JP2008048057A - Image reader, image processor and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately recognize correction executed to the paper of an original. <P>SOLUTION: A signal processing part 70 provided in a scanner comprises: a preprocessing part 100 for executing various kinds of preprocessing to input image data obtained by reading the original by respective color line sensors; an image processing part 200 for executing various kinds of image processing to the preprocessed image data; a correction detection part 300 for detecting a correction area executed on the paper of the original with correction fluid or the like from the preprocessed image data; and a composition part 400 for combining the image data to which the image processing is executed in the image processing part 200 and the data of the correction area detected in the correction detection part 300 and outputting the result. In the correction detection part 300, a fine edge near the base is detected from the base detection result of the original, and a part where the fine edge is present is detected as the correction area. The data of the correction area and the image data to which the image processing is executed are combined in the composition part 400 and then the result is outputted by a printer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image reading apparatus that reads an image of a document, an image processing apparatus that processes read image data, and a copying apparatus.

Conventionally, a copying machine is used to obtain a copy of a sheet (original) on which information such as characters and images is recorded. In addition, part of information recorded on a document is erased using, for example, a correction liquid or a correction tape, or other information is recorded after being erased.
Conventionally, a code image is embedded in a document in advance, and when this document is read by a document reading unit (scanner), a corresponding original document image is taken out based on the read code image, and the acquired original document image and A technique has been proposed in which a difference between the two is detected in comparison with a duplicate document image of a read original, and an image obtained by adding the difference portion image to the duplicate document image is output by a document output unit (printer) (for example, (See Patent Document 1).

Japanese Patent Laying-Open No. 2005-210327

  However, for example, when the original document itself is corrected using correction fluid or correction tape, it is difficult to find the difference. In addition, it is necessary to hold the original document in the storage device, which leads to an increase in size and cost of the device.

  The present invention has been made against the background of the above-described technique, and an object of the present invention is to make it possible to accurately grasp the correction made on the paper surface of the document.

  For this purpose, an image reading apparatus to which the present invention is applied includes a reading unit that reads an image formed on a document, an image processing unit that performs image processing on image data read by the reading unit, and a reading unit. A detection unit that detects a correction portion applied to the paper surface of the document from the image data read by the image data, image data subjected to image processing by the image processing unit, and data of the correction portion detected by the detection unit; And a synthesizing unit for synthesizing.

In such an image reading apparatus, the detection unit can detect the correction portion based on the detection result of the minute edge in the image data read by the reading unit. In addition, in the case of further including a color conversion unit that converts image data in the RGB color space read by the reading unit into image data in the L ^* a ^* b ^* color space, the detection unit performs color conversion in the color conversion unit. The correction location can be detected from the image data in the L ^* a ^* b ^* color space.

  From another point of view, the image processing apparatus to which the present invention is applied includes a first processing unit that performs image processing on image data obtained by reading a document, and a minute amount included in the image data from the image data. A second processing unit that detects an edge; and a third processing unit that superimposes and outputs the minute edge data detected by the second processing unit on the image data that has been subjected to image processing by the first processing unit. And a processing unit.

  In such an image processing apparatus, the second processing unit detects the background of the document from the image data, detects a minute edge close to the detected background of the document, and performs enhancement processing on the detected minute edge. Can do. In this case, the enhancement process may be a spatial filter process or a color conversion process.

  In addition, the present invention is detected in image data that has been subjected to image processing on a computer, a function that performs image processing on input image data, a function that detects minute edges included in image data from image data, and the like. It can also be understood as a program that realizes a function of superimposing and outputting data of minute edges.

According to the first aspect of the present invention, it is possible to accurately grasp the correction applied to the paper surface of the document.
According to the second aspect of the present invention, it is possible to detect the correction applied to the paper surface of the document from the level difference between the correction liquid and the document.
According to the third aspect of the present invention, it is possible to detect a correction applied to the paper surface of the document from a difference in brightness or the like.
According to the fourth aspect of the invention, it is possible to accurately grasp the correction made on the paper surface of the document.
According to the fifth aspect of the present invention, it is possible to clearly show the correction area formed on the paper surface of the document.
According to the sixth aspect of the invention, it is possible to more easily show the correction area provided on the paper surface of the document.
According to the seventh aspect of the present invention, it becomes possible to accurately grasp the correction made on the paper surface of the original document that is the source of the image data.

