JP2008167352A - Image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate blurring in an image read from an object such as a book having a binding part, and to deal with a request for accelerating a reading speed. <P>SOLUTION: On the basis of a document distance detected by a document distance detecting unit 105, a focal distance control unit 106 controls the position of a focusing lens so as to focus a document 20. A main control unit 101c reads image data of a binding part from a position of a line, which is the position of the focusing lens controlled by the focal distance control unit 106, indicating the main scanning direction used for the document distance detection unit 105 for detecting the document distance to an ending position of the binding part detected by a binding part position detection unit 104. An image compositing unit 110 overwrites the image data of the binding part, read by the main control unit 101c on document image data that are being stored in a document image data storage region 103d included in a storage unit 103. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that reads an image of a subject having a binding portion.

2. Description of the Related Art Conventionally, an image input device has been proposed that can focus on all surfaces of a subject having a binding portion of a book and obtain a beautiful image without blurring (see, for example, Patent Document 1). This image input device measures the distance between the line sensor and the subject for each line by scanning a line sensor arranged in parallel with the binding portion in the same direction as the binding portion. The image input device scans the line sensor based on the measurement data while controlling the optical system so that an image of the subject is formed on the line sensor.
JP-A-5-316302

  However, in the image input device described in Patent Document 1, as described above, when the line sensor is scanned line by line in the direction of the binding portion and the image of the subject is read, the distance between the line sensor and the subject in advance. Then, since the image is read while controlling the optical system based on the measurement data, there is a problem that it is not possible to meet the demand for higher reading speed.

  Further, in the image input device described in Patent Document 1, after measuring the distance between the line sensor and the subject, the image is only read while controlling the optical system based on the measurement data. The density value of the pixel of the image data in a certain binding part is not corrected, and the density of the image in the binding part and the density of the other part do not harmonize with each other, which may cause an unnatural image. There was a point.

  Therefore, in view of the above-described problems, the present invention can increase the reading speed without performing a wasteful process of measuring in advance the distance between the line sensor and the subject at a place other than the binding portion of the subject. An object of the present invention is to provide a simple image processing apparatus.

  Another object of the present invention is to provide an image processing apparatus in which the density of an image in a binding portion of a subject and the density of other portions can be harmonized with each other.

  In order to solve the above problems, an invention according to claim 1 is an image reading unit that reads an image of a document stacked on a document stacking surface, and a separation region detection unit that detects a separation region between the document and the document stacking surface. And a document distance detection unit that detects a document distance between the document and the document stacking surface, a focal length adjustment unit that adjusts a focal distance between the document and the document in the image reading unit, and a separation area detection unit. A reading control unit that reads the region by adjusting the focal point by the focal length adjustment unit;

  According to this configuration, since the reading control unit reads the region detected by the separated region detection unit by adjusting the focal point by the focal length adjustment unit, it is possible to meet the demand for higher reading speed.

  As described above, according to the present invention, there is no need to perform a wasteful process of previously measuring the distance between the line sensor and the subject at a place other than the binding portion of the subject, and the demand for higher reading speed is met. be able to.

  Further, according to the present invention, it is possible to harmonize the image density of the binding portion of the subject with the density of other portions.

  Next, the best mode for carrying out the present invention will be described.

  FIG. 1 is a block diagram showing the configuration of the first embodiment of the image processing apparatus according to the present invention. As shown in the figure, this image processing apparatus is an apparatus such as a scanner for reading an original 20, and includes a control unit 100, a glass plate 120, a carriage 130, and a carriage driving unit 140. .

  As shown in FIG. 2, the control unit 100 includes a main control unit 101c, a density correction unit 102, a storage unit 103, a binding unit position detection unit 104, a document distance detection unit 105, a focal length control unit 106, an image processing unit 107, An I / F 108, an A / D converter 109, and an image composition unit 110 are provided.

  The main control unit 101c controls a CCD line sensor (described later), a light source (described later), and a carriage driving unit 140, and includes a gamma correction unit 101a, a background removal unit 101b, and a main control unit 101c. ing.

  The gamma correction unit 101a includes a γ table that converts the density from the input light amount, and refers to the γ table, and an image that indicates the density from the light amount indicated in the digital image signal input from the A / D converter 109. Generate data.

The background removal unit 101 b detects the background density that is the lowest density value among several lines after starting the reading of the document, and stores the background density in the storage unit 103. Then, the background removal unit 101 b calculates a background removal density value according to the following formula, and outputs the background removal density value to the density correction unit 102.
Background removal density value = (read density value−background density value) / (255−background density value) * 255 Expression 1
Here, the read density value is the density value of the image data output from the gamma correction unit.

The density correction unit 102 uses the density correction amount Den corresponding to the assumed original distance D, which is a detection result of the original distance detection unit 105 described later, and uses the density value of the original image data input from the main control unit 101c ( (Described as the input image density value in the following expression 1) is corrected using the following expression 1, and the image data having the corrected image density value is written in the storage unit 103.
Corrected image density value = (background removal density value−density correction amount Den) / (255−density correction amount Den) × 255 Formula 2

  The density correction amount Den corresponding to the assumed original distance D is used when the corrected image density value is calculated by Equation 1, and the original assumption shown in FIG. 3A registered in the storage unit 103 is used. The distance D-density correction amount Den table 103a is described.

  The storage unit 103 is a memory device such as a RAM or a hard disk device, and includes an assumed original distance D-density correction amount Den table 103a, a background density value range-original distance table 103b, sub-scanning coordinates-original distance information d ( Y) It has a table 103c, a document image data storage area 103d, and a binding part image data storage area 103e.

  As shown in FIG. 3A, the assumed original distance D-density correction amount Den table 103a is a table showing the relationship between the assumed original distance D and the density correction amount Den. For example, the assumed original distance D is 0. In this case, since the original 20 and the glass plate 120 are in close contact with each other and it is not necessary to perform density correction, the density correction amount Den is zero. When the assumed original distance D = 2, there is a gap between the original 20 and the glass plate 120, and it is necessary to perform density correction, so the density correction amount Den is 64. Note that the density correction amount Den when the assumed original distance D is other than 0 is a value obtained through experiments.

  As shown in FIG. 3B, the background / background density value range-document distance table 103b includes a range of density values of the read document image data and a gap distance between the document 20 and the glass plate 120 (hereinafter, referred to as a distance value). For example, when the density value range is 0 to 31, the document distance indicating that the document 20 is in close contact with the glass plate 120 is 0, and the density value is Is 64 to 95, the document distance is 2. The relationship between the density value and the document distance is a value obtained in advance by experiments. Here, the background density refers to the minimum density detected for each reading line.

  As shown in FIG. 3C, the sub-scanning coordinate-original distance information d (Y) table 103c includes a binding portion and a glass plate of the original 20 in each line in the main scanning direction having a sub-scanning coordinate indicating a binding portion position. The sub-scanning coordinate-document distance information d (Y) data in which document distance information d (Y) indicating the distance to 120 is described is stored. FIG. 3C shows that the density value increases toward the center of the binding portion, and the document 20 is lifted from the glass plate 120.

  The original image data storage area 103d stores original image data of the original 20 that has not been corrected when the assumed original distance D is zero.

  The binding portion image data storage area 103e stores binding portion image data (hereinafter referred to as binding portion image data) for correcting the document image data stored in the document image data storage region 103d. In the binding portion image data, image data of the document 20 read with a document original distance D other than 0 is stored.

  The binding portion position detection unit 104 reads the original image data of the read original 20 from the original image data storage area 103d in the storage unit 103, performs a conventionally known edge detection process on the original image data, and outputs the original document data. Detect edge distortion. Then, the binding portion position detection unit 104 detects the sub-scanning coordinate Ystart indicating the start position of the binding portion and the sub-scanning coordinate Yend indicating the end position of the binding portion from the distortion of the document edge. The scanning coordinate Yend is output to the main control unit 101 c and the document distance detection unit 105.

