JPH0880642A - Picture processing device - Google Patents

Abstract

PURPOSE: To perform processes suitable for respective data by a method wherein pallet data different in image data format or image data constituted by a plurality of color component data are inputted. CONSTITUTION: Quick color processing is performed on respective image data different in format by converting pallet data inputted through a PI01 into R, G and B data so as to be inputted together with R, G and B data inputted through the PI01 in common gamma tables 2 into C, M and Y data.

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 for performing color processing.

[0002]

2. Description of the Related Art Recently, in host computers,
It handles various image data as shown below according to the user's application and outputs them to a color printer.

An appropriate color is selected from preset colors to generate an image.

An image input such as a scanner or a device is used to input a full-color image showing a document.

[0005]

However, the conventional color printer sets a plurality of multivalued color component data for each pixel obtained as described above as input image data.

Therefore, even when the image data generated as described above is output to a color printer, the selected color is converted into a plurality of multivalued color component data.

Therefore, although the number of colors is limited in advance, it takes much time to transfer the image data as in the above-mentioned processing.

The present invention has been made in view of the above points, and an image in which palette data having a different image data format or image data composed of a plurality of color component data is input and processing suitable for each is performed. An object is to provide a processing device.

[0009]

According to the present invention, a first mode for inputting palette data representing an input image and first image data composed of a plurality of color component data each represented by multiple values are inputted. Input means having a second mode for
A storage unit that stores a palette conversion table that associates the palette data with the second image data, and the palette data using the palette conversion table to store the palette data in the second format.
And a color processing unit for performing color processing on the first and second image data.

[0010]

According to the present invention, it is possible to perform color processing suitable for image data of different formats.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

FIG. 1 shows an internal block diagram of a full-color printer according to an embodiment of the present invention.

Print data and commands from the personal computer are input via one Centronics I / F. The 8 CPUs read this and analyze the command, and the necessary print data is stored in 10 RAM. The ROM 9 stores various programs and various initial value parameters.

Printer operation setting switch (online
SW, line feed SW, form feed SW, etc.) and operating status display LEDs are input / output via 12 PIOs. 13's
PIO is a port to which the printer line feed motor (LF motor), carriage motor (CR motor) and various sensors are connected. Next, the flow of print data will be described. The following types of print data are supported.

1) CMY input (2/16/256 gradations for each color) 2) RGB input (2/16/256 gradations for each color) 3) Pallet input (8 colors, 16 colors / 256 colors) However, the printer must convert the colors into the three primary colors C (cyan), M (magenta), and Y (yellow). The conversion method is shown in FIG. First, in the case of 1) CMY input, it is directly input to the C, M and Y latches shown in 3 of FIG. A method of adjusting the width to 8 bits can be realized by a simple operation shown in the following equation.

[0016]

[Equation 1]

In the case of 21 RGB inputs, the data width must be adjusted to 8 bits and then converted into R → C, G → M, B → Y, respectively. This is called complementary color conversion, and various conversion methods have been devised. For example, simply,

[0018]

[Equation 2]

There is a method shown in. In any case R
→ C, G → M, B → Y can be uniquely obtained, and the conversion work can be performed at high speed by referring to the table. Therefore, the conversion table is called a gamma table. It is shown by 1 of 2. This table 2 can actually be implemented in RAM and shared with 10 RAMs.

Next, in the case of pallet input, the pallet number and the actual expression color are determined by the sending personal computer or the frame memory side, and normally the pallet number is about 16 to 256, which is the number of expression colors of the printer. Since it is much larger than 260,000 colors, it is much more efficient to send the palette number to the printer than the expression color number. Therefore, it is necessary to register the contents of the pallet data held on the host side also on the printer side in advance. This registration area is a palette conversion table indicated by 11 in FIG. 1, and the input palette number is converted into R, G, B by this palette conversion table, and C, via the gamma table 2 described above. Converted to M, Y.

As described above, various print data are C, M,
Converted to the density value of Y to be printed (normalized to 0 to 255). This C, M, Y and C that ink has,
M and Y do not become equal because they are asymmetrical color components of the ink, and there is a masking circuit 4 shown in FIG. 1 to remove these asymmetrical color components. The masking circuit 4 typically needs to perform the calculation shown in the following equation.

