JP2015186075A - image processing method and image processing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate high-compression image data of which the data capacitance is suppressed, in an image processing apparatus 1.SOLUTION: The image processing apparatus 1 includes a control section 2 and a scanner 7. The control section 2 includes: an image separation part 22 for separating image data ID inputted from the scanner 7 into mask data MD, foreground data FD and background data BD; a temporary compression processing part 25 for temporarily compressing the data MD, FD and BD; a compressibility determination part 26 for determining compression rates CR of the data MD, FD and BD; a compression processing part 27 for compressing the data MD, FD and BD using the compression rates CR; and a high-compression PDF generation part 28 for generating a high-compression PDF file PD from the compressed data MD. FD and BD. In the case where capacitances of the data MD, FD and BD compressed by the temporary compression processing part 25 are equal to or more than a predetermined threshold, the compression is performed in the compression processing part 27 while improving the compression rates of the data MD, FD and BD.

Description

  The present invention relates to an image processing method and an image processing apparatus for compressing and converting image data.

  In an image processing apparatus that generates and saves image data by an operation of a user who is a user, it is common to compress and save the image data in order to prevent the storage medium from being compressed by the saved image data. Has been done. Recently, for the purpose of high compression ratio and high image quality, it has been developed by the High Compression PDF (Portable Document Format; Adobe Systems) that separates character information and background image information in image data and compresses them with appropriate methods. Format for electronic documents) is becoming widespread.

  Conventionally, for example, Patent Document 1 and the like describe an image processing apparatus for satisfactorily creating a high-compression PDF. This image processing apparatus can appropriately separate character information and background image information in image data by emphasizing and emphasizing character information in image data.

JP 2000-194857 A

  However, in the conventional image processing method and image processing apparatus, when the character information becomes complicated and the data capacity of the character information increases, the data capacity of the high-compression image data also increases, and there is a problem that the storage medium is compressed. It was.

  An image processing method according to a first aspect of the present invention is an image processing method for converting image data into a file of a predetermined file format, the processing type for the input image data, and the type of the image data A user setting acceptance process for accepting an image processing mode to be set from a user, an image separation process for separating the image data into a plurality of separated image data, and the plurality of separated image data as types of the image data. To compress each of the plurality of separated image data in accordance with a temporary compression process for compressing each using a corresponding set compression rate and a total data capacity of the plurality of separated image data compressed in the temporary compression process A compression rate determination process for determining a plurality of recompression rates, a compression process for compressing each of the plurality of separated image data using the recompression rate, and the pressure Said plurality of separation image data compressed in the process, and having a, a file generation processing that generates the file is converted into the predetermined file format.

  An image processing apparatus according to a second aspect of the present invention is an image processing apparatus that converts image data into a file of a predetermined file format, the image data input unit for inputting the image data, the processing type for the image data, A user setting receiving unit that receives an image processing mode for setting the type of image data from a user, an image separating unit that separates the image data into a plurality of separated image data, and the plurality of separated image data Temporary compression processing units that respectively compress using a set compression rate corresponding to the type of data, and the plurality of separated images according to the total data capacity of the plurality of separated image data compressed by the temporary compression processing unit A compression rate determining unit that determines a plurality of recompression rates for compressing each of the data; and compressing the plurality of separated image data using the recompression rate, respectively. A compression processing section, the plurality of separating the image data compressed by the compression processing section, and having a, a file generation unit for converting the predetermined file format to generate the file.

  An image processing apparatus according to a third aspect of the present invention is an image processing apparatus that converts image data into a file of a predetermined file format, the image data input unit for inputting the image data, the processing type for the image data, A user setting receiving unit that receives an image processing mode for setting the type of image data from a user, an image separating unit that separates the image data into a plurality of separated image data, and the plurality of separated image data A temporary file generation unit that compresses each using a plurality of different set compression rates corresponding to the type of data, converts them into the predetermined file format, and generates a plurality of the files for each of the plurality of different set compression rates; A user designation receiving unit that displays the plurality of files and allows a user to designate a file to be output from the plurality of files. And wherein the door.

  According to the image processing method and the image processing apparatus of the present invention, when the data capacity of the compressed image data is equal to or greater than a certain threshold, the image data is compressed again by increasing the compression rate, and the high-compression image data is output. To do. As a result, at the time of data compression, it is possible to separate character information and background image information in the image data and compress them at an appropriate compression rate. Therefore, highly compressed image data with a reduced data capacity can be output.

FIG. 1 is a schematic configuration diagram showing an image processing apparatus 1 for generating the highly compressed PDF of FIG. FIG. 2 is a diagram illustrating a process of generating a highly compressed PDF according to the first embodiment of the present invention. FIG. 3 is a diagram showing the operation panel 8 in FIG. FIG. 4 is a flowchart showing an image processing method of the image processing apparatus 1 of FIG. FIG. 5 is a flowchart showing details of the temporary compression processing in step S4 in FIG. FIG. 6 is a flowchart showing details of the compression rate determination process in step S5 in FIG. FIG. 7 is a diagram showing the compression rate for each document type in steps S58 to S60 in FIG. FIG. 8 is a schematic configuration diagram showing an image processing apparatus 1A according to the second embodiment of the present invention. FIG. 9 is a diagram showing a preview display screen 86 displayed on the operation panel 8 in FIG. FIG. 10 is a flowchart showing an image processing method of the image processing apparatus 1A of FIG.

