JP2016100785A - Image processing apparatus, image processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce image processing without causing image degradation in image processing including filter processing.SOLUTION: An image processing apparatus for performing image processing of image data includes: detection means for detecting a white line in PDL data; rendering processing means for rendering the PDL data; filter processing means for performing filter processing using a filter for referring to a plurality of pixels and converting a pixel value for each pixel represented by image data obtained with the rendering processing means; and a step of rendering by skipping part of the white line contained in the PDL data in accordance with a filter size used for the filter processing means.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image processing apparatus and method for performing image processing on image data using filter processing.

  In general, a printer that prints an image on a recording medium converts the image data into print data that can be output by the printer by performing desired image processing on the input image data. In order to speed up image processing, a method is disclosed in which processing for a white region in image data is skipped when the image data includes a white region that does not need to be printed. Such a technique is also called white skip processing. Japanese Patent Application Laid-Open No. 2004-151858 discloses a method of performing image processing by reading an image with a scanner, determining a white line of the read image data, and converting the white line into deleted image data.

JP 2011-199326 A

  However, according to the method disclosed in Patent Document 1, when the image processing includes filter processing, the colors of the two image regions may be mixed at the boundary where the white line is deleted, resulting in image quality degradation. It was.

  Accordingly, an object of the present invention is to reduce image processing without causing image deterioration in image processing including filter processing.

  In order to solve the above-described problems, the present invention provides an image processing apparatus that performs image processing on image data, a detection unit that detects a white line in PDL data, a rendering processing unit that renders the PDL data, and the rendering A filter processing unit that executes a filter process using a filter for converting a pixel value with reference to a plurality of pixels for each pixel represented by image data obtained by the processing unit, and the filter processing unit Rendering is performed by skipping a part of the white line included in the PDL data according to the size of the filter.

  According to the present invention, in image processing including filter processing, image processing can be reduced without causing image degradation.

1 is a block diagram showing an image processing apparatus according to a first embodiment. Block diagram of the RIP processing unit 102 Schematic diagram of image data when skip processing is not performed The figure explaining the process of the RIP process part 102 Schematic diagram of image data after general skip processing Schematic diagram of image data skipped according to the minimum number of white lines 2 Schematic diagram of image data skipped according to minimum number of white lines 4 The figure explaining the image processing apparatus which concerns on 2nd Embodiment. The block diagram which shows the whole structure of the image processing apparatus which concerns on 3rd Embodiment. Block diagram of the scanner image processing unit 902 The flowchart explaining operation | movement of the image processing apparatus which concerns on 1st Embodiment. The figure which shows an example of skip information The block diagram which shows the image processing apparatus which concerns on 2nd Embodiment. The block diagram which shows the image processing apparatus which concerns on 4th Embodiment The figure which shows an example of a filter

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, the structure shown in the following Examples is only an example, and this invention is not limited to the structure shown in figure.

<First Embodiment>
(overall structure)
FIG. 1 is a block diagram showing the overall configuration of an image processing apparatus applicable to the first embodiment of the present invention. In this embodiment, the image processing apparatus includes a PDL processing unit 101, a RIP processing unit 102, a CPU 103, an image processing unit 104, and a printing unit 105.

  The PDL processing unit 101 analyzes data (hereinafter referred to as PDL data) described in a page description language (PDL) included in a print job from a PC or the like (not shown). The PDL data includes an image forming command for one page. The PDL processing unit 101 interprets an image formation command of PDL data and generates intermediate data such as a display list (DL) indicating an object to be drawn. The generated intermediate data is temporarily stored in a memory (not shown).

