JP2005309681A - Image processor and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To encode part of image data without using any dictionary. <P>SOLUTION: This image processor is provided with an image reading part 102 for inputting image data, a reference region extracting part 111 for extracting part of the inputted image data as a reference region, a similar region extracting part 125 for extracting a similar region similar to the reference region extracted from the inputted image data, a code generating part 127 for generating a code associating the extracted similar region with the reference region and a transmitting part 123 for outputting the extracted reference region and the code corresponding to the similar region in predetermined configurations. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus and an image processing program, and more particularly to an image processing apparatus and an image processing program that code a part of image data.

  As a technique for reducing the amount of bitmap image data obtained by reading an original with an image reading apparatus such as a scanner, a technique for compressing using an image compression method such as JPEG is known. In addition, when character information is described in a manuscript, the amount of data is converted to a character code using an optical character recognition device (OCR: Optical Character Reader) rather than compressed using an image compression method. Can be reduced.

  However, the optical character recognition device may not be recognized although its recognition rate is improved. As a technique corresponding to this problem, there is JP-A-5-37700 (Patent Document 1). Japanese Patent Laid-Open No. 5-37700 discloses an image reading unit that converts a transmission original into image information and reads it, a character cutout unit that extracts character information from the image information, and character recognition for character encoding based on the character information. A facsimile machine having an OCR function, and a character code transmission processing means for converting the character recognized by the character recognition unit into a character code for transmission processing; Bitmap information transmission processing means for transmitting character information that could not be recognized by the character recognition unit as bitmap information is provided, and on the receiver side, the received character code information is converted into character pattern information. Character pattern generating means for performing data composition and means for synthesizing the received bitmap information and character pattern information are provided. Akushimiri device is described.

Since the facsimile apparatus described in Japanese Patent Laid-Open No. 5-37700 is for recognizing character information extracted from image information, it is necessary to provide a dictionary as a reference for character recognition. Since characters that are not in this dictionary cannot be recognized, symbols that are not in the dictionary cannot be coded. Furthermore, in the facsimile machine on the receiving side, the character code is restored using the character font that the facsimile machine has, so that it is restored with a font different from the font of the character of the document read on the transmitting side. Characters sent with bitmap data are the original font, and characters sent with the character code are the receiving font. An image different from the image is formed.
JP-A-5-37700

  The present invention has been made to solve the above-described problems, and one of the objects of the present invention is an image processing apparatus and image processing capable of coding a part of image data without using a dictionary. Is to provide a program.

  In order to achieve the above-described object, according to one aspect of the present invention, an image processing apparatus includes an input unit that inputs image data, and a reference region extraction unit that extracts a part of the input image data as a reference region. A similar region extracting unit that extracts a similar region similar to the reference region extracted from the input image data, a code generating unit that generates a code that associates the extracted similar region with the reference region, and Output means for outputting a reference area and a code corresponding to the similar area in a predetermined form.

  According to the present invention, a reference region is extracted from input image data, and a similar region similar to the reference region is extracted from input image data. Then, a code in which the similar area is associated with the reference area is generated, and the reference area and the code corresponding to the similar area are output in a predetermined form. Since the similar area that is a part of the image data is coded in association with the reference area that is a part of the image data, it is not necessary to use a dictionary separately from the image data. Therefore, it is possible to provide an image processing apparatus that can code a part of image data without using a dictionary.

  Preferably, the image processing apparatus further includes block dividing means for dividing the input image data into a plurality of blocks, the reference area extracting means extracts any of the plurality of blocks as a reference area, and the similar area extracting means includes the plurality of blocks. A block similar to the reference area is extracted as a similar area.

  According to the present invention, the reference area and the similar area are extracted from the plurality of blocks. For this reason, a process can be simplified and a processing speed can be improved.

  Preferably, an erasure unit that erases the extracted similar region from the input image data and a compression unit that compresses the image data from which the similar region is erased, and the output unit compresses the reference region by the compression unit. Output as processed data.

  According to the present invention, since the image data in which the similar area is erased from the image data is compressed, the image data can be compressed at a high compression rate. As a result, the amount of image data can be reduced.

  Preferably, the output unit includes a transmission unit that transmits the extracted reference region and the code corresponding to the similar region to another device in a predetermined form.

  According to the present invention, since the amount of data to be transmitted to other devices is reduced, the time required for communication can be shortened.

  Preferably, the code generation unit generates a code including at least a position of the similar area in the image data and a position of the reference area in the image data.

  According to the present invention, the image data can be reliably restored from the reference area and the code corresponding to the similar area.

  According to another aspect of the present invention, an image processing program includes a step of inputting image data, a step of extracting a part of the input image data as a reference area, and a reference extracted from the input image data. Extracting a similar region similar to the region, generating a code in which the extracted similar region is associated with the reference region, and outputting the code corresponding to the extracted reference region and the similar region in a predetermined form And causing the computer to execute

  According to the present invention, it is possible to provide an image processing program capable of coding a part of image data without using a dictionary.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

<First Embodiment>
FIG. 1 is a diagram showing an overall outline of an image processing apparatus according to a first embodiment of the present invention. Referring to FIG. 1, an image processing apparatus 100 includes a control unit 101 for controlling the entire image processing apparatus 100, an image reading unit 102 for reading a document, and an image, each connected to a bus 110. An image processing unit 103 for executing a process for compressing data, an image memory 104 for temporarily storing an image read by the image reading unit 102, and an image on a recording medium such as paper based on the image data An image forming unit 105 for forming, a transmission control unit 107 for connecting the image processing apparatus 100 to a communication line, a storage unit 106 for storing compression conditions and the like, and a panel control unit 108 are provided. The panel control unit 108 is connected to an operation panel 109 that receives an input of an operation by a user, and controls the operation panel 109.

  The image processing apparatus 100 is realized by a multifunction product (MFP) having an image reading function, a copying function, and a facsimile transmission / reception function. Although the image processing apparatus 100 is described as an MFP in the present embodiment, it can be realized by a general computer that compresses input image data instead of the MFP.