  Modes for carrying out the present invention will become apparent from the following description of the preferred embodiments when read in light of the accompanying drawings. However, the drawings are only for explanation and do not limit the scope of the present invention.

(Configuration of Example 1)
FIG. 2 is a diagram illustrating a process of generating a highly compressed PDF according to the first embodiment of the present invention.

  In the separation process ST1, the image data ID input to the image processing apparatus such as a scanner includes mask data MD obtained by extracting the outline of the character in the image data ID, and foreground data obtained by extracting the color of the character portion in the image data ID. The image data is separated into FD and background data BD obtained by extracting a part other than characters in the image data ID. In the compression process ST21, since the mask data MD is binary data, it is compressed by, for example, an MMR (Modified Modified READ: relative element address designate) encoding method suitable for binary data. In the compression process ST22, the foreground data FD is multi-value data, and is compressed by, for example, a JPEG (Joint Photographic Experts Group) method suitable for multi-value data. In the compression process ST23, the background data is multi-value data, and is compressed by, for example, a JPEG (Joint Photographic Experts Group) method suitable for multi-value data. Thereafter, in the combining process ST3, the compressed mask data MD, foreground data FD, and background data BD are combined to generate a highly compressed PDF file PD.

  1A and 1B are configuration diagrams showing an outline of the image processing apparatus 1 for generating the high-compression PDF of FIG. 2, and FIG. 1A shows an outline of the entire image processing apparatus 1. The configuration diagram and FIG. 4B are configuration diagrams showing the function of the control unit 2 in FIG.

  An image processing apparatus 1 shown in FIG. 1A is configured by, for example, a digital color multifunction peripheral (MFP). The image processing apparatus 1 has a control unit 2 for program-controlling the entire apparatus. The control unit 2 includes a central processing unit (hereinafter referred to as “CPU”) 3, a read only memory (hereinafter referred to as “ROM”) 4, and a random access memory (hereinafter referred to as “RAM”) 5. ing.

  The CPU 3 is a device that performs image processing control such as temporary storage of an image data ID and conversion to a highly compressed PDF file PD by calculating and executing an image processing program stored in the ROM 4. The ROM 4 is a device for storing an image processing program, various setting values, and the like, and is a read-only nonvolatile memory. The RAM 5 is a device for reading and temporarily storing an image processing program stored in the ROM 4 and is a volatile memory that can be read and written.

  A system bus 6 including a data bus, an address bus, and a control bus is connected to the control unit 2. The system bus 6 includes a scanner 7, an operation panel 8, a hard disk drive (hereinafter referred to as “HDD”) 9 as a storage medium, an external interface (hereinafter referred to as “external I / F”) 10, and image formation. A printer 11 as an apparatus is connected. For example, a personal computer (hereinafter referred to as “PC”) 12 serving as a host device for issuing a print instruction or the like to the image processing apparatus 1 is connected to the external I / F 10.

  The scanner 7 is a device that reads an image on a recording medium (for example, paper) and converts it into an image data ID, and includes, for example, a mounting table, an automatic document feeder, a light source, a light receiving device, and a signal processing unit. ing. The scanner 7 emits light from a light source to an image on a sheet placed on a mounting table or an image on a sheet conveyed by an automatic document feeder, and a light receiving element receives the reflected light. It has a function of reading as an image signal. Further, in the scanner 7, the signal processing unit performs signal processing such as analog / digital conversion (A / D conversion) on the read image signal, and red (R), green (G), and blue (B). (Hereinafter referred to as “RGB format”) of image data ID.

  The operation panel 8 is a device for transmitting a control signal for starting / interrupting image reading and the like, selecting various settings, and displaying a menu or message from the control unit 2 according to a user operation. The HDD 9 stores the image data ID acquired from the scanner 7, the high-compression PDF file PD converted by the control unit 2, and input information set from the operation panel 8. Auxiliary recording device.

  The external I / F 10 has a function of communicatively connecting the control unit 2 and the PC 12 to the PC 12, for example, a USB (Universal Serial Bus) standard interface (hereinafter referred to as “I / F”), TCP / IP, or the like. It is configured by a network I / F such as (Transport Control Protocol / Internet Protocol). The printer 11 is, for example, an electrophotographic page printer. When a print instruction is received from the PC 12 via the external I / F 10, the cyan color (C) that can be expressed by a developer according to RGB image data in the print instruction. ), Magenta (M), yellow (Y), and black (K) formats to form a developer image on the paper.