  The method for detecting the binding portion position will be described in more detail with reference to FIG. 4A. First, the binding portion position detection unit 104 first includes a coordinate Lstart in the sub-scanning direction indicating a change start point of the left line L. Then, the sub-scanning direction coordinate Lend indicating the change end point is obtained, and further, the sub-scanning direction coordinates Rstart and Rend indicating the change start point of the right line lineR and the change end point of the right line lineR are indicated. A coordinate Rend in the scanning direction is detected. Here, Lstart, Lend, Rstart, and Rend are obtained when the difference in the main scanning direction of the edge image for each line calculated by the binding position detection unit 104 exceeds a preset value. is there.

  Further, the binding portion position detection unit 104 determines the sub-scanning coordinate of the smaller Lstart and Rstart as the sub-scanning coordinate Ystart indicating the binding portion start position based on the detected Lstart, Lend, Rstart, and Rend. The sub-scanning coordinate having the larger Rend is determined as the sub-scanning coordinate Yend indicating the binding end position.

  The document distance detection unit 105 includes a peak hold circuit that detects the minimum density value from the input density values G (X, Y) of pixels for one line. The document distance detection unit 105 reads the sub-scanning coordinate Ystart indicating the binding unit start position and the sub-scanning coordinate Yend indicating the binding unit end position from the binding unit position detection unit 104. The document distance detection unit 105 first reads out the document image data for one line in the main scanning direction having the sub-scanning coordinate Ystart indicating the binding unit start position from the storage unit 103, and all of the read image data. The pixel density value G (X, Y) is input to the peak hold circuit, and the lowest density value is detected.

  Further, the document distance detection unit 105 detects the minimum density value in the document image data for one line in the main scanning direction having the sub-scanning coordinate Ystart indicating the binding unit start position, and then stored in the storage unit 103 in FIG. With reference to the background density value range-document distance table 103b shown in (b), the document distance corresponding to the lowest density previously detected is read from the background density value range-document distance table 103b, and the read document distance is The document distance between the document 20 and the glass plate 120 in one line in the main scanning direction having the sub-scanning coordinate Ystart is specified.

  Further, the document distance detection unit 105 describes the sub-scanning coordinate Ystart indicating the binding portion start position and the document distance information d (Y), where the previously specified document distance is the document distance information d (Y). Sub-scanning coordinate-document distance information data is generated, and this data is stored in the generated sub-scanning coordinate-document distance information d (Y) table 103 c in the storage unit 103.

  Similarly, the document distance detection unit 105 generates sub-scanning coordinate-document distance information data for a line in the main scanning direction having the sub-scanning coordinate Yend from the line in the main scanning direction having the sub-scanning coordinate Ystart + 1. The data is stored in the sub-scanning coordinate-document distance information d (Y) table 103c generated in the storage unit 103.

  The focal length control unit 106 outputs to the lens driving unit 138 a control signal for moving the focal lens in the sub-scanning direction in accordance with the estimated original distance D input from the main control unit 101c.

As shown in FIG. 5, in order to focus and form an image on the CCD line sensor, 11 / a + 1 / b = 1 / f Equation 3
It is necessary to satisfy. Accordingly, the focal length control unit 106 outputs a control signal to the lens driving unit 138 so as to move the lens by a focal lens moving distance L (D) that satisfies the following expression.
1 / (a + D (document distance) + L (D)) + 1 / (b−L (D)) = 1 / f Equation 4

  The image processing unit 107 reads document image data in which the image data of the binding portion is corrected from the storage unit 103, binarization processing, image compression, and outputs the image data to the I / F unit 108.

  The I / F unit 108 outputs the image data input from the image processing unit 107 to a personal computer, a printer unit, or the like.

  The A / D converter 109 converts the image signal that is an analog signal output from the CCD line sensor into image data that is an 8-bit digital signal, and sequentially outputs the image data to the main control unit 101c.

  In response to a request from the density correction unit 102, the image composition unit 110 reads the binding portion image data from the binding portion image data storage area 103e, and converts it into the original image data stored in the original image data storage area 103d included in the storage unit 103. Overwriting is performed, and then the effect of overwriting is output to the main control unit 101c.

  A glass plate 120 shown in FIG. 1 is a place where a document 20 to be read is placed. The carriage 130 reads the document 20 in units of lines while moving, and transmits the read data to the main control unit 101c. As shown in FIG. 6, the carriage 130 includes a mirror 131, a mirror 132, a mirror 133, a lens 134, a light source 135, a CCD line sensor 136, a rail 137, and a lens driving unit 138.

  The mirror 131, the mirror 132, and the mirror 133 emit the image of the document 20 reflected from the document 20 to the lens 134. The lens 134 is coupled to the lens driving unit 138 and forms an incident image of the original 20 on the CCD 136. The light source 135 is made of a fluorescent tube or the like, and irradiates the original 20 with light. The CCD line sensor 136 reads an image of the document 20 and outputs an image signal composed of an analog signal to the A / D converter 109 of the control unit 100. The rail 137 is a rail as a guide for moving the lens driving unit 138 in the sub-scanning direction. The lens driving unit 138 is controlled by the control unit 100 and moves on the rail 137 in the sub-scanning direction.

  The carriage driving unit 140 includes a motor and a belt, and moves the carriage 130 on the rail 139 in the sub scanning direction.

  The operation unit 150 includes operation keys used for the user to perform various settings when reading an image, and a liquid crystal panel that displays operation guidance and processing results.

  Next, the operation of the image processing apparatus according to the first embodiment of the present invention will be described.

  7 and 8 are flowcharts showing the operation of the image processing apparatus according to the first embodiment of the present invention. First, when a predetermined operation key on the operation unit 150 is pressed by the user, the main control unit 101c of the control unit 100 writes 0 in the numerical information i and k stored in the work area of the storage unit 103 ( Step S1).

  Next, the gamma correction unit 101a uses the γ value described in the gamma conversion table to convert the brightness of the image data of the document 20 input from the A / D converter 109 into image data composed of density values. This data is then output to the background removal unit 101b.

  The background removal unit 101 b detects the background density having the lowest density value among several lines input from the gamma correction unit 101 a and stores the background density in the storage unit 103. Thereafter, the background removal unit 101 b calculates the background removal density value according to the above-described equation 1, and outputs the background removal density value to the density correction unit 102.

  When the original 20 is read for the first time, the assumed original distance D = 0 is set, and the density correction unit 102 stores the original image data in the storage unit 103 without correcting the density of the original image data input from the background removing unit 101b. Is written in the original image data storage area 103d (step S2).

  The binding portion position detection unit 104 sequentially reads the document image data stored in the document image data storage area 103d, and performs edge detection processing for detecting the outer shape of the document 20 based on the read document image data. Next, the binding portion position detection unit 104 detects the distortion of the document edge from the outline shape of the document 20 detected by the edge detection process, and the sub-scanning coordinate Ystart indicating the start position of the binding portion from the distortion of the document edge. Then, the sub-scanning coordinate Yend indicating the binding portion end position is detected, and the sub-scanning coordinate Ystart and the sub-scanning coordinate Yend are output to the main control unit 101c and the document distance detection unit 105 (step S3).

  When the sub-scanning coordinate Ystart indicating the binding unit start position and the sub-scanning coordinate Yend indicating the binding unit end position are input from the binding unit position detection unit 104, the document distance detection unit 105 performs sub-scanning of the sub-scanning coordinate Ystart + k. It is determined whether it is below the coordinate Yend (step S4).

  If it is determined that the sub-scanning coordinate Ystart + k exceeds the sub-scanning coordinate Yend (step S4; N), the document distance detection unit 105 shifts the process to step S9. On the other hand, when the document distance detection unit 105 determines that the sub-scanning coordinate Ystart + k is equal to or less than the sub-scanning coordinate Yend (step S4; Y), the document stored in the document image data storage area 103d of the storage unit 103 is stored. From the image data, the original image data for one line in the main scanning direction located at the sub-scanning coordinate Ystart + k is read, and the density values G (X, Y) of all the pixels of the read original image data are input to the peak hold circuit. Then, the lowest density value is detected (step S5).