  The RIP processing unit 102 generates raster format image data (hereinafter referred to as raster image data or image data) from the intermediate data obtained as a result of analysis by the PDL processing unit 101. The RIP processing unit 102 includes a skip suppression register 110, and the skip suppression register 110 stores the minimum number of white lines. The RIP 102 skips some white lines when generating raster image data for each line from the intermediate data according to the minimum number of white lines. The skip processing means that the rendering processing of a line that satisfies a specific condition (here, a white line) is skipped. That is, some lines are omitted from the raster image data output from the RIP processing unit 102. Originally, the number of lines constituting the image data for one page is L, and if white processing of the number of lines M is skipped, the number of lines of raster image data becomes LM. In addition, the RIP processing unit 102 generates skip information indicating the skipped line position. Note that a line means one row in the main scanning direction (horizontal direction) in an image for one page. For example, when the image data is composed of 256 pixels × 512 pixels, one line is 1 × 256 pixels. Details of processing in the RIP processing unit 102 will be described later.

  The CPU 103 sets parameters necessary for processing in the image processing unit 104. Further, the minimum number of white lines is generated according to the size of the filter used for image processing 104 described later, and stored in the skip suppression register 110. Details of the minimum number of white lines and the CPU 103 will be described later.

  The image processing unit 104 receives the image data generated by the RIP processing unit 102 and performs various types of image processing such as filter processing, scaling processing, color conversion processing, and halftone processing. In particular, in the present embodiment, the image processing unit 104 includes a first filter processing unit 106 and a second filter processing unit 107. The filter processing is processing for converting the pixel value of the target pixel for each pixel represented by the image data based on the pixel value of the target pixel and the pixel values of the peripheral pixels of the target pixel. A filter is used to convert a pixel value with reference to a plurality of pixels. The first filter processing unit 106 performs filter processing using a filter having a 3 × 3 filter size as shown in FIG. The second filter processing unit 107 performs filter processing using a 5 × 5 filter size as shown in FIG. The filter process is a process of calculating the pixel value of the target pixel by a product-sum operation of filter coefficients corresponding to the target pixel and neighboring pixels. Accordingly, the pixel value of the target pixel after the filter processing is given a value that refers to the pixel value of the neighboring pixel determined by the filter size.

  Based on the skip information output from the CPU 103, the printing unit 105 restores the skipped white line for the image data that has been subjected to various types of image processing by the image processing unit 104. Then, the image data for one page after the white line restoration is printed on the recording medium.

(Detailed description of the RIP processing unit 102)
Next, details of the RIP processing unit 102 will be described. FIG. 2 is a block diagram illustrating a detailed configuration of the RIP processing unit 102. The object dividing unit 201 inputs intermediate data (PDL analysis result) generated by the PDL processing unit 101. The intermediate data indicates a plurality of pieces of object information (color, coordinates, etc.). The object dividing unit 201 divides a plurality of object information for each line of the image and outputs the divided object information.

  Based on the object information generated by the object dividing unit 201, the white line determination unit 202 determines whether one line (hereinafter referred to as a target line) as a determination target is a white line. As a specific determination method, when there is no edge in the object of the target line and the color is white, it is determined that the target line is a white line. In addition, as a modified example of the determination method, the determination may be performed using another known technique.

  The white line counter 203 is incremented when the white line determination unit 202 determines that the target line is a white line. That is, the number of consecutive white lines is counted. On the other hand, if the white line determination unit 202 determines that the target line is not a white line, it is initialized to zero.

  The skip suppression register 206 stores the minimum number of white lines calculated by the CPU 103. The minimum number of white lines indicates the number of white lines that must be kept at a minimum when the RIP processing unit performs skip processing. The minimum number of white lines is used by the comparison unit 204 and the skip processing unit 205 described later.

  The comparison unit 204 compares the value of the white line counter 203 with the minimum number of white lines. As a result of the comparison, when the value of the white line counter 203 is larger than the minimum number of white lines, the comparison unit 204 outputs TRUE indicating that the number of continuous white lines exceeds the minimum number of lines that need to be left. On the other hand, when the minimum white line is equal to or smaller than the value of the color line counter 203, the comparison unit 204 outputs FALSE indicating that the number of continuous white lines does not exceed the minimum number of lines that need to be left or is not a white line. Output.