  The control unit 2 shown in FIG. 1B includes an image data input unit 21, an image separation unit 22 connected to the output side of the image data input unit 21, and a user setting reception unit 23. . A user setting storage unit 24 is connected to the output side of the user setting receiving unit 23. A temporary compression processing unit 25 is connected to the output side of the image separation unit 22 and the user setting storage unit 24. A compression rate determining unit 26 is connected to the output side of the user setting storage unit 24 and the temporary compression processing unit 25. A compression processing unit 27 is connected to the output side of the image separation unit 22 and the compression rate determination unit 26. A high compression PDF generation unit 28 as a file generation unit is connected to the output side of the compression processing unit 27. The HDD 9 is connected to the output side of the high-compression PDF generation unit 28 via the system bus 6.

  The image data input unit 21 acquires an RGB image data ID scanned using the scanner 7, and performs shading correction for correcting the shading of the image uniformly for the acquired RGB image data ID, and the image density. It has a function of performing various image processing such as input gradation correction that is corrected step by step and outputting the image data ID to the image separation unit 22.

  The image separation unit 22 includes mask data MD as separated image data obtained by extracting character outlines from input image data ID, foreground data FD as separated image data obtained by extracting character color information, and characters other than characters. A function of separating the image data into background data BD as extracted image data and outputting the separated mask data MD, foreground data FD, and background data BD to the temporary compression processing unit 25 and the compression processing unit 27. Have.

  The user setting receiving unit 23 has a function of receiving a user setting US indicating the processing type for the image data ID and the type of the image data ID via the operation panel 8, and outputting the received user setting US to the user setting storage unit 24. Have.

  The user setting storage unit 24 has a function of storing the input user setting US in the HDD 9 and outputting the user setting US to the temporary compression processing unit 25 and the compression rate determination unit 26.

  The temporary compression processing unit 25 uses the set compression rate corresponding to the user setting US input from the user setting storage unit 24 to convert the mask data MD, foreground data FD, and background data BD input from the image separation unit 22. Each has a function of compressing and outputting the compressed mask data MD, foreground data FD, and background data BD to the compression rate determination unit 26.

  The compression rate determination unit 26 has a function of calculating the data capacities S by calculating the data capacities of the mask data MD, foreground data FD, and background data BD input from the temporary compression processing unit 25. Further, the compression rate determination unit 26 determines a compression rate CR as a recompression rate from the calculated data capacity total S and the user setting US input from the user setting storage unit 24, and this compression rate CR is It has a function of outputting to the compression processing unit 27.

  The compression processing unit 27 compresses the mask data MD, the foreground data FD, and the background data BD input from the image separation unit 22 by using the compression rate CR input from the compression rate determination unit 26, and these masks. The data MD, the foreground data FD, and the background data BD are output to the high-compression PDF generation unit 28.

  The high-compression PDF generation unit 28 has a function of combining the input mask data MD, foreground data FD, and background data BD to generate a high-compression PDF file PD and outputting it to the HDD 9.

  3A and 3B are views showing the operation panel 8 of the image processing apparatus 1 in FIG. 1, and FIG. 3A is a view showing the appearance of the operation panel 8, and FIG. These are figures which show the state by which the image processing mode setting screen 85 was displayed on the liquid crystal display 81 in the figure (a).

  The operation panel 8 shown in FIG. 3A includes a liquid crystal display 81, a numeric keypad 82, a selection key 83, and a reading start button 84. The liquid crystal display 81 is a device for displaying a user operation state and a menu or message from the control unit 2. The numeric keypad 82 includes a plurality of numeric keys and the like for inputting numbers to the liquid crystal display 81. The selection key 83 is used to select various functions displayed on the liquid crystal display 81, and includes an up / down / left / right key for moving in the up / down / left / right direction and an OK key for instructing selection. The reading start button 84 is for starting the reading operation of the scanner 7.

  An image processing mode setting screen 85 for setting the user setting US is displayed on the liquid crystal display 81 in the operation panel 8 shown in FIG. In the image processing mode setting screen 85, each setting item of the image processing mode is displayed on the left side and selectable contents of the setting item are displayed on the right side. On the image processing mode setting screen 85, a mode 85a, a format 85b, a document type 85c, and a set compression rate 85d are displayed as setting items.

  The mode 85a indicates the type of processing to be performed by the image processing apparatus 1. For example, a scan mode indicating scan processing, a copy mode indicating copy processing, or a facsimile mode indicating facsimile communication processing can be selected. The format 85b indicates a file format for converting the image data ID. For example, a high compression PDF, JPEG method, or TIFF (Tagged Image File Format) method can be selected. The document type 85c indicates the type of image data, and a photo, text / photo, or text can be selected. The set compression rate 85d indicates the degree of compression rate when generating the high-compression PDF file PD, and high, medium, and low can be selected.

  The compression rate is generally expressed by a numerical value of 0 to 100. When the set compression rate 85d is high, for example, compression is performed with a compression rate of 80, and when the set compression rate 85d is low, for example, compression is performed with a compression rate of 20. The compression rate when compressing the foreground data FD and the compression rate when compressing the background data BD can be set to different values, and different values are set for each document type 85c. Is also possible.

