Image processing device, control method therefor, and program

Abstract

To stably perform reading of documents at low cost while suppressing image quality degradation.SOLUTION: An image processing unit estimates the processing time for input image processing from parameters of a job to be executed, and estimates the processing time for output image processing from the parameters of the job to be executed. If the output image processing time for two pages is shorter than the input image processing time for one page, the image processing unit performs output image processing while buffering in band units without temporarily storing (buffering) in a page unit after input image processing. If the output image processing time for two pages is longer than the input image processing time for one page, the image processing unit temporarily stores the image data that has been applied with the input image processing. The image processing unit estimates the temporary storage size in each compression format and performs buffering in the compression format with the least image quality degradation in which the data size of the image data that has been applied with the input image processing for two pages becomes smaller than the buffer size.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image processing technique for processing read image data.

Background Art

[0002] Conventionally, there are scanners and multifunction devices that enable reading both sides of a document in a single pass. These devices aim to improve the reading speed by simultaneous double-sided reading, reduce the conveyance damage load on the document by reading both sides in one pass without inverting the document, and reduce noise. On the other hand, in scanners and digital multifunction devices having such a simultaneous double-sided reading mechanism, it is necessary to duplicate the image processing device for the read image in order to send image data for two pages to the output device, resulting in a significant increase in cost.

[0003] In Patent Document 1, a configuration is proposed in which the read image is temporarily stored in an inexpensive buffer memory and sequentially image-processed one page at a time by one image processing device and transferred to the output device. In Patent Document 2, a configuration is proposed in which the read image for two pages is alternately processed block by block by one image processing device so that processing can be performed with a small buffer memory. By adopting these configurations, simultaneous double-sided reading is enabled while reducing the total cost.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the configuration of Patent Document 1, in order to prevent the capacity of the buffer memory from being insufficient, it is necessary to perform data compression accompanied by image quality degradation or narrow the reading range. Further, in the configuration of Patent Document 2, the processing performed for each block on the read images for two pages cannot be completed in time, and there is a possibility of processing errors.

[0006] An object of the present invention is to stably read a document at low cost while suppressing image quality degradation.

Means for Solving the Problems

[0007] The present invention is an image processing apparatus, comprising: job acquisition means for acquiring a job for instructing reading of a document by a scanner; image data acquisition means for acquiring read image data of the document read by the scanner according to the job; first image processing for performing parallel processing on image data for two pages of the read image data; second image processing for sequentially processing the processed data of the first image processing in a predetermined processing unit; and buffer means for temporarily storing the processed data of the first image processing in the processing means, wherein the processing means sets the predetermined processing unit based on a predetermined parameter included in the job and processing speeds of the first image processing and the second image processing.

Effects of the Invention

[0008] According to the present invention, a document can be stably read at low cost while suppressing image quality degradation.

Brief Description of the Drawings

[0009]

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Best Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential to the invention, and the plurality of features may be arbitrarily combined. Further, in the accompanying drawings, the same or similar configurations are denoted by the same reference numerals, and redundant descriptions are omitted.

[0011] (Device Configuration) FIG. 1 is a diagram showing a schematic configuration of an image processing apparatus according to the present embodiment.

[0012] In FIG. 1, the image processing apparatus includes a controller unit 100, a print engine unit 200, and a scanner engine unit 300. Further, the image processing apparatus can be connected to a host device 400 via a host IF 102 or a wireless IF 103.

[0013] The controller unit 100 has a main controller 101, a print engine IF 104, a scanner engine IF 109, a RAM 105, a ROM 106, an image processing unit 107, and an operation panel 108. Further, the controller unit 100 has a host IF 102 and a wireless IF 103 for external connection, and each part of the controller unit 100 is connected via a system bus 110.

[0014] The main controller 101 composed of a CPU performs printing and maintenance operations while using the RAM 105 as a work area according to the programs and various parameters stored in the ROM 106, and controls the operation of the entire image processing apparatus. For example, when print data is input as a job from the host apparatus 400 via the host IF 102, the image processing unit 107 performs predetermined image processing on the received print data according to the instructions of the main controller 101 to generate image data. Then, the main controller 101 transmits the image data subjected to image processing to the print engine unit 200 via the print engine IF 104. Also, for example, when a read command is input as a job from the host apparatus 400, the main controller 101 transmits this command to the scanner engine unit 300 via the scanner engine IF 109.

[0015] The RAM 105 is used as a work area of the main controller 101, as a temporary storage area for various received data, and stores various setting data.

[0016] The ROM 106 stores programs for the main controller 101 to execute and various data necessary for various operations of the image processing apparatus.