  The image reading unit 102 includes a photoelectric conversion element such as a CCD (Charge Coupled Device), an analog processing unit, and an A / D conversion unit. RGB analog signals are output from the CCD. The analog processing unit performs clamp adjustment and gain adjustment on the RGB analog signal output from the CCD, and outputs it to the A / D conversion unit. The A / D converter converts the RGB analog signal into an 8-bit digital signal. This 8-bit digital signal is image data. The image reading unit 102 includes a shading correction unit, an interline correction unit, an area determination unit, and an MTF (modulation transfer function) correction unit. The shading correction unit corrects variations in the main scanning direction caused by uneven illumination of light emitted from the light source when scanning the document to the image data output from the A / D conversion unit. Execute. In the CCD, R (red), G (green), and B (blue) photodiode arrays are arranged at predetermined intervals. The inter-line correction unit corrects a gap in the interval at which the photodiode array is arranged by temporarily storing a value corresponding to a signal output from each color photodiode in the memory and delaying the value by a predetermined time. The area determination unit determines areas such as a character part, a halftone dot part, and a photograph part included in the image data. The determination result is output to the MTF correction unit. The MTF correction unit executes processing suitable for the region such as edge enhancement and smoothing according to the determination result input from the region determination unit, and outputs the processed image data to the image memory 104.

  The image memory 104 is a random access memory (RAM), and temporarily stores image data output from the image reading unit 102 and image data compressed by the image processing unit 103. In addition, image data transmitted from an external computer and received by the transmission control unit 107 is stored.

  Operation panel 109 includes a liquid crystal touch panel, a numeric keypad, and a start key for instructing start of image reading. A liquid crystal touch panel is comprised from a liquid crystal display device and the touch panel which consists of a transparent member mounted on it. The touch panel is an input device. The operation panel 109 displays a button on a liquid crystal display device, for example, and detects an operation of the user pressing the displayed button on the touch panel. Thereby, it is not necessary to use a switch button fixed to the input device, and various operations can be input.

  The panel control unit 108 is controlled by the control unit 101 and receives output control of the operation panel 109 to the display device and input of a user operation input to the input unit of the operation panel 109.

  The image processing unit 103 compresses the image data stored in the image memory 104. The storage unit 106 is a storage device such as a hard disk.

  The transmission control unit 107 is a communication interface for connecting the image processing apparatus 100 to a communication line. The transmission control unit 107 controls communication with other computers, MFPs, etc. connected to the communication line. The transmission control unit 107 may be a network interface, or a serial interface or a parallel interface directly connected to another computer or MFP. The transmission control unit 107 uses an interface according to the connection form with the communication line. As the communication line, a local area network (LAN), the Internet, a general public line, or the like can be used, and it may be wired or wireless.

  In image processing apparatus 100 according to the present embodiment, a user operates operation panel 109 to read a document with image reading unit 102. Then, the image data output from the image reading unit 102 is stored in the image memory 104. Further, the image data transmitted from the external computer or MFP is stored in the image memory 104 by the transmission control unit 107. The image processing unit 103 compresses the image data stored in the image memory 104 by the operation of the operation panel 109 by the user, and transmits the compressed image data to another apparatus.

  FIG. 2 is a functional block diagram illustrating an outline of functions of the image processing unit of the image processing apparatus according to the first embodiment. Referring to FIG. 2, an image processing unit 103 reads image data stored in the image memory 104, converts an image data into a reference region and a coding, and a reference region for storing the reference region. A reference area storage unit 115; a code storage unit 117 for storing a code; an image deletion unit 119 for deleting an area coded by the image conversion unit from image data read from the image memory 104; A compression unit 131 that compresses image data (erase data) that has been partially erased by the unit, and a transmission unit 123 that transmits the compressed erase data and code to another apparatus.

  The image conversion unit 201 includes a reference region extraction unit 111 that extracts a reference region from image data, a similar region extraction unit 125 that extracts a similar region similar to the reference region extracted by the reference region extraction unit 111, and image data. A code generation unit 127 that generates a code that associates the similar region extracted by the similar region extraction unit 125 with the reference region is included.

  The reference area extraction unit 111 reads out image data stored in the image memory 104 and extracts a reference area from the image data. The reference area extracted by the reference area extraction unit 111 may be a part of the image data. The reference area extraction unit 111 extracts the reference area based on edge pixels in the image data, or extracts based on the brightness of the pixels of the image data. The reference region for extraction based on edge pixels can be a region including edge pixels or a region in which edge pixels are continuous. The reference area in the case of extracting based on the brightness can be an area where the brightness changes gradually. Moreover, it is good also as an area | region where the brightness changes rapidly.

  The size of the reference area can be arbitrarily determined. Preferably, the size is determined based on a predetermined size, an edge pixel, or a size determined based on the brightness of the pixel. More preferably, when the reference region is extracted based on the edge pixels, the size can be set to a size determined by the number of consecutive edge pixels, or a size determined by the size of the character or symbol. Further, when the reference region is extracted based on the lightness, the lightness can be changed to a size determined by the number of consecutive pixels within a predetermined range. The reference area extraction unit 111 stores the extracted pixel value of the reference area and the position of the reference area in the image data in the reference area storage unit 115 in association with each other.

  The similar region extraction unit 125 extracts a region similar to the reference region extracted by the reference region extraction unit 111 from the image data as a similar region. Preferably, the similar region extraction unit 125 extracts a region where a difference image with the similar region satisfies a predetermined condition as a similar region.

  The reference region and the similar region may overlap each other, but in order to avoid overlapping, the similar region extracted by the similar region extraction unit 125 is the same when the similar region extraction unit 125 extracts the similar region. A new similar region may be extracted from the reference region extracted by the reference region extraction unit 111 and the portion excluding the similar region extracted by the similar region extraction unit 125 so far. The similar area is an area similar to the reference area. The size of the similar area is determined by the reference area. When the sizes of the reference area and the similar area are different, it is only necessary that either the similar area or the reference area is enlarged or reduced to make the similar area and the reference area similar in size. Here, for the sake of explanation, a case where the size of the reference area and the similar area are the same will be described as an example.

