JP2007201705A - Image processor, image processing method, program, and computer-readable recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor or the like capable of achieving miniaturization of a memory for storing image data. <P>SOLUTION: A compressor 3 has a READ DMAC 4, a compression core 5, and a final code detector 6. The READ DMAC 4 reads out image data in a band unit from an image memory 2 so as to send the image data after receiving transmission of a Req signal from the compression core 5. The compression core 5 executes compression processing to the image data by encoding them and sends out the encoded data to the final code detector 6 after adding a termination code when the image data to be processed become band termination data. The final code detector 6 checks whether or not the termination code is attached to the sent-out data, and resets an internal state of the compression core 5 when the termination code is detected. The reset compression core 5 transmits the Req signal to the READ DMAC 4, and executes compression processing after receiving the next image data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image processing method, a program, and a computer-readable recording medium, and more particularly to an image processing apparatus that compresses image data read from a memory in band units.

  Conventionally, in an image processing device, image data for one page is read from an image memory, and is temporarily expanded in a memory such as a RAM and sent to a compressor, which is compressed to obtain encoded data. Yes.

  In order to execute input / output (read / write) of image data to / from the image memory, a memory controller (hereinafter referred to as DMAC) using a DMA (Direct Memory Access) data transfer method is used. The DMAC executes control for inputting / outputting image data to / from a specific storage area (memory area) of the image memory based on memory area management information called a descriptor.

  By the way, with recent improvements in data processing functions, opportunities for handling images are increasing, and moreover, images to be handled are also handling high-resolution color images. For example, in an image forming apparatus such as a laser printer, in addition to speeding up printing processing, colorization and image quality are rapidly progressing, and further enhancement of functionality is desired.

  Further, when processing a large amount of data, the data is temporarily stored in a memory and then output. However, when the amount of data increases for colorization and high image quality of the image, the image is stored. The problem of requiring a large amount of memory also occurs. Of course, it is necessary to store not only the image but also various data added to the image, for example, and the amount of memory required is further increased.

On the other hand, for example, Patent Document 1 discloses an image processing apparatus that secures productivity by effectively using resources of a storage unit that stores image data.
JP 2004-220579 A

  By the way, in an image forming apparatus such as a laser printer or an ink jet printer, printing is performed based on data expressed in a bitmap format. However, since bitmap data has a large amount of data, when printing is performed after holding one page of data, the image forming apparatus requires a huge amount of memory.

  As described above, in an image forming apparatus provided with an image processing apparatus based on a page processing unit, a memory in which read image data is developed requires a capacity of at least one page, and the memory becomes larger and increased. There was a problem of doing.

  SUMMARY An advantage of some aspects of the invention is that it provides an image processing apparatus that can reduce the size of a memory that stores image data.

  In order to achieve such an object, the invention described in claim 1 is a storage means for storing image data, a reading means for reading image data stored in the storage means, and image data read by the reading means. In the image processing apparatus comprising the compression means for compressing the image data, the storage means stores the image data as band image data divided into a plurality of band-like areas, and the reading means stores the memory area management information. Based on this, the band image data stored in the storage unit is read out, and the compression unit encodes the band image data read out by the reading unit and adds a band end code indicating the end of the band image data. Adding means, and when the band end code added by the adding means is detected, the encoding in the compression means is performed. And having a reset means for resetting the internal state to clear the information regarding band image data.

  The invention described in this claim is an image processing apparatus including a storage unit, a reading unit, and a compression unit, and particularly has a feature in the compression unit. The compression means encodes and compresses the band-unit image data stored and read by the storage means and the read means. The compression unit further includes an addition unit and a reset unit. The adding unit adds information indicating the end of the band to the encoded image data as a code, and provides a timing at which the reset unit resets the pressure unit. The reset unit clears information related to the compressed image data in the compression unit and resets the internal state in order to perform subsequent compression processing smoothly. The reset is performed in response to the termination code by the adding means. By adopting this configuration, it is possible to compress a large amount of image data in band units and perform image expansion, etc., so only a few bands of memory are required, and miniaturization is achieved by avoiding an increase in memory. Is possible. Also, in the compression process, the processing speed can be prevented from being lowered by clearing the compressed image data in band units.

  The invention according to claim 2 is the image processing apparatus according to claim 1, further comprising a toggle buffer for temporarily accumulating band image data read by the reading means, wherein the reading means When the end information described in the memory area management information is received and the writing of the band image data corresponding to the memory area management information to the toggle buffer is finished, the band buffer for the next read band image data It is characterized in that writing is performed.

