JP2011028383A - Image processor, image forming device, image processing method, image processing program and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of applying inclination correction or size correction to image data of an already read document without newly reading the document. <P>SOLUTION: In the image processor 102, a control part 106 receives setting related to whether or not to apply at least one correction of the inclination correction and the size correction to an input image. Regardless of contents thereof, a document inclination-size detection part 5 makes the input image associated with four point coordinates specifying an area of a document image included in the input image, and records them into a storage device 104. When the control part 106 receives the setting of the effect of applying the correction to the input image recorded in the storage device 104, a document inclination-size correction part 6 applies the correction corresponding to the setting to the input image based on the four point coordinates. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image forming apparatus, an image processing method, an image processing program, and a computer-readable recording medium having a function of correcting image data obtained by reading a document.

  With the improvement of image reading technology, copiers, scanners, and the like are capable of reading a target object of a document with higher definition. In addition, with the improvement of image processing technology, printing apparatuses and copiers perform image correction that corrects input image data obtained by reading so that users can obtain better printing results and output image data. It has come to have functions.

  Such image correction functions include tilt correction and size correction. Inclination correction is correction that detects that an original has been read in an inclined state by analyzing input image data and can obtain a good output result without inclination. The size correction is a correction that analyzes input image data, detects that a document has not been read at an appropriate size, and obtains an output result of an appropriate size.

  Patent Document 1 discloses an image filing device having such an image correction function. The image filing apparatus can correct not only inclination correction and size correction, but also noise generated during document reading. In addition, when a feature point such as a character or line breakage or crushing condition included in a document is extracted and it is detected that reading is not appropriate, it is possible to notify the user to that effect.

  Specifically, the image filing device uses at least one of feature quantities such as an image inclination, a character or line included in a document, a degree of crushing, and a distribution of noisy components other than the content of the document. The image data is recorded in association with the read image data, and the image data is corrected using the feature amount. Further, the image filing device can also display the read image data as it is without performing correction according to an instruction from the user, that is, without using a feature amount.

JP 2000-268159 A (published on September 29, 2000)

  However, in the above conventional configuration, when the correction setting condition is changed, there is a problem that it is necessary to extract the feature amount again from the read image data and perform the inclination correction.

  That is, the feature quantity recorded in association with the image data by the image filing device of Patent Literature 1 depends on the setting conditions for image reading. For example, when a document is read with a setting for removing noisy components, the distribution of noisy components is recorded as a feature quantity in association with image data. Therefore, in order to obtain a display image subjected to tilt correction in this state, the original must be read again with the tilt correction setting enabled, and the tilt of the image must be recorded as a feature amount in association with the image data.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image processing apparatus capable of performing tilt correction and size correction on image data of an already read original without reading the original again. It is to be realized.

  In order to solve the above problems, an image processing apparatus according to the present invention is an image processing apparatus for processing image data of an input image generated by reading an area including an entire original image with an image reading apparatus. Setting accepting means for accepting a setting relating to whether or not to perform at least one of inclination correction for correcting the inclination of the original image and size correction for correcting the size of the input image to the size of the original image; and the setting Regardless of the content of the setting accepted by the accepting means, the area information of the original image used for the inclination correction and the size correction is generated, and the area information and the input image are associated and recorded in the storage unit. And the setting accepting means receive the setting to perform at least one of the corrections, and store the information in association with the input image. Based on the area information recorded on, is characterized by comprising a correction means for performing correction corresponding to the set in the input image.

  According to the above configuration, the image processing apparatus stores, in the storage unit, the area information of the original image used for the tilt correction and the size correction, and the input image, regardless of the content of the setting received by the setting receiving unit. Record in association. The input image recorded in the storage unit is generated by reading an original with an image reading device and is not corrected. When the image processing apparatus receives a setting for correcting the input image recorded in the recording unit, the image processing apparatus corrects the input image based on the area information of the original image indicated by the area information.

  Therefore, the image processing apparatus can perform inclination correction and size correction on the image of the already read document without reading the document again.

  In order to solve the above problems, an image processing method according to the present invention performs image processing of an image processing apparatus that processes image data of an input image generated by reading an area including the entire original image with an image reading apparatus. A method for setting whether or not the setting receiving unit performs at least one of inclination correction for correcting the inclination of the original image and size correction for correcting the size of the input image to the size of the original image. Regardless of the setting acceptance step for accepting and the content of the setting accepted by the setting acceptance means, the recording means generates area information of the original image used for the inclination correction and the size correction, and the area information and A recording step of associating and recording the input image in the storage unit, and accepting a setting that the setting accepting unit performs at least one of the corrections. A correction step of correcting the input image according to the setting based on the area information recorded in the storage unit in association with the input image. It is a feature.

  According to said structure, the image processing method which concerns on this invention has an effect similar to the image processing apparatus which concerns on this invention.

  It is desirable that the correction means performs the correction on the input image and also performs a top-and-bottom correction on the corrected image for correcting the orientation of the original image included in the corrected image obtained by the correction.

  According to the above configuration, it is possible to correct the orientation (top and bottom) of the document image included in the corrected image even if the orientation of the document image included in the input image does not match the orientation of the input image. There is a further effect.

  When the setting accepting unit accepts the setting for performing the tilt correction and the size correction, the correcting unit determines that the leftmost coordinate on the document image, the width and height of the document image are based on the region information. In addition, it is desirable to generate correction information including the angle of inclination of the original image as information, and to correct the input image based on the correction information.

  When the setting accepting unit accepts a setting that only tilt correction is performed, the correcting unit uses, as information, the width and height of the input image and the tilt angle of the document image based on the region information. It is desirable to generate correction information including the correction and to correct the input image based on the correction information.

  When the setting accepting unit accepts a setting that only size correction is performed, the correcting unit receives the leftmost coordinates on the document image, the width of the document image, and the height of the document image based on the region information. It is desirable to generate correction information including the information as the information and to correct the input image based on the correction information.