The best mode for carrying out the present invention (hereinafter referred to as an embodiment) will be described below in detail with reference to the accompanying drawings.
FIG. 1 shows a copying machine 1 to which the present embodiment is applied. The copying machine 1 includes a scanner 2 that reads an image of a document, and a printer 3 that forms an image on a sheet based on image data read by the scanner 2. Here, the scanner 2 is disposed on the upper portion of the printer 3, and a user interface (User Interface) that accepts an instruction for a copying operation or the like from a user and displays a message to the user on the front side of the scanner 2. : UI) 4 is provided.

  The printer 3 forms an image on paper using toner by, for example, an electrophotographic method. In particular, in this embodiment, the printer 3 can form a full-color image using toners of yellow (Y), magenta (M), cyan (C), and black (K). Yes. However, the printer 3 only needs to have a function of forming an image on a sheet using an image forming material such as toner or ink. For example, an ink jet method or an electrostatic recording method can be adopted.

  FIG. 2 is a diagram illustrating a configuration example of the scanner 2 described above. With this image reading apparatus, it is possible to read a fixed original image and also to read a conveyed original image. The scanner 2 includes a document feeding device 10 that sequentially conveys documents from a stacked document stack, and a reading device 50 that reads an image of the document by scanning. Here, the document feeder 10 is attached to the reading device 50 on the back side in the drawing using a hinge or the like. Therefore, the document feeder 10 is attached to the reading device 50 so as to be opened and closed with the back side in the figure as a fulcrum.

The document feeder 10 includes a document tray 11 on which a bundle of documents composed of a plurality of documents is stacked, and a paper discharge tray 12 that is provided below the document tray 11 and stacks documents that have been read. In addition, the document feeder 10 includes a take-out roll 13 that takes out and conveys a document on the document tray 11. Further, on the downstream side of the take-out roll 13 in the document conveyance direction, a mechanism 14 is provided for separating sheets one by one using a pair of roll members. A pre-registration roll 15, a registration roll 16, a backing roll 17, and an out-roll 18 are provided in order from the upstream side in the document conveyance direction in the first conveyance path 31 through which the document is first conveyed. The pre-registration roll 15 conveys the originals that have been rolled up one by one toward the downstream roll and forms a loop of the originals. The registration roll 16 rotates and temporarily stops, then restarts at the same timing, and supplies a document while performing registration adjustment on a document reading unit to be described later. The backing roll 17 assists the conveyance of the document being read by the reading device 50, and presses the document against a second platen glass 52B (described later), thereby maintaining the height of the document at the reading position substantially constant. . The out roll 18 conveys the document read by the reading device 50 further downstream.
A second transport path 32 for guiding the document to the paper discharge tray 12 is provided downstream of the out-roll 18 in the document transport direction. A discharge roll 19 is disposed in the second transport path 32.
A backing member 20 is attached to the lower surface of the paper discharge tray 12. The backing member 20 is used to press a document against a first platen glass 52A (described later) provided in the reading device 50 in a fixed reading mode described later.

Further, in the scanner 2, a third transport path 33 is provided between the outlet side of the out roll 18 and the inlet side of the pre-registration roll 15 so that the images formed on both sides of the document can be read in one process. ing. The discharge roll 19 described above also has a function of reversing and transporting the document carried into the second transport path 32 to the third transport path 33.
Furthermore, the scanner 2 is provided with a fourth transport path 34 for reversing the original and discharging it to the paper discharge tray 12 when the original is read on both sides. The fourth transport path 34 is provided on the upper side of the second transport path 32. The discharge roll 19 described above also has a function of reversing and conveying the original document carried into the second conveyance path 32 to the fourth conveyance path 34.

  On the other hand, the reading device 50 as a reading unit supports the above-described document feeding device 10 so as to be openable and closable, supports the document feeding device 10 by the device frame 51, and images of the document conveyed by the document feeding device 10. Reading is in progress. The reading device 50 includes a device frame 51 forming a casing, a first platen glass 52A as a document table on which a document to be read can be placed in a stationary state, and a document conveyed by the document feeding device 10. 2nd platen glass 52B which has the opening part of the light for reading.