  According to a third aspect of the present invention, in the image processing apparatus according to the second aspect, the reading unit includes a receiving module and a transmitting module, and the receiving module reads a band image read from the storage unit. The data is written to the toggle buffer, and the transmission module reads the band image data written by the reception module from the toggle buffer and sends the data to the compression unit.

  According to a fourth aspect of the present invention, in the image processing apparatus according to the third aspect, the writing by the receiving module and the reading by the transmitting module are performed in parallel.

  According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the second to fourth aspects, the reading unit includes a plurality of toggle buffers.

  The invention according to claim 6 is the image processing apparatus according to any one of claims 1 to 5, further comprising a writing unit that writes the band image data into the storage unit, wherein the storage unit includes at least The reading means has a capacity for storing band image data for two bands, and the reading means is already stored in the storage means when the band image data is written in the storage means by the writing means. Band image data is read out.

  The invention according to claim 7 is a storage step of storing image data, a reading step of reading out image data stored in the storage step, and a compression step of compressing the image data read out in the reading step. In the image processing method, the storage step divides the image data into band units that are a plurality of band-like regions and stores them as band image data, and the reading step is performed by the storage step based on memory region management information. The stored band image data is read, and the compression step encodes the band image data read by the reading step and adds a band end code representing the end of the band image data; and When the band end code added by the adding step is detected, the encoded band image data in the compression means is related. And having a reset step for resetting the internal state clears that information.

  The invention according to claim 8 is the image processing method according to claim 7, wherein the image processing apparatus has a toggle buffer for temporarily storing the band image data read out by the reading step. The reading step receives the end information described in the memory area management information, and when the band image data corresponding to the memory area management information has been written to the toggle buffer, the reading is performed next. The band image data thus written is written into the toggle buffer.

  The invention according to claim 9 is the image processing method according to claim 8, wherein the reading step includes a receiving module and a transmitting module, and the receiving module reads the band image read by the storing step. The data is written into the toggle buffer, and the transmission module reads out the band image data written by the reception module from the toggle buffer and sends it to the compression step.

  According to a tenth aspect of the present invention, in the image processing method according to the ninth aspect, the writing by the receiving module and the reading by the transmitting module are performed simultaneously.

  The invention according to claim 11 is the image processing method according to any one of claims 7 to 10, wherein the storage area stored by the storing step stores the band image data for at least two bands. An image processing method for an image processing apparatus comprising: a writing step for writing the band image data in the storage area, wherein the reading step writes the band image data in the storage area by the writing step. In this case, the band image data already stored in the storing step is read out.

  A twelfth aspect of the invention is a program for causing a computer included in the image forming apparatus to execute the image processing method according to the seventh to eleventh aspects.

  A thirteenth aspect of the invention is a computer-readable recording medium on which the program according to the twelfth aspect is recorded.

  According to the present invention, the present invention realizes an image processing apparatus and the like that can reduce the size of a memory that stores image data.

<Embodiment 1>
First, an image processing apparatus according to a first embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to the present embodiment. The image processing apparatus 1 includes an image memory 2 and a compressor 3. The image memory 2 is, for example, a semiconductor memory and stores image data input from the image input apparatus. The compressor 3 is an image memory. The image data stored in 2 is encoded, that is, converted in data format and output. The compressor 3 includes a READ DMAC 4, a compression core 5, a final code detection unit 6, and a WRITE DMAC 7.

  The READ DMAC 4 is a DMAC that mainly reads image data, reads image data from the image memory 2 based on the descriptor, and sends the image data to the compression core 5. In the descriptor, band end information indicating the end of image data in band units (hereinafter referred to as band data) can be described.

  The compression core 5 performs compression processing on the image data sent from the READ DMAC 4 and sends the encoded data to the final code detection unit.

  The final code detection unit 6 detects whether or not a band end code (to be described later) is added to the encoded data sent from the compression core 5, and sends the encoded data to the WRITE DMAC 7.

  The WRITE DMAC 7 is a DMAC that mainly writes image data, and writes the encoded data sent from the final code detector to the image memory 2. The encoded image data may be written in a storage device different from the image memory 2, for example, an auxiliary storage device such as an HDD (Hard Disk Drive).

  Hereinafter, the compression process in the compressor 3 will be described in detail.

  First, the READ DMAC 4 raises the KICK signal and waits for the Req signal to be transmitted by the compression core 5. When the Req signal is returned, the ACK signal and the read image data are sent to the compression core 5. While the ACK signal and the image data are being transmitted, the KICK signal is in a rising state, but the end of the band data is determined based on the band end information described in the descriptor, and the KICK signal is lowered.