  The similar region extraction unit 125 includes an edge comparison unit 125A that extracts a similar region similar to the reference region based on the edge pixel, and a lightness comparison unit 125A that extracts a similar region similar to the reference region based on the lightness of the pixel. The similar area extraction unit 125 includes position information indicating the position in the image data of the similar area extracted by the edge comparison unit 125A or the brightness comparison unit 125B, and the position in the image data of the reference area in which the similar area is similar. Is output to the code generation unit 127. Note that the similar region extraction unit 125 further outputs a ratio of the size of the similar region to the reference region to the code generation unit 127 when the sizes of the similar region and the reference region are different.

  The edge comparison unit 125A extracts a similar region similar to the reference region extracted by the reference region extraction unit 111 based on the edge pixels. A region including an array of edge pixels similar to the array of edge pixels included in the reference region is extracted as a similar region. The array of edge pixels forms a line, and the set of lines forms a character or symbol. For this reason, the determination that the arrangement of edge pixels is similar is the determination of the identity of characters and symbols. The edge comparison unit 125A determines based on the difference image between the reference area and the similar area. More preferably, the determination is made based on a difference image between the edge image of the reference area and the edge image of the similar area. More preferably, the determination is made based on a difference image between an image obtained by extending or reducing the edge image of the reference area and an image obtained by extending or reducing the edge image of the similar area.

  The brightness comparison unit 125B extracts a similar region similar to the reference region extracted by the reference region extraction unit 111 based on the brightness of the pixel. The brightness comparison unit 125B determines based on the difference image between the reference area and the similar area. More preferably, the determination is made based on a difference image of brightness between the reference area and the similar area. More preferably, an area where the absolute value sum or square sum of the pixel values of the brightness difference image of the reference area is equal to or less than a predetermined threshold is extracted as a similar area.

  The code generation unit 127 generates a code that associates the position information of the similar region, the position information of the reference region, and the size of the reference region input from the similar region extraction unit 125, and stores the generated code in the code storage unit 117. Remember. When the ratio of the size of the similar region to the reference region is input from the similar region extraction unit 125, the code generation unit 127 generates a code associated with the ratio.

  The reference area storage unit 115 associates the values (pattern data) of all the pixels included in the reference area input from the reference area extraction unit 111 with the position and size of the reference area in the image. Remember. The code storage unit 117 stores the code generated by the code generation unit 127.

  The image erasing unit 119 receives the image data read from the image memory 104 and the code output from the code generation unit 127. The image erasing unit 119 erases an area specified by the position of the reference area and the size of the reference area included in the code from the image data. Hereinafter, for the sake of explanation, an image partially erased by the image erasure unit 119 is referred to as erase data. In erasing, for example, all the pixel values in the specified area are set to “255”.

  Note that the code generated by the code generation unit 127 may be an association between the position in the image of the input reference area and the position in the image of the reference area determined to be similar. In this case, the image erasure unit 119 refers to the reference region storage unit 115, acquires the size of the reference region from the position of the reference region included in the code, and erases the reference region from the image data. Become.

  The compression unit 131 compresses the erased data using a compression method such as a JPEG method. The compression method may be either a reversible compression method or an irreversible compression method. An irreversible compression method is preferable. This is because the compression rate is expected to be relatively high.

  Since all the pixel values in the area similar to the reference area are “255”, the erasure data has a higher compression rate than the image data read from the image memory 104. The data amount of the reference area similar to the reference area and the code corresponding thereto is smaller in the code. For this reason, the data amount of the image obtained by combining the image obtained by compressing the erased data and the code is smaller than that of the image data read from the image memory 104.

  The transmission unit 123 transmits the compressed data obtained by compressing the erasure data by the compression unit 131 and the code stored in the code storage unit 117 from the transmission control unit 107 to another device via a communication line. The transmission destination may be directly input by the user from the operation panel 109, or the network address of the transmission destination may be stored in advance in the storage unit 106 and read from there. The network address is, for example, an electronic mail address, an IP (Internet Protocol) address, a MAC (Media Access Control) address, or the like. When the transmission unit 123 transmits the deletion data and the code by e-mail, the code may be included in the e-mail body, and the compressed data may be an attached document.

  FIG. 3 is a diagram illustrating an example of reference area information stored in the reference area storage unit. Referring to FIG. 3, the reference area information stores, for each address in reference area storage unit 115, coordinates indicating the position of the reference area in the image data, the size of the reference area, and the pixel value of the reference area. The coordinates represent the pixel at the upper left of the image data as the origin (0, 0), the order arranged from the origin pixel in the right direction as the X coordinate, and the order arranged from the origin pixel in the downward direction as the Y coordinate. Although the reference area is indicated by the symbol “*”, the pixel values (pattern data) of the pixels included in the reference area are actually recorded.

  FIG. 4 is a diagram illustrating an example of codes stored in the code storage unit 117. Referring to FIG. 4, code storage unit 117 stores a code for each reference area. The code includes coordinates indicating the position of the reference area in the image data, coordinates of the reference area, and the size of the reference area. The size of the reference area is represented by the number of pixels in the horizontal direction and the number of pixels in the vertical direction of the reference area. In FIG. 4, the reference area at coordinates (0,0), (200,0), (400,0) is similar to the reference area of size (200,200) at coordinates (0,0). It is shown. In addition, the reference area at coordinates (300, 0) is similar to the reference area of size (200, 200) at coordinates (100, 0), and the reference area at coordinates (600, 600) is coordinate (400 , 600) is similar to the reference area of size (200, 200), and the reference area at coordinates (900, 900) is similar to the reference area of size (200, 200) at coordinates (500, 600). It has been shown.