  When the setting accepting unit accepts a setting indicating that neither the tilt correction nor the size correction is performed, the correcting unit generates parameters representing the width and height of the input image, and based on the parameters It is desirable to generate an output image from the input image.

  It is desirable that the correction means performs the tilt correction on the input image only when the angle included as information in the correction information is a predetermined value or more.

  According to the above configuration, the image processing apparatus performs useless tilt correction processing by setting the predetermined value to an angle at which there is no visual difference between images output with and without tilt correction. There is an additional effect that it can be suppressed.

  When the setting received by the setting receiving means is a setting for performing the tilt correction, the display control means for displaying the input image as a display image on the display unit, and whether the tilt correction is performed on the input image. An instruction receiving means for receiving an instruction on whether or not from the user, and the display control means only when the angle included as information in the correction information generated by the correction means is less than a predetermined value. When the display image is displayed on the display unit and the instruction receiving unit receives the instruction from the user, and the instruction received by the instruction receiving unit indicates that the tilt correction is to be performed, the input image is tilt corrected. It is desirable to apply.

  According to the above configuration, when the angle included as information in the correction information is less than a predetermined value, the image processing apparatus displays a display image obtained by performing tilt correction on the display unit. The image processing apparatus receives an instruction from the user as to whether or not to perform tilt correction, and receives an instruction to perform tilt correction and performs tilt correction on the input image.

  Accordingly, the image processing apparatus can display the display image obtained by performing the tilt correction on the display unit, thereby allowing the user to show the display image and determine whether to perform the tilt correction. There is an effect.

  The area information generated by the recording means includes a) coordinates of four vertices of the original image, b) coordinates of any three vertices of the four original images, and c) four vertices of the original image. 2) the coordinates of two opposing vertices and the inclination angle of the document image, d) the coordinates of any of the four vertices of the document image, the width of the document image, the height of the document image, and the document It is desirable that any one of the inclination angles of the image includes a) to d) as information.

  The present invention may also be an image forming apparatus including the image processing apparatus and the image reading apparatus.

  The image processing apparatus may be realized by a computer. In this case, an image processing program for realizing the image processing apparatus in the computer by operating the computer as each of the above means and a computer-readable recording medium on which the image processing program is recorded also fall within the scope of the present invention.

  The image processing apparatus of the present invention has an effect that it is possible to perform tilt correction and size correction on image data of a document that has already been read without reading the document again.

FIG. 2 is a block diagram illustrating the image forming apparatus according to the first exemplary embodiment, and is a block diagram illustrating a flow of image data when performing print processing in a full color mode. FIG. 2 is a block diagram illustrating the image reading apparatus according to the first exemplary embodiment, and is a block diagram illustrating a flow of image data when image transmission processing is performed in a full color mode. It is the block diagram which showed the detail of the flow of data in inclination correction | amendment and size correction | amendment. (A) is a flowchart showing a tilt correction and a size correction process during a printing process or an image transmission process, and (b) is a flowchart of a tilt correction and a size correction during a reprint process or a re-image transmission process. It is the flowchart which showed the process. FIG. 3 is a block diagram illustrating a detailed configuration of a document inclination / size detection unit. FIG. 6 is a diagram illustrating processing for extracting vertex coordinates of a document image to be recorded in association with input image data. It is a figure which shows the tangent angle table used in order to calculate a correction angle. It is a figure for demonstrating the method of calculating the pixel value of each coordinate of the original image after inclination correction | amendment using bilinear correction, (a) (b) is 4 coordinates before inclination correction used for calculation. It shows the relationship between the pixel value and the pixel value of the coordinate after inclination correction. FIG. 6 is a diagram illustrating a table used for determining a paper size to be used for printing by the image output apparatus during a printing process. It is a block diagram which shows the detailed structure of an image input device. FIG. 6 is a diagram illustrating four-point coordinates of a document image recorded in association with input image data. FIG. 4 is a diagram illustrating three-point coordinates of a document image recorded in association with input image data. FIG. 4 is a diagram illustrating two-point coordinates of an original image recorded in association with input image data, and an inclination angle of the original image. FIG. 4 is a diagram showing the left end coordinates, width, height, and inclination angle of an original image recorded in association with input image data. FIG. 5 is a block diagram illustrating an image forming apparatus according to a second exemplary embodiment, and is a block diagram illustrating a flow of image data when performing print processing in a full color mode. FIG. 6 is a block diagram illustrating an image reading apparatus according to a second embodiment, and is a block diagram illustrating a flow of image data when performing image transmission processing in a full color mode. (A) and (b) are both UIs displayed on the image display device in order to allow the user to designate whether or not tilt correction is necessary in the second embodiment. This is a UI displayed on the image display device for allowing the user to specify whether to enable / disable the tilt correction function and the size correction function. (A) shows an input image obtained by reading an area including the entire original image, and (b) to (e) are diagrams for explaining correction parameters.

(Embodiment 1)
An image forming apparatus according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram illustrating a schematic configuration of an image forming apparatus 100 according to the present embodiment.

  The image forming apparatus 100 is a multifunction machine having a copier function, a printer function, a facsimile transmission function, a scan to e-mail function, and the like.

  As shown in FIG. 1, the image forming apparatus 100 according to the present embodiment includes an image reading apparatus including an image input apparatus 500 and an image processing apparatus 102, an image output apparatus 103, a storage apparatus 104, and a communication apparatus 105.

  The image input device 500 is an image reading unit that reads a document and generates image data. The image input device 500 will be specifically described with reference to FIG. FIG. 10 is a schematic diagram showing the configuration of the image input apparatus 500. The image input apparatus 500 includes a document conveyance unit configured by an upper casing 510, a scanner unit configured by a lower casing 560, and the like.