In addition, the reading device 50 includes a full rate carriage 53 and a half rate carriage 54. The full-rate carriage 53 is stationary under the second platen glass 52B or scans the entire first platen glass 52A to read an image. The half-rate carriage 54 is stationary when the full-rate carriage 53 is stationary, and moves in conjunction with the full-rate carriage 53 so that the light obtained by the full-rate carriage 53 is supplied to the imaging unit. To do. The full-rate carriage 53 is provided with a light source 55 and a first mirror 57 </ b> A that receives reflected light from a document irradiated with light from the light source 55. Further, the half-rate carriage 54 is provided with a second mirror 57B and a third mirror 57C that provide the light obtained from the first mirror 57A to the imaging unit. Furthermore, the reading device 50 includes an imaging lens 58 and a CCD (Charge Coupled Device) image sensor 59. Among these, the imaging lens 58 optically reduces the optical image obtained from the third mirror 57C. The CCD image sensor 59 photoelectrically converts the optical image formed by the imaging lens 58. That is, in the reading device 50, an image is formed on the CCD image sensor 59 using a so-called reduction optical system.
A white reference plate 56 extending along the main scanning direction is attached to the lower part of a member provided between the first platen glass 52A and the second platen glass 52B.

  The reading device 50 further includes a control / image processing unit 60. The control / image processing unit 60 performs predetermined processing on the image data of the document input from the CCD image sensor 59. The control / image processing unit 60 controls the operation of each unit in the reading operation of the scanner 2 (the document feeding device 10 and the reading device 50).

  FIG. 3 is a diagram showing a schematic configuration of a CCD image sensor 59 provided in the reading device 50. The CCD image sensor 59 functioning as a light receiving unit includes a rectangular sensor substrate 59a and three line sensors 59R, 59G, and 59B disposed on the sensor substrate 59a. In the following description, these three line sensors 59R, 59G, and 59B are referred to as a red line sensor 59R, a green line sensor 59G, and a blue line sensor 59B, respectively. The line sensor for red 59R, the line sensor for green 59G, and the line sensor for blue 59B are arranged along the direction (main scanning direction) orthogonal to the document conveying direction and the moving direction of the full rate carriage 53 (see FIG. 2). Each line sensor is arranged in parallel. Each of the red line sensor 59R, the green line sensor 59G, and the blue line sensor 59B includes, for example, n photodiodes PD each having a size of 10 μm × 10 μm arranged on a straight line. The distance between the blue line sensor 59B and the green line sensor 59G and the distance between the green line sensor 59G and the red line sensor 59R are respectively two lines in the sub-scanning direction.

  FIG. 4 is a block diagram of the control / image processing unit 60 shown in FIG. The control / image processing unit 60 includes a signal processing unit 70 and a control unit 80. The signal processing unit 70 processes the read data input from the red line sensor 59R, the green line sensor 59G, and the blue line sensor 59B provided in the CCD image sensor 59. On the other hand, the control unit 80 controls the operations of the document feeder 10 and the reading device 50.

The control unit 80 includes a reading controller 81, a CCD driver 82, a light source driver 83, a scan driver 84, and a transport mechanism driver 85.
The reading controller 81 controls the entire document feeder 10 and the reading device 50 shown in FIG.
The CCD driver 82 controls the image data capturing operation by the CCD image sensor 59 (red line sensor 59R, green line sensor 59G, blue line sensor 59B).
The light source driver 83 outputs a lighting signal and controls turning on / off of the light source 55 in accordance with the reading timing of the document.
The scan driver 84 controls the scanning operation by the full rate carriage 53 and the half rate carriage 54 by turning on / off the motor in the reading device 50.
The transport mechanism driver 85 controls motor control, various rolls, clutches, and gate switching operations in the document feeder 10.