[0017] The image processing unit 107 has various image processing parts, which are roughly classified into an input image processing part and an output image processing part. The input image processing part performs input image processing such as shading correction processing, gamma correction processing, color deviation correction, MTF correction, etc. on the image data input from the scanner engine unit 300 via the scanner engine IF 109. Also, the output image processing part performs output image processing such as color conversion and quantization processing on the image data after input image processing to make the image data printable by the print engine unit 200. The image data subjected to input image processing and output image processing by the image processing unit 107 is stored in the RAM 105.

[0018] The operation panel 108 includes hard keys, panels for receiving input from the user and enabling various operations by the user, and a display unit for displaying (notifying) various information to the user. Further, for the display of information to the user, the operation panel 108 may output sound (such as a buzzer, voice, etc.) based on acoustic information from the sound generator.

[0019] The print engine unit 200 is a printing unit that performs image formation. The print engine unit 200 includes a controller IF 201, a print controller 202, a ROM 203, a RAM 204, and an image processing controller 205. Further, for performing various controls, the print engine unit 200 includes a maintenance control unit 210, an ink supply control unit 209, a head carriage control unit 208, a conveyance control unit 207, and a head IF 206. Each part is connected via a system bus 211, and the print engine unit 200 is connected to the recording head 500 via the head IF 206.

[0020] The print controller 202 composed of a CPU controls various mechanisms included in the print engine unit 200 while using the RAM 204 as a work area according to the programs and various parameters stored in the ROM 203. When various commands and image data are received via the controller IF 201, the print controller 202 temporarily stores them in the RAM 204. The print controller 202 causes the image processing controller 205 to generate recording data based on the stored image data so that the recording head 500 can be used for the recording operation. When the recording data is generated in the image processing controller 205, the print controller 202 causes the recording head 500 to execute a recording operation based on the recording data. At this time, the print controller 202 causes the conveyance control unit 207 to convey the recording medium. In accordance with the instructions of the print controller 202, the recording operation by the recording head 500 is executed in conjunction with the conveyance operation of the recording medium, and the printing process is performed.

[0021] The head carriage control unit 208 changes the orientation and position of the recording head 500 according to the operating state such as the maintenance state and the recording state of the image processing apparatus. The ink supply control unit 209 controls so that the pressure of the ink supplied to the recording head 500 falls within an appropriate range. The maintenance control unit 210 controls the cleaning of the conveyance roller and the recording head 500 controlled by the conveyance control unit 207.

[0022] The recording head 500 is a printing unit that prints an image, and prints an image on a recording medium based on image data. The recording head 500 holds, for example, a plurality of printing heads for a plurality of colors, and ejects ink in synchronization with the conveyance of the recording medium to form an image on the recording medium.

[0023] Note that the image processing apparatus according to the present embodiment will be described by taking an inkjet printer using ink as a recording material as an example, but is not limited thereto. The present invention is applicable to printing apparatuses of various printing methods such as electrophotographic methods such as thermal printers (sublimation type, thermal transfer type, etc.), dot impact printers, LED printers, and laser printers.

[0024] The scanner engine unit 300 includes a controller IF 301, a RAM 303, a scanner controller 302, a conveyance control unit 304, and a sensor 305. Each part is connected via a system bus 306.

[0025] The main controller 101 controls the hardware resources of the scanner controller 302 while using the RAM 105 as a work area according to the programs and various parameters stored in the ROM 106. As a result, various mechanisms included in the scanner engine unit 300 are controlled. For example, when the main controller 101 controls the hardware resources in the scanner controller 302 via the controller IF 301, the document set by the user is conveyed via the conveyance control unit 304 and read by the sensor 305. Then, the scanner controller 302 stores the read image data in the RAM 303. By providing the sensor 305 for each of the front page and the back page of the document, the conveyance control unit 304 conveys the document once, while the configuration is such that the read image data for two pages is acquired simultaneously.

[0026] In addition, in this embodiment, the operation panel 108 exists inside the image processing apparatus, but it is not limited to this. For example, it may be connected as an external configuration via the host IF 102. Further, the host apparatus 400 may also serve as the operation panel 108. Also, in addition to the operation panel 108, the image processing apparatus may be further connectable to other input / output devices via the host IF 102 or the like.

[0027] Also, in this embodiment, the print data, image data, and read image data are stored in the RAM 105, RAM 303, and RAM 204, but they may be stored in a non-volatile device such as an HDD.

[0028] The host apparatus 400 is an external apparatus that is a source of print data. For example, it is a PC installed with a printer driver or a server apparatus. Instead of the host apparatus 400, for example, a data providing apparatus such as a digital camera or a smartphone that can be a source of print data may be provided.

[0029] The connection form between each device and the image processing apparatus is not limited to the one via the host IF102. For example, it may be directly connected by wireless communication via the wireless IF103.

