JP2009265776A - Image processor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor performing high-speed image processing. <P>SOLUTION: A reading access controller 204 decides whether a line presently during processing is within an effective area or not. Specifically, when the present processing line is after an effective area start line and before an effective area end line, it is decided that the present processing line is within the effective area. Otherwise, it is decided that the present processing line is within an ineffective area. When the present processing line is within the effective area, the reading access controller 204 starts a reading DMA (Direct Memory Access) controller 201 to make it generate memory access. When it is decided that the present processing line is out of the effective area, the memory access is not generated. Similarly in the case of writing, it is decided whether the present processing line is within the effective area or not, and the memory access is not generated when out of the effective area. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing apparatus capable of transferring data by a direct memory access (abbreviated as DMA) system.

  2. Description of the Related Art In recent years, color processing has been performed in image processing apparatuses that process image data that are mounted on a composite apparatus that combines functions such as a copying apparatus, a scanner apparatus, a printer apparatus, and a facsimile apparatus. Data capacity increases due to colorization, and such image processing apparatuses are required to increase data processing speed. In an image processing apparatus, data processing is speeded up by transferring data by a direct memory access (abbreviated as DMA) system.

  Patent Document 1 discloses an apparatus including a central processing unit (abbreviated as CPU), which is a main control unit, and a programmable DMA control device. The CPU downloads the necessary DMA transfer program and parameters to the DMA controller. The DMA controller executes a DMA transfer program to perform data transfer. When the DMA controller completes the data transfer, it sends an interrupt to the CPU.

  In the technique disclosed in Patent Document 2, a plurality of DMA circuits and a selector circuit that activates each DMA circuit are provided, and each DMA circuit is linked. Coordination settings for coordinating the DMA circuits are performed by the CPU writing and reading command output.

Japanese translation of PCT publication No. 2001-502082 JP 2006-172107 A

  Some image processing apparatuses divide image data for one page into a plurality of bands and sequentially process each band.

  When the technique disclosed in Patent Document 1 is used in such an image processing device, in order to sequentially perform different data transfer for each divided band, the DMA control device An interrupt is sent to the CPU, and each time the CPU is given an interrupt, the CPU needs to download the necessary DMA transfer program and parameters to the DMA controller. Therefore, there is a problem that the processing load of the CPU is generated and the performance of the CPU is lowered.

  When the technique disclosed in Patent Document 2 is used in such an image processing apparatus, there is a problem that even when processing is unnecessary, data is transferred by the DMA circuit, and the bandwidth of the bus is compressed. . The image data for one page includes a band that requires processing and a band that does not require processing. Nevertheless, since the data is transferred and processed by the DMA circuit for all the bands, the above-described problem occurs.

  An object of the present invention is to provide an image processing apparatus capable of realizing high-speed image processing.

The present invention is an image processing apparatus that divides image data for one page into a plurality of bands and sequentially processes each band,
A memory capable of writing image data and reading image data;
An image input module that transfers image data for each band from an image reading device that reads an image to the memory, and outputs a one-band transfer completion notification each time image data for one band is transferred;
In response to the one-band transfer completion notification from the image input module, the image input module reads out one band of image data transferred from the image reading device to the memory, performs image processing, and performs one band after image processing. An image processing module that outputs a one-band transfer completion notification each time image data is transferred to the memory;
In response to the one-band transfer completion notification from the image processing module, the image data for one band after the image processing transferred from the image processing module to the memory is read, post-processing is performed, and one band for the post-processing is performed. An image compression module that outputs a one-band transfer completion notification each time image data is transferred to the memory,
When the image processing module determines whether the image data for one band transferred from the image reading device to the memory by the image input module is a band to be subjected to image processing or not, and determines that the band is not to be used The image processing apparatus outputs a one-band transfer completion notification to the post-processing module without performing memory access.

  In the invention, it is preferable that the image input module does not write the image data from the image reading device to the memory until the post-processing module receives a one-band transfer completion notification.

In the present invention, when an area where image processing is performed on a memory is set as an effective image area, and an area where image processing is not performed is set as an invalid image area,
When the image input module is notified by the image input module of the completion of 1-band transfer of the band including the set effective image area, the image processing module performs image processing only on the effective image area and generates access to the memory. When the band transfer is completed, the post-processing module is notified of the completion of one band transfer.

  According to the present invention, the image processing module performs processing for combining watermarks in a series of image processing in cooperation between the modules.

  Further, the present invention is characterized in that when processing for combining watermarks, images of three bands or more are alternately transferred using two areas on the memory.