  Thereafter, the document distance detection unit 105 detects the minimum density value for one line in the main scanning direction located at the sub-scanning coordinate Ystart + k, and then stores the background density value range shown in FIG. -The document distance table 103b is referred to, and the document distance corresponding to the previously detected minimum density value is read (step S6).

  When the document distance detection unit 105 reads the document distance corresponding to the lowest density value detected earlier from the background density value range-document distance table 103b, the document distance detection unit 105 calculates the sub-scanning coordinate Ystart + k indicating the binding portion start position and the read document distance. Sub-scanning coordinate-document distance information data in which the document distance information d (Y) is described is generated, and this data is stored in the sub-scanning coordinate-document distance information d (Y) table 103c generated in the storage unit 103. (Step S7).

  Thereafter, the document distance detection unit 105 adds 1 to the numerical information k stored in the work area of the storage unit 103 (step S8), shifts the process to step S4, and continues the same process as described above. Let

  In step S4, when the document distance detection unit 105 determines that the sub-scanning coordinate Ystart + k exceeds the sub-scanning coordinate Yen (step S4; N), the fact is output to the main control unit 101c.

  Then, the main control unit 101c outputs a control signal for setting the carriage 130 at the position of the sub-scanning coordinate Ystart + i * n to the carriage driving unit 140 (step S9). n is the number of moving unit lines of the start line for reading by moving the focal lens.

  When a control signal for setting the carriage 130 is input from the main control unit 101c to the position of the sub-scanning coordinate Ystart + i * n, the carriage driving unit 140 sets the carriage 130 to this position (step S10).

  Thereafter, the main control unit 101c refers to the sub-scanning coordinate-document distance information d (Y) table 103c stored in the storage unit 103, and the sub-scanning in which the sub-scanning coordinate is described as Ystart + i * n (n is a positive number). Document distance information d (Y) is read from the coordinate-document distance information d (Y) data. Next, the main control unit 101c sets the read document distance information d (Y) as the assumed document distance D, and outputs this estimated document distance D to the focal length control unit 106 (step S11).

  The focal distance control unit 106 calculates the focal lens movement amount Ld (D) according to the above-described equation 4 that calculates the focal lens movement amount based on the assumed original distance D input from the main control unit 101c (step S12). A control signal for moving the focal lens 134 by the focal lens movement amount Ld (D) is output to the lens driving unit 138 included in the carriage 130.

  Then, the lens driving unit 138 of the carriage 130 moves the focal lens 134 by the focal lens movement amount Ld (D) based on the control signal input from the focal distance control unit 106 (step S13).

)
Thereafter, the main control unit 101 c outputs the estimated original distance D to the density correction unit 102.

  The density correction unit 102 refers to the assumed original distance D-density correction amount Den table 103a in the storage unit 103, and sets the assumed density correction Den corresponding to the input original assumed distance D to the assumed original distance D-density correction amount Den. Read from table 103a. Next, the density correction unit 102 sets the density correction amount Den to be read at the location of the density correction amount Den described in Equation 2 for calculating the corrected image density value (step S14), and this density correction amount Den is set. The setting is output to the main control unit 101c.

  Then, the main control unit 101c reads Yend− (Ystart + i * n) +1 line binding portion image data from the line indicated by Ystart + i * n to the line indicated by Yend from the A / D converter 209 ( In step S15, the read binding portion image data is output to the density correction unit 102.

  The density correction unit 102 stores the binding unit image data obtained by correcting the density value of the binding unit image data input from the main control unit 101c using Expression 2 in which the previously set density correction amount Den is described. The data is written in the binding portion image data storage area 103e in 103 (step S16). Next, the main control unit 101c requests the image composition unit 210 to overwrite the original image data stored in the original image data storage area 103d with the binding part image data stored in the binding part image data storage area 103e. Output.

  Then, the image composition unit 210 reads the binding part image data from the binding part image data storage area 103e, and the original image from the line indicated by Ystart + i * n stored in the storage part 103 to the line indicated by Yend. The data is overwritten (step S17), and the overwriting is output to the main control unit 101c.

  Thereafter, the main control unit 101c adds 1 to the numerical information i stored in the work area of the storage unit 103 (step S18). Next, the main control unit 101c determines whether or not the sub-scanning coordinate Ystart + i * n is equal to or less than Yend (step S19), and determines that the sub-scanning coordinate Ystart + i * n is equal to or less than Yend (step S19). S19; Y), the process proceeds to step 9, and the same process as described above is continued. On the other hand, if the main control unit 101c determines that the sub-scanning coordinate Ystart + i * n is not less than Yend (step S19; N), for example, a request for executing image processing such as binarization processing and image compression processing is performed on the image. The data is output to the processing unit 107.

  When the above request is input from the main control unit 101c, the image processing unit 107 reads out the original image data stored in the original image data storage area 103d of the storage unit 103 based on this request, and binarizes it. Image processing such as processing and image compression processing is performed (step S20), and the document image data subjected to the image processing is output to the I / F unit 108.

  The I / F unit 108 transmits the document image data input from the image processing unit 107 to the host (step S21), and ends the process.

  FIG. 9 is a diagram for explaining the content of the original image data stored in the original image data storage area 103d of the storage unit 103 being overwritten on the binding portion image data by repeating the operations from step S9 to step S21.

  As shown in FIG. 9A, when i is 0, sub-scanning starts from the line indicated by the sub-scanning coordinate Ystart in the original image data stored in the original image data storage area 103d in the storage unit 103. The document image data for Yend-Ystart + 1 line of the line indicated by the coordinate Yend is Yend-Ystart + 1 line of the line indicated by the sub-scanning coordinate Yend from the line indicated by the sub-scanning coordinate Ystart read and read in the process of step S15. Is overwritten in step S17.

  As shown in FIG. 9B, when i is 1, from the line indicated by the sub-scanning coordinate Ystart + 1 * n in the document image data stored in the document image data storage area 103d of the storage unit 103. The original image data for Yend− (Ystart + 1 * n) +1 line of the line indicated by the sub-scanning coordinate Yend is changed from the line indicated by the sub-scanning coordinate Ystart + 1 * n read and read in the process of step S15 to the sub-scanning coordinate Yend. The Yend− (Ystart + 1 * n) +1 line binding portion image data of the indicated line is overwritten in step S17.

  As shown in FIG. 9C, when i is 2, from the line indicated by the sub-scanning coordinate Ystart + 2 * n in the document image data stored in the document image data storage area 103d of the storage unit 103. The original image data for Yend− (Ystart + 2 * n) +1 line of the line indicated by the sub-scanning coordinate Yend is changed to the sub-scanning coordinate Yend from the line indicated by the sub-scanning coordinate Ystart + 2 * n read and read in step S15. The Yend− (Ystart + 2 * n) +1 line binding portion image data of the indicated line is overwritten in step S17.

  As shown in FIG. 9D, when i is m, from the line indicated by the sub-scanning coordinate Ystart + m * n in the document image data stored in the document image data storage area 103d in the storage unit 103. The original image data for Yend− (Ystart + m * n) +1 line of the line indicated by the sub-scanning coordinate Yend is changed to the sub-scanning coordinate Yend from the line indicated by the sub-scanning coordinate Ystart + m * n read and read in step S15. The Yend− (Ystart + m * n) +1 line binding portion image data of the indicated line is overwritten in step S17.

  N described in the sub-scanning coordinate Ystart + i * n may be 1. However, since it is unlikely that the document distance is changed for each line, the image of n is not blurred for high-speed processing. A large number indicating a plurality of lines may be used.

  According to the first embodiment, the image data of the sub-scanning coordinate Yend indicating the binding portion end position is read from the sub-scanning coordinate Ystart + i * n stored in the binding portion image data storage area 103e, which is read by the main control unit 101c. Since the image composition unit 110 overwrites the document image data stored in the document image data storage area 103d, the distance between the line sensor and the subject is measured in advance at a location other than the binding portion of the document 20. This eliminates the need for unnecessary processing that has been performed by this apparatus, and can meet the demand for higher reading speed.