  A document set sensor 514 that detects a document placed on the document tray 511, a call roller 512 for conveying the document one by one, and a document for reading an image on the document are conveyed to the upper casing 510. Conveying rollers 513a and 513b, a document discharge roller 50 for discharging a document, a document discharge sensor 567 for detecting a document to be discharged, and the like are provided. The conveyance roller (alignment roller) 513b includes an electromagnetic clutch (not shown) on the drive shaft, and can control transmission of driving force from a drive motor (not shown), so that there is no document. Then it has stopped. Then, when the leading edge of the document comes into contact with the feeding timing sensor 515 and a predetermined signal is transmitted from this sensor, the document is set to rotate in the direction in which the document is conveyed downstream. The conveyance roller 513b is in a stopped state so that the leading edge of the document conveyed from the upstream side comes into contact with the nip portion of the conveyance roller 513b and forms a predetermined deflection on the document, and then conveys the document downstream. Rotate. At this time, the leading edge of the document is aligned by the nip portion of the conveying roller 513b so as to be perpendicular to the conveying direction.

  The lower housing 560 is provided with scanning units 562 and 563 that reciprocate in parallel along the lower surface of the mounting table 561, an imaging lens 564, a CCD line sensor 565 that is a photoelectric conversion element, a discharge tray 566, and the like. . The scanning unit 562 has a light source 562a (for example, a halogen lamp) for irradiating light on a document conveyed from the document tray 511 or a document placed on the table 561, and light reflected by the document. And a mirror 562b for guiding it to the optical path. The scanning unit 563 also includes mirrors 563a and 563b for guiding the light reflected from the document to a predetermined optical path.

  The imaging lens 564 images the reflected light guided from the scanning unit 563 at a predetermined position on the CCD line sensor 565. The CCD line sensor 565 photoelectrically converts the formed optical image and outputs an electrical signal. That is, based on a color image read from an original (for example, the surface of the original), data separated into R (red), G (green), and B (blue) color components is output to the color image processing apparatus.

  Next, the image processing apparatus 102 will be described.

The image processing apparatus 102 is an integrated circuit that performs image processing on image data (image signal), and includes an ASIC (Application Specific Integrated Circuit). As shown in FIG. 1, the image processing apparatus 102 includes an A / D (analog / digital) conversion unit 2, a shading correction unit 3, an input processing unit 4, a document inclination / size detection unit 5, a document inclination / size correction unit. 6. Document direction detection unit 7, document direction correction unit 8, area separation unit 9, color correction unit 10, black generation / under color removal unit 11, spatial filter unit 12, and halftone generation unit 13 Yes. The processing content of each block included in the image processing apparatus 102 will be described in detail later.

  Note that the image processing apparatus 102 according to the present embodiment performs image processing on image data sent from the image input apparatus 500. The image processing apparatus 102 transmits the image data subjected to the image processing to the image output apparatus 103.

  The image output device (printer) 103 prints (forms) an image (output image) represented by the image data sent from the image processing device 102 on a recording medium (for example, paper). A color printer using a method or an inkjet method can be given. Note that “printing” in the present embodiment means either printing in the print mode or printing in the copier mode.

  The storage device 104 is a hard disk for temporarily storing image data handled by the image processing device 102. In the storage device 104, an image input device 500 reads and generates an area including the entire original image, and records image data (input image) input to the image processing device 102. When the document is placed on the document table of the image input device 500 in a tilted state and scanned, the input image includes not only a portion representing the document (document image) but also a portion other than the document. Will be.

  The communication device 105 is connected to a telephone line or the Internet, and is a device that performs image processing on the input image input by the image input device 500 and transmits the obtained output image to an external device.

  The control unit 106 is a computer including a processor such as a CPU (Central Processing Unit) or a DSP (Digital Signal Processor), and comprehensively controls various hardware included in the image forming apparatus 100. The control unit 106 also has a function of controlling data transfer between each piece of hardware provided in the image forming apparatus 100.

  Further, the image processing apparatus 102 according to the present embodiment includes an inclination correction function for correcting the inclination of the document image. The image processing apparatus 102 also has a size correction function that corrects the size of the input image to the size of the original image (crop (cuts out) the original image area from the input image). By enabling the size correction function, the image processing apparatus 102 can remove the part other than the original from the input image and output the output image.

  Next, a process executed in each block of the image processing apparatus 102 for a printing process and an image transmission process performed by receiving input image data from the image input apparatus 500 when an instruction for printing or image transmission is received from the user. Will be described in detail. Note that when the input image is recorded in the storage device 104, the image processing apparatus 102 can accept an instruction to print the input image or transmit the image from the user.

  Hereinafter, such print processing and image transmission processing will be referred to as “reprint processing” and “reimage transmission processing”. The descriptions simply “print processing” and “image transmission processing” refer to printing processing and image transmission processing performed when input image data is received from the image input device 500 when an instruction for printing or image transmission is received from the user. It shall be shown.

(1) Printing Process Hereinafter, the operation of the image processing apparatus 102 during the printing process will be described with reference to FIG. 1, but FIG. 1 illustrates the flow of image data in the image processing apparatus 102 when performing a full color printing process. It is stated that

  The A / D (analog / digital) converter 2 is a block that converts a color image signal (RGB analog signal) sent from the image input apparatus 500 into digital image data (RGB digital signal). The shading correction unit 3 is a block that performs processing for removing various distortions generated in the illumination system, the imaging system, and the imaging system of the image input apparatus 500 on the image data sent from the A / D conversion unit 2. . The input processing unit 4 is a block that performs gradation conversion processing such as γ correction processing on each of the RGB image data sent from the shading correction unit 3.

  The document inclination / size detection unit 5 stores the RGB image data (RGB density signal) subjected to processing such as γ correction by the input processing unit 4 in the storage device 104 as input image data. Then, the document inclination / size detection unit 5 calculates four-point coordinates indicating the apex of the document image in the input image as the area information, and records the four-point coordinates in association with the input image data in the storage device 104. Further, the document inclination / size detection unit 5 calculates correction parameters based on the four-point coordinates and supplies them to the document inclination / size correction unit 6. The processing of the document inclination / size detection unit 5 is performed regardless of whether the inclination correction function and the size correction function are valid or invalid. Further, the input image data stored in the storage device 104 may be managed as filing data. In this case, the image data is stored after being compressed into a JPEG code based on, for example, a JPEG compression algorithm. When a copy output operation or print output operation is instructed, a JPEG code is extracted from the storage device 104, transferred to a JPEG decompression unit (not shown), decoded, and converted into RGB data.