  Next, a specific example of processing in which the reference region extraction unit 111 extracts a reference region based on edge pixels will be described.

  (1) An edge determination process for determining an edge of image data is performed to generate an edge image. FIG. 5 is a diagram illustrating an example of image data, an edge image, and a character region. FIG. 5A shows image data, FIG. 5B shows an edge image, and FIG. 5C shows a character area in the image data. Referring to FIG. 5A, the image data includes an area where characters are represented and an area where photographs are represented. The area where the characters are represented includes the characters “ABAB” on the first line, “BABA” on the second line, and “ABAB” on the third line. This image data is subjected to edge discrimination processing using a secondary differential filter, for example, to extract edge pixels. As a result, an edge image including only the region represented by the characters shown in FIG. 5B is generated. Here, an example will be described in which an edge image includes a region where characters are represented, but in addition to characters, regions where symbols, lines, and line drawings are represented are included as well.

  (2) Next, the edge discrimination result is sequentially scanned to detect pixels discriminated as edge pixels, and the detected pixel is set as a reference pixel.

  (3) Then, the continuity of the edge region is detected with reference to the reference pixel. Edge region continuity is detected by enlarging the rectangle so that there is no edge pixel on the side of the rectangle with reference to the reference pixel, and using the largest rectangle with the edge pixel on the side of the rectangle as the reference region , Detect its position and size. The reference area is specified by the position in the image data and the size of the rectangle. FIG. 5C shows a character region extracted from the edge image shown in FIG. Each character area is indicated by a dotted rectangle.

  The reference area extraction unit 111 extracts an arbitrary character area from the extracted character areas as a reference area.

  FIG. 6 is a diagram illustrating an example of a rectangular enlargement method in the edge region continuity detection process. Edge region continuity detection processing includes a method of scanning from left to right, a method of scanning from the center to the left and right, and a method of scanning from the right to the left. 6A shows a method for scanning from left to right, FIG. 6B shows a method for scanning from the center to the left and right, and FIG. 6C shows a method for scanning from right to left.

  With reference to FIG. 6A, the method of scanning from left to right determines whether or not an edge pixel exists on the side of the rectangle 11 in the rectangle 11 having the reference pixel 10 as the upper left vertex, If present, the same processing is performed with the rectangles enlarged in the order of the rectangles 12, 13, 14, and 15. A region defined by a rectangle smaller than the rectangle in which the edge pixel no longer exists is defined as a character region. For example, when it is detected that no edge pixel exists on the side of the rectangle 14, a region surrounded by the rectangle 13 having the reference pixel 10 as the upper left vertex is set as a character region.

  With reference to FIG. 6B, the method of scanning from the center to the left and right is to determine whether or not an edge pixel exists on the side of the rectangle 21 with the rectangle 21 on the upper side having the reference pixel 20 as a midpoint. If present, the same processing is performed on the rectangles 22, 23, 24, and 25 that are enlarged in this order. A region defined by a rectangle smaller than the rectangle in which the edge pixel no longer exists is defined as a character region. For example, when it is detected that no edge pixel exists on the side of the rectangle 24, the region surrounded by the rectangle 23 on the upper side with the reference pixel 20 as the middle point is set as the character region.

  With reference to FIG. 6C, the method of scanning from right to left determines whether or not an edge pixel exists on the side of the rectangle 31 in the rectangle 31 having the reference pixel 30 as the upper right vertex, If present, the same processing is performed with the rectangles enlarged in the order of the rectangles 32, 33, 34, and 35. A region defined by a rectangle smaller than the rectangle in which the edge pixel no longer exists is defined as a character region. For example, when it is detected that no edge pixel exists on the side of the rectangle 34, a region surrounded by the rectangle 33 having the reference pixel 30 as an upper right vertex is set as a character region.

  Three methods have been described for edge region continuity detection processing, but these methods may be used alone, in combination with any two, or in combination. By combining two or more, the character region can be extracted more accurately.

  The character region can be extracted by obtaining a circumscribed rectangle of the edge pixel in the edge image.

  Next, a specific example of processing in which the reference region extraction unit 111 extracts a reference region based on the brightness of the pixel will be described.

  (1) A pixel having the highest brightness in the image data is extracted and set as a reference pixel.

  (2) Then, the rectangle based on the reference pixel is expanded until a pixel whose brightness difference based on the reference pixel exceeds a predetermined range is included, and the brightness difference based on the reference pixel is A maximum rectangle including pixels within a predetermined range is set as a reference area, and its position and size are detected. The reference area is specified by the position in the image data and the size of the rectangle.

  (3) When the next reference area is determined, the brightness is lowered in (1) to determine the reference pixel, and the process in (2) is executed.

  Further, the process of extracting the reference area based on the brightness of the pixel may use an area having a predetermined shape and size from the area where the photograph is represented as the reference area.

  FIG. 7 is a flowchart showing a flow of processing executed by the image processing apparatus according to the first embodiment. Referring to FIG. 7, image processing apparatus 100 reads image data from image memory 104, and extracts a reference area (step S01). And it memorize | stores in the reference area memory | storage part 115 as the reference area information which linked | related the pixel value of the extracted reference area, and the position in image data (step S02).

  Then, a similar area similar to the extracted reference area is extracted from the image data (step S03). In the extraction of the similar area, an area having the same size as the reference area is extracted from the image data, and when the processing area is similar to the reference area, the processing area is extracted as the similar area. The processing area is moved in the image data until a processing area similar to the reference area is extracted. If the processing area similar to the reference area is not extracted even if the processing area is moved to the end of the image data, the similar area is not extracted.

  In the next step S04, it is determined whether or not a similar region has been extracted. If extracted, the process proceeds to step S05, and if not, the process proceeds to step S07. In step S05, a code in which the position of the reference area extracted in step S01 in the image data, the position of the similar area extracted in step S03 in the image data, and the size of the reference area is generated is generated. The generated code is stored in the code storage unit 117 (step S06).

