JP2002316444A - Color image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand compressed color image data even by a low-speed expander and supply it to a high-speed printer. SOLUTION: Color image data is divided by each color component by a data divider 6. After each of the divided color image data is compressed by a compressor 7a or 7b, the data is stored separately to regions 8a and 8b of a coded code buffer 8. At this time, the regions 8a and 8b of the coded code buffer 8 are divided by a ratio corresponding to the number of color components included in each block of the divided color image data. In other words, when the data is divided to YMC and K, the buffer 8 is divided by the ratio of 3:1. Moreover, each divided region is treated as a ring buffer.

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 and, more particularly, to a method for storing compressed data and supplying the stored data to a color printer at a high speed in response to a request from an output device. The present invention relates to a color image processing device.

[0002]

2. Description of the Related Art There is known an information processing apparatus which supplies data stored in a buffer memory (hereinafter simply referred to as "buffer") to an output device as needed. For example, in an electrophotographic color printer, the printing speed is faster than that of a color image bitmap data generating unit, so that the data generated by the bitmap data generating unit is temporarily stored in a buffer and stored in one buffer. A method is adopted in which the transfer to the printer is started when the minute data is accumulated. Since the color bitmap data is very large, it is often compressed data when stored in a buffer.

[0003] In color printing, image data may be decomposed into a plurality of color components when a bitmap is created.
Generally, C (cyan), M, which are the primary colors of color printing
(Magenta), Y (yellow), and K (black).
Japanese Patent Laying-Open No. 6-292023 describes a color image processing apparatus having a memory for storing data of each color component for one page. If all color components are compressed and stored in an interleaved format, the expansion speed by the expansion means may not be able to catch up with the printing speed of the printer.

A plurality of bitmap images are stored in the buffer, and writing from the bitmap creating means to the buffer and transfer from the buffer to the color printing apparatus can be performed asynchronously. In such a case, it is easier to handle the buffer if it is managed as a ring buffer. For example, JP-A-6-155819 discloses a configuration in which a buffer for storing image data (band) for one page divided into a plurality of segments is used as a ring buffer, and reception and transfer are repeated for each segment. An image processing apparatus is described.

[0005]

The above-mentioned conventional image processing apparatus has the following problems. As described above, since the amount of color bitmap data is very large, a bitmap creating apparatus that divides data of one page into a plurality of pieces and creates data for each of a plurality of strip-shaped areas called segments or bands is generally used. . When the band is output to a runaway type printer such as a laser printer, the band for one page must be continuously output. Therefore, when compressing data using a general-purpose compression / decompression device, it is necessary to place bands in the memory area so that data for one page is continuous. However, since the data size after compression cannot be known without actually compressing it,
The compressed data of all the color components for one page cannot be continuously stored in the buffer by calling the bitmap creating means only once.

In order to continuously store the compressed data of all the color components for one page in the buffer, the following two methods are conceivable. One is to create bitmap data for one page only for a certain color component, compress it, and write it to a buffer. Next, bitmap data of the same page is created for other color components. This is a method of repeating the same number of times as the number of types of color components. In this method, since it is necessary to repeatedly call the bitmap creating means for the same page as many as the necessary color components, there is a problem that the processing takes a long time.

Another method is to previously divide the area of the buffer to be used for each color component, create a bitmap containing all the color components for one band, and distribute the bitmap to each color component when writing to the buffer. Is the way. This method requires only one call to the bitmap creation means,
Since the buffer is divided and used for each color component, the use efficiency of the buffer deteriorates. Further, it is necessary to perform a special read / write process in consideration of the boundary of each region, so that there is a problem that the process becomes complicated.

[0008] As described above, when banding and data compression are attempted to be used together when decomposing image data into respective color components, the bitmap creating means is used repeatedly or a method that sacrifices the buffer use efficiency is used. There was no choice.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color image processing apparatus which can solve the above-mentioned problems and can supply color image data obtained by separating color components to a high-speed color printer.

[0010]

According to the present invention, there is provided a color image processing apparatus connected to a color printer, which divides color image data for each color component. Compression means for compressing color image data for each color component divided by the division means; an encoding code buffer for accumulating data compressed by the compression means; and data accumulated in the encoding code buffer. And a stretching means for stretching.

According to the above feature, the color image data is divided for each color component, compressed, and stored in the encoding code buffer. Therefore, the amount of color image data stored in each encoded code buffer is reduced. As a result, when decompressing and outputting the stored color image data, it is possible to cope with a high-speed printer even if a decompressing unit having a relatively low speed is used.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of an information processing apparatus according to an embodiment of the present invention. This embodiment shows a case where the KYMC color bitmap data created by the bitmap creation means is divided into two color component data, a YMC component and a K component, and each is compressed, stored, decompressed, and output. . In FIG. 1, a host computer 1 has a print information input unit 2, a drawing unit 3, and a band buffer 4. The drawing means 3 converts the page description language input from the print information input means 2 having, for example, a word processing function into color components, and performs banding of one page of information into small unit bands, and Is developed as bitmap data.