  When the inclination correction function is enabled, the document inclination / size correction unit 6 performs output correction by applying inclination correction to the input image data recorded in the storage device 104 based on the acquired four-point coordinates. Image data is generated separately from the input image data and recorded in the storage device 104. When the tilt correction function is disabled, output image data identical to the input image data is generated separately and recorded in the storage device 104.

  When the size correction function is enabled, the document inclination / size correction unit 6 corrects the output image data so that the size of the output image matches the size of the document image (hereinafter, referred to as “image correction data”). Called size correction).

  Finally, the document inclination / size correction unit 6 supplies output image data (corrected image) obtained by performing size correction and inclination correction to the document direction detection unit 7. The tilt correction and the size correction will be described in detail later.

  The document direction detection unit 7 detects the vertical direction of the output image data by determining whether the document image included in the input output image data is oriented in the up, down, left, and right directions, and detects the detection result. Output to the document orientation correction unit 8.

  The document direction correcting unit 8 acquires the output image data from the storage device 104 and rotates the output image data in accordance with the vertical direction obtained from the document direction detecting unit 7 (hereinafter referred to as vertical correction). Then, the document direction correcting unit 8 supplies the output image data obtained by performing the top / bottom correction to the region separating unit 9 and the color correcting unit 10. The top / bottom correction will be described later in more detail.

  The area separation unit 9 determines, based on the RGB output image data sent from the document direction correction unit 8, for what pixel area the pixel is classified for each pixel of the input image. A process for generating a region separation signal indicating the discrimination result is performed. Here, the image areas discriminated by the area separating unit 9 include a black character area, a color character area, a halftone dot area, a photographic paper photograph area (continuous tone area), and the like. Note that the region separation processing may be in a form in which the image region is determined for each block including a plurality of pixels, instead of determining the image region for each pixel. The region separation unit 9 supplies the generated region separation signal to the black generation / undercolor removal unit 11, the spatial filter unit 12, and the halftone generation unit 13.

  The control unit (CPU) 108 controls the document inclination / size detection unit 5 and the document inclination / size correction unit 6 according to the inclination correction and size correction settings received via the operation unit (not shown). Notify whether or not to detect or correct.

  The color correction unit 10 performs color correction processing for converting RGB output image data output from the document direction correction unit 8 into CMY image data, and performs processing for improving color reproducibility on the image data. It is a block. The color correction process described above is realized by creating an LUT (lookup table) in which input values (RGB) and output values (CMY) are associated with each other, and looking up the output values from the created LUT. .

  The black generation / under color removal unit 11 performs black generation for generating black (K) image data from the CMY image data output from the color correction unit 10, while black (K) from the original CMY image data. This is a block for performing a process of generating new CMY image data by subtracting the image data. As a result, the CMY image data is converted into CMYK four-color image data by the black generation / undercolor removal unit 11.

  The spatial filter unit 12 performs spatial filter processing (enhancement processing, smoothing processing) on the CMYK image data output from the black generation / undercolor removal unit 11 using a digital filter based on a region separation signal (region identification signal). Etc.). That is, the spatial filter unit 12 executes different image processing for each image region based on the region separation signal.

  The halftone generation unit 13 performs tone reproduction processing (halftone generation processing) necessary for printing an image in the image output apparatus 103 using an error diffusion method or a dither method.

  Then, the CMYK image data output from the halftone generation unit 13 is transferred to the image output device 103, and the image output device 103 prints the image of the image data as an output image on a recording medium (for example, paper). .

(2) Image Transmission Process Next, the operation of the image processing apparatus 102 during the image transmission process will be described.

  In the image transmission mode, the A / D (analog / digital) conversion unit 2, the shading correction unit 3, the input processing unit 4, the document inclination / size detection unit 5, the document inclination / size correction unit 6, and the document direction detection unit 7 The same operation as in the copier mode is performed.

  The document direction correcting unit 8 performs top / bottom correction, but does not supply RGB output image data obtained by the correction to the region separating unit 9 or the color correcting unit 10.

  Further, the region separation unit 9, the color correction unit 10, the black generation / undercolor removal unit 11, the spatial filter unit 12, and the halftone generation unit 13 do not perform any operation.

  On the other hand, the control unit 106 generates a PDF file based on the output image data recorded in the storage device 104. Then, the control unit 106 transmits the PDF file generated via the communication device 105 to the outside. The file generated for transmission to the outside is not limited to a PDF file, and may be an image file such as JPEG or a document file that can store other image information.

(3) Details of tilt correction, size correction, and top / bottom correction Next, details of tilt correction, size correction, and top / bottom correction performed by the image processing apparatus 102 will be described below with reference to FIGS. .

  FIG. 3 shows the flow of data exchanged by the document inclination / size detection unit 5 to the document direction correction unit 8 for the above corrections. FIG. 4A is a flowchart showing a flow of processing performed by the document inclination / size detection unit 5 to the document direction correction unit 8 at the time of print processing or image transmission processing.

  As illustrated in FIG. 3, the document inclination / size detection unit 5 performs document image inclination / size detection processing based on the input image data recorded in the storage device 104, and indicates a vertex 4 of the document image in the input image. Point coordinates are calculated (S1 in FIG. 4A). The document inclination / size detection unit 5 records the calculated four-point coordinates in the storage device 104 in association with the input image data. Then, the document inclination / size detection unit 5 calculates correction parameters to be passed to the document inclination / size correction unit 6 based on the four-point coordinate information based on the setting of validity / invalidity of the inclination correction / size correction (S2).

  Here, the correction parameters will be described with reference to FIG. 19B to 19E show the document inclination / size detection unit 5 when the inclination correction and the size correction are performed on the input image in a state where the original image is inclined by 20 ° as shown in FIG. It is the figure which showed visually which information in input image data is used as a parameter for correction to compute. The correction parameters are composed of parameters of correction processing start coordinates, corrected image size, and correction angle, but the coordinates represented by black circles in the drawings (b) to (e) and the length of the solid line portion , Deg values are used as correction parameters.