  In step S07, it is determined whether or not there is a processing region to be processed for extracting a similar region in step S03. When it exists, it returns to step S03, and when it does not exist, it progresses to step S09. In the processing from step S03 to step S07, when there are a plurality of regions similar to the one reference region extracted in step S01 in the image data, all of the similar regions are extracted as similar regions.

  In step S08, it is determined whether or not an area to be the next reference area exists in the image data. This determination is determined to be true when, for example, the image data obtained by deleting the reference area and the similar area extracted from the image data so far is a solid image. Further, it may be determined to be true when there is an area excluding the reference area and the similar area. Furthermore, it may be determined to be true when an edge pixel exists in an area excluding the reference area and the similar area. Furthermore, it may be determined to be true when pixels having different brightness values exist in a region excluding the reference region and the similar region.

  In step S08, if it is determined that there is a reference area to be processed next, the process returns to step S01, a new reference area is extracted, and the processes in steps S03 to S07 described above are repeated.

  If it is determined in step S08 that there is no reference area to be processed next, the process proceeds to step S09. In step S09, erased data is generated by erasing all similar regions extracted in step S03 from the image data. In the next step S10, the erased data is compressed by a predetermined compression method. The compression method may be reversible compression or irreversible compression.

  Then, the code is read from the code storage unit 117 (step S11), and the read code and the erased data (compressed data) compressed at step S08 are transmitted from the transmission unit 123 to another computer or MFP connected to the communication line. (Step S12).

  Next, a similar region extraction process executed by the edge comparison unit 125A will be described in detail. The edge comparison unit 125A determines a processing area to be compared from the character areas described with reference to FIG. The processing area is determined as an area determined by moving the image data in the horizontal direction or the vertical direction in units of one pixel in the same shape and size as the reference area.

  FIG. 8 is a flowchart showing the flow of the similar region extraction process executed in step S03 of FIG. Here, the processing after the processing region to be compared with the reference region in order to extract the similar region is shown. The similar region extraction process shown in FIG. 8 is a process executed by the edge comparison unit 125A. Here, it is assumed that the pixel value takes a value from 0 to 255, the lightness increases as the value increases, and the character is composed of pixels with low lightness.

  Referring to FIG. 8, first, an extension process is executed on the processing area to extend the line (step S21). The expansion processing is processing for setting the pixel value of each pixel as the minimum value of the pixel values of the pixel and the surrounding pixels for all the pixels of the processing target image. By this expansion processing, points in the processing area are expanded. A processing area in which this extension processing is executed is called an extension processing area. Then, a reduction process is executed on the reference area to reduce the line (step S22). The reduction processing is processing for setting the pixel value of each pixel as the maximum value of the pixel values of the pixel and the surrounding pixels for all the pixels of the processing target image. By this reduction processing, the points in the reference area are reduced. The reference area on which the reduction process has been executed is referred to as a reduced reference area.

  In the expansion process or the reduction process, for example, a 3 × 3 filter can be used. The size of the filter is appropriately determined according to the size of characters, the thickness of lines, and the like.

  Next, the corresponding pixel values in the extended processing area and the reduced reference area are compared (step S23). As a result of the comparison, it is determined whether or not all pixel values in the reduced reference area are equal to or larger than the corresponding pixel values in the extended processing area (step S24). If true, the process proceeds to step S25. finish.

  Next, a reduction process is performed on the processing area to reduce the line (step S25). The processing area where the reduction process is executed is called a reduction process area. Then, an extension process is executed on the reference area to extend the line (step S26). The reference area in which this extension process has been executed is called an extended reference area. Next, the corresponding pixel values of the reduction processing area and the extended reference area are compared (step S27). As a result of the comparison, it is determined whether or not all the pixel values in the reduction processing area are equal to or larger than the corresponding pixel values in the expansion reference area (step S28). If true, the process proceeds to step S29. finish. In step S29, the processing area is extracted as a similar area, and the process ends.

  In the edge comparison unit 125A described above, pixel values are compared between the reference region and the processing region. In this case, the image data is premised on monochrome binary data or multi-value gray scale data. When the image data is color, one pixel is composed of three pixel values of red (R), green (G), and blue (B). When the image data is color, the edge comparison unit 125A may perform (1) comparison by brightness (shape comparison) and (2) comparison by hue in addition to brightness. The comparison by brightness is the same as in the case of the above-described black and white binary or gray scale, and therefore description thereof will not be repeated here.

When comparing by hue in addition to lightness comparison, (1) When image data is converted from RGB color space to L * a * b * color space, and (2) Lightness L is compared and it is determined that they are similar (3) If the difference in the ratio of a * and b * between the reference area and the reference area is within a predetermined value, it is determined that they are similar. By comparing the hue in addition to the lightness and determining the analogy, the analogy can be determined more accurately. Further, saturation may be added to the analogy determination. In the comparison of saturation, if the difference between ((a *) ² + (b *) ² ) between the reference area and the reference area is within a predetermined value, it is determined that they are similar. By comparing the lightness and hue in addition to the saturation, the analogy can be determined more accurately.

  Next, similar region extraction processing executed by the lightness comparison unit 125B will be described in detail. The brightness comparison unit 125B determines the processing area by scanning all of the image data. That is, the processing area is determined by moving the image data in units of one pixel in the horizontal direction or the vertical direction with the same shape and size as the reference area. Further, the processing area may be an area having a predetermined size and shape existing in an area where a photograph or a figure is represented.

  FIG. 9 is another flowchart showing the flow of the similar region extraction process executed in step S03 of FIG. The similar region extraction process illustrated in FIG. 9 is a process executed by the brightness comparison unit 125B. Here, the processing after the processing region to be compared with the reference region in order to extract the similar region is shown. Actually, the processing area is determined by scanning all of the image data. That is, the processing area is determined by moving the image data in units of one pixel in the horizontal direction or the vertical direction with the same shape and size as the reference area.