  The rendering processing unit 205 inputs the object information of the target line generated by the object dividing unit 201. Then, either the skip process or the image data generation process is executed for each line according to the comparison result in the comparison unit 204. When TRUE is output from the comparison unit 204 (that is, the target line is a white line and greater than the minimum number of white lines), the rendering processing unit 205 skips without generating image data of the target line. If FALSE is output from the comparison unit 205 (that is, the target line is not a white line, or a white line and the number of white lines is equal to or less than the minimum number of white lines), the rendering processing unit 205 generates image data of the target line and stores it in a memory (not shown). ).

  In addition, the rendering processing unit 205 generates skip information indicating whether or not the target line is skipped. When the rendering processing unit 205 skips generation of the image data of the target line (the output of the comparison unit 204 is TRUE), the skip information is set to 1. When the image data is generated without skipping (the output of the comparison unit 204 is FALSE), the skip information is set to 0. That is, the skip information indicates information of 0 or 1 corresponding to the number of lines H of image data for one page. Note that the skip information is stored in a memory (not shown).

(About the generation method of the minimum white line information according to the filter size)
Next, the minimum white line information generated by the CPU 103 will be described. As described above, the skip process is a technique of skipping (omitting) a white line when the rendering unit 205 generates image data. Assume that the PDL data of the image shown in FIG. 3 is input. Conventionally, as shown in FIG. 5, there is a method of performing rendering processing by skipping (omitting) all the lines detected as white lines in the image shown in FIG. As can be seen from the rendering result of FIG. 5, the white areas A to C are skipped, and the object in the object area A and the object in the object area B are adjacent to each other. When the image data shown in FIG. 5 is filtered, the filtering process is performed across two object areas separated by the white skip area. For this reason, the pixel values of the triangular object in the object area A and the square object in the object area B are mixed to cause image quality degradation.

  Therefore, in the present embodiment, the RIP processing unit 102 performs skip processing according to the filter processing. The CPU 103 calculates the minimum number of white lines according to the filter size, and the RIP 102 skips only white lines that exceed the minimum number of white lines. However, it is important that the minimum number of white lines is calculated from the maximum filter size in the image processing unit 104. The reason is as follows. As an example, it is assumed that the maximum filter size among the filter processes included in the image processing unit 104 is 5 (5 × 5 filters). FIG. 6 is a diagram schematically illustrating filter processing for image data when skip processing is performed in accordance with the minimum number of white lines 2. In the case of performing a filtering process with a 3 × 3 filter size as shown in FIG. 15A, if the number of white lines is three or more, pixel values of different objects between object areas are not mixed. However, as shown in FIG. 6, even if two white areas exist between the object area A and the object area B, the 5 × 5 filter straddles the object.

  FIG. 7 is a diagram schematically illustrating filter processing on image data skipped according to the minimum number of white lines 4 (5-1) corresponding to the filter size 5. Since the minimum number of white lines is 4, four white lines in the white area B are left and skip processing is performed. In this case, as shown in FIG. 7, even if the pixel processing is performed on the pixel located at the boundary of the object region, the pixel values of the triangular object and the square object are not mixed.

  Thus, when there are a plurality of filter processes included in the image processing unit 104, the minimum number of white lines is calculated using the maximum filter size. This prevents pixel values of different objects from being mixed as a result of skipping the white line at the boundary of the object area separated by the white line.

(Overall operation)
Next, the operation of the image processing apparatus according to the first embodiment will be described using the flowchart shown in FIG.

  First, in step S1101, the CPU 103 acquires the filter size used for the filter processing included in the image processing unit 104, and specifies the maximum filter size. In the image processing unit 104 in the present embodiment, the maximum filter size 5 corresponding to the 5 × 5 filter processing unit 107 is acquired.

In step S1102, the CPU 103 calculates the minimum number of white lines according to the equation (1). For example, when the maximum filter size is 5, the minimum number of white lines is 4 (5-1).
MIN_LINE = F_SIZE-1 (1)
MIN_LINE: Minimum number of white lines F_SIZE: Maximum filter size Next, in step S1103, the CPU 103 sets the minimum number of white lines to 4 in the skip suppression register 110 in the RIP processing unit. The above is the description of the initial setting by the CPU 103.

