, when a predetermined image is read from an image scanner and an output image is obtained on a recording sheet, it is not always possible to obtain an output image having the same tint.

The above points will be described in more detail with reference to FIG. An RGB signal obtained as a result of scanning the color original 41 with the color image scanner 42 is subjected to color conversion by a color conversion unit (not shown) in the color printer 43, and a signal obtained is referred to as a Y′M′C′K ′ signal. To do. The RG obtained as a result of being read by the color image scanner 42
If the signal obtained by masking the B signal by the masking processing circuit 44 is the YMCK signal, this YMCK signal has not always been the same as the Y'M'C'K 'signal described above. .

Further, when the user (user) wants to adjust the tint of the output image in order to prevent the above-mentioned color shift, he / she purchases expensive application software on purpose and tints himself. Had to be manually adjusted each time, which wasted money and work time.

The present invention has been made in view of the above problems, and an object of the present invention is not to be influenced by secular change or individual difference of a scanner or a printer during color conversion. It is an object of the present invention to provide a color image output device that can always obtain an output image having an accurate tint.

[0007]

To achieve the above object, the present invention provides a color image output device for converting an image signal input from a color image input device into a recording color signal and outputting the image. An input conversion table that converts a first image signal input from the image input device into a second image signal that is not affected by the input characteristics of the color image input device, a reference color signal, and the reference signal are formed. An output conversion table for converting the second image signal into a recording color signal corresponding to the output characteristics of the color image output device based on the output signal from the input conversion table corresponding to the image An output unit for outputting a color image using the obtained recording color signal is provided.

Further, in a preferred aspect of the present invention, in the input conversion table, a set of a plurality of color input values obtained by reading a color patch original with the color image input device indicates the color patch original. It can be characterized in that it has scanner calibration data created to be mapped to a set of a plurality of color input values obtained through a spectrophotometer.

As another aspect of the present invention, preferably, the output conversion table stores the first image signal obtained by reading the color patch document output from the output means with the color image input device. The recording color signal converted using the input conversion table has printer calibration data created so as to be mapped with the recording color signal used to output the color patch original from the output unit. Can be

Further, the present invention preferably further has a masking means, and the masking means further comprises:
It is determined in which area of the input color space the second image signal is divided into a plurality of areas, and interpolation processing is performed using the converted input data corresponding to the points forming the existing area. It can be characterized in that the first color signal for recording is obtained by carrying out.

[0011]

According to the present invention, the color conversion section of the color image output device is provided with two conversion tables, a scanner input conversion table and a printer output conversion table, whereby the scanner calibration function and the printer calibration function are provided inside the color image output device. Since both of the image conversion functions are executed, an output image having an accurate tint can always be obtained without being affected by the secular change or individual difference of the scanner or printer device.

[0012]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows a schematic configuration of a system including a color image output device and its peripheral devices according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an RGB image obtained by reading a color original.
A color scanner 2 for outputting a signal has Y'M'C 'whose input RGB signals have been calibrated (referred to as scanner calibration) using a scanner input conversion table 3 described later in accordance with the reading characteristics of the color scanner. The first color conversion unit 4 for converting into the K'signal uses the printer output conversion table 5 described later to calibrate the Y'M'C'K 'signal according to the output characteristics of the printer (printer calibration and Second) to convert to YMCK signal
A color conversion unit 6 is a printer engine that receives the YMCK signal and obtains an output image. The YMCK signal input to the printer engine 6 is calibrated by the tables 3 and 5 so that an output image having an accurate tint can be obtained at all times. It is possible to always obtain an output image having an accurate color tone without being affected by.

Reference numeral 7 is the scanner input conversion table 3 described above.
A control unit for creating data of the printer output conversion table 5, 8 is a ROM (read only memory) in which programs such as the conversion table data creation processing procedure shown in FIG. 2 or 3 are stored in advance, and 9 is a control unit. Is a RAM (random access memory) used for a work area or the like. Reference numeral 10 denotes a spectrophotometer for measuring the color of the color patch original when the conversion table 3 is created.