  From these various drivers, control signals are output to the document feeder 10 and the reading device 50, and these operations can be controlled based on the control signals. The reading controller 81 sets the reading mode based on a control signal from the host system, a sensor output detected in the automatic selection reading function, a selection from the user received via the UI 4 (see FIG. 1), and the like. The document feeder 10 and the reading device 50 are controlled. Examples of the reading mode include a fixed reading mode for reading a document placed on the first platen glass 52A, a transport reading mode for reading a document transported on the second platen glass 52B, and the like. Further, in the conveyance reading mode, there are a single-side mode for reading an image on one side of a document, a double-side mode for reading images on both sides of a document, and the like.

  Now, a copying operation by the copying machine 1 will be described with reference to FIGS. In the scanner 2 of the copying machine 1, as described above, reading of a document placed on the first platen glass 52A (fixed reading mode) and reading of a document conveyed by the document feeder 10 (conveyance reading) Mode) is executable.

  First, the fixed reading mode will be described. In the fixed reading mode, the document feeder 10 is opened with respect to the reading device 50, and after the document is set on the first platen glass 52A, the document feeder 10 is closed. As a result, the document on the first platen glass 52A is pressed against the first platen glass 52A by the backing member 20 provided in the document feeder 10. Then, when a start instruction from the user is accepted via the UI 4, the following operation is executed.

  That is, when reading an image of a document placed on the first platen glass 52A, the full rate carriage 53 and the half rate carriage 54 move in the scanning direction (arrow direction) at a ratio of 2: 1. At this time, the light source 55 of the full-rate carriage 53 is turned on, and the light from these lights is applied to the read surface of the document. Then, the reflected light from the document is reflected in the order of the first mirror 57A, the second mirror 57B, and the third mirror 57C and guided to the imaging lens 58. The light guided to the imaging lens 58 is imaged on the light receiving surface of the CCD image sensor 59. That is, the blue line sensor 59B receives reflected light in the blue region, the green line sensor 59G receives reflected light in the green region, and the red line sensor 59R receives reflected light in the red region. Each of the blue line sensor 59B, the green line sensor 59G, and the red line sensor 59R is composed of a one-dimensional sensor as described above, and processes one line at a time. The full rate carriage 53 and the half rate carriage 54 are moved in this line direction (scanning sub-scanning direction) to read the next line of the document. By executing this over the entire document, reading of one page of the document is completed.

  Next, the conveyance reading mode will be described. In the transport reading mode, a document or a bundle of documents is set on the document tray 11 in a state where the document feeder 10 is closed with respect to the reading device 50. Thereafter, when a start instruction from the user is received via the UI 4, the conveyance of the document by the document feeder 10 is started.

  When reading an image of a document transported by the document feeder 10, the transported document passes over the second platen glass 52B while being pressed against the second platen glass 52B by the backing roll 17. At this time, the full rate carriage 53 and the half rate carriage 54 are stopped at the position indicated by the solid line in FIG. Then, the light of the light source 55 of the full rate carriage 53 is irradiated on the read surface of the document. At this time, the backing roll 17 faces the original reading position by the full rate carriage 53 with the original interposed therebetween. Then, the reflected light of the first line of the original is imaged by the imaging lens 58 via the first mirror 57A, the second mirror 57B, and the third mirror 57C. The light guided to the imaging lens 58 is imaged on the light receiving surface of the CCD image sensor 59. That is, the blue line sensor 59B receives reflected light in the blue region, the green line sensor 59G receives reflected light in the green region, and the red line sensor 59R receives reflected light in the red region. Then, after each line sensor constituting the CCD image sensor 59 simultaneously processes one line in the main scanning direction, one line in the next main scanning direction of the document conveyed by the document feeder 10 is read. Then, after the leading edge of the document reaches the reading position of the second platen glass 52B, the trailing edge of the document passes through the reading position of the second platen glass 52B, thereby reading one page of the document in the sub-scanning direction. Is completed.