  Next, operations from the PDL processing unit 101 to the RIP processing unit 102 will be described. In step S1104, the PDL processing unit 101 analyzes PDL data included in a print job from a PC (not shown) and generates intermediate data. In step S1105, the RIP processing unit 102 generates raster format image data for each line based on the intermediate data. When the line of interest is a white line and the number of consecutive white lines is greater than the minimum number of white lines, the generation of the image data of the line of interest is skipped. Otherwise, if the target line is not a white line, or if the number of white lines and the number of consecutive white lines is equal to or less than the minimum number of white lines, image data of the target line is generated.

  In step S1106, the RIP processing unit 102 generates skip information according to the skip processing. The skip information is represented by a binary value of 1 bit for each line. In the case of the skip information shown in FIG. 12, since the 3 lines from the top and the 2 lines from the bottom are 0, this indicates a line that has not been skipped. Since the other three lines are 1, this indicates a line that has been skipped. The above is the description of the operation from the PDL processing unit 101 to the RIP processing unit 102.

  Here, the progress of the rendering process according to the present embodiment will be described with reference to FIGS. The object information input from the PDL processing unit 101 is assumed to be composed of the 18-line white background object, the triangular object (shaded portion), and the square object (vertical line portion) shown in FIG. The minimum number of white lines is 2.

  When skip processing is not performed under this condition, the raster image data after rendering is as shown in FIG. It is composed of white areas A to C made up of white lines, an object area A in which a triangular object exists, and an object area B in which a square object exists, and becomes 18-line image data.

  Next, the results of processing performed by the RIP processing unit 102 in the present embodiment under the same conditions will be described with reference to FIGS. First, the RIP processing unit 102 processes the white area A (line number 0) shown in FIG. Since the number of continuous white lines is 1, the white line counter 203 indicates 1. In this case, since the white line counter 203 has a minimum number of white lines of 2 or less, the line number 0 is not skipped. That is, the RIP processing unit 102 generates image data with line number 0 as it is. Also, 0 is added to the skip information for one line to indicate that the corresponding line has not been skipped. As a result, the image data shown in FIG. 4A is stored in the memory.

  Next, the object area A (line numbers 1 to 5) shown in FIG. 3 is processed. Since no white line exists in the object area A, the white line counter 203 indicates 0. In this case, the white line counter 203 is not skipped because the minimum number of white lines is 2 or less. That is, the RIP processing unit 102 generates image data with line numbers 1 to 5. Further, in order to indicate that the corresponding line is not skipped, 0 is added to the skip information for five lines. As a result, the image data shown in FIG. 4B is stored in the memory, and the skip information is updated.

  Next, the white area B (line numbers 6 to 10) shown in FIG. 3 is processed. First, the processing of line numbers 6 and 7 will be described. When the line numbers 6 and 7 are processed, the continuous white lines are 1 and 2, respectively. Therefore, the white line counter 203 indicates 1 when the line number 6 is processed and 2 when the line number 7 is processed. In this case, since the white line counter 203 is equal to or smaller than the minimum number of white lines 2, neither the line numbers 6 and 7 are skipped, and the RIP processing unit 192 generates image data of the line numbers 6 and 7. Further, in order to indicate that the line numbers 6 and 7 are not skipped, 0 is added to the skip information for two lines. Processing for line numbers 8 to 10 will be described. Since the number of continuous white lines is 3 to 5 when continuing from line number 7, white line counter 203 is 3 when processing line number 8, 4 when processing line number 9, and 5 when processing line number 10. Indicates. In this case, since the white line counter 203 is larger than the minimum number of white lines 2, skip processing is performed when line numbers 8 to 10 are the target lines. That is, the RIP processing unit 102 does not generate image data of line numbers 8, 9, and 10. Also, 1 is added to the skip information for three lines to indicate that the lines with the line numbers 8, 9, and 10 are skipped. As a result, the image data shown in FIG. 4C is stored in the memory, and the skip information is updated.