[0030] In addition, the program for realizing the functions of the present embodiment may be supplied to the image processing apparatus via a network or various storage media. Further, the processing unit (such as a CPU or MPU) of the image processing apparatus may read out the program and execute the functions, or cause various mechanisms to execute them. Also, this program may be executed by one computer or by the cooperation of a plurality of computers. In addition, it is not necessary to realize all of the above-described processing by software, and part or all of the processing may be realized by hardware such as an ASIC. Furthermore, the form is not limited to the one in which all processing is performed by one CPU, and a form in which a plurality of CPUs perform processing while appropriately cooperating with each other may be adopted, or a form in which one CPU executes one of the processes and a plurality of CPUs cooperate with each other to perform the other processes may be adopted.

[0031] FIG. 2 is a diagram showing a functional configuration example for realizing conventional image processing by the image processing unit 107 and the RAM 105. As described in the prior art, it shows a configuration example in which each image processing unit is duplicated and can perform parallel processing for simultaneous duplex reading. The first input unit 2001 and the second input unit 2002 acquire read image data for two pages from the scanner engine unit 300 via the scanner engine IF 109. For one of the acquired read image data for two pages, the first input image processing unit 2003 performs input image processing and stores the input image processed image data in the first band buffer 2005 in units of bands. The first output image processing unit 2007 performs output image processing on the input image processed image data in units of bands read from the first band buffer 2005 and outputs it to the first compression processing unit 2009. Here, a band refers to a block obtained by dividing the read image acquired by the scanner engine unit 300 into strips. The first compression processing unit 2009 reversibly compresses the output image processed image data output from the first output image processing unit 2007 and stores it in the output buffer 2011. The second input image processing unit 2004, the second band buffer 2006, the second output image processing unit 2008, and the second compression processing unit 2010 also perform the same processing on the other of the acquired read image data for two pages. The output unit 2012 appropriately expands the reversibly compressed output image processed image data stored in the output buffer 2011 and sequentially outputs it to the print engine unit 200 or transmits it to the host device 400.

[0032] FIG. 3 is a diagram showing a functional configuration example for realizing conventional image processing by the image processing unit 107 and the RAM 105. The example shown in FIG. 3 has a configuration with reduced cost compared to FIG. 2, and the output image processing unit is not duplicated. That is, in the input image processing, image data for two pages is processed in parallel in page units, but in the output image processing, the image data is processed sequentially in page units. The first input unit 3001 and the second input unit 3002 acquire read image data for two pages input from the scanner engine unit 300 via the scanner engine IF 109. Until the first input image processing unit 3003 and the second input image processing unit 3004 perform input image processing on each of the acquired read image data for two pages, the configuration is the same as that shown in FIG. 2. The first compression processing unit 3005 irreversibly compresses the input image-processed image data output from the first input image processing unit 3003 and stores it in the page buffer 3007 in page units. Similarly, the second compression processing unit 3006 performs parallel processing on the input image-processed image data output from the second input image processing unit 3004. The output image processing unit 3008 sequentially performs output image processing on the irreversibly compressed image data for two pages stored in the page buffer 3007. The third compression processing unit 3009 reversibly compresses the output image-processed image data and stores it in the output buffer 3010. The output unit 3011 appropriately expands the reversibly compressed output image-processed image data stored in the output buffer 3010 and performs output or transmission in the same manner as the configuration shown in FIG. 2.

[0033] In the present embodiment, as shown in FIG. 3, even in a configuration where the output image processing unit is not duplicated, by switching the image processing method, it is possible to reduce the occurrence of processing errors and image quality degradation without increasing the memory usage.

[0034] (Embodiment 1) Image processing for processing the read image data according to this embodiment will be described. FIG. 4 is a flowchart showing the image processing when executing a job for simultaneous duplex reading in this embodiment. Note that in this embodiment, when performing simultaneous duplex reading, for two pages of image data, in the input image processing, parallel processing is performed in page units, and in the output image processing, the processing unit is changed to page units or band units according to the parameters of the job to be executed, and sequential processing is performed.

[0035] In S401, the main controller 101 acquires a job from a host device 400 or the like via the operation panel 108, or via the host IF 102 or the wireless IF 103, and receives an execution instruction for the job. When the main controller 101 acquires a job, according to the content of the job, it issues an instruction to read one page or a plurality of pages of originals to the scanner engine unit 300 via the scanner engine IF 109.

[0036] In S402, the image processing unit 107 acquires the read image data from the scanner engine unit 300 via the scanner engine IF 109, and performs various image processes on the acquired read image data.

[0037] In S403, the image processing unit 107 transmits the read image data subjected to image processing to the print engine unit 200 via the print engine IF 104, or to the host device 400 via the host IF 102 or the wireless IF 103. When the read image data subjected to image processing is received by the printer engine unit 200, it is printed by the printer engine unit 200, and when it is received by the host device 400, it is stored in the storage unit of the host device 400.