  Further, according to the first embodiment, the density correction unit 102 refers to the assumed original distance D-density correction amount Den table 103a stored in the storage unit 103, and the detected density value of the image data of the binding portion corresponds to the original distance. Since the correction is performed, the density of the image in the binding portion of the document 20 and the density of other portions can be harmonized with each other.

  In the first embodiment, the contour image of the image is detected, and the binding portion area of the document is calculated from the shape of the contour image. However, other than this, for example, an image of a shadow generated in the binding portion (in other parts of the document) In comparison, a portion having a high background density value) may be detected and detected as a document binding portion region (a region separated from the document stacking surface).

FIG. 10 is a block diagram illustrating a configuration of a control unit included in the image processing apparatus according to the second embodiment of the present invention.
The image processing apparatus according to the second embodiment of the present invention is an apparatus such as a scanner for reading a document, like the image processing apparatus according to the first embodiment, and includes a control unit 200, a glass plate, a carriage, and the like illustrated in FIG. And a carriage drive unit. Here, since the glass plate, the carriage, and the carriage drive unit have the same configuration as that of the first embodiment, description of these configurations is omitted and reference numerals are not attached.

  As shown in FIG. 10, the control unit 200 includes a main control unit 201c, a density correction unit 202, a storage unit 203, a binding unit position detection unit 204, a document distance detection unit 205, and a focal length control unit 206. An image processing unit 207, an I / F 208, an A / D converter 209, and an image synthesis unit 210. Here, the density correction unit 202, the focal length control unit 206, the image processing unit 207, the I / F 208, and the A / D converter 209 have functions similar to those of the image processing apparatus of the first embodiment. Therefore, explanation of these is omitted.

  The reading control unit 201 includes a gamma correction unit 201a, a background removal unit 201b, and a main control unit 201c. The gamma correction unit 201a and the background removal unit 201b have the same configuration as that of the image processing apparatus according to the first embodiment.

  In addition to the first embodiment, the main control unit 201c includes a pixel position G (X, Y) and a pixel position of each image in the main scanning direction of the binding unit of the document image data input from the document distance detection unit 205. When document distance information consisting of a pair of document distance information d (X, Y) at position G (X, Y) is input, document distance information d (X, Y) described in the input document distance information. Among them, the smallest one is specified as the minimum document distance d_mind, and the largest one is specified as the maximum document distance d_max.

  In addition, the main control unit 201c focuses on the estimated original distance D different from the previous time every time all the lines between the sub-scanning coordinate YLstart indicating the binding unit start position and the sub-scanning coordinate YLend indicating the binding unit end position are read a plurality of times. The data is output to the distance control unit 206. Here, the assumed original distance D is a value between the minimum original distance d_min and the maximum original distance d_max.

  The storage unit 203 is a memory device such as a RAM or a hard disk device, and the original image data and the binding portion image having corrected image density values obtained by correcting the density values of the original image data and binding portion image data of the read original 20. When data is input from the density correction unit 202, these document image data and binding portion image data are temporarily stored. The storage unit 203 also stores an assumed original distance D-density correction amount Den table 203a, a background density value range-original distance table 203b, and a sub-scanning coordinate-main scanning coordinate table 203c.

  The assumed original distance D-density correction amount Den table 203a and the background density value range-original distance table 103b are tables having the same configuration as that of the first embodiment.

  As shown in FIG. 11, the sub-scanning coordinate-main scanning coordinate table 203c includes document distance information d (the distance between the binding portion of the document 20 and the glass plate in the pixels on each line in the main scanning direction regarding the document image data. The sub-scanning coordinate-main scanning coordinate data indicating X, Y) is stored.

  As in the image processing apparatus according to the first exemplary embodiment, the binding unit position detection unit 204 reads the document image data of the read document from the storage unit 203, and performs a conventionally known edge detection process on the document image data. To detect document edge distortion. Then, the binding portion position detection unit 204 detects the binding portion start position P (X, Ystart) and the binding portion end position P (X, Yend) from the distortion of the document edge, and starts the binding portion start position P. (X, Ystart) and the binding end position P (X, Yend) are output to the main control unit 101c and the document distance detection unit 105. Here, X is a coordinate in the main scanning direction, and Ystart is a coordinate in the sub-scanning direction.

  Here, as shown in FIG. 12, when the document distance HL at the left end of the binding portion of the document 20 placed on the glass table is larger than the document distance HR at the right end, the binding portion detected by the binding portion position detection unit 204 is detected. The position detection method will be specifically described. First, the binding position detection unit 204 performs edge detection processing to generate a case of an edge image as shown in FIG. Incidentally, as shown in FIG. 13B, the density value in the sub-scanning direction at the left end of the binding portion is higher than the density value in the sub-scanning direction at the left end. Further, as shown in FIG. 13C, the density value in the main scanning direction from the left end to the right end of the binding portion has the highest density value at the left end and decreases toward the right end.

  The binding portion position detection unit 204 first obtains a sub-scanning direction coordinate YLstart indicating the change start point of the left line lineL and a sub-scanning direction coordinate YLend indicating the change end point, and further calculates the right line lineR. The sub-scanning direction coordinate YRstart indicating the change start point and the sub-scanning direction coordinate YRend indicating the change end point of the right line lineR are detected. Here, YLstart, YLend, YRstart, and YRend are obtained when the difference in the main scanning direction for each line of the edge image calculated by the binding position detection unit 204 exceeds a preset value. is there.

  Then, the binding part position detection unit 204 specifies the sub-scanning coordinate Ystart indicating the start position of the binding part for YLstart and YRstart, which has a smaller coordinate in the sub-scanning direction, and performs sub-scanning for YLend and YRend. The one with the larger direction coordinate is specified as the sub-scanning coordinate Yend indicating the end position of the binding portion. Here, the distance between the sub-scanning coordinate YLstart and the sub-scanning coordinate YLend is larger than the distance between the sub-scanning coordinate YRstart and the sub-scanning coordinate YRend.

  The document distance detection unit 205 reads the document image data for one line in the main scanning direction at the binding unit start position P (X, Ystart) from the storage unit 103, and reads the document image data in pixel units (pixel units in the main scanning direction). ) To detect the density value G (X, Y), and determine the density value for specifying the document distance from the detected density value.

  Note that the density value input to the document distance detection unit 205 does not include the image data of the binding portion of the document as it is, so it is necessary to detect the density value excluding this. Therefore, the document distance detection unit 205 includes a low-pass filter that can remove the influence of image data having a high spatial frequency component in the image input unit. Thereby, image data of high frequency components such as characters of a document are removed, and only the density due to the shadow of the binding portion can be detected. The document distance detection unit 205 detects the density value of each pixel forming document image data for one line in the main scanning direction at the sub-scanning coordinate Ystart at the binding unit start position, and then stores the density value in the storage unit 103. Referring to the density value range-document distance table 203b shown in FIG. 13B, the document distance corresponding to the detected density value is read from the background density value range-document distance table 203b. The distance between the document 20 and the glass plate 120 at each pixel is estimated.

  Further, the document distance detection unit 205 generates sub-scanning coordinate-main scanning coordinate data in which the document position information d (X, Y) can be described with the pixel position and the document distance described above, and this data is stored in the storage unit 203. Are stored in the sub-scanning coordinate-main scanning coordinate table 203c.

  When the assumed document distance D is input from the main control unit 201c, the image composition unit 210 receives the document binding portion image data read at the input document assumed distance D and stores the document image data storage area 203d in the storage unit 203. Read from. Then, the image composition unit 210 refers to the sub-scanning coordinate-main scanning coordinate data stored in the sub-scanning coordinate-main scanning coordinate table 203c in the storage unit 203, and describes the sub-scanning coordinate-main scanning coordinate data. The original image data stored in the original image data storage area 203d is image data of pixels of the binding portion image data in which the original original distance information d (X, Y) matches the input original original distance D. Overwrite the pixels of.

  Next, the operation of the image processing apparatus according to the second embodiment of the present invention will be described.