  Next, the object area B (line numbers 11 to 13) shown in FIG. 3 is processed. Since no white line exists in the object area B, the white line counter 203 indicates 0. In this case, since the white line counter 203 has a minimum number of white lines of 2 or less, the line numbers 11 to 13 are not skipped. That is, the RIP processing unit 102 forms the image data of line numbers 11, 12, and 13 in FIG. 3, and stores the image data of line numbers 8, 9, and 10 in the memory in the raster image data. Also, in order to indicate that the line numbers 11 to 13 are not skipped, three lines of 0 are added to the skip information. As a result, the image data and skip information shown in FIG.

  Next, the white area C (line numbers 14 to 17) shown in FIG. 3 is processed. First, the processing of line numbers 14 and 15 will be described. When the line numbers 14 and 15 are processed, the number of continuous white lines is 1, 2, respectively. Therefore, the white line counter 203 indicates 1 when the line number 14 is processed and 2 when the line number 15 is processed. In this case, since the white line counter 203 has a minimum number of white lines of 2 or less, the line numbers 14 and 15 are not skipped. That is, the RIP 102 forms image data with line numbers 14 and 15, and stores the image data with line numbers 11 and 12 in the raster image data in the memory. Further, 0 is added to the skip information for two lines to indicate that the lines with the line numbers 14 and 15 are not skipped. Next, processing of line numbers 16 and 17 in FIG. 3 will be described. When the line numbers 16 and 17 are processed, the number of continuous white lines is 3 and 4 when continuing from the line number 12, respectively. Therefore, the white line counter 203 indicates 3 when processing the line number 16 and 4 when processing the line number 17. In this case, since the white counter 203 is larger than the minimum number of white lines 2, line numbers 16 and 17 are skipped. That is, the RIP processing unit 102 does not form image data with line numbers 16 and 17. Further, 1 for two lines is added to the skip information to indicate that the corresponding line is skipped. As a result, raster image data and skip information shown in FIG. 4 are obtained.

  As described above, the output image data when processed by the RIP processing unit 102 is finally 13-line image data as shown in FIG. That is, 5 lines out of 18 lines are output as skipped image data.

  Next, returning to FIG. 11, the operation from the image processing unit 104 to the printing unit 105 will be described. In step S1108, the image processing unit 104 performs image processing on the raster image data after rendering processing including skip processing. In the image processing 104, only the first filter processing unit 106 and the second filter processing unit 107 are shown in FIG. 1 for simplicity of explanation, but other scaling processing, color conversion processing, halftone processing, etc. Is also done. If there is a scaling process, the skip information is also scaled. In step S <b> 1109, the printing unit 105 acquires the image data generated by the image processing unit 104, and restores the skipped white line based on the skip information acquired from the RIP processing unit 102. The printing unit 105 prints an image on a recording medium based on the restored image data. As described above, according to the present embodiment, the white line amount of skip processing in rendering is adjusted according to the filter size used for the filter processing in the image processing unit 104. As a result, it is possible to suppress image degradation caused by the filter processing resulting from the skip processing.

  Note that the skip information in the present embodiment is data in which 1 or 0 continues. Therefore, it goes without saying that a significant reduction in the amount of data can be expected by compressing the data by a compression method such as run length compression. Further, in the present embodiment, the white line has been described as a skip processing target, but a line composed of a single pixel value (for example, black) may be skipped. Alternatively, it is possible to detect a white line including pixels including noise by setting a white line by regarding a pixel value of a predetermined value (for example, 2) or less as a white pixel.