[0038] In S404, if there is read image data for the next page to be processed, the image processing unit 107 returns to S402, and repeats S402 to S404 to perform the processing of the entire job.

[0039] FIG. 5 is a flowchart showing details of the process in S402 shown in FIG. 4 in Embodiment 1.

[0040] In S501, the image processing unit 107 estimates the processing time of the input image processing in each job from the parameters of the job to be executed and the processing speed for performing the input image processing. The input image processing time is calculated, for example, when performing the scaling process for output as the input image processing, as follows. Tin = N1in + N1out / Np (Equation 1) Tin: Input image processing time N1in: Number of input pixels for the input image processing per page = Document size × Reading resolution × Reading color number N1out: Number of output pixels from the input image processing per page = Output paper size × Output resolution × Output color number Np: Number of pixels that can be processed per unit time (processing speed) The reading resolution and the output resolution are determined by the job type and the magnification / reduction setting, which are parameters of the job. Also, the reading color number and the output color number are determined by the color / monochrome setting, which is a parameter of the job. In the case of duplex reading, since the input image processing for two pages is performed in parallel, the input image processing time estimates the processing time for one page.

[0041] In S502, the image processing unit 107 estimates the processing time of the output image processing in each job from the parameters of the job to be executed and the processing speed for performing the output image processing. The output image processing time is calculated, for example, when performing the scaling process for output as the input image processing, as follows. Tout = N2in + N2out / Np (Equation 2) Tout: Output image processing time N2in: Number of input pixels for the output image processing for two pages = Output paper size × Output resolution × Output color number N2out: Number of output pixels from the output image processing for two pages = Output paper size × Output resolution × Output color number Even in the case of simultaneous double-sided reading, since the output image processing unit is not duplicated and processes data for two pages sequentially, the processing time for two pages is estimated for the output image processing time.

[0042] In S503, the image processing unit 107 compares the input image processing time and the output image processing time. If the output image processing time for two pages is shorter than the input image processing time for one page, it proceeds to S504; if it is equal to or longer than the input image processing time for one page, it proceeds to S506.

[0043] In S504, the image processing unit 107 selects an image processing method in which, after input image processing, temporary storage (buffering) is not performed page by page, but output image processing is performed while buffering the input image processed image data for two pages in band units. FIG. 6 shows a functional configuration example of implementing the image processing method selected in S504. The first input unit 6001 and the second input unit 6002 acquire read image data for two pages from the scanner engine unit 300 via the scanner engine IF 109. The first input image processing unit 6003 performs input image processing on one of the read image data for two pages and stores the input image processed image data in the first band buffer 6005 in band units. Similarly, the second input image processing unit 6004 and the second band buffer 6006 perform parallel processing on the other of the read image data for two pages. The output image processing unit 6007 alternately reads the read image data for two pages in band units, performs output image processing on the data in which the input image processed image data for two pages is mixed, and outputs the output image processed image data to the compression processing unit 6008. The compression processing unit 6008 reversibly compresses and stores the output image processed image data in the output buffer 6009. The output unit 6010 expands the reversibly compressed output image processed image data stored in the output buffer 6009 block by block at the timing of output or transmission, and performs output or transmission in order.

[0044] In S505, the image processing unit 107 performs the processing method selected in any one of S504, S508, S511, and S512 and ends the operation of the image processing unit 107.

[0045] In S506, the image processing unit 107 estimates the data size of the input image processed image data for two pages without compression from the parameters of the job to be executed in order to determine the storage format when buffering in page units. The data size of the input image processed image data without compression is calculated as follows, for example, when the scaling process for output is performed in the input image processing. Data size per page without compression = Number of input pixels for the output image processing for two pages Number of input pixels for the output image processing = Output paper size × Output resolution × Number of output colors

[0046] In S507, if the data size of the input image processed image data for two pages without compression is smaller than the threshold value indicating the buffer size secured in the RAM 105, the image processing unit 107 proceeds to S508, and if it is equal to or larger than the buffer size, it proceeds to S509.

[0047] In S508, the image processing unit 107 temporarily stores the non-compressed input image processed image data in page units, and selects an image processing method for sequentially performing output image processing on the input image processed image data read from the storage destination in page units. FIG. 7 shows a functional configuration example of performing the image processing method selected in S508. The first input unit 7001 and the second input unit 7002 acquire two pages of read image data from the scanner engine unit 300 via the scanner engine IF 109. For one of the two pages of read image data, the first input image processing unit 7003 performs input image processing and stores the input image processed image data in the page buffer 7005 in page units without compression. Similarly, the second input image processing unit 7004 performs processing in parallel on the other of the two pages of read image data. The output image processing unit 7006 sequentially performs output image processing on the stored input image processed image data in page units and outputs it to the compression processing unit 7007. The compression processing unit 7007 reversibly compresses and stores the output image processed image data in the output buffer 7008. The output unit 7009 appropriately decompresses and outputs or transmits the reversibly compressed output image processed image data stored in the output buffer 7008.