  FIG. 3B shows a state in which the setting compression ratio 85 d that is shaded is set, and the setting item can be moved by the up, down, left, and right keys of the selection key 83.

(Image Processing Method of Example 1)
FIG. 4 is a flowchart showing an image processing method of the image processing apparatus 1 shown in FIGS.

The image processing method of the image processing apparatus 1 in FIGS. 1A and 1B will be described with reference to FIG.
When the power of the image processing apparatus 1 in FIG. 1A is turned on, an image processing mode setting screen 85 is displayed on the liquid crystal display 81 in the operation panel 8 as shown in FIG. It progresses to the user setting reception process of step S1.

  In step S <b> 1, the user setting receiving unit 23 in FIG. 1B receives the user setting US when the user operates the operation panel 8. The user setting reception unit 23 outputs the user setting US to the user setting storage unit 24. When the user presses the reading start button 84 on the operation panel 8, the reading operation of the scanner 7 of the image processing apparatus 1 shown in FIG. 1A is started, and the process proceeds to the image acquisition process in step S2.

  In step S <b> 2, the image data input unit 21 acquires an RGB image data ID from the scanner 7. The image data input unit 21 outputs the acquired image data ID to the image separation unit 22, and proceeds to the image separation process in step S3.

  In step S3, the image separation unit 22 uses a technique such as edge extraction processing for extracting a light / dark boundary in the image data ID for the image data ID input from the image data input unit 21 in step S2. Extract the outline of the character. The image separation unit 22 creates the mask data MD by creating binary data in which the location that is the outline of the character is “1” and the location that is not the outline of the character is “0”. The image separation unit 22 creates the foreground data FD obtained by extracting the color information of the character outline portion from the extracted character outline. The image separation unit 22 creates background data BD in which color information of portions that do not correspond to the foreground data FD is extracted. Furthermore, the image separation unit 22 outputs the mask data MD, the foreground data FD, and the background data BD to the temporary compression processing unit 25 and the compression processing unit 27, and proceeds to the temporary compression processing in step S4.

  In step S4, the temporary compression processing unit 25 compresses the mask data MD, which is binary data, using the MMR encoding method, and compresses the foreground data FD and the background data BD, which are multi-value data, using the JPEG method. . The compression rate at this time corresponds to the document type 85c and the set compression rate 85d of the user setting US stored in the user setting storage unit 24. The temporary compression processing unit 25 outputs the compressed mask data MD, foreground data FD, and background data BD to the compression rate determination unit 26, and proceeds to the compression rate determination process in step S5.

  In step S5, the compression rate determination unit 26 receives the mask data MD, foreground data FD, and background data BD input from the temporary compression processing unit 25 in step S4, and the user setting storage unit 24 in step S2. The compression rate CR is determined from the user setting US. The compression rate determination unit 26 outputs the determined compression rate CR to the compression processing unit 27, and proceeds to the compression processing in step S6.

  In step S6, the compression processing unit 27 compresses the mask data MD, foreground data FD, and background data BD input from the image separation unit 22 in step S3, and the compression input from the compression rate determination unit 26 in step S5. Each compression is performed using the rate CR. The mask data MD is compressed by the MMR encoding method, and the foreground data FD and the background data BD are compressed by the JPEG method. The compression processing unit 27 outputs the compressed mask data MD, foreground data FD, and background data BD to the high compression PDF generation unit 28, and proceeds to the high compression PDF creation processing as the file generation processing in step S7.

  In step S7, the high compression PDF generation unit 28 combines the mask data MD, foreground data FD, and background data BD input from the compression processing unit 27 in step S6, and generates a high compression PDF file PD. Thereafter, the high-compression PDF generation unit 28 outputs the generated high-compression PDF file PD to the HDD 9 and ends the processing.

FIG. 5 is a flowchart showing details of the temporary compression processing in step S4 in FIG.
When the temporary compression process in step S4 in FIG. 4 is started, the temporary compression processing unit 25 in FIG. 1B proceeds to the document type determination process in step S41 in FIG.

  In step S41, the temporary compression processing unit 25 determines the document type 85c of the user setting US. If the document type 85c is a photograph, the process proceeds to the temporary compression process in step S42. If the document type 85c is text / photo, the process proceeds to a temporary compression process in step S43. If the document type 85c is a character, the process proceeds to the temporary compression process in step S44.

  In step S42, the temporary compression processing unit 25 uses the foreground data compression rate RF1 and the background data compression rate RB1 as the set compression rates set in advance in the ROM 4 when the document type 85c is a photograph, and uses the foreground data FD and the background data. The data BD is compressed, and the process ends.

  In step S43, the temporary compression processing unit 25 uses the foreground data compression rate RF2 and the background data compression rate RB2 as the set compression rates set in advance in the ROM 4 when the document type 85c is text / photographs, and uses the foreground data FD. Then, the background data BD is compressed and the process is terminated.

  In step S44, the temporary compression processing unit 25 uses the foreground data compression rate RF3 and the background data compression rate RB3 as the set compression rates set in advance in the ROM 4 when the document type 85c is a character, and uses the foreground data FD and the background data. The data BD is compressed, and the process ends.