  According to the present invention, the image processing module determines whether or not the image data for one band transferred from the image reading apparatus to the memory by the image input module should be subjected to image processing. When it is determined that the band is not subjected to image processing, a one-band transfer completion notification is output to the post-processing module without performing memory access.

  As a result, for a band that does not require image processing, a transfer completion notification is output without performing memory access. Therefore, data transfer processing more than necessary does not occur, and high-speed image processing can be realized.

According to the invention, the image input module does not write the image data from the image reading device to the memory until a one-band transfer completion notification is given from the post-processing module.
Thereby, overwriting of image data on the memory can be prevented.

  According to the invention, the image processing module performs image processing only on the effective image area when the image input module is notified of the completion of the one-band transfer of the band including the set effective image area, and stores it in the memory. When the transfer of the relevant band is completed, the post-processing module is notified of the completion of one-band transfer.

  As a result, even if the effective image area is switched from the invalid image area to the invalid image area in the middle line of one band, or the invalid image area is switched to the valid image area, only the valid image area can be processed. Image processing can be realized.

  Further, according to the present invention, the image processing module performs processing for combining watermarks in a series of image processing in cooperation of the modules.

  Since the watermark synthesis is an image process performed only on a part of the area, a higher-speed image process can be realized when performing such a synthesis process.

  Further, according to the present invention, when processing for combining watermarks, images of three or more bands are transferred alternately using two areas on the memory.

  By using the so-called ring buffer operation, the storage capacity required for the memory can be reduced.

FIG. 1 is a schematic diagram showing a configuration of an image processing apparatus 1 according to an embodiment of the present invention.
The image processing apparatus 1 includes an image input module 101, an image composition module 102, an image compression module 103, a memory controller 104, and a memory 105.

  The image input module 101 transfers image data from an image reading apparatus externally connected to the image processing apparatus 1 to the memory 105 via the memory controller 104 for each band. When data is transferred to the memory 105, a one-band transfer completion notification is output to the image composition module 102 every time image data for one band is transferred.

  The image composition module 102 performs image composition processing for one part, for example, one band of one page of image data, and the image data for one band transferred from the image input module 101 to the memory 105 is converted into the image input module. In response to the transfer completion notification output from 101, the composition processing is performed.

  When the processed data is transferred to the memory 105, a one-band transfer completion notification is output to the image compression module 103 each time image data for one band is transferred.

  The image compression module 103 reads the image data transferred from the image composition module 102 to the memory 105 for each band, performs post-processing such as image compression processing, and then transfers the data to the memory 105.

  The memory controller 104 is an interface when image data from each module is written to the memory 105 and when each module reads image data from the memory 105.

The memory 105 stores image data written from each module.
The image input module 101 and the image composition module 102, and the image composition module 102 and the image compression module 103 are configured to be capable of DMA cooperation.

FIG. 2 is a block diagram illustrating a configuration of the image composition module 102.
The image composition module 102 includes a read DMA controller 201, an image calculation unit 202, a write DMA controller 203, a read access controller 204, a control register 205, and a write access controller 206.

  For data that requires image processing, the read DMA controller 201 accesses the memory 105 to read image data, the image calculation unit 202 performs image processing, and the write DMA controller 203 accesses the memory 105 to perform image processing. Write processed image data.

  The read DMA controller 201 reads image data from the memory controller 104 when the activation signal from the read access controller 204 is valid.

  The image calculation unit 202 is a module that performs predetermined image processing on the image data read from the memory 105 by the read DMA controller 201.

  The write DMA controller 203 writes image-processed data to the memory controller 104 when the activation signal from the write access controller 206 is valid.

  The read access controller 204 recognizes the valid area and invalid area included in one page of image data from the offset cooperation setting set in the control register 205 and the valid area start line and valid area end line setting information.

  When the band transfer completion notification signal is given from the image input module 101, if the area is an invalid area, it is not necessary to perform image processing by the image calculation unit 202, so the read DMA controller 201 is not activated and the band is not activated. Issue only a transfer completion response. If the area is a valid area, the read DMA controller 201 is activated to generate a memory access.

  The write access controller 206 recognizes the valid area and invalid area included in one page of image data from the offset cooperation setting set in the control register 205 and the valid area start line and valid area end line setting information.

  If it is an invalid area, there is no need to perform image processing by the image calculation unit 202, so only the band transfer completion response is issued without activating the write DMA controller 203. If it is a valid area, the write DMA controller 203 is activated to generate a memory access.