[0048] In S509, the image processing unit 107 estimates the data size after reversible compression of the input image processed image data for two pages from the parameters of the job to be executed. The data size of the input image processed image data for two pages after reversible compression is calculated as follows, for example, when performing scaling processing for output in the input image processing. Size after reversible compression = Number of input pixels for output image processing for two pages × Minimum compression ratio of reversible compression Number of input pixels for output image processing = Output paper size × Output resolution × Number of output colors

[0049] In S510, if the size after reversible compression of the input image processed image data for two pages is smaller than the threshold indicating the buffer size secured in the RAM 105, the process proceeds to S511; if it is equal to or larger than the buffer size, the process proceeds to S512.

[0050] In S511, the image processing unit 107 selects an image processing method in which the input image processed image data for two pages is reversibly compressed in page units, temporarily stored, read from the storage destination, expanded, and then output image processing is sequentially performed on the input image processed image data in page units. FIG. 8 shows a functional configuration example of implementing the image processing method selected in S511. The first input unit 8001 and the second input unit 8002 acquire the read image data for two pages input from the scanner engine unit 300 via the scanner engine IF 109. The first input image processing unit 8003 performs input image processing on one of the read image data for two pages, and outputs the input image processed image data to the first compression processing unit 8005. The first compression processing unit 8005 reversibly compresses the input image processed image data and stores it in the page buffer 8007 in page units. Similarly, the second input image processing unit 8004 and the second compression processing unit 8006 perform processing in parallel on the other of the read image data for two pages. The output image processing unit 8008 sequentially performs output image processing on the input image processed image data stored in the page buffer 8007, and reversibly compresses and stores the output image processed image data in the output buffer 8010. The output unit 8011 appropriately expands and outputs or transmits the reversibly compressed output image processed image data stored in the output buffer 8010.

[0051] In S512, the image processing unit 107 selects an image processing method in which the input image processed image data for two pages is irreversibly compressed in page units, temporarily stored, read from the storage destination, expanded, and then output image processing is sequentially performed on the input image processed image data in page units. That is, the image processing method shown in FIG. 3 described above is selected.

[0052] As described above, in this embodiment, by appropriately selecting an image processing method according to the status of hardware resources, it is possible to stably perform image processing that maximally utilizes hardware resources.

[0053] (Embodiment 2) The image processing for processing the read image data executed by the image processing apparatus according to Embodiment 2 will be described. FIG. 9 is a flowchart showing details of the image processing in S402 shown in FIG. 4 in Embodiment 2. Embodiment 2 is different from Embodiment 1 in that the processes of S1001 to S1004 are added, but other processes are the same as those in Embodiment 1. However, in S507, when the data size of the input image processed image data for two pages in non-compressed form is equal to or greater than the threshold value indicating the buffer size secured in the RAM 105, the process proceeds to S901. Also, in S510, when the size after reversible compression of the input image processed image data for two pages is equal to or greater than the threshold value indicating the buffer size secured in the RAM 105, the process proceeds to S903.

[0054] In S901, the image processing unit 107 determines whether the data size of the input image processed image data for one page in non-compressed form is smaller than the threshold value indicating the buffer size and whether the output image processing time for one page is shorter than the input image processing time for one page. Here, the output image processing time for one page is half of the output image processing time in S503, and the input image processing time for one page is the same as the input image processing time in S503. If the conditions set in S901 are satisfied, the process proceeds to S902, and if the conditions are not satisfied, the process proceeds to S509.

[0055] In S902, the image processing unit 107 selects an image processing method in which it buffers the input image processed image data for one page and performs output image processing while buffering the input image processed image data for the other page in bands. FIG. 10 shows a functional configuration example of implementing the image processing method selected in S902. The first input unit 10001 and the second input unit 10002 acquire read image data for two pages input from the scanner engine unit 300 via the scanner engine IF 109. The first input image processing unit 10003 performs input image processing on one of the read image data for two pages and stores the input image processed image data in the band buffer 1005 in bands. On the other hand, the second input image processing unit 10004 performs input image processing on the other of the read image data for two pages and stores the input image processed image data in the page buffer 10006 without compression in pages. The output image processing unit 10007 sequentially performs output image processing on the input image processed image data buffered in bands or the input image processed image data buffered in pages and outputs it to the compression processing unit 10008. The compression processing unit 10008 reversibly compresses the output image processed image data and stores it in the output buffer 10009. The output unit 10010 appropriately expands the reversibly compressed output image processed image data stored in the output buffer 11010 and performs output or transmission.