  Referring to FIG. 9, first, a difference image between the reference area and the processing area is generated (step S31). Then, the absolute value sum of the pixel values of the difference image is calculated (step S32). It is determined whether or not the calculated absolute value sum is smaller than a predetermined threshold value T (step S33). If true, the process proceeds to step S34, and if false, the process ends. In step S34, the processing area is extracted as a similar area, and the process ends.

  According to the image processing apparatus 100 in the first embodiment, the similar area that is a part of the image data is encoded in association with the reference area that is a part of the image data. Need not be used.

  In addition, since the erased data in which the similar area is erased from the image data is compressed, it can be compressed at a high compression rate. For this reason, the data amount of image data can be reduced.

  In addition, since the amount of data transmitted from the transmission unit 123 is reduced, the time required for communication can be shortened.

<First Modification of Image Processing Unit>
FIG. 10 is a functional block diagram illustrating an outline of functions of the image processing unit in the first modification. Referring to FIG. 10, the image processing unit 103 </ b> A is different from the image conversion unit 201 of the image processing unit 103 described above. The image conversion unit 201A of the image processing unit 103A in the first modification includes a block division unit 202 that divides image data into a plurality of blocks, a reference region extraction unit 111 that extracts a reference region from the plurality of blocks, A similar region extraction unit 125 that extracts a similar region similar to the reference region extracted by the reference region extraction unit 111 from a plurality of blocks, and a code that associates the similar region extracted by the similar region extraction unit 125 with the reference region Includes a code generation unit 127 for generating.

  The block dividing unit 202 reads the image data stored in the image memory 104 and divides the read image data into a plurality of blocks. The block size may be determined in advance, or may be determined according to the size of the image data.

  The reference area extracting unit 111 extracts an arbitrary block as a reference area from among a plurality of blocks obtained by dividing the image data by the block dividing unit 202.

  The similar area extracting unit 125 extracts a block similar to the reference area extracted by the reference area extracting unit 111 from the plurality of blocks obtained by dividing the image data by the block dividing unit 202 as a similar area.

  Since the image processing unit 103A in the first modification extracts the reference region and the similar region from the plurality of blocks, the processing can be simplified and the processing speed can be improved.

<Second Modification of Image Processing Unit>
The image processing unit 103 compresses erased data and transmits the compressed erased data and code. The image processing unit 103B according to the second modification is different in that the erasure data is compressed, and composite data obtained by combining the compressed erasure data and the code is transmitted.

  FIG. 11 is a functional block diagram illustrating an outline of functions of the image processing unit in the second modification. Referring to FIG. 11, image processing unit 103 </ b> B in the second modification is different from image processing unit 103 in that a synthesizing unit 133 is provided between compression unit 131 and transmission unit 123. Since other configurations are the same, description thereof will not be repeated here.

  The synthesis unit 133 synthesizes the image data compressed by the compression unit 131 and the code stored in the code storage unit 117. The synthesizing unit 133 synthesizes the compressed data compressed by the compressing unit 131 and the code read from the code storage unit 117 into one synthesized data that can be distinguished. For example, the header portion includes a code, and the main body portion includes erasure data.

  Note that the image conversion unit 201A of the image processing unit 103A in the first modification can be applied to the image processing unit 103B in the second modification.

<Third Modification of Image Processing Unit>
The image processing unit 103B according to the second modification compresses erased data, combines the compressed erased data and the code, and transmits the synthesized data. The image processing unit 103C in the third modification is different in that the erasure data and the code are combined, the combined data is compressed by a lossless compression method, and the compressed combined data is transmitted. Since other configurations are the same, description thereof will not be repeated here.

  FIG. 12 is a functional block diagram showing some functions of the image processing unit in the third modification. Referring to FIG. 12, modified image processing unit 103 </ b> C synthesizes erasure data and code, synthesizer 133, and reversible compression unit 137 that compresses the synthesized data output from synthesizer 133 by a lossless compression method. Including. The synthesizing unit synthesizes the erased data input from the image erasing unit 119 and the code read from the code storage unit 117 into one synthesized data that can be distinguished. For example, the composite data includes a code in the header portion and erase data in the main body portion. The lossless compression unit 137 compresses the composite data using a lossless compression method. The lossless compression method is used to reliably reproduce the code when the compressed composite data is expanded.

  Note that the image processing unit 103C in the third modification can apply the image conversion unit 201A of the image processing unit 103A in the first modification.

<Fourth Modification of Image Processing Unit>
The image processing unit 103D according to the fourth modified example compresses the combined data obtained by combining the reference area information and the code information without creating erasure data, and transmits the compressed data.

  FIG. 13 is a functional block diagram illustrating an outline of functions of the image processing unit in the fourth modification. Referring to FIG. 13, the image processing unit 103D includes an image conversion unit 201, a reference region storage unit 115, a code storage unit 117, a combining unit 141 that combines reference region information and a code, and a combined composition. It includes a lossless compression unit 137 that compresses data and a transmission unit 123 that transmits the compressed data to another device.

  The lossless compression unit 137 compresses the composite data using a lossless compression method. This is to prevent the reference area information and code from being lost by compression. For this reason, the data amount of image data can be further reduced and transmitted.

  Note that the image conversion unit 201A of the image processing unit 103A in the first modification can be applied to the image processing unit 103C in the fourth modification.

<Fifth Modification of Image Processing Unit>
The image processing unit 103E in the fifth modification synthesizes the reference area information and the code information without creating erase data, and transmits the synthesized data.

  FIG. 14 is a functional block diagram illustrating an outline of functions of the image processing unit in the fifth modification. Referring to FIG. 14, the image processing unit 103E includes an image conversion unit 201, a reference region storage unit 115, a code storage unit 117, a combining unit 141 that combines reference region information and a code, and a combined composition. And a transmission unit 123 that transmits data to other devices.

  The synthesis unit 141 reads the reference area information stored in the reference area storage unit 115 and the code stored in the code storage unit 117 and combines them to generate synthesized data. The composite data is data in a format in which the reference area information and the code are distinguished. For example, the header includes a code, and the main body includes reference area information.