  Further, when reading images formed on both sides of the original, the discharge roll 19 is immediately before the rear end of the original, which has been read on the front side, passes through the discharge roll 19 provided in the second conveyance path 32. The driving direction is switched to the reverse direction. At this time, the document is guided to the third conveyance path 33 by switching the direction of the gate (not shown). At this time, the trailing edge side of the document is now the leading edge side. Then, the original passes again over the second platen glass 52B with the front and back sides reversed, and the back side is read in the same manner as the above-described process. Thereafter, the drive direction of the discharge roll 19 is switched to the reverse direction again immediately before the rear end of the document that has been read on the back side passes through the discharge roll 19 provided in the second conveyance path 32. At this time, the document is guided to the fourth conveyance path 34 by switching the direction of the gate (not shown). At this time, the leading and trailing edges of the document are replaced again, and the document is discharged onto the paper discharge tray 12 in a state where the front and back of the document are reversed. By doing so, the arrangement order of a plurality of document bundles can be made the same when placed on the document tray 11 and when ejected onto the paper discharge tray 12.

  The red (R), green (G), and blue (B) image data (RGB data: referred to as R data, G data, and B data, respectively) obtained in the fixed reading mode or the conveyance reading mode are Predetermined image processing is performed in the image processing unit 60 and converted into yellow (Y), magenta (M), cyan (C), and black (K) image data (referred to as YMCK data) and then applied to the printer 3. Is output. Then, the printer 3 forms a full color image with each color toner on the paper based on the input YMCK data.

  By the way, in this copying machine 1, based on the image data of each color of red, green, and blue obtained by reading the image of the document with the scanner 2, the signal processing unit 70 corrects the document with a correction liquid or a correction tape. The presence or absence of traces is detected. When a correction trace is detected, output image data in which the correction trace data is added to the original read data is output to the printer 3.

FIG. 5 shows a detailed block diagram of the signal processing unit 70 shown in FIG. The signal processing unit 70 includes a preprocessing unit 100, an image processing unit 200, a correction detection unit 300, and a synthesis unit 400.
The preprocessing unit 100 converts, for example, analog / digital conversion (A / A) into image data (input image data) input from the CCD image sensor 59 (red line sensor 59R, green line sensor 59G, blue line sensor 59B). Various pre-processing such as D conversion) is performed.
The image processing unit 200 functioning as the first processing unit performs various image processing such as highlight adjustment (background removal) on the image data preprocessed by the preprocessing unit 100, and uses the obtained image data. Output.
The correction detection unit 300 functioning as the detection unit and the second processing unit is obtained by extracting a correction region (correction part) with a correction liquid or the like based on the image data preprocessed by the preprocessing unit 100 The corrected area data (corrected part data) is output.
The synthesizing unit 400 functioning as the third processing unit is obtained by synthesizing the image data subjected to various image processing by the image processing unit 200 and the correction area data extracted by the correction detection unit 300. Output image data is output to the printer 3.

FIG. 6 shows a block diagram of the preprocessing unit 100. The preprocessing unit 100 includes an analog processing unit 110, an analog-digital (A / D) conversion unit 120, a delay processing unit 130, and a first color conversion unit 140.
The analog processing unit 110 performs analog correction such as gain / offset adjustment on the input R data, G data, and B data.
The A / D conversion unit 120 converts R data, G data, and B data subjected to analog correction into digital data.

  The delay processing unit 130 corrects a gap due to a difference in attachment positions of the blue line sensor 59B, the green line sensor 59G, and the red line sensor 59R (see FIG. 3). That is, as shown in FIG. 3, the green line sensor 59G is shifted by two lines in the sub scanning direction with respect to the red line sensor 59R, and the blue line sensor 59B is subordinate to the green line sensor 59G. They are shifted by two lines in the scanning direction. For this reason, when the scanner 2 performs a document reading operation in the fixed reading mode and the conveyance reading mode, a specific part (main scanning direction line) of the document is first read by the blue line sensor 59B, and then this specification is performed. Is read by the green line sensor 59G, and finally this specific part is read by the red line sensor 58R. In other words, at the same timing, the blue line sensor 59B, the green line sensor 59G, and the red line sensor 59R each read an image of a portion shifted by two lines in the sub-scanning direction. Become. Therefore, the delay processing unit 130 uses the R data from the red line sensor 59R to be read last as a reference, delays the G data from the green line sensor 59G by two lines in the sub-scanning direction with respect to the R data, Further, the B data by the blue line sensor 59B is delayed by 4 lines in the sub-scanning direction with respect to the R data (for G data by 2 lines in the sub-scanning direction). As a result, R data, G data, and B data obtained by reading the same part (the same main scanning direction line) of the document are output from the delay processing unit 130 in synchronization.