Second Embodiment
FIG. 13 is a block diagram showing the overall configuration of an image processing apparatus according to the second embodiment of the present invention. In the first embodiment, the CPU 103 directly sets each parameter in the image processing unit 104. In the second embodiment, an example in which the control unit 1309 is provided in the image processing unit 1304 will be described. In addition, the CPU 1303 in the second embodiment applies to the image processing submodule 1308 of the image processing unit 1304 (in FIG. 13, the first filter processing unit 1306 and the second filter processing unit 1307) via the control unit 1309. , Has a configuration that can be set through. The processing unit in the image processing submodule 1308 set to through does not perform any processing and outputs the input as it is. In this way, the image processing submodule 1308 used in the image processing unit 104 can be selected according to the use case (mode). For example, in mode A, neither the first filter processing unit 1306 nor the second filter processing unit 1307 is set to through, and in mode B, the second filter processing unit 1307 is set to through. That is, in mode A, only the first filter processing 1306 using a filter of 3 × 3 filter size is performed on the raster image data. Note that reference numerals 1301 to 1302 and reference numerals 1305 to 1307 in FIG. 13 have the same configurations as the reference numerals 101 to 102 and 105 to 107 in FIG.

  In the first embodiment, the CPU 103 acquires the maximum filter size among the circuit configurations in the first filter processing 106 and the second filter processing 107. This is because the minimum number of white lines input to the RIP processing unit 102 does not change even if the use case changes, and thus the synchronization between the RIP processing unit 102 and the image processing unit 104 is simplified. However, depending on the use case, redundant processing may be performed in the first embodiment. For example, both the first filter processing unit 106 and the second filter processing unit 107 are used in mode A, and only the first filter processing unit 106 is used in mode B. In this case, in the first embodiment, the minimum number of white lines is always set to 4 in accordance with the second filter processing 107, but the minimum number of white lines 4 is the optimum value for mode A and the optimum for mode B. Not a value. Therefore, in the second embodiment, a method for enabling the minimum number of white lines corresponding to the maximum filter size to be set more adaptively according to the mode will be described.

(How to calculate the minimum number of white lines)
A method for calculating the minimum number of white lines in the CPU 1303 will be described below. However, only differences from the first embodiment will be described. First, the CPU 1303 acquires a use case in the image processing unit 1304. The maximum filter size is acquired from the image processing submodule 1308 used in the acquired use case. For example, only the processing unit that is not set to the through setting in the image processing submodule 1308 may be picked up and the maximum filter size may be acquired. Next, the CPU 1303 calculates the minimum number of white lines according to the equation (1). The subsequent operation is the same as the operation of the CPU 103 described in the first embodiment, and is omitted.

(Synchronization of RIP processing unit 1302 and image processing unit 1304)
The RIP processing unit 1302 and the image processing unit 1304 have different timings for executing processing on the same image. For this reason, in order to efficiently switch the minimum number of white lines given to the RIP processing unit 1302, it is necessary to pay attention to the switching timing. For example, FIG. 8A is a diagram illustrating a case where the value of the minimum number of white lines is switched at the same timing as the timing of switching from mode B to mode A during the processing of the image processing unit 1304. In such a case, the value of the minimum number of white lines set in the RIP processing unit 1302 is switched after a predetermined time after the print instruction corresponding to mode A is input. Therefore, during the NG period shown in FIG. 8A, skip processing is performed on the image data corresponding to mode A based on the minimum number of white lines corresponding to mode B. As a result, the image quality may be deteriorated as well as processing redundant data.

  In order to avoid the above, for example, as shown in FIG. 8B, the value of the minimum number of white lines is set at the timing when the RIP processing unit 1302 switches from the process corresponding to mode B to the process corresponding to mode A. It is better to switch. This prevents the skip processing corresponding to mode B from being performed on the image data corresponding to mode A.

  As described above, according to the present embodiment, it is possible to cope with the case where the maximum value of the filter size to be used varies depending on the use case (mode). In other words, the amount of white lines during skip processing is adjusted according to the filter size of image processing associated with the use case. Thereby, image degradation due to skip processing can be suppressed.

<Third Embodiment>
In the first embodiment, the PDL processing unit 101 and the RIP processing unit 102 are mounted. However, according to the minimum number of white lines, there is a condition for adjusting the amount of white lines during skip processing and outputting skip information. It is important that That is, the same embodiment can be realized even if the scanner system image processing (image processing is performed on the data captured by the scanner) satisfying the above conditions instead of the PDL processing unit 101 and the RIP processing unit 102. An example of the configuration is shown below.