[0056] In S903, the image processing unit 107 determines whether the data size of the input image processed image data for one page in reversible compression is smaller than the threshold indicating the buffer size and whether the output image processing time for one page is shorter than the input image processing time for one page. If the conditions set in S903 are satisfied, the process proceeds to S904; if not, the process proceeds to S512.

[0057] In S904, the image processing unit 107 selects an image processing method in which it buffers the input image processed image data for one page on one hand, and performs output image processing while buffering the input image processed image data for the other page in units of bands. FIG. 11 shows a functional configuration example of performing the image processing method selected in S904. The first input unit 11001 and the second input unit 11002 acquire two-page read image data input from the scanner engine unit 300 via the scanner engine IF 109. The first input image processing unit 11003 performs input image processing on one of the two-page read image data, and stores the input image processed image data in the band buffer 11005 in units of bands. On the other hand, the second input image processing unit 11004 performs input image processing on the other of the two-page read image data, and outputs the input image processed image data to the first compression processing unit 11006. The first compression processing unit 11006 reversibly compresses the input image processed image data in units of pages and stores it in the page buffer 11007. The output image processing unit 11008 sequentially performs output image processing on the input image processed image data buffered in units of bands or the input image processed image data buffered in units of pages, and outputs it to the second compression processing unit 11009. The second compression processing unit 11009 reversibly compresses the output image processed image data and stores it in the output buffer 11010. The output unit 11011 appropriately expands the reversibly compressed output image processed image data stored in the output buffer 11010 and performs output or transmission.

[0058] (Embodiment 3) The image processing for processing the read image data executed by the image processing apparatus according to Embodiment 3 will be described. FIG. 12 is a flowchart showing the details of the image processing in S402 shown in FIG. 4 in Embodiment 3. Embodiment 3 is different from Embodiment 2 in that the processes of S1201 to S1204 are added, but the other processes are the same as those in Embodiment 1. However, if the conditions set in S903 are not satisfied, the process proceeds to S1201.

[0059] In S1201, the image processing unit 107 causes the operation panel 108 to display a user selection.

[0060] FIG. 13 shows an example of an image page to be displayed on the operation panel 108. Since an irreversible compression image processing method is selected for double-sided reading on the display image page 1301, a warning indicating that image quality degradation will occur is displayed. Further, as user options, an "Execute" button 1302, a "Change to single-page reading" button 1303, and a "Cancel" button 1304 are displayed.

[0061] When the image processing unit 107 acquires a user input indicating that the user has selected the "Execute" button 1302, it proceeds to S512 and selects an image processing method to be performed with the functional configuration shown in FIG. 3 described above.

[0062] When the image processing unit 107 acquires a user input indicating that the user has selected the "Change to single-page reading" button 1303, it proceeds to S1203 and selects an image processing method that performs buffering and processing in units of bands one page at a time for single-page reading. Incidentally, when the output image processing time for one page is longer than the input image processing time for one page in S903, it may be changed to an image processing method that performs buffering and processing in units of pages.

[0063] When the image processing unit 107 determines that the user has selected the "Execute" button 1302 or the "Change to single-page reading" button 1303, in S505, it performs image processing using the image processing method selected in S512 or S1203 and ends the processing of the read image data.

[0064] On the other hand, when the image processing unit 107 acquires a user input indicating that the user has selected the "Cancel" button 1304, it proceeds to S1204, cancels the job, and ends the processing of the read image data without performing image processing.

[0065] As described above, according to the present invention, the processing time and data size of each image processing means are estimated from the parameters of a job that uses simultaneous double-sided reading, and the image processing method is switched according to the estimation result. Specifically, it is possible to select whether to perform buffering in units of bands or in units of pages between the input image processing and the output image processing, or to determine the storage format when performing buffering in units of pages. As a result, it is possible to reduce processing errors without increasing the memory usage while suppressing the occurrence of image quality degradation.