The first color conversion unit 140 converts, from the RGB color space to the L ^* a ^* b ^* color space, for each pixel with respect to R data, G data, and B data input in synchronization with the delay processing unit 130. Perform color conversion processing. Therefore, the L ^* data, a ^* data, and b ^* data after color conversion are output from the first color conversion unit 140, that is, the preprocessing unit 100. These L ^* data, a ^* data, and b ^* data (hereinafter referred to as Lab data as necessary in the following description) are output to the image processing unit 200 and the correction detection unit 300, respectively.

FIG. 7 shows a block diagram of the image processing unit 200. The image processing unit 200 includes an edge detection unit 210, a filter processing unit 220, a highlight adjustment unit 230, and a second color conversion unit 240.
The edge detection unit 210 detects an edge of an image based on L ^* data for lightness among Lab data input from the preprocessing unit 100.
The filter processing unit 220 performs spatial filter processing on the Lab data, and emphasizes or blurs the edges detected by the edge detection unit 210.
The highlight adjustment unit 230 acquires the background data of the document from the Lab data, removes the background data from the Lab data, and outputs the data.
The second color conversion unit 240 converts the L ^* data, a ^* data, and b ^* data input from the highlight adjustment unit 230 from the L ^* a ^* b ^* color space to the YMCK color space for each pixel. The color conversion process is performed. For this reason, Y data, M data, C data, and K data (hereinafter referred to as YMCK data as necessary in the following description) are supplied as image data from the second color conversion unit 240, that is, the image processing unit 200. It is output to the synthesis unit 400.

FIG. 8 shows a block diagram of the correction detection unit 300. The correction detection unit 300 includes a background detection unit 310, a minute edge detection unit 320, an edge enhancement processing unit 330, and a third color conversion unit 340.
The background detection unit 310 detects the background level of the document based on L ^* data corresponding to the lightness among the Lab data input from the preprocessing unit 100.
The minute edge detection unit 320 detects minute edges close to the background level using the Lab data input from the preprocessing unit 100 and the background level of the document detected by the background detection unit 310.
The edge enhancement processing unit 330 performs processing for enhancing the minute edge detected by the minute edge detection unit 320.
The third color conversion unit 340 performs color conversion processing from the L ^* a ^* b ^* color space to the YMCK color space for each pixel on the Lab data input from the edge enhancement processing unit 330. For this reason, Y data, M data, C data, and K data are output from the third color conversion unit 340, that is, the correction detection unit 300, to the synthesis unit 400 as correction area data.

  5 combines the image data (YMCK data) input from the image processing unit 200 and the correction area data (YMCK data) input from the correction detection unit 300 for each color and each pixel. And output image data obtained is output.

  Note that the function of each unit constituting the signal processing unit 70 is realized by cooperation of software and hardware resources. That is, a CPU (Central Processing Unit) (not shown) provided in the signal processing unit 70 implements a program for realizing the functions of the preprocessing unit 100, the image processing unit 200, the correction detection unit 300, and the synthesis unit 400, such as a hard disk or the like. These functions are realized by reading from the external storage device into the main memory.

Here, FIG. 9A exemplifies a document that is not corrected with a correction liquid or the like (referred to as an uncorrected document).
On the other hand, FIG. 9B shows a document (corrected document) in which a partial area of the uncorrected document shown in FIG. 9A (“Aiueo” in the third line of the text image) is corrected with a correction liquid or the like. This is exemplified. In the corrected original shown in FIG. 9B, an area corrected with correction liquid or the like is referred to as a correction area W.

FIG. 10A is based on the read data (pixel numbers 1 to n: corresponding to the number of photodiodes PD of each line sensor) of the uncensored line L1 in the uncensored document shown in FIG. The L ^* data output from the processing unit 100 is shown. In unmodified line L1, a text image "ABCDE" value of L ^* is small in the recorded region (dark) becomes, "ABCDE" is not area (background area), the L ^* value is large which is recorded (bright )Become.