(overall structure)
FIG. 9 is a block diagram showing an overall configuration of an image processing apparatus applicable to the third embodiment. A configuration different from FIG. 1 showing the overall configuration of the first embodiment is an image acquisition unit 901, a scanner image processing unit 902, and a CPU 903. The other reference numerals 904 to 907 are the same as the reference numerals 104 to 107 shown in FIG.

  The image acquisition unit 901 acquires image data obtained by reading a document using a line image sensor (not shown). A scanner image processing unit 902 corrects, processes, and edits the read image data acquired by the image acquisition unit 901. For example, shading correction, character processing, noise removal, and the like. In addition to the above, the scanner image processing 902 performs skip processing based on the minimum number of white lines output from the CPU 903. Also, the scanner image processing unit 902 generates skip information indicating the skipped line position. Details of the scanner image processing unit 902 will be described later.

  The CPU 903 performs the same operation as the CPU 103 of the first embodiment. However, since the scanner image processing unit 902 may include filter processing, it is necessary to generate the minimum number of white lines with the maximum filter size in the print image processing 904 and the scanner image processing 902.

(Scanner image processing unit 902)
Next, details of the scanner image processing unit 902 will be described with reference to the block diagram of FIG. A shading correction unit 1001 flatly corrects unevenness in the main scanning direction of image data acquired by the image acquisition unit 901.

  The skip processing unit 1002 deletes white lines so that the number of continuous white lines does not exceed the minimum number of white lines calculated by the CPU 903 with respect to the white lines of the image data corrected by the shading correction unit 1001. In addition, skip information is generated accordingly. The skip information is the same as the skip information described in the first embodiment.

  The image processing unit 1003 includes an image processing submodule group (not shown), and performs image processing such as character processing and noise removal on the image data after skip processing generated by the skip processing unit 1002.

  As described above, according to the present embodiment, the pre-processing of the image processing unit 904 adjusts the amount of white lines during skip processing according to the minimum number of white lines, and is accompanied by a condition for outputting skip information. Good. That is, it is possible to provide an image processing apparatus that suppresses image degradation due to skip processing by adjusting the amount of white lines during skip processing in scanner image processing as in this embodiment.

<Fourth embodiment>
FIG. 14 is a block diagram showing an overall configuration of an image processing apparatus applicable to the fourth embodiment.

  A difference from FIG. 1 showing the overall configuration of the first embodiment is that a minimum white line number calculation unit 1411 and a skip information conversion unit 1412 are mounted in the image processing 1404. Another difference is that the minimum white line number calculation unit 1411 writes directly to the skip suppression register 1410. Another difference is that the skip information generated in the RIP process 1402 is input to the skip information conversion unit 1412. The other reference numerals 1401 to 1410 have the same configurations as the reference numerals 101 to 110 shown in FIG.

  In the first embodiment, the CPU 103 calculates the minimum number of white lines from the filter size of the image processing unit 104. In the second embodiment, when the skip information changes in accordance with the use case of the print image processing unit 104, the CPU 103 handles it. Therefore, the CPU 103 is indispensable for the synchronization between the RIP processing 102 and the image processing unit 104.

  In the fourth embodiment, a method for synchronizing RIP processing and print image processing without a CPU will be described.

  The minimum white line number calculation unit 1411 acquires the filter size of the image processing unit 1404 and calculates the minimum number of white lines using Expression (1). Then, the minimum white line number is stored in the skip suppression register 1410.

  The skip information conversion unit 1412 receives the skip information output from the RIP processing unit 1402. And when skip information changes with a use case, it responds to it. For example, when there is a scaling process, the skip information is also scaled.

  As described above, according to the fourth embodiment, it is possible to synchronize data between the RIP processing unit 1402 and the print image processing unit 1404 without the CPU 1403.