The control unit 7 outputs a predetermined color patch original from the printer engine 6 in accordance with the processing procedure of the ROM 8, causes both the color scanner 1 and the spectrophotometer 10 to read the color patch original, and reads these color data. Based on the above, the data of the scanner input conversion table 3 is created as described later.

Next, the procedure for creating the scanner calibration data and the printer calibration data according to the embodiment of the present invention will be described with reference to the flowchart of FIG.

First, the scanner input conversion table 3
The creation of scanner calibration data for creating is described.

First, a color patch original is prepared (step 101). As the color patch document here, a commercially available product such as PANTONE (trademark) may be used. To improve the accuracy of calibration, it is necessary to use as many color patches as possible.

After the color patch document is created, the color patch document is color-measured by the spectrophotometer 10 (step 102). By this colorimetry, a set of a plurality of color input values corresponding to each color patch and independent of the color scanner 1 can be obtained. The color input value is measured on the XYZ color space.

Next, the input data represented by the XYZ colors is converted into RGB color data in a standard color space such as NTSC-RGB (step 103).

On the other hand, the color patch original is read by the color scanner 1 (step 104).
This read data is a color that depends on the reading characteristics of the color scanner 1. Here, this data is R ′.
Name it G'B '.

Next, the scanner input conversion table 3 is created so that the R'G'B 'data read from the color scanner 1 is mapped to the standard RGB data of the spectrophotometer 10. With this scanner input conversion table 3, calibrated scanner calibration data is obtained (step 106).

Next, the creation of printer calibration data for creating the printer output conversion table 5 will be described.

First, the control unit 7 selects a color patch to be output from the printer engine 6 (step 10).
6). As in the case of creating the scanner calibration data, it is necessary to select a certain number of color patches in order to improve the accuracy of printer calibration.

Next, the selected color patch is created in the RAM 9 in the form of an RGB image file (step 1).
07).

Thereafter, this RGB image file is masked to generate YMCK data (step 108). This masking process is performed by the control unit 7 independently of the color conversion inside the printer by the first and second color conversion units 2 and 4. Therefore, this processing makes it possible to obtain a set of color output values, which correspond to each color patch and are independent of the printer. As a result of this operation, Y
The MCK color data will be obtained.

On the other hand, the color patch data in the RGB image file format is output from the printer engine 6 (step 109). Next, the image of the color patch data output from the printer engine 6 is read from the color scanner 1 (step 110).

Thereafter, in order to convert the color patch data read from the color scanner 1 into RGB color data in a standard color space such as NTSC-RGB, step 1 is performed.
Conversion to RGB color data in the standard color space is performed using the scanner input conversion table 3 created by the scanner calibration processing previously obtained in step 05 (step 11).
1).

Next, the RGB represented in the standard color space
The color data is masked to obtain Y'M'C'K 'data (step 112). Since this Y'M'C'K 'data is the printer-dependent color output value data, this data should be mapped to the printer-independent color output value YMCK data obtained in the previous step 108. Then, the printer output conversion table 5 is created. By using this printer output conversion table 5, calibrated printer calibration data can be obtained (step 1
13).

(Other Embodiments) FIG. 3 shows a procedure for creating scanner calibration data and printer calibration data according to another embodiment (referred to as a second embodiment) of the present invention. Since the circuit configuration of this example is the same as that of FIG. 1, its description is omitted.

The procedure for creating the scanner calibration data will be described first with reference to FIG. In the second embodiment, in the same manner as the previous embodiment (referred to as the first embodiment), a color patch original is created (step 201), and then the color patch original is color-measured by the spectrophotometer 10 (step 201). 202), XYZ the measured values of each color patch
Get in color. The XYZ color measurement values (referred to as XYZ data) are a set of a plurality of color input values that do not depend on the color scanner 1 and correspond to each color patch.