FIG. 6 is a flowchart showing details of the compression rate determination process in step S5 in FIG.
When the compression rate determination process in step S5 in FIG. 4 is started, the compression rate determination unit 26 in FIG. 1B proceeds to the data capacity calculation process in step S51 in FIG.

  In step S51, the compression rate determination unit 26 calculates the total data capacity S by adding the data capacities of the mask data MD, foreground data FD, and background data BD input from the temporary compression processing unit 25, and step S52. Proceed to the data capacity comparison process.

  In step S <b> 52, the compression rate determination unit 26 compares the data capacity total S calculated in step S <b> 51 with the data capacity threshold TH stored in advance in the ROM 4. If the data capacity total S is larger than the data capacity threshold TH (YES), the process proceeds to the document type determination process in step S57. If the data capacity total S is less than or equal to the data capacity threshold TH (NO), the process proceeds to the document type determination process in step S53. move on.

  In step S53, the compression rate determination unit 26 determines the document type 85c of the user setting US. If the document type 85c is a photograph, the process proceeds to the compression rate setting process in step S54. If the document type 85c is text / photo, the process proceeds to the compression rate setting process in step S55. If the document type 85c is a character, the process proceeds to the compression rate setting process in step S56.

  In step S54, the compression rate determination unit 26 sets the foreground data compression rate RF1 and the background data compression rate RB1 used when the temporary compression processing unit 25 performs compression in step S42 as the compression rate CR. Exit.

  In step S55, the compression rate determination unit 26 sets the foreground data compression rate RF2 and the background data compression rate RB2 used when the temporary compression processing unit 25 performs compression in step S43 as the compression rate CR, and performs processing. Exit.

  In step S56, the compression rate determination unit 26 sets the foreground data compression rate RF3 and the background data compression rate RB3 used when the temporary compression processing unit 25 performs compression in step S44 as the compression rate CR, and performs processing. Exit.

  In step S57, the compression rate determination unit 26 determines the document type 85c of the user setting US. If the document type 85c is a photograph, the process proceeds to the compression rate setting process in step S58. If the document type 85c is text / photo, the process proceeds to the compression rate setting process in step S59. If the document type 85c is a character, the process proceeds to the compression rate setting process in step S60.

  In step S58, the compression rate determination unit 26 increases the foreground data compression rate RF_H1 as the first recompression rate, which is significantly higher than the foreground data compression rate RF1 in step S42, and a minute amount higher than the background data compression rate RB1 in step S42. The background data compression rate RB_H1 as the second recompression rate is set as the compression rate CR, and the process ends.

  In step S59, the compression rate determination unit 26 sets the foreground data compression rate RF_H2 as the first recompression rate that is smaller than the foreground data compression rate RF2 in step S43 and the background data compression rate RB2 that is smaller than the background data compression rate RB2 in step S43. 2. The background data compression rate RB_H2 as the recompression rate is set as the compression rate CR, and the process ends.

  In step S60, the compression rate determination unit 26 significantly increases the foreground data compression rate RF_H3 as the first recompression rate that is higher by a minute amount than the foreground data compression rate RF3 in step S44, and the background data compression rate RB3 in step S44. The background data compression rate RB_H3 as the second recompression rate is set as the compression rate CR, and the process ends.

  FIGS. 7A to 7C are diagrams showing an example of the compression rate for each document type 85c in steps S58 to S60 in FIG. 6, and FIG. 7A shows a case where the document type 85c is a photograph. FIG. 4B is a diagram showing a case where the document type 85c is text / photograph. FIG. 5C is a diagram showing a case where the document type 85c is text.

  When the document type 85c is a photograph, as shown in FIG. 7A, the temporary compression processing unit 25 performs temporary compression using the foreground data compression rate RF1 and the background data compression rate RB1 in step S42. If the total data capacity S after the temporary compression is larger than the data capacity threshold TH, the compression processing unit 27 performs compression using the foreground data compression rate RF_H1 and the background data compression rate RB_H1 in step S58. When the document type 85c is a photograph, background data representing color information other than characters is important. Therefore, the foreground data compression rate RF_H1 is significantly increased compared to the foreground data compression rate RF1, and the background data compression rate RB_H1 is changed to a minute amount compared to the background data compression rate RB1.

  When the document type 85c is text / photo, as shown in FIG. 7B, the temporary compression processing unit 25 performs temporary compression using the foreground data compression rate RF2 and the background data compression rate RB2 in step S43. If the total data capacity S after temporary compression is larger than the data capacity threshold TH, the compression processing unit 27 performs compression using the foreground data compression rate RF_H2 and the background data compression rate RB_H2 in step S59. When the document type 85c is text / photo, both the foreground data representing the color information of the text and the background data representing the color information other than the text are equally important. Therefore, the foreground data compression rate RF_H2 is increased to a small value compared with the foreground data compression rate RF2, and the background data compression rate RB_H2 is increased to a small value compared with the background data compression rate RB2.