[0066] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiment to a system or apparatus via a network or a storage medium, and causing one or more processors in a computer of the system or apparatus to read and execute the program. It can also be realized by a circuit (for example, an ASIC) that realizes one or more functions. The present disclosure includes the following configurations and methods. [Configuration 1] Job acquisition means for acquiring a job that instructs the scanner to read a document, Image data acquisition means for acquiring the read image data of the document read by the scanner according to the job, Processing means for performing first image processing for parallel processing of two pages of image data of the read image data and second image processing for sequentially processing the processed data of the first image processing in a predetermined processing unit, Buffer means for temporarily storing the processed data of the first image processing in the processing means, Comprising The processing means sets the predetermined processing unit based on the predetermined parameters included in the job and the processing speeds of the first image processing and the second image processing. An image processing apparatus characterized by the above. [Configuration 2] The processing means sets the predetermined processing unit in units of pages or in units of bands obtained by dividing a page into a plurality of parts. The image processing apparatus according to Configuration 1, characterized in that... [Configuration 3] When the processing unit is the band unit, the processing means alternately processes the image data for two pages that are processed in parallel in the first image processing in the second image processing in units of the band. The image processing apparatus according to Configuration 2, characterized in that... [Configuration 4] The processing means calculates a first processing time required for the first image processing and a second processing time required for the second image processing for the image data for two pages of the read image data based on a predetermined parameter included in the job and the processing speeds of the first image processing and the second image processing. When the second processing time is shorter than the first processing time, the predetermined processing unit is set as the band unit. When the second processing time is equal to or longer than the first processing time, the predetermined processing unit is set as the page unit. The image processing apparatus according to Configuration 2 or 3, characterized in that... [Configuration 5] When the page unit is set as the predetermined processing unit, the processing means determines a storage format for temporarily storing in the buffer means according to the data size of the processed data of the first image processing and the buffer size of the buffer means. The image processing apparatus according to Configuration 4, characterized in that... [Configuration 6] When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is smaller than the buffer size, the processing means buffers at least the processed data of the first image processing for one page in the buffer means in an uncompressed manner in units of pages. The image processing apparatus according to Configuration 5, characterized in that... [Configuration 7] When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is smaller than the buffer size, the processing means buffers the processed data of the first image processing for two pages in the buffer means in an uncompressed manner in units of pages. The image processing apparatus according to Configuration 6, characterized in that... [Configuration 8] When the data size of the processed data of the first image processing for two pages calculated based on the job is equal to or greater than the buffer size, the data size of the processed data of the first image processing for one page is smaller than the buffer size, and half of the second processing time is shorter than the first processing time, the processing means buffers, in an uncompressed manner, one of the processed data of the first image processing for two pages processed in parallel in the buffer means, and buffers the other in the buffer means in band units. The image processing apparatus according to Configuration 6, characterized in that... [Configuration 9] When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is equal to or greater than the buffer size, the processing means buffers, in a reversibly compressed manner and in page units, at least the processed data of the first image processing for one page in the buffer means. The image processing apparatus according to Configuration 5, characterized in that... [Configuration 10] When the data size of the reversibly compressed data obtained by performing the reversible compression on the processed data of the first image processing for two pages is smaller than the buffer size of the buffer means, the processing means reversibly compresses the processed data of the first image processing for two pages and buffers it in the buffer means in page units. The image processing apparatus according to Configuration 9, characterized in that... [Configuration 11] When the data size of the reversibly compressed data of the processed data of the first image processing for two pages calculated based on the job is equal to or greater than the buffer size, the data size of the reversibly compressed data of the processed data of the first image processing for one page is smaller than the buffer size, and half of the second processing time is shorter than the first processing time, the processing means buffers, in a reversibly compressed manner, one of the processed data of the first image processing for two pages processed in parallel in the buffer means, and buffers the other in the buffer means in band units. The image processing apparatus according to Configuration 9, characterized in that... [Configuration 12] When the data size of the reversibly compressed data obtained by performing reversible compression on the processed data of the first image processing for two pages is equal to or greater than the buffer size of the buffer means, or when half of the second processing time is equal to or greater than the first processing time, the processed data of the first image processing for two pages is buffer-stored in the buffer means by irreversible compression. The image processing apparatus according to Configuration 5, characterized in that... [Configuration 13] Further comprising receiving means for receiving user input. When the data size of the reversibly compressed data obtained by performing reversible compression on the processed data of the first image processing for two pages is equal to or greater than the buffer size of the buffer means, or when half of the second processing time is equal to or greater than the first processing time, it is determined whether to buffer-store the processed data of the first image processing in the buffer means based on the user input received by the receiving means. The image processing apparatus according to Configuration 5, characterized in that... [Configuration 14] The image data for two pages is image data obtained by simultaneously reading both sides of the document. The image processing apparatus according to any one of Configurations 1 to 13, characterized in that... [Configuration 15] A step of acquiring a job for instructing the scanner to read a document. A step of acquiring the read image data of the document read by the scanner according to the job. A step of performing a first image processing for parallel processing of the image data for two pages of the read image data, and a second image processing for sequentially processing the processed data of the first image processing in a predetermined processing unit. A step of temporarily storing the processed data of the first image processing in the processing means. Comprising. The step of performing the processing sets the predetermined processing unit based on a predetermined parameter included in the job and processing speeds of the first image processing and the second image processing. An image processing method characterized by the above. [Configuration 16] A program for causing a computer to function as the image processing apparatus according to any one of Configurations 1 to 14.