  Next, when the KICK signal enters the rising state, the compression core 5 transmits a Req signal to the READ DMAC 4 when the internal state is cleared. Then, the image data sent from the READ DMAC 4 is encoded, and the encoded data is sent to the final code detector 6 as needed. When the KICK signal is lowered, termination processing is further performed, and finally a band termination code is added and transmitted. The band end code is the same as the band end information described above in that it means the end of the band data, but it is encoded data in the same data format as the compressed image data, and the descriptor information is not the object of encoding. It is different in point.

  Next, the final code detection unit 6 resets the compression core 5 when the band termination code is attached to the encoded data sent from the compression core 5. That is, a Reset signal is transmitted to the compression core 5. The compression core 5 receives the Reset signal from the final code detection unit 6 and clears the information regarding the compressed data in the compression core 5 and resets the internal state.

  By configuring as in the present embodiment, image data is subjected to compression processing in band units and image expansion is performed, so that an increase in memory can be avoided and miniaturization can be achieved. Further, when the compression process is performed, the image data that has been subjected to the compression process is cleared in band units, thereby preventing a reduction in processing speed.

<Embodiment 2>
Next, an image processing apparatus according to the second embodiment of the present invention will be described with reference to FIG.

  FIG. 1 is a block diagram illustrating a configuration of an image processing apparatus according to the present embodiment. The basic configuration is the same as that of the first embodiment, but differs in that a module and a toggle buffer are provided in the READ DMAC 4.

  The READ DMAC 4 of the compressor 3 includes a reception module 21, a transmission module 22, a first toggle buffer 23, and a second toggle buffer 24.

  The receiving module 21 is a receiving-side module that receives image data from the image memory 2 and writes the received image data to the two toggle buffers.

  The transmission module 22 is a module on the transmission side that transmits image data to the compression core, and reads out the image data written in the toggle buffer by the reception module 21.

  The first toggle buffer 23 and the second toggle buffer 24 are storage areas for temporarily storing image data for compression processing. When writing is performed by the reception module 21 on one side, transmission is performed on the other side. The image data written by the module 22 is read out. If there is only one buffer, one of the requests is waited when there is a write request and a read request, but by using two buffers, the write request and the read request can be performed in parallel. .

  Hereinafter, the compression process in the compressor 3 of this embodiment will be described in detail. Since the basic flow is the same as that of the first embodiment, the differences will be mainly described.

  First, the READ DMAC 4 operates by receiving a descriptor. When receiving the image data, the receiving module 21 writes the data in the first toggle buffer, for example. Normally, data writing to the other toggle buffer is started when there is no more free space in the toggle buffer that has been written.

  When the band end information is described in the descriptor corresponding to the image data to be transferred, the reception module 21 finishes writing the image data described in the descriptor in one toggle buffer, and then receives the image data of the next received descriptor. Is written to the other toggle buffer.

  Next, the transmission module 22 reads the toggle buffer that has run out of capacity or the toggle buffer that has not been written, and transmits the read image data to the compression core 5. First, the KICK signal is raised, and the Req signal from the compression core 5 is waited. When receiving the descriptor in which the band end information is written from the receiving module 21, the KICK signal is lowered when transmission of the last data of the band written in the toggle buffer is completed.

  Since the compression processing, final code detection, reset processing, and the like are the same as those in the first embodiment, description thereof is omitted.

  By configuring as in the present embodiment, compression for each band data is possible without stopping the flow of data read, and the compression processing becomes efficient. In order for this mechanism to be established, the toggle core must have sufficient margin between the end of the compression process and the return of the Req signal after receiving the End Of Data signal after the KICK signal is lowered. is required.

<Embodiment 3>
Next, an image processing apparatus according to a third embodiment of the present invention will be described with reference to FIG.

  FIG. 3 is a block diagram showing the configuration of the image processing apparatus according to this embodiment. In this embodiment, the image memory and other modules connected to the compressor are separately configured. As for the mounting inside the compressor 3, either the first embodiment or the second embodiment described above may be used.

  The other module 31 accesses the memory 2 for writing image data, and the compressor 3 reads the written image data. The memory 2 has an area for storing image data in band units. For example, the memory 2 includes an m-band image data storage area 32 and an m + 1 band image data storage area 33.

  Further, the writing of the other module 31 and the reading of the compressor 3 are performed in parallel. For example, when the other module 31 is writing the m-th band image data into the storage area 32, the compressor 3 reads out the m + 1 band image data and performs the compression process.

