JP3912372B2 - Color image processing device - Google Patents

Description

  The present invention relates to a color image processing apparatus that compresses and encodes image data.

  As a color image processing apparatus, for example, a copy, a scanner, a printer, a facsimile, and a complex machine of these are conventionally known. Such an apparatus generates RGB data using a scan function.

  When compressing and encoding such RGB data by the JPEG method, the RGB data is converted into YCC data (luminance color difference signal), and compression encoding is performed in block units (for example, 64 pixels of 8 × 8). Thereby, the amount of calculation can be reduced and the compression effect can be enhanced.

  By the way, RGB data is sent to an image processing module that performs JPEG compression processing by DMA (direct memory access) transfer, and after being subjected to compression encoding processing, it is transferred again to the output side memory by DMA transfer.

In Patent Document 1, in an image processing module having a signal processing unit that executes predetermined processing on block-unit data, a DMA request control unit on the input side or output side when signal processing in the signal processing unit is completed A technique is disclosed in which signal processing by the signal processing unit is stopped when a DMA request is generated from the signal processing unit. As a result, even in an image processing module with a low priority, it is possible to prevent an abnormality or the like from occurring in the data.
JP 2002-328880 A

  The DMA transfer as described above is performed via a general-purpose bus that uses not only the image processing module but also other systems. Therefore, transfer of image data to and from the image processing module needs to be performed by controlling the timing so that other systems can also use the general-purpose bus. However, since the amount of image data changes due to compression encoding, the amount of data cannot be grasped, and it is difficult to control the transfer timing of image data from the image processing module.

  The present invention has been made under the above background, and an object thereof is to provide a color image processing apparatus capable of performing data transfer at an appropriate timing.

The color image processing apparatus of the present invention stores a first transfer control means for transferring a predetermined amount of image data for each predetermined unit, a compression encoding means for compressing and encoding the image data, and storing the compression encoded data. And a second transfer control means for transferring the compression-encoded data from the compression encoding means to the storage means. Second transfer control means, the first transfer control means starts the image data transfer to start data transfer, the first transfer control means transfers the data for each timing of the predetermined unit transfers the image data By stopping, the data is divided and transferred.

  Thereby, the compression-encoded data can be divided and transferred at an appropriate timing. The first transfer control unit and the second transfer control unit can transfer image data using a general-purpose bus. According to the present invention, even in such a case, since the data is appropriately divided and transferred, it can be shared with other systems without occupying the general-purpose bus.

The color image processing apparatus of the present invention includes a first transfer control unit that transfers a predetermined amount of image data for each predetermined unit, a compression encoding unit that compresses and encodes image data, and a compression encoding unit that compresses and encodes the image data. Storage means for storing the processed data, and second transfer control means for transferring the compression encoded data from the compression encoding means to the storage means. The first transfer control means transmits an interrupt signal to the second transfer control means every time image data is transferred in a predetermined unit, and the second transfer control means receives an interrupt signal from the first transfer control means. The data is divided and transferred by stopping the transfer of data each time .

In the color image processing apparatus of the present invention, the first transfer control unit can transmit an end signal to the second transfer control unit when the transfer of all the predetermined amount of image data is completed. When the means receives the end signal from the first transfer control means , the means can continue the data transfer until there is an encoding / compression processing end interrupt by the compression encoding means.

  It should be noted that any combination of the above-described constituent elements and a conversion of the expression of the present invention between a method, an apparatus, a system, a recording medium, a computer program, etc. are also effective as an aspect of the present invention.

  As described above, according to the present invention, an image processing apparatus that can perform data transfer at an appropriate timing is provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a functional block diagram showing a color image processing apparatus according to the present embodiment. In the present embodiment, the color image processing apparatus 100 has a scanner function and a copy function. FIG. 1 shows the main elements relevant to the present invention. Although not shown, the color image processing apparatus 100 has a configuration provided in a normal copying machine such as an operation panel and a paper feeding unit. Further, the color image processing apparatus 100 may further include a communication function such as a fax communication function, and may be provided with a configuration therefor.

  In the color image processing apparatus 100, the control unit 120 controls the entire apparatus together with various elements shown in FIG.

  The reading unit 102 has a scanner function, and reads an original to generate RGB color image data (hereinafter, RGB data). Here, the reading unit 102 reads an image for each predetermined line.

  The first storage unit 104 stores the RGB data read by the reading unit 102. The first storage unit 104 is, for example, an SDRAM.

