JPH09226179A - Color image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply alter conversion processing by inputting a color image from an external device to convert the same by a first table and converting this color image data to the color image data corresponding to the kind of a recording agent used in an image output part by using a second table. SOLUTION: The content of a first lookup (LUT) is usually same to that of the display on the side of a host and preliminarily transmitted to be set to the certain allotted area in an RAM 24. The LUT is referred to in the CPU 22 on the side of a printer by sending this set color number to the printer to clear content to be printed. In order to perform color reproduction by cyan C, magenta M and yellow Y in the printer, it is necessary to convert R, B, B to C, M, Y and this conversion can be performed by a second LUT. The content of the second LUT is also a table capable of being arbitrarily set from the host.

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 converting color image information using a table and outputting it to an image output section.

[0002]

2. Description of the Related Art In a conventional color image processing apparatus, R
An arbitrary table is selected from a plurality of tables stored in the OM, and the conversion process is performed on the input color image information using the selected table.

[0003]

In the conventional color image processing apparatus, conversion processing other than a plurality of tables stored in advance in the ROM cannot be performed.

Therefore, there is a problem in that the conversion process desired by the user may not be provided in some cases.

The present invention has been made in view of the above problems, and an object thereof is to provide a conversion process desired by a user. Further, another object of the present invention is to make it possible to easily change the conversion process by performing the conversion process using the first table and the second table.

[0006]

In order to achieve the above-mentioned object, the present invention is a color image processing apparatus for converting color image information and outputting it to an image output section, wherein the color image information is stored in an external device. Input means for inputting the color image information, first converting means for converting the color image information using the first table, and second table for the color image data output from the first converting means. Second conversion means for converting into color image data according to the type of recording material used in the image output section, and the first table and the second table are set according to data from the external device. And setting means for setting.

[0007]

FIG. 2 shows an overall block diagram of a full color printer.

The operation will be described according to the flow of data.
First, the image input data is transferred to the RAM 2 via the input port 10.
Stored in 4.

The input port 10 is a Centronics compliant system for parallel signals and RS for serial signals.
It is a well-known standard interface such as a 232C compliant system. Image data can be input in R, G, B and C,
There is a method of inputting M, Y (cyan, magenta, yellow), but in either method, when one line of data is input and a print command command is received, printing of one line is started. Carriage motor (CR) 30
Starts the main scan, and the position of the head is confirmed by various sensors. R synchronized with the timing from these sensors
The print data stored in the AM 24 is input to the image processing circuit 14, subjected to removal of asymmetric color components of ink and UCR processing, and input to the D / A converter 16.

The output voltage of the D / A converter 16 is converted into an appropriate voltage pulse by the next head driver 18 and applied to the ink jet head 20. Here, since the piezo type inkjet head is used, it is possible to express the gray scale according to the level of the voltage.
Full color printing is possible with Y and BK.

A ROM storing these control programs around the CPU, a line feed motor (LF) in the sub-scanning direction, various SWs, sensors, and L
The ED and the like are connected via the input / output port.

Now, as a concrete example of the LUT, only a certain area in the RAM 24 is allocated in terms of hardware. FIG. 1 shows an example in which the contents of appropriate 16 colors out of 4096 colors are entered. As the contents of this LUT, the same contents as the LUT of the display on the host side are usually transferred and set in advance. The set color number 0 to the printer
The CPU 22 on the printer side sends an LUT by sending 15.
You can see the colors to be printed by referring to. Printer is C, M,
Since color reproduction is performed with Y, R, G, B → C, M, Y conversion is necessary, but this is also the second LUT as shown in FIG. 3, for example.
Can be converted by This content is also a table that can be arbitrarily set from the host side.

In the above embodiment, the gradation numbers of the printer are C, M,
16 gradations of 4 bits for each Y, and the number of input colors is 1 out of 4096 colors
Six colors are used, but the number of gradations of the printer is 6 bi for each of C, M, and Y.
Depending on the printer, it is possible to set t or 8 bits or more. Input is also 8 bits for each of R, G, B
There is also a display capable of simultaneously displaying 256 colors or more out of 16 million colors, and in any case, it can be realized only by increasing the sizes of the first LUT and the second LUT. Further, the second LUT for R, G, B → C, M, Y conversion can be realized only by calculation.

For example, simply

[0015]

[Outside 1] It can be. For example, assuming that C, M, and Y each have a gradation range of 8 bits, the following formula is obtained.

C = 255-RM = 255-G Y = 255-B (where 0≤R, G, B≤255)

[0017]

According to the present invention, the conversion processing desired by the user can be provided. Furthermore, the conversion process can be easily changed by performing the conversion process using the first table and the second table.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a lookup table.

FIG. 2 is a block diagram of a printer according to this embodiment.

FIG. 3 is a diagram showing another example of a lookup table.

Claims (1)

[Claims] 1. A color image processing device for converting color image information and outputting the color image information to an image output unit, the input device inputting the color image information from an external device, and the color image information in a first table. A first conversion means for converting the color image data using the second table for the color image data output from the first conversion means, and a color image according to the type of recording agent used in the image output section. A color image processing apparatus comprising: a second conversion unit that converts the data into data; and a setting unit that sets the first table and the second table according to data from the external device.