On the other hand, the color patch original is read by the color scanner 1 (step 203). The data read from the color scanner 1 is a set of color input values depending on the color scanner 1, and is named R'G'B 'data. Then, the scanner input conversion table 3 is created so that the R'G'B 'data is mapped to the XYZ data. By this operation, the calibrated scanner calibration data is obtained from the scanner input conversion table 3 (step 204).

Next, a procedure for creating printer calibration data will be described. Similar to the first embodiment, a color patch to be output from the printer is selected (step 205) and an RGB image file is created (step 206).

Thereafter, the RGB image file is masked to generate YMCK data (step 207). As a result, YMC, which is a set of printer-independent color output values corresponding to each color patch, is generated.
K color data can be obtained. On the other hand, the above R
The color patch data in the GB image file format is output from the printer engine 6 (step 208). This printer output image is read from the color scanner 1 (step 209), and in order to convert the read data into the XYZ space data, the scanner input conversion table 3 created by the previously obtained scanner calibration process is used. Convert to XYZ space data (step 2)
10).

Next, the XYZ color data in the standard color space is converted into RGB color data (step 211), masking processing is further performed, and YMCK dependent on the printer is executed.
Y'M'C'K 'which is the color output value data of the color is obtained (step 212). A printer output conversion table 5 is created in which the Y'M'C'K 'data is mapped to the color output value YMCK data independent of the printer obtained in the previous step 207 (step 213). By this operation, calibrated printer calibration data can be obtained from the printer output conversion table 5.

The scanner input conversion table 3 is preferably created for each image input device to be used.
Further, it is preferable that the scanner input conversion table 3 and the printer output conversion table 5 are updated with data as needed or periodically based on FIG. 2 or FIG.

[0037]

As described above, according to the present invention,
Since the color conversion section of the color image output device is provided with two conversion tables, an input conversion table and an output conversion table, and the printer calibration function is executed inside the color image output device, the printer device is aged. There is a remarkable effect that an output image having a correct tint can always be obtained without being affected by changes and individual differences.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a color image output device according to an embodiment of the present invention.

FIG. 2 is a flowchart illustrating a procedure of creating scanner calibration data and printer calibration data according to an embodiment (first embodiment) of the present invention.

FIG. 3 is a flowchart showing a procedure for creating scanner calibration data and printer calibration data according to another embodiment (second embodiment) of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a conventional color image output device.

[Explanation of symbols]

 1 Color Scanner 2 First Color Converter 3 Scanner Input Conversion Table 4 Second Color Converter 5 Printer Output Conversion Table 6 Printer Engine 7 Controller 8 ROM 9 RAM 10 Spectrophotometer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location G03G 15/00 303 15/01 S 15/04 114 H04N 1/46 H04N 1/46 Z

Claims (4)

[Claims] 1. A color image output device for converting an image signal input from a color image input device into a recording color signal and outputting the image, wherein the first image signal input from the color image input device is the color image. Second that is not affected by the input characteristics of the input device
An input conversion table for converting the second image signal into a color image output based on an output signal from the input conversion table corresponding to a reference color signal and an image formed using the reference signal. A color comprising an output conversion table for converting into a recording color signal according to the output characteristics of the apparatus, and an output means for outputting a color image using the recording color signal obtained from the output conversion table. Image output device. 2. The input conversion table is such that a set of a plurality of color input values obtained by reading a color patch original with the color image input device is a plurality of colors obtained by passing the color patch original through a spectrophotometer. The color image output device according to claim 1, further comprising scanner calibration data created so as to be mapped to a set of input values. 3. The output conversion table is for recording in which the first image signal obtained by reading the color patch document output from the output means with the color image input device is converted using the input conversion table. 3. The color calibration signal according to claim 1 or 2, wherein the color signal has printer calibration data created so as to be mapped with a recording color signal used for outputting the color patch original from the output means. Color image output device. 4. A masking means is further provided, and the masking means determines in which area of the input color space the second image signal is divided into a plurality of areas, and the existing area is present. 4. The color image output device according to claim 1, wherein the first recording color signal is obtained by performing an interpolation process using conversion input data corresponding to the points configuring .