The processing board 5 has a data divider 6, compressors 7a and 7b, an encoding code buffer 8, a decompressor 9, a color matching device 10, and a resolution converter 11. A printer 12 is connected to the processing board 5, and the processing board 5 performs data processing according to the output form of the printer 12.
The printer 12 is a color laser printer, and receives frame-sequential KYMC data from the processing board 5 as its input. Although the encoding code buffer 8 can be constituted by a DRAM having a capacity of 16 MB, a general-purpose extension module such as a SIMM including a plurality of DRAMs is preferably used so that the capacity can be easily increased or decreased. The encoded code buffer 8 has two areas 8a and 8 divided at a predetermined ratio.
b. In this example, since the image data is divided into the YMC component data and the K component data and these are separately stored, the ratio between the regions 8a and 8b is set to 3: 1. That is, a plurality of areas corresponding to the number of divisions of image data are set in the encoding code buffer 8. In each of the areas 8a and 8b, data for a plurality of pages can be stored. Writing and reading of data to and from the encoded code buffer 8 is performed by the memory controller 13.
Is controlled by

The K developed in the band buffer 4
The YMC data is input to the data divider 6 in band units, and is divided into YMC and K color components only. The data divider 6 can be composed of, for example, an input buffer followed by a two-stage synchronization register. That is, the operation of selectively extracting the color components of only YMC or K from the 4-byte data of KYMC input to the input buffer and sequentially transferring the color components to the subsequent register is repeated a number of times corresponding to the number of divisions, that is, twice. Thus, data division can be realized. The YMC component data divided by the data divider 6 is compressed by a compressor 7a.
The data of the K component is compressed by the compressor 7b and stored in the areas 8a and 8b of the encoded code buffer 8.

The decompressor 9 inputs the data read from the encoded code buffer 8 to the color converter 10. The color converter 10 receives the YMC dot-sequential data as an input, and outputs any one of Y, M, and C plane-sequential data by changing parameters. In the method of simultaneously compressing the KYMC data without dividing it, and extracting the YMC data after decompression, the decompression speed of the easily available general-purpose decompression means is low, so that it cannot be applied to a high-speed printer. For this purpose, in this embodiment, when writing to the encoded code buffer 8, the data is divided in advance to reduce the total data amount,
The apparent elongation speed is increased. The data in the frame sequential format output from the color converter 10 is converted in resolution by the resolution converter 11 if necessary,
Is input to

Next, the memory control device 13 will be described. In FIG. 2, the memory control device 13
A transfer function is provided. The memory controller 13 has an address register 131 for setting a memory address, a size register 132 for setting a transfer size, and a transfer counter 133. Further, it has a register 134 for designating the start of transfer and a means for notifying the end of transfer, for example, a carry terminal for displaying the count up of the transfer counter 133.

The memory control device 13 is connected to the coded code buffer 8. Since a SIMM is used as the encoded code buffer 8, the amount of memory to be mounted can be easily changed. For example, 16MB, 32MB,
64 MB and 128 MB memory mounting is possible. The memory control device 13 is also connected to the data input / output bus DB, and receives the encoded code buffer 8 from the compressors 17a and 7b.
Writing data to the buffer and encoding code buffer 8
Data is read from the memory controller 1 to the decompressor 9 by the memory controller 1.
3 is performed.

The coded code buffer 8 is divided into a plurality of areas as described above, and the division is performed at a ratio to the total memory amount. When the data is divided at a ratio of 3: 1 as described above, the memory is divided into 12 MB and 4 MB when the memory mounting amount is 16 MB. Similarly, 32MB
24MB and 8MB for 64MB, 48MB for 64MB
And 16 MB and 128 MB are 96 MB and 32 MB. That is, in proportion to the amount of memory to be mounted, the size of each of the regions 8a and 8b changes while the ratio is fixed.

Taking the case where the capacity of 16 MB is divided by 3: 1 as an example, the memory address C00000
The lower region is the region 8a and the upper region is the region 8b from H. When the DMA transfer is performed through the memory control device 13, when the transfer is started from an address lower than C00000H, and when the address matches C00000H in the middle of the transfer, the address returns to “0” and the transfer is continued from there. . When the transfer is started from an address higher than C00000H, when the address reaches 10000H which is the highest in the middle of the transfer, C0000
Returning to address 0H, transfer is continued from there. Thus, each of the regions 8a and 8b of the encoded code buffer 8 is configured as a ring buffer.

The memory control device 13 constructed as described above
Will be described in more detail with respect to writing and reading of data. In FIG. 1, when the memory controller 13 takes out the data of the YMC component from the compressor 7a, the address register 131 sets the transfer start address in the area 8a of the encoded code buffer 8 (the initial value of the pointer is the area 8a , And starts data transfer. The fact that the transfer address of the DMA matches the address of C00000H is determined by the fact that the upper two bits of the address register 131 have become “11”. The content of the address register 131 becomes 0 when this condition is satisfied. Thus, when writing and reading the data of the YMC component, the address specification is C
The address is returned to address 0 without exceeding address 00000H.