  As described with reference to FIG. 3, the reference area information includes the position of the reference area in the image data, the size, and the reference area itself. Therefore, the device on the side that has received the reference area information can reproduce erased data including the reference area from the reference area information. Further, as described with reference to FIG. 4, the code includes the position of the similar area in the image data, the position of the similar reference area and the size thereof. For this reason, the device that has received the reference area information and the code can reproduce the image data from the reproduced erased image.

  Further, since the synthesized data obtained by synthesizing the reference area information and the code is transmitted, the amount of data can be reduced without compressing the image data. The reference area is left as bitmap data, but the reference area similar to the reference area is coded in association with the reference area, so that the amount of data is reduced while maintaining the image of the image data. be able to.

  Note that the combined data obtained by combining the reference area information and the code information is transmitted, but the reference area information and the code information may be transmitted separately without being combined. This is because the image data can be reproduced if the receiving device can detect that the reference area information and the code are related.

  Note that the image conversion unit 201A of the image processing unit 103A in the first modification can be applied to the image processing unit 103E in the fifth modification.

<Second Embodiment>
Although the image processing apparatus according to the first embodiment has been described above, the processing executed by these image processing apparatuses can also be realized by a general computer.

  FIG. 15 is a block diagram illustrating an outline of a hardware configuration of a computer. Referring to FIG. 15, a computer 300 is executed by a CPU (Central Processing Unit) 301 and a ROM (Read Only Memory) 302 storing programs sent to the operating system, which are connected to the bus 307. RAM (Random Access Memory) 303 for storing a program to be executed and data for executing the program, a hard disk 304, a communication unit 306 for connecting the computer 300 to the communication line 314, and a mouse 308 A keyboard 309, a display unit 310, an image scanner 311, a printer 312, and a CD-ROM (Compact Disc Read Only Memory) drive 305. A CD-ROM 313 is attached to the CD-ROM drive 305. Since the operation of the computer thus configured is well known, detailed description thereof will not be repeated here.

  The operation panel 109 of the image processing apparatus 100 illustrated in FIG. 1 includes a display unit 310, a mouse 308 or a keyboard 309, an image reading unit 102, an image scanner 311, a storage unit 106, a hard disk 304, and an image memory 104. In the RAM 303, the image processing units 103, 103A, 103B, and 103C, the control unit 101 and the panel control unit 108 correspond to the CPU 301, the transmission control unit 107 corresponds to the communication unit 306, and the image forming unit 105 corresponds to the printer 312.

  The computer 300 executes the processing shown in FIGS. 10 and 11 by executing the image processing program by the CPU 301.

  Generally, such a program is stored and distributed in a recording medium such as a CD-ROM 313, read from the recording medium by a CD-ROM drive 305 or the like, and temporarily stored in the hard disk 304. Further, it is read from the hard disk 304 to the RAM 303 and executed by the CPU 301.

  The recording medium is not limited to the CD-ROM 313 and the hard disk 304, but a flexible disk, cassette tape, optical disk (MO (Magnetic Optical Disc) / MD (Mini Disc) / DVD (Digital Versatile Disc)), IC card (memory card) A medium carrying a fixed program such as a semiconductor memory such as an optical card, a mask ROM, an EPROM, an EEPROM, or a flash ROM.

  The program here includes not only a program directly executable by the CPU 301 but also a program in a source program format, a compressed and displayed program, an encrypted program, and the like.

  The image processing apparatus according to the above-described embodiment includes the following concept.

(1) It further comprises synthesis means for synthesizing the compressed data and a code corresponding to the similar region,
The image processing apparatus according to claim 3, wherein the output unit outputs the combined data.

  According to the present invention, the compressed image data and the code corresponding to the processing area are synthesized. For this reason, image data and a code can be handled as one data.

(2) erasing means for erasing the extracted similar region from the input image data;
A synthesizing unit that synthesizes the image data from which the similar area is erased and a code corresponding to the similar area;
Compression means for compressing the data synthesized by the synthesis means by a reversible compression method,
The image processing apparatus according to claim 1, wherein the output unit outputs the data compressed by the compression unit.

  According to the present invention, since the image data and the code are combined and then compressed by a reversible compression method, the compression rate can be increased and the code can be reliably restored.

(3) combining means for combining the reference region, the position of the reference region in the image data, and the code corresponding to the similar region;
Compression means for compressing the data synthesized by the synthesis means by a reversible compression method,
The image processing apparatus according to claim 1, wherein the output unit outputs the data compressed by the compression unit.

  (4) The image processing apparatus according to claim 1, wherein the similar region extraction unit includes a comparison unit that compares the arrangement of the edge pixels included in the processing target region and the edge pixels included in the reference region.

  According to the present invention, since the arrangement of edge pixels is compared, the same region as the reference region including characters, symbols, and the like including lines and dots, and the similar region including characters, symbols, and the like are extracted. For this reason, characters, symbols, and the like made up of lines, points, etc. can be coded.

(5) The similar region extraction unit includes an expansion unit that replaces a pixel value with a minimum value of surrounding pixels;
Reduction means for replacing the pixel value of the pixel included in the processing target area with the maximum value of the surrounding pixels,
Each pixel value of the reduced reference area obtained by reducing the reference area by the reducing means is equal to or greater than the corresponding pixel value of the extended processing area obtained by extending the processing target area by the extending means, and the processing target by the reducing means. The reference area and the processing target area are similar on the condition that each pixel value of the reduced processing area obtained by reducing the area is equal to or greater than the corresponding pixel value of the extended reference area obtained by extending the reference area by the extension means. The image processing device according to claim 1, wherein the image processing device is determined to be.

  According to this invention, the analogy can be accurately determined, and a similar region can be accurately extracted.

  (6) The image processing apparatus according to claim 1, wherein the similar region extraction unit includes a comparison unit that compares brightness of a pixel included in the processing target region and a pixel included in the reference region.