  14 and 15 are flowcharts showing the operation of the image processing apparatus according to the second embodiment of the present invention. First, when a predetermined operation key on the operation unit is pressed by the user, the main control unit 201c of the control unit 200 sets the numerical information d, the numerical information j, and k stored in the work area of the storage unit 203 to 0. Is written (step S31).

  Next, the gamma correction unit 201a converts the brightness of the image data of the document 20 input from the A / D converter 209 into image data composed of density values using the γ value described in the gamma conversion table. This data is then output to the background removal unit 201b.

  The background removal unit 201 b detects the background density having the lowest density value among several lines input from the gamma correction unit 201 a and stores the background density in the storage unit 203. Thereafter, the background removal unit 201 b calculates a background removal density value according to the above-described equation 1, and outputs the background removal density value to the density correction unit 202.

  When the original 20 is first read, the assumed original distance D = 0 is set, and the density correction unit 202 stores the original image data in the storage unit 203 without correcting the density of the original image data input from the correction main control unit 201c. Write to the area 203d (step 32).

  The binding portion position detection unit 204 reads document image data from the document image data storage area 203d in the storage unit 203, performs edge detection processing on the read document image data, and detects document edge distortion. Thereafter, the binding portion position detection unit 204 detects the binding portion start position P (X, Ystart) and the binding portion end position P (X, Yend) from the detected document edge distortion, and the binding portion start position P. (X, Ystart) and the binding end position P (X, Yend) are output to the main control unit 201c (step S33).

  The document distance detection unit 205 reads the binding portion start position P (X, Ystart) and the binding portion end position P (X, YLend). Next, the document distance detection unit 205 determines whether or not the sub-scanning coordinate YLstart + k is equal to or smaller than the sub-scanning coordinate YLen (step S34).

  When the document distance detection unit 205 determines that the sub-scanning coordinate Ystart + k exceeds the sub-scanning coordinate Yend (step S34; N), the process proceeds to step S41. On the other hand, when the document distance detection unit 205 determines that the sub-scanning coordinate Ystart + k is equal to or smaller than the sub-scanning coordinate Yend (step S34; Y), the document image data for one line in the main scanning direction having the sub-scanning coordinate Ystart + k. Is read from the storage unit 103. Thereafter, the document distance detection unit 205 detects the density value G (X, Y) for the pixel located at P (X + j, Ystart + k (constant)) in the read document image data.

  When the document distance detection unit 205 detects the density value G (X + j, YLstart + k) of the pixel at the position of P (X + j, Ystart + k (constant)), the document distance detection unit 205 is stored in the storage unit 203 as shown in FIG. With reference to the density value range-document distance table 203b, the document distance corresponding to the density value G (X + j, YLstart + k) detected from the density value range-document distance table 203b is read, and the read document distance is read for this pixel. The document distance d (X + j, YLstart + k) between the document 20 and the glass plate is detected (step S36) and stored in the work area of the storage unit 203.

  Next, the document distance detection unit 205 determines whether or not the pixel located at P (X + j, Ystart + k (constant)) is the last pixel on the line (step S37). If the document distance detection unit 205 determines that the pixel located at P (X + j, Ystart + k (constant)) is not the last pixel on the line (step S37; N), it is stored in the work area of the storage unit 203. 1 is added to the numerical information j (step S38), the process proceeds to step S35, and the same process as described above is continued.

  On the other hand, when the document distance detection unit 205 determines that the pixel located at P (X + j, Ystart + k (constant)) is the last pixel on the line (step S37; Y), it is stored in the storage unit 203. All the original document distances d (X + j, Ystart + k) (l = 0, 1, 2, 3,...) Are sequentially read out to generate sub-scanning coordinate-main scanning coordinate data in the main scanning direction with respect to the sub-scanning coordinate Ystart + k. Then, this data is stored in the sub-scanning coordinate / main scanning coordinate table 203c generated in the storage unit 203 (step S39).

  Next, the document distance detection unit 205 adds 1 to the numerical information k stored in the work area of the storage unit 203, further substitutes 0 for the numerical information j (step S40), and shifts the processing to step S35. Then, the same processing as described above is continued.

  In step S34, when the document distance detection unit 205 determines that the sub-scanning coordinate Ystart + k has exceeded the sub-scanning coordinate YLen (step S34; N), the document distance detection unit 205 outputs a message indicating that the sub-scanning coordinate Ystart + k has exceeded this to the main control unit 201c.

  Then, the main control unit 201c outputs a control signal for setting the carriage to the Ystart position as a position for reading the binding unit of the CCD line sensor 136 again to the carriage driving unit.

  The carriage drive unit receives this signal and sets the carriage at this position (step S41).

  Thereafter, the main control unit 201c adds 1 to the numerical information d stored in the work area of the storage unit 203 (step S42). Next, the main control unit 201c determines whether or not the added numerical information d is equal to or less than the largest document distance information d_max (step S43). If the main control unit 201c determines that the added numerical information d is not equal to or less than the document distance information d_max (step S43; N), the process proceeds to step S53. On the other hand, when the main control unit 201c determines that the added numerical information d is equal to or less than the original distance information d_max (step S43; Y), the main original distance D of the value indicated in the numerical information d is set to the focal distance. It outputs to the control part 106 (step S44).

  The focal length control unit 106 calculates the focal lens movement amount Ld (D) according to the above-described equation 4 that calculates the focal lens movement amount based on the assumed original distance D input from the main control unit 101c (step S45). A control signal for moving the focal lens by the focal lens movement amount Ld (D) is output to a lens driving unit having the carriage.

  Then, the lens driving unit of the carriage moves the focal lens by the focal lens movement amount Ld (D) based on the control signal input from the focal distance control unit (step S46).

  Thereafter, the main control unit 201 c outputs the estimated original distance D to the density correction unit 202.

The density correction unit 202 refers to the assumed original distance D-density correction amount Den table 203a stored in the storage unit 203, reads the density correction amount Den corresponding to the input assumed original distance D,
The density correction amount Den described in the above-described equation 2 for calculating the density correction value is set to the read density correction amount Den (step S47), and the fact that the setting has been reset is output to the main control unit 201c.

  Then, the main control unit 201c reads again the image data for correction of the document 20 (hereinafter referred to as binding portion image data) from Ystart to Yend (step S48), and the read binding portion image data is read by the density correction unit 102. Output.

  The density correction unit 202 corrects and corrects the density value of the binding part image data input from the main control unit 201c by using the previously set density correction amount Den and the above-described equation 2 for density correction. The binding portion image data is stored in the binding portion image data storage area 203e of the storage unit 203 (step S49).

  After that, the main control unit 201c overwrites the original image data stored in the original image data storage area 203d with the binding part image data stored in the binding part image data storage area 203e. Output the request.

  Then, the image composition unit 210 reads the binding portion image data read at the input original document assumed distance D from the binding portion image data storage area 203e of the storage unit 203. Next, the image composition unit 210 refers to the sub-scanning coordinate-main scanning coordinate data stored in the sub-scanning coordinate-main scanning coordinate table 203 (c) in the storage unit 203, and this sub-scanning coordinate-main scanning. The original image data stored in the original image data storage area 203d is the pixel data of the binding portion image data in which the original distance information d (X, Y) described in the coordinate data matches the input original expected distance D. The image data for the data pixel is overwritten (step 50). Thereafter, the image composition unit 210 shifts the process to step S42 and continues the same process as described above.

  In step S43, when the main control unit 201c determines that the added numerical information d is not equal to or less than the document distance information d_max (step S43; N), the document image stored in the storage unit 203 is compared with the image processing unit 207. A request for executing image processing of the corrected document image data stored in the data storage file 202d is output.

  Based on the request input from the main control unit 201c, the image processing unit 207 reads the document image data stored in the document image data storage area 203d as needed, and performs image processing such as binarization processing and image compression processing. (Step S51), the image processed image data is output to the I / F unit 208.

  The I / F unit 208 transmits the image data input from the image processing unit 207 to the host (step S52), and ends the process.

  FIG. 16 is a diagram for explaining the contents over which the document image data stored in the storage unit 203 is overwritten using the binding portion image data by repeating the operations from step S43 to step S51.