  FIG. 19B is a diagram showing correction parameters when both inclination correction and size correction are effective. When both tilt correction and size correction are valid as shown in FIG. 19B, the correction processing start coordinate is the coordinate value of the left end coordinate of the four point coordinates of the document image, the correction angle is 20 °, The corrected image size is the width and height of the solid line portion of the original image. FIG. 19C is a diagram showing correction parameters when tilt correction is invalid and size correction is valid. When tilt correction is disabled and size correction is enabled as shown in FIG. 19C, the correction processing start coordinate is the coordinate value of the left edge coordinate of the input image, the correction angle is 0 °, and the corrected image size Is the width and height of the solid line part of the input image.

  FIG. 19D is a diagram showing correction parameters when tilt correction is enabled and size correction is disabled. When tilt correction is enabled and size correction is disabled as shown in FIG. 19D, the correction processing start coordinate is a coordinate value of a coordinate rotated 20 degrees around the center coordinate of the input image, and the correction angle is The corrected image size is the width / height of the input image. FIG. 19E is a diagram showing correction parameters when both tilt correction and size correction are invalid. As shown in FIG. 19E, when both the tilt correction and the size correction are invalid, the correction processing start coordinate is the coordinate value of the left end coordinate of the input image, the correction angle is 0 °, and the corrected image size is input. The width and height of the solid line part of the image.

  Next, how the skew / size detector 5 calculates the above parameters and passes them to the skew / size corrector 6 when the skew correction or size correction is set. This will be described in more detail below.

  As shown in FIG. 5, the document inclination / size detection unit 5 includes an edge detection processing unit 51 and a parameter calculation unit 52.

As shown in FIG. 6, the edge detection processing unit 51 obtains the gradation value of each pixel on the line in order from the line 1 for each line (line N: N = 1, 2,...) Of the input image. , it extracts the leftmost coordinate value of the pixels of the pixel having the tone value than a predetermined threshold value (L _N, N) and the rightmost coordinate values of the pixels (R _{N, N).} This process may be performed for all the lines of the image, or when there is no pixel having a gradation value equal to or higher than a predetermined threshold on the line, all four-point coordinate values are obtained. Since it is considered that it has been extracted, the processing may be terminated there.

  Finally, the edge detection processing unit 51 selects the coordinates with the minimum and maximum values of the X coordinate and the coordinates with the minimum and maximum values of the Y coordinate out of all the extracted coordinate values as four-point coordinates, The value of the four-point coordinates is supplied to the parameter calculation unit 52.

  The parameter calculation unit 52 calculates a correction parameter that includes correction processing start coordinates, a corrected image size (width / height (pixel unit) of the corrected output image), and a correction angle. The correction parameters are calculated as follows according to the validity / invalidity of the inclination correction / size correction setting.

(When tilt correction is enabled, size correction is enabled)
The parameter calculation unit 52 calculates the correction angle α based on the uppermost and leftmost edge coordinates among the edge coordinates detected by the edge detection processing unit 51.

In other words, the value of tanα is calculated by the formula of tanα = (EdgeT _y −EdgeL _y ) / (EdgeT _x −EdgeL _x ), and the tangent in which the value of α and the value of tanα are correlated as shown in FIG. The value of α is obtained using an angle table.

Then, when the calculated α is equal to or greater than a predetermined threshold value (correction function cancellation angle threshold value, for example, 0.5 °) and equal to or less than 45 °, the parameter calculation unit 52 uses (EdgeL, StartL) as the correction process start coordinates (StartL, StartY). _x , EdgeL _y )

On the other hand, when the calculated α is greater than 45 ° and the absolute value of α-90 is equal to or greater than the correction function cancellation angle threshold, (EdgeT _x , EdgeT _y ) is used as the correction processing start coordinates (StartX, StartY). Set.

  If none of the above applies, the parameter calculation unit 52 calculates the same correction parameter as when the inclination correction / size correction setting is set to “inclination correction function: invalid, size correction function: valid”. Process.

Next, the parameter calculator 52 determines the coordinates of the four vertices (EdgeT _x ′, EdgeT _y ′), (EdgeB _x ′, EdgeB _y ′) constituting the document image after the inclination correction based on the calculated α value. , (EdgeL _x ′, EdgeL _y ′), (EdgeR _x ′, EdgeR _y ′) are calculated by the following Equation 1. Where (EdgeT _x ', EdgeT _y ') is the top vertex, (EdgeB _x ', EdgeB _y ') is the bottom vertex, (EdgeL _x ', EdgeL _y ') is the left vertex, (EdgeR _x ', EdgeR _y ' ) Is the rightmost vertex.

The parameter calculation unit 52 calculates the corrected image size using the calculated coordinate values of the four vertices.
Image height after correction = MAX (EdgeT _y ', EdgeB _y ', EdgeL _y ', EdgeR _y ')-MIN (EdgeT _y ', EdgeB _y ', EdgeL _y ', EdgeR _y ')
Corrected image width = MAX (EdgeT _x ', EdgeB _x ', EdgeL _x ', EdgeR _x ')-MIN (EdgeT _x ', EdgeB _x ', EdgeL _x ', EdgeR _x ')
(When tilt correction is enabled, size correction is disabled)
The parameter calculation unit 52 calculates the correction angle α in the same manner as in the case of inclination correction: valid, size correction: valid, but when the value of α or the absolute value of α-90 is less than the correction function cancellation angle threshold value. Performs the same correction parameter calculation processing as when the inclination correction / size correction setting is set to “inclination correction function: invalid, size correction function: invalid”.

  Further, the parameter calculation unit 52 sets the height and width of the input image recorded in the storage device 104 as parameters of the corrected image size.

(When tilt correction is disabled, size correction is enabled)
The parameter calculation unit 52 sets the correction angle α to 0.