  According to the present invention, since the brightness of the pixels is compared, it is possible to code an area where a photograph or a figure is represented.

  (7) In (6), the comparison means includes determination means for determining whether or not a difference image between the processing target area and the reference area satisfies a predetermined condition.

  According to the present invention, it is possible to easily extract a similar area from areas where photographs, figures, and the like are represented.

  (8) The image processing apparatus according to (1), wherein the input unit includes a document reading unit that optically reads a document.

  (9) The image processing apparatus according to (1), further comprising an image forming unit that forms an image of the image data input by the input unit on a recording medium.

(10) The image data includes three color values of red, green, and blue per pixel,
The similar region extraction means includes a color space conversion means for converting the image data into an L * a * b * color space;
Expansion means for replacing the L * value of the pixel to be processed with the maximum L * value of surrounding pixels;
Reduction means for replacing the L * value of the pixel to be processed with the minimum L * value of surrounding pixels;
The L * value of each pixel in the reduced reference area obtained by reducing the reference area by the reducing means is equal to or greater than the L * value of the corresponding pixel in the extended processing area obtained by extending the processing area by the extending means, and the reducing means. The reference region is provided on the condition that the L * value of each pixel of the reduced processing region obtained by reducing the processing region by the expansion means is equal to or greater than the L * value of the corresponding pixel of the extended reference region obtained by extending the reference region by the extension means. The image processing apparatus according to claim 1, further comprising: a shape comparison unit that determines that the processing area is similar to the processing area.

  According to the present invention, it is possible to determine the similarity of the shape of the reference region to be compared.

  (11) In the image processing device according to (10), the similar region extraction unit is configured on the condition that a difference in L * values of corresponding pixels between the reference region and the processing region is equal to or less than a predetermined value. And a luminance comparison means for determining that the reference area is similar to the processing area.

  According to the present invention, since the similarity of luminance is determined in addition to the similarity of the shape of the reference region to be compared, the similarity can be determined more accurately.

  (12) In the image processing apparatus according to (10), the similar region extraction unit has a ratio of a * value and b * value of corresponding pixels in the reference region and the processing region equal to or less than a predetermined value. It further includes a hue comparison unit that determines that the reference area is similar to the processing area on the condition that the difference is a difference.

  According to the present invention, the similarity of the hue is determined in addition to the similarity of the shape and brightness of the reference region to be compared, so that the similarity can be determined more accurately.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a diagram illustrating an overall outline of an image processing apparatus according to a first embodiment of the present invention. 2 is a functional block diagram illustrating an outline of functions of an image processing unit of the image processing apparatus according to the first embodiment. FIG. It is a figure which shows an example of the reference area information memorize | stored in a reference area memory | storage part. It is a figure which shows an example of the code memorize | stored in the code memory | storage part. It is a figure which shows an example of image data, an edge image, and a character area. It is a figure which shows an example of the expansion method of the rectangle in the detection process of the continuity of an edge area | region. 3 is a flowchart showing a flow of processing executed by the image processing apparatus according to the first embodiment. It is a flowchart which shows the flow of the similar area | region extraction process performed by step S03 of FIG. It is another flowchart which shows the flow of the similar area | region extraction process performed by step S03 of FIG. It is a functional block diagram which shows the outline | summary of the function of the image process part in a 1st modification. It is a functional block diagram which shows the outline | summary of the function of the image process part in a 2nd modification. It is a functional block diagram which shows a part of function of the image process part in a 3rd modification. It is a functional block diagram which shows the outline of the function of the image process part in a 4th modification. It is a functional block diagram which shows the outline of the function of the image process part in a 5th modification. It is a block diagram which shows the outline of the hardware constitutions of a computer.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 Image processing apparatus, 101 Control part, 102 Image reading part, 103, 103A, 103B, 103C, 103D, 103E Image processing part, 104 Image memory, 105 Image formation part, 106 Storage part, 107 Transmission control part, 108 Panel control , 109 operation panel, 110 bus, 111 reference region extraction unit, 115 reference region storage unit, 117 code storage unit, 119 image deletion unit, 121, 121A compression / combination unit, 123 transmission unit, 125 similar region extraction unit, 127 Code generation unit, 131 compression unit, 133, 135, 141 synthesis unit, 137 lossless compression unit, 201, 201A image conversion unit, 300 computer, 304 hard disk, 305 drive, 306 communication unit, 307 bus, 308 mouse, 309 keyboard, 310 Display 311 an image scanner, 312 a printer, 314 communication line.

Claims (6)

Input means for inputting image data;
A reference area extracting means for extracting a part of the input image data as a reference area;
Similar region extraction means for extracting a similar region similar to the extracted reference region from the input image data;
Code generating means for generating a code in which the extracted similar region is associated with the reference region;
An image processing apparatus comprising: an output unit that outputs the extracted reference area and a code corresponding to the similar area in a predetermined form. Block division means for dividing the input image data into a plurality of blocks;
The reference area extracting means extracts any of the plurality of blocks as a reference area;
The image processing apparatus according to claim 1, wherein the similar area extracting unit extracts a block similar to the reference area as the plurality of blocks as a similar area. Erasing means for erasing the extracted similar region from the input image data;
Compression means for compressing the image data from which the similar area has been deleted,
The image processing apparatus according to claim 1, wherein the output unit outputs the reference area as data compressed by the compression unit.   The image processing apparatus according to claim 1, wherein the output unit includes a transmission unit that transmits the extracted reference area and a code corresponding to the similar area to another apparatus in a predetermined form.   The image processing apparatus according to claim 1, wherein the code generation unit generates a code including at least a position of the similar area in the image data and a position of the reference area in the image data. Inputting image data;
Extracting a part of the input image data as a reference area;
Extracting a similar region similar to the extracted reference region from the input image data;
Generating a code associating the extracted similar region with the reference region;
An image processing program causing a computer to execute the step of outputting the extracted reference area and the code corresponding to the similar area in a predetermined form.

Images