  As shown in FIG. 16A, when the image of the binding portion is read with the assumed original distance D being 1, the original image having the original distance 1 stored in the original image data storage area 203d in the storage unit 203. The image data of the pixel in the data is overwritten on the image data of the pixel of the binding portion image data read with the assumed original distance D as 1. Here, 0, 1, 2, 3, 4, and 5 shown in the figure indicate document distance information in each pixel of the document image data. In this case, the image of the pixel indicated by 1 is displayed. Only the data is overwritten with the binding portion image data.

  As shown in FIG. 16B, when reading the binding portion image with the assumed original distance D being 2, the original image having the original distance 2 stored in the original image data storage area 203 d in the storage unit 203. The image data of the pixel in the data is overwritten with the image data of the pixel of the binding portion image data read out with the assumed original distance D as 2. In this case, only the image data of the pixel indicated by 2 is overwritten by the binding portion image data.

  As shown in FIG. 16C, when the image of the binding portion is read with the assumed original distance D being 3, the original image having the original distance 3 stored in the original image data storage area 203d in the storage unit 203. The image data of the pixel in the data is overwritten by the image data of the pixel of the binding portion image data read out with the assumed original distance D as 3. In this case, only the image data of the pixel indicated by 3 is overwritten by the binding portion image data.

  According to the second embodiment, the binding unit is read a plurality of times by moving the lens so that the focal point is in accordance with the assumed original distance D = 1 mm to d_max mm, and the read binding unit is controlled each time the lens position is controlled. Image data of pixels having the same binding portion distance and assumed distance at each pixel position of the binding portion stored in the document image data storage region 203d among all the pixels of the image data of the image data is stored in the document image data storage region 203d. Since the image data of the pixels in the image data of the original 20 being overwritten is overwritten, there is a need to perform a useless process of measuring in advance the distance between the line sensor and the subject at a place other than the binding portion of the original 20. And can meet the demand for higher reading speed.

  In addition, since the original distance can be detected in units of pixels and an image read at an optimum focal length in units of pixels can be obtained, an image without blur can be obtained, and the right and left edges of the binding portion of the original can be obtained. Even when the document distance is not uniform, an image free from distortion and density unevenness can be obtained.

  According to the second embodiment, the density correction unit 202 refers to the estimated original distance D-density correction amount Den table 203a in the storage unit 203, and the detected density value of the image data of the binding portion is corrected by the original distance. Therefore, the image density in the binding portion of the document 20 and the density of other portions can be harmonized with each other.

  FIG. 17 is a block diagram illustrating a configuration of a control unit included in the image processing apparatus according to the third embodiment of the present invention. The image processing apparatus according to the third embodiment of the present invention is an apparatus such as a scanner for reading a document, like the image processing apparatus according to the second embodiment, and includes a control unit 300, a glass plate, a carriage, and the like illustrated in FIG. And a carriage drive unit. Here, since the glass plate, the carriage, and the carriage driving unit have the same configuration as that of the second embodiment, description of these configurations is omitted. In addition, when these things are described in description of operation | movement, it demonstrates without attaching | subjecting a reference code.

  As illustrated in FIG. 17, the control unit 300 includes a reading control unit 301, a density correction unit 302, a storage unit 303, a binding unit position detection unit 304, a document distance detection unit 305, and a focal length control unit 306. An image processing unit 307, an I / F 308, an A / D converter 309, and an image composition unit 310. Here, the density correction unit 302, the storage unit 303, the document distance detection unit 305, the focal length control unit 306, the image processing unit 307, the I / FI / F 308, the A / D converter 209, and the image composition unit 310 are It has the same function as that of the image processing apparatus of the second embodiment. Therefore, explanation of these is omitted.

  The reading control unit 301 includes a gamma correction unit 301a, a background removal unit 301b, and a main control unit 301c, which have the same configuration as that of the image processing apparatus according to the second embodiment.

  The binding unit position detection unit 304 has the same function as the binding unit position detection unit 204 of the second embodiment, and further detects the installation direction of the document 20. Here, the function of the binding portion position detection unit 304 detecting the direction of the binding portion of the document 20 will be specifically described.

  When the binding part position detection unit 304 performs edge detection processing and generates a case of an edge image as shown in FIG. 18, for example, the binding part position detection unit 304 sets the minimum and maximum coordinates in the sub-scanning direction on the line TOP. The greater of the difference ΔY and the difference ΔX between the maximum coordinate and the minimum coordinate in the main scanning direction on line L is obtained. Then, the binding portion position detection unit 304 compares ΔY and ΔX, and if it is determined that ΔY> ΔX, it determines that the binding portion is parallel to the sub-scanning direction, On the other hand, if it is determined that ΔY <ΔX, it is determined that the direction of the binding portion is the main scanning direction.

  Further, the binding portion position detection unit 304 reads the document image data from the storage unit 303 again, performs edge detection processing on the read document image data, and detects document edge distortion. Then, the binding portion position detection unit 304 detects the binding portion start position and the binding portion end position from the detected document edge distortion, and sets the binding portion start position and binding portion end position to the main control unit 301c and the document distance. Output to the detection unit 305. Here, when the direction of the binding portion is the sub-scanning direction, the start position of the binding portion is, for example, P1 (Xstart, Ystart), and the end position of the binding portion is P2 (Xend, Yend).

  Next, the operation of the image processing apparatus according to the third embodiment of the present invention will be described.

  19 and 20 are flowcharts showing the operation of the image processing apparatus according to the third embodiment of the present invention. First, when a predetermined operation key on the operation unit is pressed by the user, the main control unit 301c of the control unit 300 causes the numerical information d, numerical information i, numerical information l, numerical information in the work area of the storage unit 303 to be displayed. 0 is written in m and numerical information n (step S61).

  Next, the gamma correction unit 301a converts the brightness of the image data of the document 20 input from the A / D converter 309 into image data composed of density values using the γ value described in the gamma conversion table. The image data is output to the background removal unit 301b.

  The background removal unit 301 b detects the background density having the lowest density value among several lines input from the gamma correction unit 201 a and stores the background density in the storage unit 303. Thereafter, the background removal unit 301 b calculates the background removal density value according to the above-described equation 1 and outputs the background removal density value to the density correction unit 302.

  Since the assumed original distance D = 0 when the original 20 is first read and read, the density correction unit 302 does not correct the density of the original image data input from the main control unit 301c and stores it as data before correction in the storage unit 303. The data is written in the document image data storage area 303d (step 62).

  The binding portion position detection unit 304 performs edge detection processing for detecting the edge of the document 20 from the pre-correction data read from the storage unit 303. Next, the binding portion position detection unit 304 obtains a difference ΔY between the minimum coordinate and the maximum coordinate in the sub-scanning direction for the edge portion having a smaller sub-scanning coordinate when the sub-scanning direction of the edge image is used as a reference. When the main scanning direction of the edge image is used as a reference, the difference ΔX between the minimum coordinate and the maximum coordinate in the main scanning direction is obtained for the edge portion having the smaller main scanning coordinate.

  Next, the binding portion position detection unit 304 compares ΔY and ΔX, and detects the direction of the binding portion (step S63). Thereafter, the binding portion position detection unit 304 determines whether the direction of the binding portion is the main scanning direction or the sub-scanning direction (step S64).

  When the binding unit position detection unit 304 determines that the direction of the binding unit is the main scanning direction (step S64; main scanning direction), the same processing as in the second embodiment is performed. That is, the document image data is read again from the storage unit 303, edge detection processing is performed on the read document image data, and distortion of the document edge is detected. Thereafter, the binding portion position detection unit 304 detects the binding portion start position P (X, Ystart) and the binding portion end position P (X, Yend) from the detected document edge distortion, and the binding portion start position P. (X, Ystart) and the binding end position P (X, Yend) are output to the main control unit 301c (step S65).

  The document distance detection unit 305 reads the binding portion start position P (X, Ystart) and the binding portion end position P (X, Yend) from the binding portion position detection unit 304. Next, the document distance detection unit 305 determines whether or not the sub-scanning coordinate Ystart + m is equal to or smaller than the sub-scanning coordinate Yend (Ystart + m <= Yend) (step S66).