  When the document type 85c is a character, as shown in FIG. 7C, the temporary compression processing unit 25 performs temporary compression using the foreground data compression rate RF3 and the background data compression rate RB3 in step S44. If the total data capacity S after temporary compression is larger than the data capacity threshold TH, the compression processing unit 27 performs compression using the foreground data compression rate RF_H3 and the background data compression rate RB_H3 in step S60. When the document type 85c is a character, foreground data representing character color information is important. Therefore, the foreground data compression rate RF_H3 is changed by a minute amount compared with the foreground data compression rate RF3, and the background data compression rate RB_H3 is significantly increased compared with the background data compression rate RB3.

(Effect of Example 1)
According to the image processing method and the image processing apparatus 1 of the first embodiment, there are the following effects (a) to (c).

(A) Data capacity compression When the total data capacity S of the mask data MD, foreground data FD, and background data BD compressed by the temporary compression processor 25 is larger than the data capacity threshold TH, the compression processor 27 performs compression. Create a highly compressed PDF file PD at a higher rate. This makes it possible to output a highly compressed PDF file PD with a reduced data capacity.

(B) Implementation of appropriate compression processing The compression rate determination unit 26 determines different foreground data compression rates RF_H1, RF_H2, RF_H3 and background data compression rates RB_H1, RB_H2, RB_H3 depending on the document type 85c. As a result, the compression rate of important information corresponding to the document type 85c can be lowered, and the compression rate of unimportant information can be increased.

(C) Reduction of user burden When the total data capacity S is larger than the data capacity threshold TH, the compression ratio determination unit 26 increases the compression ratio without depending on the user's judgment. This makes it possible to output a highly compressed PDF file PD with a small data capacity without burdening the user with operation.

(Configuration of Example 2)
FIGS. 8A and 8B are configuration diagrams showing an outline of the image processing apparatus 1A according to the second embodiment of the present invention. FIG. 8A is a configuration diagram showing an outline of the entire image processing apparatus 1A. FIG. 2B is a block diagram showing the function of the control unit 2A in FIG. In FIGS. 8A and 8B, elements common to those in FIGS. 1A and 1B showing the first embodiment are denoted by common reference numerals.

  An image processing apparatus 1A according to the second embodiment illustrated in FIG. 8A includes a control section 2A having a configuration different from that of the control section 2 in the image processing apparatus 1 according to the first embodiment. Other configurations of the image processing apparatus 1A are the same as those in the first embodiment.

  The control unit 2A according to the second embodiment illustrated in FIG. 8B is different from the control unit 2 according to the first embodiment in that the temporary compression processing unit 25, the compression rate determination unit 26, the compression processing unit 27, and the high-compression PDF. Instead of the generation unit 28, a high-compression PDF temporary generation unit 29 as a temporary file generation unit, a user designation receiving unit 30, and a high-compression PDF output unit 31 are provided. A high-compression PDF temporary generation unit 29 is connected to the output side of the image separation unit 22 and the user setting storage unit 24. A user designation receiving unit 30 is connected to the output side of the user setting storage unit 24 and the high compression PDF temporary generation unit 29. A high compression PDF output unit 31 is connected to the output side of the high compression PDF temporary generation unit 29 and the user designation reception unit 30.

  The high-compression PDF temporary generation unit 29 uses the compression rate corresponding to the user setting US input from the user setting storage unit 24 to use the mask data MD, foreground data FD, and background data BD input from the image separation unit 22. Are compressed, and a high-compression PDF file PD1 is temporarily generated. The high-compression PDF temporary generation unit 29 has a function of temporarily generating high-compression PDF files PD2 and PD3 having a high compression rate when the data capacity total S of the temporarily generated high-compression PDF file PD1 is equal to or greater than a predetermined value. . Further, the high-compression PDF temporary generation unit 29 outputs a plurality of temporarily generated high-compression PDF files PD1, PD2, and PD3 to the user designation receiving unit 30, or the temporarily generated high-compression PDF file PD1 is output as a high-compression PDF. The function of outputting to the unit 31 is provided.

  The user designation receiving unit 30 displays the high-compression PDF files PD1, PD2, and PD3 input from the high-compression PDF temporary generation unit 29 on the operation panel 8, causes the user to designate one of them, and designates the designated high-compression It has a function of outputting the PDF file PD to the user designation receiving unit 30.

  The high-compression PDF output unit 31 sends either the high-compression PDF file PD1 input from the high-compression PDF temporary generation unit 29 or the high-compression PDF file PD input from the user designation receiving unit 30 to the HDD 9. Has a function to output. Other functions of the control unit 2A are the same as those in the first embodiment.

  FIG. 9 is a diagram showing a state in which a preview display screen 86 is displayed on the liquid crystal display 81 in the operation panel 8 in FIG.

  A liquid crystal display 81 in the operation panel 8 displays a preview display screen 86 for allowing the user to select one of the high-compression PDF files PD1, PD2, and PD3. On the preview display screen 86, a preview 86a and a data capacity 86b are displayed for each of the high-compression PDF files PD1, PD2, and PD3.