In addition, the parameter calculation unit 52 includes the four-point coordinates (EdgeT _x , EdgeT _y ), (EdgeB _x , EdgeB _y ), (EdgeL _x , EdgeL _y ), (EdgeR _x , EdgeR _y ) supplied from the edge detection processing unit 51. ) To calculate the corrected image size.
Image height after correction = MAX (EdgeT _y , EdgeB _y , EdgeL _y , EdgeR _y )-MIN (EdgeT _y , EdgeB _y , EdgeL _y , EdgeR _y )
Corrected image width = MAX (EdgeT _x , EdgeB _x , EdgeL _x , EdgeR _x )-MIN (EdgeT _x , EdgeB _x , EdgeL _x , EdgeR _x )
Further, the parameter calculation unit 52 obtains coordinates (CenterX, CenterY) indicating the center point of the input image, and calculates correction processing start coordinates (StartX, StartY) by the following equation 2.

(When tilt correction is disabled, size correction is disabled)
The parameter calculation unit 52 sets the correction angle α to 0.

  Further, the parameter calculation unit 52 sets the height and width of the input image recorded in the storage device 104 as parameters of the corrected image size.

  The correction parameter values calculated by the parameter calculation unit 52 in accordance with the validity / invalidity of the settings for inclination correction and size correction have been described above. The parameter calculation unit 52 uses the calculated correction parameter values as the values for the document. Supply to the inclination size correction unit 6.

  After the process of S2, the document inclination / size correction unit 6 determines the inclination / size of the input image data separately from the input image data based on the value of the correction parameter received from the document inclination / size detection unit. Output image data subjected to correction processing is generated and stored in the storage device 104 (S3).

  Hereinafter, the inclination / size correction processing will be described in detail. The coordinates used in the description here are the correction processing start coordinates (StartX, StartY) calculated by the parameter calculation unit 52 as the origin (0, 0). It is described in advance that the coordinates are on the XY coordinate system.

  The document inclination / size correction unit 6 calculates the vertex coordinates (x ′, y ′) of the original image after the inclination correction, and the vertex coordinates (x, y) of the original image before correction calculated by the document inclination / size detection unit 5. Then, the correction angle parameter θ is calculated by applying it to Equation 3.

The document inclination / size correction unit 6 performs bilinear correction on the pixel values (gradation values) at the coordinates (x ′, y ′) of the document image after inclination correction as shown in FIG. Use to find. That is, a value (x _s , y _s ) obtained by rotating (x ′, y ′) by −θ is calculated using Equation 4.

Then, when both x _s and y _s are decimal numbers, the original inclination / size correction unit 6 includes the four-point integer coordinate values shown in FIG. 8A, that is, the calculated (x _s , y _s ) adjacent. (X _i , y _i ), (x _{i + 1} , y _i ), (x _i , y _{i + 1} ), and (x _{i + 1} , y _{i + 1} ) are obtained. Further, the document skew / size correction unit 6 has a ratio of x _s -x _i to x _{i + 1} -x _{s and} a ratio of y _s -y _i to y _{i + 1} -y _s , respectively, u: Calculate u and v such that 1-u, v: 1-v.

The document inclination / size correcting unit 6 then coordinates (x _i , y _i ), (x _{i + 1} , y _i ), (x _i , y _{i + 1} ), (x _i ) of the four adjacent points. The gradation values Z ₁ , Z ₂ , Z ₃ , and Z ₄ at ₊₁ , y _{i + 1} ) are obtained.

Finally, the document inclination / size correction unit 6 applies the calculated Z ₁ , Z ₂ , Z ₃ , Z _4w , u, and v to the following equation 5 to coordinate the original image after the inclination correction (x ′, y The gradation value Z in ') is calculated.

When one of the calculated values (x _s , y _s ) is an integer, the original skew / size correction unit 6 sets the weighted average of the gradation values at two adjacent points as Z, and (x _s , y If both values of _s ) are integers, the gradation value at (x _s , y _s ) is Z.

  Further, the document inclination / size correction unit 6 does not have to directly calculate the values of cos θ and sin θ used for calculating the coordinate value rotated by θ from the value of θ. That is, referring to the value of tanθ using a tangent angle table in which the value of θ and the value of tanθ corresponding to θ are associated in advance as shown in FIG. 7, the values of cosθ and sinθ are determined from the referenced tanθ values. May be obtained. In this way, the coordinates after rotation can be calculated at high speed.

  By performing the above processing for calculating the pixel value using the bilinear correction for each coordinate of the original image after the inclination correction, the pixel value of each coordinate is obtained. As a result, the output image data after the inclination correction is obtained. can get.

  Then, the document inclination / size correction unit 6 performs size correction on the output image data after the inclination correction based on the corrected image size parameters (width and height) received from the document inclination / size detection unit 5. I do. In other words, when the size correction is valid, the document inclination / size correction unit 6 stores the corrected output image in the size of the original image in the storage device 104 as an output image after size correction. .

  Further, at the time of printing processing, the size of paper to be printed is determined as follows.

  Hereinafter, with reference to FIG. 9, a method for determining the paper size during the printing process will be described.

  FIG. 9 is an output size table in which the paper size is associated with values indicating the width / height of the paper size in units of pixels. When the output resolution of printing is 300 dpi, document skew / size correction is performed. Reference is made to part 6. This output size table is recorded in the storage device 104, and output size tables corresponding to output resolutions other than 300 dpi (600 dpi, 1200 dpi, etc.) are also recorded in the storage device 104. The number of pixels indicating the width / height of each table is set to be about 10 mm larger than the actual paper size.

  The document inclination / size correction unit 6 refers to an output size table corresponding to the output resolution to be printed. Then, a paper size having a width value larger than the parameter indicating the width of the corrected image size and associated with the minimum width value is selected as a candidate. Then, the document inclination / size correction unit 6 selects a paper size having a height value larger than the parameter indicating the height of the corrected image size and associated with the minimum height value as a candidate. Select from paper sizes. Further, the control unit 106 notifies the image output apparatus 103 of the paper size selected by the document inclination / size correction unit 6 as the paper size to be used for printing.