  The first DMA controller 106 transfers the RGB data stored in the first storage unit 104 to the second storage unit 110. The first DMA controller 106 transfers the RGB data in units of several lines. Note that data transfer from the first storage unit 104 to the second storage unit 110 is performed via a general-purpose bus. Second storage unit 110 is, for example, an SDRAM. In the present embodiment, the control unit 120 controls the timing at which the first DMA controller 106 transfers RGB data to the second storage unit 110. In addition, the first DMA controller 106 does not continuously transfer the RGB data stored in the first storage unit 104 to the second storage unit 110, but transfers the data every predetermined unit. As a result, even when data is transferred from the first storage unit 104 to the second storage unit 110 via the general-purpose bus, the general-purpose bus is not occupied by the transfer of the first DMA controller 106, so that it is shared with other systems. can do.

  The writing / reading processing unit 108 controls writing of RGB data to the second storage unit 110. In the present embodiment, the writing / reading processing unit 108 writes RGB data in different banks for each of R data, G data, and B data. The write / read processing unit 108 counts the amount of data transferred by the first DMA controller 106, and data necessary for forming a block of a predetermined size (here, 8 × 8 64 pixels) is stored in the second storage unit 110. When written, data transfer from the second storage unit 110 to the YCC conversion unit 112 is started. The writing / reading processing unit 108 transfers the RGB data to the YCC conversion unit 112 in units of blocks.

  The color image processing apparatus 100 may be configured not to include the writing / reading processing unit 108 and the second storage unit 110. In this case, the first DMA controller 106 includes the first storage unit 104. RGB data is transferred to the YCC conversion unit 112. Also in this case, the control unit 120 controls the transfer timing of the first DMA controller 106.

  The YCC conversion unit 112 converts RGB data into color image data (hereinafter referred to as YCC data) in YCC (luminance color difference) format in units of pixels. The compression encoding unit 114 compresses and encodes YCC data in the JPEG format.

  The second DMA controller 116 transfers the JPEG data compression encoded by the compression encoding unit 114 to the third storage unit 118. Data transfer from the compression encoding unit 114 to the third storage unit 118 is also performed via the general-purpose bus. The third storage unit 118 is also an SDRAM, for example.

  In the present embodiment, the control unit 120 controls the timing at which the second DMA controller 116 transfers the JPEG data compression encoded by the compression encoding unit 114 to the third storage unit 118. As a result, even when data is transferred from the compression encoding unit 114 to the third storage unit 118 via the general-purpose bus, the general-purpose bus is not occupied by the transfer of the second DMA controller 116, so that it is shared with other systems. be able to. Details of this processing will be described later.

  The third storage unit 118 stores JPEG data. The JPEG data stored in the third storage unit 118 is then output to a personal computer or the like via a LAN or USB, for example, by a data output unit (not shown).

  FIG. 2 is a diagram schematically showing data transfer in the color image processing apparatus 100. Here, the second storage unit 110, the YCC conversion unit 112, the compression encoding unit 114, and the like are attached to an option board.

  The first DMA controller 106 sequentially transfers R data, G data, and B data every several lines.

  The second storage unit 110 includes a plurality of banks bank0 to 2 in which R data, G data, and B data are written. Here, R data is written in bank 0, G data is written in bank 1, and B data is written in bank 2. The horizontal direction of each bank indicates a column address, and the vertical direction indicates a row address.

The data transferred from the first DMA controller 106 is written while incrementing the row address for each predetermined pixel unit (eight pixels here). When the data for one line is written, it moves to the next column and the data for the next line is written. In this manner, when the bank0~2 to 8 lines of data are written, data of 8 lines by fixing the row address from the second storage section 110 (64 pixels) is read out. Thereby, data of a block (64 pixels) of a predetermined size can be read. In this way, reading from the second storage unit 110 can be performed in units of blocks without changing the row address, so that the data reading time can be shortened and processed quickly.

  Next, a procedure in which the control unit 120 controls the transfer timing of JPEG data from the compression encoding unit 114 to the third storage unit 118 will be described with reference to FIG. The reading unit 102 reads a document in units of pages for each predetermined line.

  FIG. 3 is a flowchart showing the processing procedure of the first DMA controller 106 and the second DMA controller 116.

  First, the first DMA controller 106 and the second DMA controller 116 each set the number of transfer bytes (S10 and S24). Here, the first DMA controller 106 sets the number of transfer bytes to N bytes. Here, the N bytes can be the data amount of a predetermined line of the document. The second DMA controller 116 sets the transfer byte count to the maximum number of bytes (N bytes or more).