[0022]

(Equation 3)

ROM (masking) ROM for practically high speed
It is realized by the table conversion by. Furthermore, in order to improve the gradation expression and color reproduction of the black part, black ink is used separately for printing. This is called under color removal, and this printer shares black with this masking ROM to generate black. Thus, in the masking circuit 4, C ', M
Ink density data for four colors of C ″, M ″, Y ″, and K, which have undergone masking and undercolor removal, are output in response to the inputs of ‘′ and Y’.

With respect to the four-color density data, three ink heads having different densities are actually used for cyan and magenta, so that which head is to be used is selected and gradation of the highlight portion is expressed. 5 dither processing for selection ROM
It is realized by (selection ROM of cyan, magenta, yellow, and black). In this way, the selection ROM 5 determines the voltage to drive the ink heads of 8 colors for color reproduction at a certain point, and the head drive pulse is generated by the 6 head drivers which input the data. And applied to each of the seven heads.

The CR motor for controlling the main scanning direction of the head (not shown) and the LF motor for controlling the paper feed are 13 PIs.
Connected via O, the CPU 8 controls the whole based on timing signals from various sensors and performs print processing.

Now, in such a full-color printer, there are various commands shown below in relation to image processing.

Change of palette table Change of gamma table Change of number of bits per pixel Selection from three print modes of RGB / CMY / pallet There are magnification factors and so on. It is set to a certain default value immediately after power-on or reset. The user can change it freely by sending the above command.

In the present embodiment, the CPU 8 controls the selection ROM 5 and the head driver 6 by a panel switch (SW) or a command so as to test-print the internal state of the printer.

There is also a method of providing a dedicated SW as the panel SW, but in this case, test printing is started by simultaneously pressing a plurality of keys. For example, multiple push of online SW and line feed or form feed SW. Of course, it is also possible to send a special command.

FIG. 3 shows a concrete copy sample thereof.

According to this test print, the internal state of the above-mentioned printer is designed to be visually expressed, and the actual print of the color registered in the palette data and the display of the gamma curve, print mode, bit size The enlargement ratios in the X and Y directions are printed.

FIG. 3 shows an example of the test print for outputting the color patches of the color palette. When the input is not the palette mode but the R, G, B input modes, 256 color patches R, G, It is also possible to use a mixed color patch of B,
It is more useful to use color patches in a mode that actually operates. It is also conceivable to additionally write numerical data (0 to 255) of R, G, B or C, M, Y along with the color patch.

Further, although the ink jet printer has been described, it is needless to say that it can be utilized in other than the ink jet printer, for example, in a thermal thermal transfer or thermal sublimation printer.

Further, even if the functions other than those described above are increased or decreased as the image processing function, it is possible to cope with the increase and decrease in the content of the self-test.

As described above, in a full-color printer capable of color reproduction using a palette, for example, it is possible to check the correspondence between the palette number and the actual print color by simply performing a test print, and avoid wasteful actual print. Not only can it be done, but if it is not a palette input, the expression color after masking or gamma curve can be confirmed as a color patch.

[0036]

As described above, according to the present invention,
It is possible to perform color processing suitable for image data of different formats.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a conversion flowchart of various print data.

FIG. 3 is a diagram showing an example of a test print.

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Claims (3)

[Claims] 1. A first mode for inputting palette data representing an input image, and a second mode for inputting first image data composed of a plurality of color component data each represented by multivalues. An input unit; a storage unit that stores a palette conversion table that associates the palette data with the second image data; a conversion unit that converts the palette data into the second image data using the palette conversion table; An image processing apparatus comprising: a color processing unit that performs color processing on the first and second image data. 2. The image according to claim 1, wherein in the first mode, the palette data is input from an external device, and the same palette table as the palette conversion table is stored in the external device. Processing equipment. 3. The image processing apparatus according to claim 2, further comprising a changing unit that changes the palette conversion table based on a palette conversion table change command from the external device.