  For example, when printing at 300 dpi, if the parameter indicating the width is 2480 and the parameter indicating the height is 3500, A4 and A5R whose width value is 2492 are selected as paper size candidates to be output. Then, A4 having a width value of 3519 is selected from A4 and A5R selected as candidates. The control unit 106 notifies the image output apparatus 103 of the A4 paper size as the paper size to be printed.

  After completion of the process of S3, the document direction detection unit 7 performs correction corresponding to the correction setting conditions designated by the user (in this embodiment, tilt correction and size correction have been performed). Is detected, the image data for output stored in the storage device 104 is read out, and the top and bottom of the document image included in the image for output is determined (S4).

The top / bottom determination by the document direction detection unit 7 can be realized by performing character recognition using an OCR technique, as described in, for example, Japanese Patent Laid-Open No. 6-188903. In the document orientation detection, RGB image data is converted into luminance data Y _i.
Y _i = 0.30R _i + 0.59G _i + 0.11B _i
Y: Luminance signal of each pixel R, G, B: Value of each color component of each pixel Subscript i: Value assigned to each pixel (i is an integer of 1 or more)
The luminance data is converted into black and white binary image data.

  That is, a character pattern obtained by cutting out a character from a black and white binary image and patterning the character is matched with a character pattern represented by character pattern information stored in a database. Superimpose the databased character pattern and the extracted character pattern, compare each pixel to see if both are “white” or both are “black”, and all pixels are both “white” or If both are “black”, it is determined that the database matches the character pattern in the database.

  If there is no databased character pattern that is both “white” or both “black” for all pixels, both of the databased character patterns are “white” or both “black” Is determined to be a character obtained by matching a character pattern having the maximum number of pixels equal to or greater than a predetermined threshold value. If the number of pixels that are both “white” or both “black” in the database of character patterns is less than a predetermined threshold, it is determined that matching is impossible.

  A matching process is applied to all the extracted character patterns, and the number of matched characters is detected.

  For each image obtained by rotating the black and white binary image by 90 °, 180 °, and 270 °, image data representing such an image is temporarily generated, and the OCR technique is also applied to the image data. Apply character recognition processing by.

  Finally, the document direction detection unit 7 supplies angle information indicating an angle that maximizes the number of matched characters to the document direction correction unit 8.

Then, based on the angle information received from the document direction detection unit 7, the document direction correction unit 8 performs processing so as to rotate the document image represented by the output image data recorded in the storage device 104. (S5). That is, when the angle information is 90 °, 180 °, and 270, the gradation values of (X ′, Y ′) (coordinates included in the corrected document image) represented by the following equations are the values before correction. The output image data is corrected so as to match the gradation value of the coordinates (X, Y) included in the document image.
When rotated by 90 ° X ′ = height of the image represented by the image data before vertical correction—1-Y
Y '= X
When rotated 180 ° X ′ = width of the image represented by the image data before vertical correction—1-X
Y ′ = the height of the image represented by the image data before the top and bottom correction—1-Y
When rotating 270 ° X '= Y
Y ′ = the width of the image represented by the image data before and after correction—1-X
(3) Reprint processing / Reimage transmission processing (3-1 Reprint processing)
The operation of the image processing apparatus 102 during the reprint process will be described with reference to FIG. FIG. 4B is a flowchart showing the operation of the image processing apparatus 102 during the reprint process. Here, the image processing apparatus 102 will be described on the assumption that the tilt correction function and the size correction function are set to be valid.

  When receiving an instruction to reprint input image data that has already been read and recorded in the storage device 104 via an operation unit (not shown), the control unit 106 receives the input image data and the input image data from the storage device 104. The four-point coordinates associated with the image data are read and supplied to the document inclination / size detection unit 5. The document inclination / size detection unit 5 calculates correction parameters based on the four-point coordinates and supplies them to the document inclination / size correction unit 6 (S11).

  The document inclination / size correction unit 6 outputs an image obtained by performing an inclination / size correction process on the input image data separately from the input image data based on the value of the correction parameter received from the document inclination / size detection unit 5. Image data is generated and stored in the storage device 104 (S12).

  When the document direction detection unit 7 detects that the correction corresponding to the correction setting condition specified by the user has been performed (in this embodiment, the tilt correction and the size correction have been performed), the storage device 104 is detected. The image data for output stored in is read out and the top / bottom determination of the document image included in the image for output is performed (S13).

  Then, based on the angle information received from the document direction detection unit 7, the document direction correction unit 8 performs processing so as to rotate the document image represented by the output image data recorded in the storage device 104. (S14).

  Note that the specific processing contents of tilt correction, size correction, and top / bottom correction in S11 to S14 are the same as those in the printing process.

  The operations performed by the region separation unit 9 to the halftone generation unit 13 until the output image data is output to the image output device 103 are the same as those during the printing process.

(3-2 Re-image transmission processing)
Upon receiving an instruction for a re-image transmission process for image data that has already been read and recorded in the storage device 104 via an operation unit (not shown), the control unit 106 reads from the storage device 104 in the same way as during the re-print process. The input image data and the four-point coordinates associated with the input image data are read and supplied to the document inclination / size detection unit 5. Thereafter, the PDF file representing the image data subjected to the tilt correction, the size correction, and the top / bottom correction is transmitted to the outside via the communication device 105, and the document tilt / size detection unit 5 to the document direction correction unit 8 and the control unit are transmitted. The operation performed by 106 is the same as in the image transmission process.

(User operation for reprint processing and reimage transmission processing)
Note that the procedure of an operation performed by the user for causing the image forming apparatus 100 to read out the image data recorded in the storage device 104 during the reprinting process or the reimage transmission process is as follows. That is,
1) Designate data to be processed from filing data stored in the hard disk.
2) Select the document correction mode.
3) Select a correction processing method. Specifically, as shown in FIG. 18A, a correction processing method is selected from four correction methods. Alternatively, as shown in FIG. 18B, a correction processing method is selected from four correction methods by selecting or deselecting check boxes for tilt correction and document size correction.