Claims

1. Job acquisition means for acquiring a job that instructs the scanner to read a document; Image data acquisition means for acquiring the read image data of the document read by the scanner according to the job; Processing means for performing a first image process for parallel processing of image data for two pages of the read image data, and a second image process for sequentially processing the processed data of the first image process in a predetermined processing unit; Buffer means for temporarily storing the processed data of the first image process in the processing means; Comprising: The processing means sets the predetermined processing unit based on a predetermined parameter included in the job and the processing speeds of the first image process and the second image process. An image processing apparatus characterized by the above.

2. The processing means sets the predetermined processing unit in page units or band units obtained by dividing a page into a plurality of parts. The image processing apparatus according to claim 1, characterized by the above.

3. When the processing means sets the predetermined processing unit as the band unit, in the second image process, the image data for two pages processed in parallel in the first image process is processed alternately in the band unit. The image processing apparatus according to claim 2, characterized by the above.

4. The processing means calculates a first processing time required for the first image process for the image data for two pages of the read image data and a second processing time required for the second image process based on a predetermined parameter included in the job and the processing speeds of the first image process and the second image process. When the second processing time is shorter than the first processing time, the predetermined processing unit is set as the band unit. When the second processing time is equal to or longer than the first processing time, the predetermined processing unit is set as the page unit. The image processing apparatus according to claim 2, characterized by the above.

5. When the processing means sets the page unit as the predetermined processing unit, the storage format for temporary storage in the buffer means is determined according to the data size of the processed data of the first image process and the buffer size of the buffer means. The image processing apparatus according to claim 4, characterized by the above.

6. When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is smaller than the buffer size, the processing means buffers, in an uncompressed manner and in page units, at least the processed data of the first image processing for one page in the buffer means. The image processing apparatus according to claim 5, characterized by the above.

7. When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is smaller than the buffer size, the processing means buffers, in an uncompressed manner and in page units, the processed data of the first image processing for two pages in the buffer means. The image processing apparatus according to claim 6, characterized by the above.

8. When the data size of the processed data of the first image processing for two pages calculated based on the job is equal to or greater than the buffer size, the data size of the processed data of the first image processing for one page is smaller than the buffer size, and half of the second processing time is shorter than the first processing time, the processing means buffers, in an uncompressed manner, one of the processed data of the first image processing for two pages processed in parallel in the buffer means, and buffers the other in the buffer means in band units. The image processing apparatus according to claim 6, characterized by the above.

9. When the data size of the processed data of the first image processing for two pages calculated based on the parameters of the job is equal to or greater than the buffer size, the processing means buffers, in a reversible compression manner and in page units, at least the processed data of the first image processing for one page in the buffer means. The image processing apparatus according to claim 5, characterized by the above.

10. When the data size of the reversibly compressed data obtained by performing the reversible compression on the processed data of the first image processing for two pages is smaller than the buffer size of the buffer means, the processing means performs reversible compression on the processed data of the first image processing for two pages and buffers it in the buffer means in page units. The image processing apparatus according to claim 9, characterized by the above.

11. When the data size of the reversibly compressed data of the processed data of the first image processing for two pages calculated based on the job is equal to or greater than the buffer size, the data size of the reversibly compressed data for one page is smaller than the buffer size, and half of the second processing time is shorter than the first processing time, one of the processed data of the first image processing for two pages processed in parallel is buffer-stored in the buffer means by reversible compression, and the other is buffer-stored in the buffer means in band units. The image processing apparatus according to claim 9, characterized in that.

12. When the data size of the reversibly compressed data obtained by performing reversible compression on the processed data of the first image processing for two pages is equal to or greater than the buffer size of the buffer means, or when half of the second processing time is equal to or greater than the first processing time, the processed data of the first image processing for two pages is buffer-stored in the buffer means by irreversible compression. The image processing apparatus according to claim 5, characterized in that.

13. Further comprising receiving means for receiving user input. When the data size of the reversibly compressed data obtained by performing reversible compression on the processed data of the first image processing for two pages is equal to or greater than the buffer size of the buffer means, or when half of the second processing time is equal to or greater than the first processing time, it is determined whether to buffer-store the processed data of the first image processing in the buffer means based on the user input received by the receiving means. The image processing apparatus according to claim 5, characterized in that.

14. The image data for two pages is image data obtained by simultaneously reading both sides of the document. The image processing apparatus according to any one of claims 1 to 13, characterized in that.

15. Obtaining a job for instructing the scanner to read a document. Obtaining the read image data of the document read by the scanner according to the job. Performing a first image processing for parallel processing of two-page image data of the read image data, and a second image processing for sequentially processing the processed data of the first image processing in a predetermined processing unit. Temporarily storing the processed data of the first image processing in the step of performing the processing. Comprising. The step of performing the processing sets the predetermined processing unit based on a predetermined parameter included in the job and processing speeds of the first image processing and the second image processing. An image processing method characterized by the above.

16. A program for causing a computer to function as the image processing apparatus according to any one of Claims 1 to 13.

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