  The preview 86a shows a part of the highly compressed PDF files PD1, PD2, and PD3. The data capacity 86b indicates the data capacity of the highly compressed PDF files PD1, PD2, and PD3. FIG. 9 shows a state in which the high-compression PDF file PD2 that is shaded is selected, and the high-compression PDF files PD1, PD2, and PD3 selected by the up / down / left / right keys of the selection key 83 can be moved. It has become.

(Image Processing Method of Example 2)
FIG. 10 is a flowchart showing the image processing method of the image processing apparatus 1A shown in FIGS. 8A and 8B. Elements common to those shown in FIG. ing.

  In the flowchart of FIG. 10, the image processing apparatus 1 </ b> A performs the same processing as steps S <b> 1 to S <b> 3 of the first embodiment, and proceeds to the high-compression PDF temporary generation processing of step S <b> 11.

  In step S11, the high-compression PDF temporary generation unit 29 compresses the mask data MD, foreground data FD, and background data BD as in step S4 of the first embodiment. The high compression PDF temporary generation unit 29 temporarily generates a high compression PDF file PD1 from the compressed mask data MD, foreground data FD, and background data BD. The high-compression PDF temporary generation unit 29 calculates the data capacity total S of the high-compression PDF file PD1, and proceeds to the data capacity comparison process in step S12.

  In step S <b> 12, the high-compression PDF temporary generation unit 29 compares the data capacity total S calculated in step S <b> 11 with the data capacity threshold TH stored in advance in the ROM 4. If the data capacity total S is larger than the data capacity threshold TH (YES), the process proceeds to the high compression PDF regeneration process in step S13. If the data capacity total S is less than or equal to the data capacity threshold TH (NO), the high compression PDF file PD1 is stored. The data is output to the high-compression PDF output unit 31, and the process proceeds to the high-compression PDF output process in step S15.

  In step S13, the high-compression PDF temporary generation unit 29 temporarily generates a high-compression PDF file PD2 using a higher compression rate than the high-compression PDF file PD1 temporarily generated in step S11. The high-compression PDF temporary generation unit 29 temporarily generates the high-compression PDF file PD3 using a higher compression rate than the high-compression PDF file PD2. The high-compression PDF temporary generation unit 29 outputs the high-compression PDF files PD1, PD2, and PD3 to the user designation reception unit 30, and proceeds to the user designation reception process in step S14.

  In step S14, as shown in FIG. 9, the user designation receiving unit 30 displays a preview display screen 86 on the liquid crystal display 81 in the operation panel 8, and allows the user to designate one of them. The user designation receiving unit 30 outputs the high-compression PDF file PD designated by the user to the high-compression PDF output unit 31, and proceeds to the high-compression PDF output process in step S15.

  In step S15, the high-compression PDF output unit 31 is either one of the high-compression PDF file PD1 input from the high-compression PDF temporary generation unit 29 or the high-compression PDF file PD input from the user designation receiving unit 30. Is output to the HDD 9, and the process is terminated.

(Effect of Example 2)
According to the image processing method and the image processing apparatus 1 of the second embodiment, in addition to the effects of the first embodiment, there are the following effects (d).

(D) Selection of output data by user The user designation receiving unit 30 displays output candidates of the high-compression PDF files PD1, PD2, and PD3 on the preview display screen 86, and designates the high-compression PDF file PD to be output to the user. Let As a result, it is possible to output a highly compressed PDF file PD having a compression rate desired by the user without imposing a heavy operation burden on the user.

(Modification)
The present invention is not limited to the first and second embodiments, and various usage forms and modifications are possible. For example, the following forms (i) to (ix) are used as the usage form and the modification examples.

  (I) In the first and second embodiments, the image data ID is separated into the mask data MD, the foreground data FD, and the background data BD. However, the image data ID may be separated into two or four or more.

  (Ii) In the first and second embodiments, the data capacity threshold TH to be compared with the data capacity total S is one, but a plurality of different data capacity thresholds TH may be set for each document type 85c.

  (Iii) In the first and second embodiments, the data capacity threshold TH to be compared with the total data capacity S is one, but a plurality of data capacity thresholds TH are set, and the foreground data compression is performed in correspondence with the data capacity threshold TH. A plurality of rates RF_H1 to RF_H3 and background data compression rates RB_H1 to RB_H3 may be set.

  (Iv) In the first embodiment, when the document type 85c is a photograph, the background data compression rate RB_H1 is increased by a minute amount. When the document type 85c is character, the foreground data compression rate RF_H3 is increased by a minute amount. You don't have to. Even if it changes in this way, the same effect as Example 1 is acquired.

  (V) In the compression processing unit 27 in the first embodiment, when the total data capacity S is equal to or less than the data capacity threshold TH, the foreground data compression rates RF1 to RF3 and the background data compression rates RB1 to RB3 used in the temporary compression processing unit 25 However, the mask data MD, foreground data FD, and background data BD compressed by the temporary compression processing unit 25 may be input and output to the high compression PDF generation unit 28 as they are.