  If the document distance detection unit 305 determines that the sub-scanning coordinate Ystart + m exceeds the sub-scanning coordinate Yend (step S66; N), the document distance detection unit 305 shifts the process to step S74. On the other hand, when the document distance detection unit 305 determines that the sub-scanning coordinate Ystart + m is equal to or less than the sub-scanning coordinate Yen (step S66; Y), document image data for one line in the main scanning direction having the sub-scanning coordinate Ystart + m. Are read from the storage unit 303.

  Thereafter, the document distance detection unit 305 detects the density value G for the pixel located at P (X + i, Ystart + m (constant)) in the read document image data (step S67). Next, when the document distance detection unit 305 detects the density value G (X + i, Ystart + m), the density value range-document distance table 303b shown in FIG. The document distance corresponding to the density value G (X + i, Ystart + m) detected from the range-document distance table 303b is read out, and the read document distance is read as the document distance d (X + i, Ystart + m) is detected (step S68), and the document distance d (X + i, Ystart + m) is stored in the work area of the storage unit 203.

  Next, the document distance detection unit 305 determines whether or not the pixel located at P (X + i, Ystart + m (constant)) is the last pixel on the line (step S69). If the document distance detection unit 305 determines that the pixel located at P (X + i, Ystart + m (constant)) is not the last pixel on the line (step S69; N), it is stored in the work area of the storage unit 303. 1 is added to the current numerical information i (step S70), the process proceeds to step S67, and the same process as described above is continued.

  On the other hand, when the document distance detection unit 305 determines that the pixel located at P (X + i, Ystart + m (constant)) is the last pixel on the line (step S69; Y), it is stored in the storage unit 303. Sequentially read all document distances d (X + i, Ystart + m) (l = 0, 1, 2, 3,...), And generates sub-scanning coordinate-main scanning coordinate data in the main scanning direction with respect to the sub-scanning coordinate Ystart + m. Then, this data is stored in the sub-scanning coordinate-main scanning coordinate table 303c generated in the storage unit 303 (step S71).

  Next, the document distance detection unit 305 adds 1 to the numerical information m stored in the work area of the storage unit 303, further substitutes 0 for the numerical information i (step S72), and shifts the processing to step S67. Then, the same processing as described above is continued.

  In step S66, when the document distance detection unit 305 determines that the sub-scanning coordinate Ystart + k exceeds the sub-scanning coordinate Yend (step S66; N), the fact is output to the main control unit 301c.

  Then, the main control unit 301c outputs to the carriage drive unit a control signal for setting the carriage to the Ystart position where the CCD line sensor reads the binding unit again.

  The carriage drive unit receives this signal and sets the carriage at the Ystart position (step S73).

  Thereafter, the main control unit 301c adds 1 to the numerical information d stored in the work area of the storage unit 303 (step S74). Next, the main control unit 301c determines whether or not the added numerical information d is equal to or less than the largest document distance information d_max (step S75). When the main control unit 301c determines that the added numerical information d is not less than or equal to the original distance information d_max (step S75; N), the process proceeds to step S83. On the other hand, when the main controller 301c determines that the added numerical information d is equal to or smaller than the original distance information d_max (step S75; Y), the main original distance D of the value indicated in the numerical information d is set to the focal distance. It outputs to the control part 306 (step S76).

  The focal distance control unit 306 calculates the focal lens movement amount Ld (D) according to the above-described equation 4 that calculates the focal lens movement amount based on the assumed original distance D input from the main control unit 301c (step S77). A control signal for moving the focal lens by the focal lens movement amount Ld (D) is output to a lens driving unit having the carriage.

  Then, the lens driving unit of the carriage moves the focal lens by the focal lens movement amount Ld (D) based on the control signal input from the focal distance control unit (step S78).

  Thereafter, the main control unit 301 c outputs the estimated original distance D to the density correction unit 102.

  The density correction unit 302 refers to the assumed original distance D-density correction amount Den table 303a shown in FIG. 17 in the storage unit 303, reads the density correction amount Den corresponding to the input assumed original distance D, and sets the density correction value. The density correction amount Den described in the above-described equation 2 for calculating the value is set to the read density correction amount Den (step S79), and the fact that it has been reset is output to the main control unit 301c.

  Then, the main control unit 301 c reads the binding portion image data of the document 20 from the A / D converter 309 again (step S 80), and outputs the read binding portion image data to the density correction unit 302.

  The density correction unit 302 corrects the density value of the binding portion image data input from the main control unit 301c by using the previously set density correction amount Den and the above-described equation 2 for density correction. The data is stored in the binding portion image data storage area 303e of the storage unit 303 (step S81).

  After that, the density correction unit 302 overwrites the original image data stored in the original image data storage region 303d with the binding unit image data stored in the original image data storage region 303d, with respect to the image composition unit 310. Output the request.

  Then, the image composition unit 310 reads the binding portion image data of the original read at the input original assumed distance D from the binding portion image data storage area 303e of the storage unit 303. Next, the image composition unit 310 refers to the sub-scanning coordinate-main scanning coordinate data stored in the sub-scanning coordinate-main scanning coordinate file 303c in the storage unit 303, and uses this sub-scanning coordinate-main scanning coordinate data. The pixel data of the binding portion image data in which the described document distance information d (X, Y) matches the input document assumed distance D is converted into an image of the pixels of the document image data stored in the storage unit 303. The data is overwritten (step S82), the process proceeds to step S74, and the same process as described above is continued.

  In step S75, when the main control unit 301c determines that the added numerical information d is not less than or equal to the original distance information d_max (step S75; N), the main control unit 301c stores the image processing unit 307 in the storage unit 303. A request for executing image processing of the corrected original image data is output.

  Based on the request input from the main control unit 301c, the image processing unit 307 reads the corrected document image data stored in the storage unit 303 as needed, and performs image processing such as binarization processing and image compression processing. (Step S83), the image processed image data is output to the I / F unit 308.

  The I / F unit 308 transmits the image data input from the image processing unit 307 to the host (step S84), and ends the process.

  In step S64, when the binding unit position detection unit 304 determines that the direction of the binding unit is the sub-scanning direction (step S64; sub-scanning direction), the binding unit takes a long time to scan in the sub-scanning direction. Is displayed on a display unit (not shown) (step S85).

  Thereafter, the binding unit position detection unit 304 determines whether or not a signal indicating that the cancel key included in the operation unit 150 has been pressed by a user operation is input (step S87). If the binding unit position detection unit 304 determines that a signal indicating that the cancel key has been pressed has been input (step S86; Y), the process ends. On the other hand, if the binding unit position detection unit 304 determines that a signal indicating that the cancel key has been pressed is not input (step S86; N), whether or not the start key included in the operation unit 150 has been pressed. Is determined (step S87).

  If it is determined that the start key has not been pressed (step S87; N), the binding position detection unit 304 proceeds to step S86 and continues the same process as described above. On the other hand, when the binding portion position detection unit 304 determines that the start key has been pressed (step S87; Y), Ystart is set to the minimum value in the sub-scanning direction of document placement (Line TOP in FIG. 18). At the same time, Yend is set to the maximum value in the sub-scanning direction of document placement (Line BTM in FIG. 18), and the process proceeds to step S73.

  This means that the entire surface of the document is handled in the same manner as the binding portion, and every time the focal point of the lens is changed, the entire document surface is read. Then, an image of the entire surface of the original is stored in the binding portion image data storage area 303e, and pixel data in which the estimated original distance D and the original distance information d (X, Y) coincide with each other is generated by the image composition unit 310. The document image data stored in the data storage area 303d is overwritten. Therefore, in order to acquire an image with a focal length, full-face reading is performed and processing time is required.