  The first DMA controller 106 monitors a DMA transfer request from the control unit 120 (S12). When there is a DMA transfer request from the control unit 120 (YES in S12), the first DMA controller 106 starts DMA transfer (S14). The second DMA controller 116 also starts DMA transfer (S26).

  The first DMA controller 106 monitors whether or not DMA transfer for N bytes has been completed (S16). When the N-byte DMA transfer is completed (YES in S16), it is determined whether or not the DMA transfer for one page is completed (S18). If the DMA transfer for one page has not been completed (NO in S18), the first DMA controller 106 issues an interruption interrupt to the control unit 120 (S20). Thereby, the control unit 120 interrupts the DMA transfer of the second DMA controller 116 (S30). Thereafter, the process returns to step S14 again, and DMA transfer is started in the first DMA controller 106 and the second DMA controller 116 (S14 and S26).

  On the other hand, if the DMA transfer for one page is completed in step S18 (YES in S18), the first DMA controller 106 issues a page end interrupt to the control unit 120 (S22). Upon receiving the page end interrupt in step S22, the control unit 120 continues the DMA transfer until there is an encoding / compression processing end interrupt by the compression encoding unit 114. When there is an encoding / compression processing end interrupt by the compression encoding unit 114 (YES in S28), the processing of this page is ended.

  As described above, in this embodiment, the data after compression encoding is divided and transferred in accordance with the timing at which the image data before compression encoding is divided and transferred in predetermined units. Can be transferred at an appropriate timing. As a result, even if the data amount of the data after compression encoding cannot be grasped in advance, the data having an appropriate data amount can be sequentially transferred.

  Further, in the present embodiment, the data compression-encoded by the compression-encoding unit 114 is divided into appropriate units and transferred to the third storage unit 118. Therefore, even when a general-purpose bus is used. The general-purpose bus is not occupied by the transfer by the second DMA controller 116, and can be shared with other systems.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and it goes without saying that those skilled in the art can modify the above-described embodiments within the scope of the present invention.

  In the above example, RGB data was converted into YCC data and compression encoding processing was performed. However, RGB data can be converted into Lab data, for example, and compression encoding processing can be performed.

  The color image processing apparatus 100 may be configured not to include the YCC conversion unit 112. In this case, the compression encoding unit 114 compresses and encodes the RGB data transferred from the first storage unit 104 as it is. Can be processed.

  The present invention can provide a suitable data transfer technique applied to a color image processing apparatus, and is useful.

1 is a functional block diagram illustrating a color image processing apparatus according to an embodiment of the present invention. It is a figure which shows typically the data transfer in a color image processing apparatus. It is a flowchart which shows the process sequence of a 1st DMA controller and a 2nd DMA controller.

Explanation of symbols

100 color image processing apparatus 102 reading unit 104 first storage unit 106 first DMA controller 108 write / read processing unit 110 second storage unit 112 YCC conversion unit 114 compression encoding unit 116 second DMA controller 118 second 3 storage unit 120 control unit

Claims (3)

First transfer control means for transferring a predetermined amount of image data for each predetermined unit;
Compression encoding means for compressing and encoding the image data;
Storage means for storing data compressed and encoded by the compression encoding means;
Second transfer control means for transferring the compression-encoded data from the compression-encoding means to the storage means;
Including
The second transfer control means starts transferring the data when the first transfer control means starts transferring the image data, and the first transfer control means transfers the image data in the predetermined unit. A color image processing apparatus , wherein the data is divided and transferred by stopping the transfer of the data at each timing . First transfer control means for transferring a predetermined amount of image data for each predetermined unit;
Compression encoding means for compressing and encoding the image data;
Storage means for storing data compressed and encoded by the compression encoding means;
Second transfer control means for transferring the compression-encoded data from the compression-encoding means to the storage means;
Including
The first transfer control means transmits an interrupt signal to the second transfer control means every time the image data is transferred in the predetermined unit,
Said second transfer control means, by stopping the transfer of the data each time it receives the interrupt signal from said first transfer control means, a color characterized by transfer by dividing the data Image processing device. The color image processing apparatus according to claim 1 or 2,
The first transfer control means transmits an end signal to the second transfer control means when the transfer of all the predetermined amount of image data is completed,
When the second transfer control unit receives the end signal from the first transfer control unit, the second transfer control unit continues to transfer the data until there is an encoding / compression processing end interrupt by the compression encoding unit. A color image processing apparatus.

Images