  (Vi) In the high compression PDF temporary generation unit 29 in the second embodiment, when the total data capacity S is larger than the data capacity threshold TH, two high compression PDF files PD2 and PD3 are provisionally generated. It may be generated. Even if it changes in this way, the same effect as Example 2 is acquired.

  (Vii) The image forming apparatus 1 in FIG. 1A and the image forming apparatus 1A in FIG. 8A may be changed to configurations other than those illustrated. Furthermore, the control unit 2 in FIG. 1B and the control unit 2A in FIG. 8B may be changed to functions having functions other than those illustrated.

  (Viii) In the first and second embodiments, the configuration of the operation panel 8 includes the liquid crystal display 81 for output, the numeric keypad 82 used for the input operation, the selection key 83, and the reading start button 84. A touch panel system in which input / output is performed on the same screen may be used.

  (Ix) In the first and second embodiments, the digital color multifunction peripheral has been described as an example of the image processing apparatuses 1 and 1A. It can be used in different devices such as a portable terminal with a camera function.

1, 1A Image processing device 2, 2A Control unit 8 Operation panel 21 Image data input unit 22 Image separation unit 23 User setting reception unit 25 Temporary compression processing unit 26 Compression rate determination unit 27 Compression processing unit 28 High compression PDF generation unit 29 High Compressed PDF temporary generation unit 30 User designation reception unit

Claims (12)

An image processing method for converting image data into a file of a predetermined file format,
A user setting reception process for receiving an image processing mode for setting a processing type for the input image data and a type of the image data from a user;
An image separation process for separating the image data into a plurality of separated image data;
A temporary compression process for compressing the plurality of separated image data using a set compression rate corresponding to the type of the image data;
A compression rate determination process for determining a plurality of recompression rates for compressing each of the plurality of separated image data according to a total data capacity of the plurality of separated image data compressed in the temporary compression processing;
A compression process for compressing each of the plurality of separated image data using the recompression rate;
A file generation process for generating the file by converting the plurality of separated image data compressed in the compression process into the predetermined file format;
An image processing method comprising:   The plurality of separated image data indicate mask data indicating outline information of characters included in the image data, foreground data indicating color information of characters included in the image data, and a background image included in the image data. The image processing method according to claim 1, further comprising: background data.   3. The image processing method according to claim 1, wherein the predetermined file format is a highly compressed PDF. An image processing apparatus that converts image data into a file of a predetermined file format,
An image data input unit for inputting the image data;
A user setting receiving unit that receives an image processing mode for setting a processing type for the image data and a type of the image data from a user;
An image separation unit for separating the image data into a plurality of separated image data;
A temporary compression processing unit that compresses each of the plurality of separated image data using a set compression rate corresponding to the type of the image data;
A compression rate determining unit that determines a plurality of recompression rates for compressing each of the plurality of separated image data according to a total data capacity of the plurality of separated image data compressed by the temporary compression processing unit;
A compression processor that compresses each of the plurality of separated image data using the recompression rate;
A file generation unit that converts the plurality of separated image data compressed by the compression processing unit into the predetermined file format and generates the file;
An image processing apparatus comprising: The compression rate determining unit
The image processing apparatus according to claim 4, wherein when the total data capacity exceeds a threshold value, the recompression ratio higher than the set compression ratio is determined.   The plurality of separated image data indicate mask data indicating outline information of characters included in the image data, foreground data indicating color information of characters included in the image data, and a background image included in the image data. 6. The image processing apparatus according to claim 4, further comprising background data. The compression rate determining unit
Corresponding to the type of image data, a first recompression rate for compressing the foreground data and a second recompression rate different from the first recompression rate for compressing the background data are determined. The image processing apparatus according to claim 6. An image processing apparatus that converts image data into a file of a predetermined file format,
An image data input unit for inputting the image data;
A user setting receiving unit that receives an image processing mode for setting a processing type for the image data and a type of the image data from a user;
An image separation unit for separating the image data into a plurality of separated image data;
The plurality of separated image data are respectively compressed using a plurality of different set compression rates corresponding to the type of the image data, converted into the predetermined file format, and a plurality of the plurality of the separated image data for each of the plurality of different set compression rates. A temporary file generator for generating files,
A user designation receiving unit that displays the plurality of files and allows a user to designate a file to be output from the plurality of files;
An image processing apparatus comprising:   The plurality of separated image data indicate mask data indicating outline information of characters included in the image data, foreground data indicating color information of characters included in the image data, and a background image included in the image data. The image processing apparatus according to claim 8, further comprising: background data.   The processing type for the image data includes a scan mode for performing a scan process for the image data, a copy mode for performing a copy process for the image data, and a facsimile mode for performing a facsimile communication process for the image data. The image processing apparatus according to any one of claims 4 to 9. The type of the image data is a document type,
11. The document type according to claim 4, wherein the document type includes a character type composed of character information, a photograph type composed of a photographic image, and a character photograph type composed of character information and a photographic image. An image processing apparatus according to 1.   The image processing apparatus according to claim 4, wherein the predetermined file format is a highly compressed PDF.

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