  According to the third embodiment, when the direction of the binding portion is the same as the main scanning direction, as in the second embodiment, the lens is adjusted so as to be in focus corresponding to the assumed original distance D = 1 mm to d_max mm. Each time the binding portion is moved and read, and the lens position is controlled, out of all the pixels of the read binding portion image data, at each pixel position of the binding portion stored in the document image data storage file 303d. Since the image data of the pixels having the same binding portion distance and the assumed distance is overwritten on the pixel image data in the image data of the document 20 stored in the document image data storage file 303d, a portion other than the binding portion of the document 20 Thus, there is no need to perform a wasteful process of measuring the distance between the line sensor and the subject in advance, and it is possible to meet the demand for higher reading speed.

  Further, according to the third embodiment, when the direction of the binding portion is the same as the main scanning direction, the document distance is detected in units of pixels as in the second embodiment, and the optimum focal length is determined in units of pixels. Since the scanned image can be obtained, an image without defocus can be obtained, and an image free from distortion and density unevenness can be obtained even when the document distance between the right end and the left end in the binding portion of the document is not uniform. it can.

  Further, according to the third embodiment, when the direction of the binding portion is the same as the main scanning direction, as in the second embodiment, the density correction unit 302 causes the estimated original distance D- With reference to the density correction amount Den table 303a, the detected density value of the image data of the binding portion is corrected by the document distance, so that the density of the image in the binding portion of the document 20 and the density of the other portions are in harmony with each other. Can be made.

  Further, according to the third embodiment, the binding unit position detection unit 304 determines that the direction of the binding unit from the document image data stored in the document image data storage file 303d is the main scanning direction or the sub scanning. By detecting whether the direction is the direction and prompting the user to change the direction of the document, it is possible to avoid the process of changing the focal length of the entire surface of the document and reading it multiple times.

  In the image processing apparatuses according to the first to third embodiments, the detection of the document distance is detected from the density value, but a distance measurement sensor may be used instead. In the image processing apparatuses according to the first to third embodiments, the color of the image to be processed is monochrome, but it is needless to say that the color may be a color.

  In the image processing apparatus according to the third exemplary embodiment, the binding unit position detection unit 304 automatically detects the orientation of the binding unit of the document. Information for specifying the direction of the binding portion may be input in advance by the user.

1 is a block diagram illustrating a configuration of an image processing apparatus according to a first embodiment of the present invention. It is a block diagram which shows the structure of the control part in FIG. (A) An example of an assumed original distance D-density correction amount Den table, (b) an example of a density value range-original distance table, and (c) sub-scanning coordinates-original distance information d. (Y) It is a figure which shows an example of a file. (A) It is explanatory drawing explaining the binding part start position and the binding part end position, (b) It is a figure which shows the density value change in a binding part. It is a figure used in order to obtain the focal lens movement amount Ld (D). It is a schematic block diagram of the carriage in FIG. 5 is a flowchart (part 1) illustrating an operation of the image processing apparatus according to the first exemplary embodiment of the present invention. 6 is a flowchart (part 2) illustrating an operation of the image processing apparatus according to the first exemplary embodiment of the present invention. It is a figure explaining the content by which the image data memorize | stored in the memory | storage part is overwritten. It is a block diagram which shows the structure of the control part which has in the image processing apparatus of Example 2 which concerns on this invention. FIG. 11 is a diagram illustrating an example of a sub-scanning coordinate-main scanning coordinate table in FIG. 10. It is a figure which shows the state of the binding part of the read original. (A) It is explanatory drawing explaining the binding part start position and the binding part end position, (b) It is a figure which shows the density value change in the binding part in the main scanning direction, (c) The left end of the binding part in the sub-scanning direction It is a graph which shows the density value and density value of the right end. It is a flowchart (the 1) which shows operation | movement of the image processing apparatus of Example 2 which concerns on this invention. It is a flowchart (the 2) which shows operation | movement of the image processing apparatus of Example 2 which concerns on this invention. It is a figure explaining the content by which image data is overwritten. It is a block diagram which shows the structure of the control part which has in the image processing apparatus of Example 3 which concerns on this invention. It is explanatory drawing for demonstrating the method to detect the direction of a binding part. It is a flowchart (the 1) which shows operation | movement of the image processing apparatus of Example 3 which concerns on this invention. It is a flowchart (the 2) which shows operation | movement of the image processing apparatus of Example 3 which concerns on this invention.

Explanation of symbols

100, 200, 300 Control unit 101, 201, 301 Reading control unit 101a, 201, 301 Gamma correction unit 101b, 201b, 301b Background removal unit 101c, 201c, 301c Main control unit 102, 202, 302 Density correction unit 103, 203 303 Storage units 103a, 203a, 303a Estimated original distance D—Density correction amount tables 103b, 203b, 303b Background density value range—Original distance table 103c Sub-scanning coordinates—Original distance information d (Y) tables 203c, 303c Sub-scanning coordinates Main scanning coordinate table 103d, 203d, 303d Document image data storage area 103e, 203e, 303e Binding section image data storage area 104, 204, 304 Binding section detection section 105, 205, 305 Document distance detection section 106, 206, 306 Focus Separation control unit 107, 207, 307 Image processing unit 108, 208, 308 I / F unit 109, 209, 309 A / D converter 210, 310 Image composition unit 120 Glass plate 130 Carriage 131, 132, 133 Mirror 134 Focus lens 135 Light source 136 CCD line sensor 137 Rail 138 Lens drive unit 139 Rail 140 Carriage drive unit 150 Operation unit

Claims (8)

An image reading unit that reads an image of a document loaded on the document loading surface;
A separation area detector for detecting a separation area between the document and the document stacking surface;
A document distance detector for detecting a document distance between the document and the document stacking surface;
A focal length adjustment unit for adjusting a focal length with the original in the image reading unit;
A reading control unit that reads the region detected by the separation region detection unit by adjusting the focal point by the focal length adjustment unit;
An image processing apparatus comprising: A contour detecting unit for detecting a contour of the document based on the image read by the image reading unit;
The image processing apparatus according to claim 1, wherein the separation area detection unit detects a separation area between the document and the document stacking surface based on a contour of the document detected by the contour detection unit. A binding portion direction detection unit that detects a binding portion direction of the image of the document from the separation region detected by the separation region detection unit;
Further comprising
The document distance detection unit
The image processing apparatus according to claim 1, wherein the document distance is detected according to a binding portion direction detected by the binding portion direction detection unit.   The image processing apparatus further includes an image composition unit configured to combine an image of the document in the separated area read by the image reading unit at the focal point adjusted by the focal length adjustment unit with the separated area portion of the image of the first document. The image processing apparatus according to claim 1. A density value detection unit for detecting a density value of the image read by the image reading unit;
A density value correction unit that corrects the density value of the separated area among the density values detected by the density value detection unit based on the document distance detected by the document distance detection unit;
Further comprising
The image composition unit
The document image in the separated area read by the image reading unit at the focal point adjusted by the focal length adjusting unit is transferred to the separated area of the first document image with the density value corrected by the density value correcting unit. The image processing apparatus according to claim 4, wherein the images are synthesized. A synthesis region existence determination unit that determines whether or not there is a synthesis region to be synthesized by the image synthesis unit within the previous separation distance region synthesized by the image synthesis unit;
Further comprising
The image composition unit
When the composite region presence determination unit determines that the composite region is present, an image of the document in the composite region read by the image reading unit at the focal point adjusted by the focal length adjustment unit, The image processing apparatus according to claim 4, wherein the composite region presence determination unit combines the composite region that is a determination target of the composite region.   The composite region presence determination unit determines whether the composite region within the previous separation distance region synthesized by the image synthesis unit is a composite region synthesized by the image synthesis unit or not. The image processing apparatus according to claim 6, wherein the image processing apparatus determines whether or not there is a composite area to be combined by the image combining section in the previous separation distance area combined by the combining section. The document distance detection unit detects the document distance for each pixel forming the image,
The focal length adjustment unit adjusts a focal point of the image reading unit with the document based on the document distance detected by the document distance detection unit;
The image synthesizing unit includes the first original image having the same original distance among the pixels forming the original image in the separated area read by the image reading unit at the focal length adjusted by the focal length adjusting unit. The image processing apparatus according to claim 4, wherein an image having pixels forming the image is combined with a separated area portion of the image of the first document.

Images