  The control register 205 includes various setting registers including an offset cooperation valid / invalid setting register, a valid area start line, and a valid area end line setting register.

  Here, image processing performed by the image composition module 102 includes watermark composition processing. The watermarks are combined so that they are arranged not in the whole image data of one page but in a part, for example, in the center in the vertical direction of one page. Accordingly, image data for one page includes a band in which watermark data is combined and a band in which watermark data is not combined.

  The valid area is an area including a band where the watermark data is combined, and the invalid area is an area including a band where the watermark data is not combined.

FIG. 3 is an image data read DMA control flow at the time of offset cooperation.
When the transfer of image data for one page is started, the process waits for a band transfer completion notification from the image input module 101 in step S1.

  When the band transfer completion notification is detected from the image input module 101, the read access controller 204 compares the current processing line with the effective area start line in step S2.

  Subsequently, in step S3, the read access controller 204 compares the current processing line with the effective area end line.

  FIG. 4 is a conceptual diagram for explaining valid / invalid areas of image data on the memory 105.

  The image data 10 for one page is divided into a plurality of bands (Band1, Band2,...). The effective area 11, that is, the area that needs to be subjected to image processing, and the invalid area 12, that is, the area that does not need to be subjected to image processing, are set regardless of the boundaries of the divided bands. Therefore, one effective area 11 and invalid area 12 may be set across a plurality of bands. In the example shown in FIG. 4, for example, the invalid area 12 is set from the first line of Band 1 to Band 3 and is valid from the next line of Band 3 (effective area start line L1) to the middle line of Band 5 (effective area end line L2). Area 11 is set.

  The effective area 11 is recognized as the effective area 11 from the effective area start line L1 to the effective area end line L2, and the other is recognized as the invalid area 12.

  The band is composed of a plurality of lines in the main scanning direction of image data, and the effective area start line L1 and the effective area end line L2 are also lines in the main scanning direction. Therefore, the area width in the sub-scanning direction is determined by the effective area start line L1 and the effective area end line L2.

  With respect to the effective area width in the main scanning direction, for example, both end portions of the image in the main scanning direction become invalid areas with a certain width, and all central portions other than the invalid areas become effective areas.

  Thus, the effective area and the invalid area are determined by the width in the main scanning direction and the width in the sub-scanning direction, but the effective area in the main scanning direction is determined in advance and does not change for each band. The determination of the area and the invalid area depends on the area width in the sub-scanning direction.

  In step S4, the read access controller 204 determines whether the current processing line is within the valid area. Specifically, if the current processing line is greater than or equal to the valid area start line and less than or equal to the valid area end line, it is determined that the current process line is within the valid area.

  When multiple effective areas are set in one page, there are multiple start lines and end lines, so the current processing line is within the area for each pair of start line and end line corresponding to one effective area. To determine whether or not

  If the current processing line is within the valid area, the process proceeds to step S5, where the read access controller 204 activates the read DMA controller 201 to generate a memory access. If it is determined that it is outside the valid area, no memory access occurs.

  In step S6, the current processing line is counted up. In step S7, it is determined whether or not the current processing line is the last line of the band. If the current processing line is not the last line of the band, the process returns to step S2, and the above processing is repeated for the next current processing line. If the current processing line is the last line of the band, the process proceeds to a band transfer completion response generation process in step S8, and a band transfer completion response is sent to the image input module 101.

  In step S9, it is determined whether or not the transfer for one page has been completed. If the transfer for one page is not completed, the process returns to step S1 to wait for a transfer completion notification for the next band. If the transfer for one page is completed, the image read DMA process is terminated.

FIG. 5 is an image data writing DMA control flow at the time of offset cooperation.
The write access controller 206 counts the current processing line based on the line management signal from the read access controller 204. This line management signal is supplied to the write access controller 206 regardless of the valid area and invalid area. Write control is started when the counter that counts the line management signal reaches the effective area.

  When transfer of image data for one page is started, the write access controller 206 compares the current processing line with the effective area start line in step S11. Subsequently, in step S12, the write access controller 206 compares the current processing line with the effective area end line.

  In step S13, the write access controller 206 determines whether the current processing line is within the valid area. Specifically, if the current processing line is greater than or equal to the valid area start line and less than or equal to the valid area end line, it is determined that the current process line is within the valid area.

  If the current processing line is within the valid area, the process proceeds to step S14, where the write access controller 206 activates the write DMA controller 203 to generate a memory access. If it is determined that it is outside the valid area, no memory access occurs.