<Other embodiments>
In the above-described embodiment, the line that is the target of the skip processing executed by the rendering processing unit and the scanner image processing unit has been described as a white line. However, the specific condition to be skipped can be applied to lines other than white pixels. For example, by setting a specific condition that is a target of the skip process as a line composed of black pixels, the black line is a target of the skip process. A specific line set as a target of the skip process is detected, and the minimum number of specific lines is calculated according to the filter size used for the subsequent filter process. The rendering processing unit and the scanner image processing unit perform the skip processing according to the minimum number of specific lines, so that the same effect as that of the above-described embodiment can be obtained.

  In addition, the present invention supplies 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 one or more processors in a computer of the system or apparatus read the program. It can also be realized by processing to be executed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101 PDL processing obtaining unit 102 RIP processing unit 103 CPU
104 Image processing unit 105 Printing unit 106 3 × 3 filter processing unit 107 5 × 5 filter processing unit 110 Skip suppression register

Claims (10)

An image processing apparatus that performs image processing on image data,
Detecting means for detecting white lines in the PDL data;
Rendering processing means for rendering the PDL data;
Filter processing means for executing filter processing using a filter for converting pixel values with reference to a plurality of pixels for each pixel represented by image data obtained by the rendering processing means;
An image processing apparatus that performs rendering by skipping a part of a white line included in PDL data in accordance with a size of a filter used in the filter processing unit.   The rendering processing unit sets the minimum number of white lines according to the size of the filter used in the filter processing unit, and when the white lines continue more than the minimum number of white lines, the minimum number of white lines is exceeded. The image processing apparatus according to claim 1, wherein the rendering processing is skipped for the white lines corresponding to the number of white lines. The image processing means includes a plurality of filter processing means having different filter sizes,
The image processing apparatus according to claim 1, wherein the setting unit sets the minimum number of white lines based on a maximum filter size among the plurality of filter processing units. Furthermore, it has an input means for inputting a mode for executing at least two different image processes,
The image processing means includes a plurality of filter processing means having different filter sizes,
The mode is a mode in which filter processing means used for image processing among the plurality of filter processing means is different,
The image processing apparatus according to claim 1, wherein the setting unit sets a minimum number of white lines according to the mode.   The image processing apparatus according to claim 1, wherein the setting unit sets the minimum number of white lines based on the maximum filter size−1. Furthermore, it has a printing means for printing an image on a recording medium based on the image processed image data obtained from the image processing means,
The rendering processing unit generates skip information indicating whether or not each line is skipped,
The image processing apparatus according to claim 1, wherein the printing unit performs printing after restoring the image processed image data based on the skip information. An image processing apparatus that reads an image on a recording medium and performs image processing for printing the image on the recording medium based on the read image,
Reading means for reading an image on a recording medium;
First image processing means for executing image processing according to the reading means on the image data read by the reading means;
Detecting means for detecting a white line in the image data read by the reading means;
Filter processing means for executing filter processing using a filter for converting a pixel value with reference to a plurality of pixels for each pixel represented by image data obtained from the first image processing means;
An image processing apparatus that performs image processing by skipping a part of white lines included in image data read by the reading unit in accordance with a size of a filter used in the filter processing unit. An image processing apparatus that performs image processing on image data,
Detecting means for detecting a specific line having a predetermined pixel value in the PDL data;
Rendering processing means for rendering the PDL data;
Filter processing means for executing filter processing using a filter for converting pixel values with reference to a plurality of pixels for each pixel represented by image data obtained by the rendering processing means;
An image processing apparatus that performs rendering while skipping a part of a specific line included in PDL data according to a size of a filter used in the filter processing unit.   A computer program for causing a computer to function as the image processing apparatus according to any one of claims 1 to 8 by being read and executed by a computer. An image processing method for performing image processing on image data,
Detect white lines in PDL data,
A rendering process for rendering the PDL data;
For each pixel represented by the image data obtained by the rendering process, a filter process using a filter for converting a pixel value with reference to a plurality of pixels is performed,
An image processing method characterized by skipping a part of a white line included in PDL data in accordance with a size of a filter used for the filter processing.

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