On the other hand, FIG. 10B is output from the preprocessing unit 100 based on the read data (pixel numbers 1 to n) of the corrected line L2 including the correction area W in the corrected document shown in FIG. 9B. L ^* data is shown. In the corrected line L2, the value of L ^* is slightly smaller (darker) in the minute edge portion E corresponding to the end of the correction region W shown in FIG. 9B, and the value of L ^* is in other regions. It becomes bigger (brighter). Here, the L ^* value at the minute edge portion E is changed because a slight step is formed between the correction liquid or the correction tape and the original itself.

Then, the following processing is performed in the correction detection unit 300 shown in FIG.
First, the background detection unit 310 detects the background level based on the obtained L ^* data. In the example shown in FIG. 10, L ^* = g is detected as the background level.
Next, the minute edge detection unit 320 performs edge detection, and the minimum value of L ^* of each pixel at the detected edge is in the range of g + α <L ^* <g + β, or g−β <L ^* <g−α. If the minimum value of L ^* is within this range, the presence of a minute edge is detected. That is, the correction detection unit 300 detects a shadow caused by a minute step caused by a correction liquid or the like. Here, | α | <| β |. For example, when L ^* = 90, α is set to about 3 and β is set to about 5. In this embodiment, when the minimum value of L ^{* is in} the range of g−α ≦ L ^* ≦ g + α, the presence of a minute edge is not detected. This is to prevent erroneous detection of a minute edge due to a measurement error or the like.

In the case of the uncorrected line L1 shown in FIG. 10A, the minimum value of L ^* of the part corresponding to the edge of the text image is significantly smaller than g-β. That, L ^* minimum of ^{g + α <L * <g} + β range or,, g-β <not present in the range of L ^* <g-α. Therefore, the minute edge detector 320 does not detect minute edges from the uncorrected line L1 that has not been corrected.

On the other hand, in the case of the corrected line L2 shown in FIG. 10B, the minimum value of L ^* of the minute edge portion E which is the boundary of the correction area W is within the range of g−β <L ^* <g−α. Therefore, the minute edge detector 320 detects the presence of minute edges (two locations in this example) from the corrected line L2 that has been corrected.

  The edge enhancement processing unit 330 executes enhancement processing for enhancing the minute edges detected by the minute edge detection unit 320. Here, as a process for emphasizing a minute edge, for example, a spatial filter process using a high-pass filter can be cited. Moreover, the process etc. which convert the detected minute edge into Lab data corresponding to the color which is conspicuous, such as red, etc. may be sufficient, and also these may be combined.

  Then, the third color conversion unit 340 performs color conversion on Lab data obtained by emphasizing minute edges into correction area data including YMCK data, and outputs the correction area data.

  In this example, the determination of the presence or absence of a minute edge in the main scanning direction line (uncorrected line L1 and corrected line L2) of the document (corrected document) is described. Similarly, the presence / absence of a minute edge is also determined for the sub-scanning direction line perpendicular to the line.

FIG. 11A is a diagram illustrating the flow of data obtained by reading the uncorrected document shown in FIG.
11A-1 shows the image data output from the image processing unit 200, FIG. 11A-2 shows the correction area data output from the correction detection unit 300, and FIG. ) Represents output image data output from the combining unit 400 by combining the image data and the correction area data. In the case of an uncorrected document, the correction area data is substantially empty and empty as shown in FIG. For this reason, the output image data shown in FIG. 11A-3 is the same as the image data shown in FIG.

On the other hand, FIG. 11B is a diagram illustrating the flow of data obtained by reading the corrected document shown in FIG. 9B.
11B-1 shows the image data output from the image processing unit 200, FIG. 11B-2 shows the correction area data output from the correction detection unit 300, and FIG. ) Represents output image data output from the combining unit 400 by combining the image data and the correction area data. In the case of a corrected original, the area corresponding to the correction area W (see FIG. 9B) is empty (white) in the image data as shown in FIG. 11B-1. On the other hand, in the correction area detection data, frame-shaped data appears in an area corresponding to the edge of the correction area W as shown in FIG. For this reason, the output image data shown in FIG. 11 (b-3) has a frame indicating that the corresponding part of the correction area W has been corrected.