  In step S15, the current processing line is counted up. In step S16, it is determined whether or not the current processing line is the last line of the band. If the current processing line is not the last line of the band, the process returns to step S11 and the above processing is repeated for the next current processing line. If the current processing line is the last line of the band, the process proceeds to a band transfer completion notification generation process in step S17, and a band transfer completion notification is sent to the image compression module 103.

  In step S18, a state of waiting for a band transfer completion response from the image compression module 103 is entered. When a band transfer completion response is detected from the image compression module 103, the process proceeds to step S19, where it is determined whether or not the transfer for one page has been completed. If the transfer for one page is not completed, the process returns to step S11, and if the transfer for one page is completed, the image writing DMA process is terminated.

  In the present invention, the transfer of the image of the memory 105 is not particularly limited, but it is possible to use a so-called ring buffer operation in which images of 3 bands or more are alternately transferred using two areas on the memory. As a result, the storage capacity required for the memory can be reduced.

  When ring buffer operation is used, there is a risk of data overwriting. In the conventional band buffer transfer, two circuits transfer data via a band buffer. In the present invention, the image input module 101, the image composition module 102, and the image compression module 103 share the same band area.

  Since the image data is overwritten when the transfer of the image data of the next band from the image input module 101 is started before the image data is transferred from the image composition module 102 to the image compression module 103, the image composition module 102 After waiting for a bunt transfer completion response from the image compression module 103, the image input module 101 is notified of the band transfer completion response.

  FIG. 6 is a diagram for explaining a case where the transfer of the image input module 101 is forcibly terminated.

  When the image composition module 102 completes image processing for one page before the image input module 101, it issues a forced end signal to the image input module 101 and forcibly terminates DMA transfer from the image input module 101. Let

  In such a case, if the transfer process from the image input module 101 occurs, the image data on the memory 105 may be overwritten. Therefore, the transfer process from the image input module 101 is forcibly terminated to overwrite the data. Can be prevented.

1 is a schematic diagram illustrating a configuration of an image processing apparatus 1 according to an embodiment of the present invention. 3 is a block diagram showing a configuration of an image composition module 102. FIG. It is an image data read DMA control flow at the time of offset cooperation. 3 is a conceptual diagram for explaining valid / invalid areas of image data on a memory 105. FIG. It is an image data writing DMA control flow at the time of offset cooperation. FIG. 10 is a diagram for describing a case where transfer of the image input module 101 is forcibly terminated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 101 Image input module 102 Image composition module 103 Image compression module 104 Memory controller 105 Memory 201 Read DMA controller 202 Image operation part 203 Write DMA controller 204 Read access controller 205 Control register 206 Write access controller

Claims (5)

An image processing apparatus that divides image data for one page into a plurality of bands and sequentially processes each band,
A memory capable of writing image data and reading image data;
An image input module that transfers image data for each band from an image reading device that reads an image to the memory, and outputs a one-band transfer completion notification each time image data for one band is transferred;
In response to the one-band transfer completion notification from the image input module, the image input module reads out one band of image data transferred from the image reading device to the memory, performs image processing, and performs one band after image processing. An image processing module that outputs a one-band transfer completion notification each time image data is transferred to the memory;
In response to the one-band transfer completion notification from the image processing module, the image data for one band after the image processing transferred from the image processing module to the memory is read, post-processing is performed, and one band for the post-processing is performed. An image compression module that outputs a one-band transfer completion notification each time image data is transferred to the memory,
When the image processing module determines whether the image data for one band transferred from the image reading device to the memory by the image input module is a band to be subjected to image processing or not, and determines that the band is not to be used An image processing apparatus that outputs a one-band transfer completion notification to a post-processing module without performing memory access.   The image processing apparatus according to claim 1, wherein the image input module does not write image data from the image reading apparatus to the memory until a one-band transfer completion notification is given from the post-processing module. When an area where image processing is performed in memory is set as an effective image area, and an area where image processing is not performed is set as an invalid image area,
When the image input module is notified by the image input module of the completion of 1-band transfer of the band including the set effective image area, the image processing module performs image processing only on the effective image area and generates access to the memory. 2. The image processing apparatus according to claim 1, wherein when the band transfer is completed, the post-processing module is notified of the completion of one band transfer.   The image processing apparatus according to claim 1, wherein the image processing module performs processing for combining watermarks in a series of image processing in cooperation between the modules.   5. The image processing apparatus according to claim 4, wherein when performing processing for combining watermarks, images of three bands or more are alternately transferred using two areas on the memory.

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