  In addition, the compressor 3 writes the encoded data compressed for each band to the image memory 2, but may write it to another storage device.

  According to the configuration of the present embodiment, it is sufficient to have at least two bands of memory as storage means for storing image data, and the memory can be reduced in size. In the present embodiment, writing to and reading from the image memory 2 are performed using the DMAC, which is different from using a toggle buffer as in the second embodiment.

  Note that the program for the CPU to execute the processing according to each embodiment constitutes a program according to the present invention. The recording medium for recording the program constitutes a computer-readable recording medium according to the present invention. As the recording medium, for example, a floppy disk, HDD, optical disk, magneto-optical disk, CD-ROM, CD-R, magnetic tape, nonvolatile memory card, ROM, or the like can be used.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible.

It is a block diagram which shows the structure of the image processing apparatus in embodiment of this invention. It is a block diagram which shows the structure of the image processing apparatus in embodiment of this invention. It is a block diagram which shows the structure of the image processing apparatus in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 2 Image memory 3 Compressor 4 READ DMAC
5 Compression core 6 Final code detection unit 7 WRITE DMAC
21 Reception Mod (module)
22 Transmission Mod (module)
23 First toggle buffer 24 Second toggle buffer 31 Other module 32 m-band image data area 32 m + 1 band image data area

Claims (13)

In an image processing apparatus comprising storage means for storing image data, reading means for reading image data stored in the storage means, and compression means for compressing image data read by the reading means,
The storage means divides the image data into band units that are a plurality of band-like regions and stores them as band image data,
The reading means reads the band image data stored by the storage means based on the memory area management information,
The compression means includes
Encoding the band image data read by the reading means;
Adding means for adding a band end code representing the end of the band image data;
Image processing, comprising: a reset unit that clears information about the encoded band image data in the compression unit and resets an internal state when the band end code added by the addition unit is detected apparatus. A toggle buffer for temporarily storing band image data read by the reading means;
The reading means receives the termination information described in the memory area management information, and when the band image data corresponding to the memory area management information has been written to the toggle buffer, the next read band The image processing apparatus according to claim 1, wherein the image data is written to the toggle buffer. The reading means has a receiving module and a transmitting module,
The receiving module writes the band image data read from the storage means to the toggle buffer,
The image processing apparatus according to claim 2, wherein the transmission module reads out the band image data written by the reception module from the toggle buffer and sends the data to the compression unit.   The image processing apparatus according to claim 3, wherein the writing by the receiving module and the reading by the transmitting module are performed in parallel.   The image forming apparatus according to claim 2, wherein the reading unit includes a plurality of toggle buffers. Writing means for writing the band image data into the storage means;
The storage means has a capacity to store band image data for at least two bands,
The reading means reads the band image data already stored in the storage means when the band image data is written in the storage means by the writing means. The image processing apparatus according to any one of the above. In an image processing method comprising: a storage step for storing image data; a read step for reading image data stored in the storage step; and a compression step for compressing image data read by the read step.
The storing step divides the image data into band units that are a plurality of band-like regions and stores them as band image data,
The reading step reads the band image data stored by the storing step based on the memory area management information,
The compression step includes
While encoding the band image data read by the reading step,
An additional step of adding a band end code representing the end of the band image data;
An image processing comprising: a reset step of clearing information on the encoded band image data in the compression means and resetting an internal state when the band end code added by the adding step is detected Method. An image processing method of an image processing apparatus having a toggle buffer for temporarily storing band image data read by the reading step,
The reading step receives the termination information described in the memory area management information, and when the band image data corresponding to the memory area management information has been written to the toggle buffer, the next read band 8. The image processing method according to claim 7, wherein the image data is written to the toggle buffer. The reading step includes a receiving module and a transmitting module,
The reception module writes the band image data read out in the storage step to the toggle buffer,
9. The image processing method according to claim 8, wherein the transmission module reads out the band image data written by the reception module from the toggle buffer, and sends the band image data to the compression step.   The image processing method according to claim 9, wherein writing by the receiving module and reading by the transmitting module are performed simultaneously. An image processing method of an image processing apparatus, wherein the storage area stored by the storage step has a capacity to store band image data for at least two bands,
A writing step of writing the band image data in the storage area;
The read-out step reads out the band image data already stored in the storage step when the band image data is written in the storage area in the writing step. The image processing method according to any one of the above.   The program for making the computer with which an image forming apparatus is provided perform the image processing method of Claim 7-11.   A computer-readable recording medium on which the program according to claim 12 is recorded.

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