When the K component data is extracted from the compressor 7b, the transfer start address is set in the area 8b by the address register 131 (the initial value of the pointer is the lowest address of the area 8b), and the data transfer is started. .
In this case, it is determined that the last address of the area 8b has been reached because the upper two bits of the address register 131 have become "00". become. As a result, the transfer start address becomes C000
Returned to address 00H.

Thus, the end of the area is determined by looking at the upper two bits of the effective address of the address register 131.
A ring buffer that returns from this position to the head of the area is configured. In the present embodiment, since the memory area is divided by the ratio, even when the mounting memory amount is changed,
It is only necessary to change the turning point, that is, the address for determining the boundary of the area. Therefore, it is possible to cope with any change in the mounting memory amount.

Next, a modification of this embodiment will be described. The division ratio of the encoded code buffer 8 can be changed. Here, a case is shown in which the encoded code buffer 8 is equally divided into four regions. FIG. 3 is a diagram showing a modification of the division of the encoded code buffer 8. In this modification, KYMC
It is assumed that data is output to a color printer having a color space of. In the example shown earlier, the color converter 10
In order to perform color matching, the color components of CMY are collectively handled up to the color converter 10, but an example in which the color matching is omitted is shown here. Since it is not always the case that a high-quality image is required, in such a case, the data divider 6 separates the YMC components into C, M, and Y, respectively.
It is better to focus on the point that the data amount is further reduced and the processing time in the decompressor 9 is reduced.

In this case, the memory control device 1 divides the 16 MB area into 4 MB areas.
Constituting No. 3. As shown in FIG. 3, from address 0 to 3FFF
The first area Ak is up to the address FFH, and the second area Ay is 80000 from the address 400000H to 7FFFFFH.
The third area Am is from address 0H to address BFFFFFH.
The fourth from address C00000H to address FFFFFFH
This is the area Ac. Data of each color component of K, Y, M, C is stored in each of the regions Ak, Ay, Am, Ac.

In this case, as in the previous embodiment, the boundary of the area is determined by looking at the upper two bits of the effective address. In the first area Ak, when the upper 2 bits are "01", the address is 0, in the second area Ay, it is 400000H when it is 10, and in the third area Am, it is 800000H when it is "11". When the address becomes “00” in the fourth area Ac, the content of the address register 131 changes to the address C00000H.

With this configuration, in the conventional configuration, banding and compression of data for each CMYK color component, which could only be performed by activating the bitmap generation means for the same page four times, are performed. While using
It can be handled as a ring buffer by a single activation of the bitmap creating means. Also, by determining some upper bits of the effective address of the transfer address register and changing the contents of the address register when these bits meet the conditions, the same ratio can be obtained for a plurality of memory mounting amounts. To form a ring buffer.

[0027]

As is apparent from the above description, according to the first aspect of the present invention, the color image data is divided for each color component and stored in the encoding code buffer. In the case of stretching for each color component, the apparent stretching speed is increased. Therefore, color image data can be supplied to a high-speed color printer by using a low-speed expansion unit.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a color image processing apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a memory control device included in the color image processing device according to one embodiment of the present invention.

FIG. 3 is a schematic diagram showing an example of division of a region of an encoded code buffer according to a second embodiment of the present invention.

[Explanation of symbols]

2 ... Print information input means 6 ... Data divider 7a,
7b: Compressor, 8: Coded code buffer, 9: Decompressor, 10: Color converter, 12: Printer, 13: Memory controller

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Junichi Goto 3-1-1 Hommachi, Iwatsuki-shi, Saitama WAT SU Building West Building 4th Floor Fuji Xerox Co., Ltd. In-house (72) Inventor Michio Kondo 3-chome, Honcho, Iwatsuki-shi, Saitama No. 1-1 WAT SU Building West Building 4th Floor Fuji Xerox Co., Ltd. In-house (72) Inventor Kenji Imamura 3-1-1 Hommachi, Iwatsuki City, Saitama Prefecture WAT SU Building West Building 4th Floor Fuji Xerox Co., Ltd. In-house (72) Inventor Yoshino Yuji 3-1, 1-1 Won SU Building West Building, Iwatsuki City, Saitama Prefecture Fuji Xerox Co., Ltd. In-house (72) Inventor Taku Kawahara 3-1-1 Won SU Building West Building, 4 1-1 Wat SU Building West Building, Fuji Xerox Co., Ltd. Association In-house F term (reference) 2C087 AA15 AC08 BA01 BA02 BA03 BA07 BC01 BD24 BD36 BD 40 2C262 AB20 GA13 GA14 GA15 5C077 MP08 NP05 PP33 PQ22 RR21 TT02 5C078 AA09 CA31 CA35 DA01 5C079 HB03 LA02 LA27 MA02 NA11 PA03

Claims (1)

[Claims] 1. A color image processing apparatus connected to a color printer, comprising: a dividing unit for dividing color image data for each color component; and a compression unit for compressing color image data for each color component divided by the dividing unit. A color image processing apparatus comprising: an encoded code buffer that stores data compressed by the compression unit; and an expansion unit that expands data stored in the encoded code buffer.