  In the present embodiment, the copying operation using the scanner 2 and the printer 3 has been described as an example. For example, image data obtained by reading a document with the scanner 2 is transferred to a device such as a PC (Personal Computer). The output scan-in operation can also be executed. In this case, it is preferable to output the processed image data as described above as RGB data instead of YMCK data to a device such as a PC.

  Further, in the present embodiment, the description has been made with respect to a corrected document in which an uncorrected document is corrected using a correction liquid, a correction tape, or the like, but the present invention is not limited to this. That is, for example, when a partial area of the original is hidden by overlaying another piece of paper (for example, white paper) on a part of the uncensored original, or a partial area of the original is hidden by cutting a part of the uncensored original Even in this case, the correction area can be extracted from the reading result of the minute step formed in the boundary area.

1 is a diagram illustrating a configuration of a copier to which the exemplary embodiment is applied. It is a figure which shows the structural example of a scanner. It is a figure which shows schematic structure of a CCD image sensor. It is a block diagram of a control and image processing unit. It is a block diagram of a signal processing part. It is a block diagram of the pre-processing part in a signal processing part. It is a block diagram of the image processing part in a signal processing part. It is a block diagram of the correction detection part in a signal processing part. (A) is a view showing an uncorrected document, and (b) is a corrected document obtained by correcting an uncorrected document with a correction liquid or the like. (A) is a L ^* data of unmodified lines in chromatic revised manuscript, the L ^* data chromatic repair line in (b) is Yes revised manuscript illustrates respectively. (A) is a diagram schematically showing image data, correction area data, and output image data of an uncorrected document, and (b) is a diagram schematically showing image data, correction area data, and output image data of a corrected document. is there.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Copy machine, 2 ... Scanner, 3 ... Printer, 10 ... Document feeder, 50 ... Reading apparatus, 59 ... CCD image sensor, 60 ... Control and image processing unit, 70 ... Signal processing part, 80 ... Control part, 100 ... Pre-processing unit, 110 ... Analog processing unit, 120 ... A / D conversion unit, 130 ... Delay processing unit, 140 ... First color conversion unit, 200 ... Image processing unit, 210 ... Edge detection unit, 220 ... Filter processing unit , 230 ... highlight adjustment unit, 240 ... second color conversion unit, 300 ... correction detection unit, 310 ... background detection unit, 320 ... minute edge detection unit, 330 ... edge enhancement processing unit, 340 ... third color conversion unit, 400: synthesis unit, W: correction area

Claims (7)

A reading unit for reading an image formed on a document;
An image processing unit that performs image processing on the image data read by the reading unit;
A detection unit for detecting a correction portion applied to the paper surface of the document from the image data read by the reading unit;
An image reading apparatus comprising: a combining unit that combines image data that has been subjected to image processing by the image processing unit and data of the correction portion detected by the detecting unit.   The image reading apparatus according to claim 1, wherein the detection unit detects the correction portion based on a detection result of a minute edge in the image data read by the reading unit. A color conversion unit that converts image data in the RGB color space read by the reading unit into image data in an L ^* a ^* b ^* color space;
The image reading apparatus according to claim 1, wherein the detection unit detects the correction portion from image data of the L ^* a ^* b ^* color space that has been color-converted by the color conversion unit. A first processing unit that performs image processing on image data obtained by reading a document;
A second processing unit for detecting a minute edge included in the image data from the image data;
An image processing apparatus including: a third processing unit that superimposes and outputs the minute edge data detected by the second processing unit on the image data subjected to image processing by the first processing unit. . The second processing unit includes:
Detecting the background of the document from the image data;
Detect a minute edge close to the detected background of the document,
The image processing apparatus according to claim 4, wherein enhancement processing is performed on the detected minute edge.   The image processing apparatus according to claim 5, wherein the enhancement process is a spatial filter process or a color conversion process. On the computer,
A function to perform image processing on input image data;
A function of detecting minute edges included in the image data from the image data;
A program for realizing a function of superimposing and outputting the detected data of the minute edge on the image data subjected to the image processing.

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