  As a result, the image forming apparatus 100 reads out the image data and executes correction processing. The corrected output image data is output.

  The operations 1) to 3) are performed from the operation panel of the image forming apparatus 100. Further, instead of operating the image forming apparatus 100, the image forming apparatus 100 may be accessed and operated from a computer (not shown) connected through a communication line. In this case, the operations 1) to 3) are performed through an operation screen (UI) displayed on a display connected to the computer.

(Advantages of the image forming apparatus 100)
As described above, the image forming apparatus 100 according to the present embodiment includes the input image and the input image during the printing process and the image transmission process regardless of whether the inclination correction function or the size correction function is enabled or disabled. The coordinates of the four vertices (four-point coordinates) of the original image to be stored are associated with each other and stored in the storage device 104. Accordingly, even when the settings of the inclination correction function and the size correction function are changed and reprint processing or reimage transmission processing is instructed, the image forming apparatus 100 outputs image data for output from the input image data and the four-point coordinates. As a result, printing and image transmission based on the setting can be performed without scanning the original again.

(Modification)
As described above, the image forming apparatus 100 stores the input image data and the four-point coordinates (the coordinates of P1 to P4 in FIG. 11) in association with the storage device 104 during the printing process or the image transmission process. The area information recorded in association with the image data may not be four-point coordinates. That is, as area information to be recorded in association with input image data,
(1) Three-point coordinates of the document image (for example, the coordinates of the left end and the upper and lower ends as P1, P2, and P3 in FIG. 12)
(2) Two point coordinates on the diagonal line of the document image (P1, P4 coordinates in FIG. 13) and an angle formed by the document image and the Y-axis direction of the input image represented by the input image data (θ in FIG. 13)
(3) The left end coordinates (P1 coordinates in FIG. 14) of the document image, the width / height of the document, and the angle formed by the document image and the Y-axis direction of the input image represented by the input image data (θ in FIG. 14)
For example, other data for determining the position of the document image in the input image may be stored. Here, how the image forming apparatus 100 performs tilt correction and size correction in the cases (1) to (3) will be described below.

(Tilt / size correction when recording three-point coordinates in the storage device 104)
In the printing process or the image transmission process, the document inclination / size detection unit 5 extracts the three-point coordinates indicating the vertex of the document image in the image, and associates the three-point coordinates with the input image data in the storage device 104. To record. Note that the extraction of the three-point coordinates is performed in the same manner as the extraction of the four-point coordinates.

That is, as shown in FIG. 6, the edge detection processing unit 51 performs each line on the line in order from line 1 for each line (line N: N = 1, 2,...) Of the input image represented by the input image data. obtains the gradation value of the pixel extracted, the leftmost coordinate value of the pixels of the pixel having the tone value than a predetermined threshold value (L _N, N) and most coordinate value in the right pixel (R _N, N) To do. This process is performed for all the lines of the image as in the case of extracting the four-point coordinates.

  Finally, the edge detection processing unit 51 selects the coordinates of the minimum and maximum values of the X coordinate and the coordinates of the minimum and maximum values of the Y coordinate (ie, four-point coordinates) among all the extracted coordinate values. 3 points are selected to obtain 3 point coordinates, and the value of the 3 point coordinates is supplied to the parameter calculation unit 52.

  On the other hand, in the reprint process or the re-image transmission process, the document inclination / size detection unit 5 reads the three-point coordinates recorded in the storage device 104.

  Then, the document inclination / size detection unit 5 calculates a correction parameter from the three-point coordinates.

  Thereafter, the inclination correction and size correction processing performed by the image forming apparatus 100 is the same as when the data stored in the storage device 104 in association with the input image data is four-point coordinates.

(Inclination / size correction when recording the two-point coordinates and the inclination angle θ in the storage device 104)
At the time of print processing or image transmission processing, the document inclination / size detection unit 5 extracts four-point coordinates in the same manner as the four-point coordinate extraction described so far. Then, the document inclination / size detection unit 5 selects two adjacent vertices among the four vertices represented by the four-point coordinates, and the distance in the X-axis direction (for example, P1 and P3 in FIG. 13) ( For example, x3-x1) and the distance in the Y-axis direction (y3-y1) are calculated. Then, tan θ is calculated based on the two distances, and the tilt angle θ is obtained based on the tangent angle table of FIG. After that, the document inclination / size detection unit 5 records data representing the coordinates of two diagonal points (P1 and P4 in FIG. 13) and the inclination angle θ among the extracted coordinates in association with the input image data.

  During the reprint process or the reimage transmission process, the document inclination / size detection unit 5 reads the two-point coordinates and the inclination angle θ recorded from the storage device 104.

  Then, the document inclination / size detection unit 5 calculates a correction parameter from the two-point coordinates on the diagonal line and the inclination angle θ.

  Thereafter, the inclination correction and size correction processing performed by the image forming apparatus 100 is the same as when the data stored in the storage device 104 in association with the input image data is four-point coordinates.

(Tilt / size correction when the left end coordinate, document width / height, and tilt angle θ are recorded in the storage device 104)
At the time of print processing or image transmission processing, the document inclination / size detection unit 5 extracts the four-point coordinates by the same method as the four-point coordinate extraction described so far, and records the input image data in the storage device 104. . Regardless of the settings of the tilt correction function and the size correction function, the document tilt / size detection unit 5 performs correction parameters when tilt correction or size correction is effective, that is, correction processing start coordinates (the left end of the document image). Parameters such as coordinates (P1 in FIG. 14), corrected image size (width / height of the original image), and correction angle (tilt angle θ) are calculated. The document inclination / size detection unit 5 records the correction parameter in the storage device 104 in association with the input image data.

  On the other hand, during the reprint process or the re-image transmission process, the document inclination / size detection unit 5 reads the correction parameters recorded in the storage device 104.

  The document inclination / size detection unit 5 calculates correction parameters based on the correction processing start coordinates, the corrected image size width, height value, and correction angle parameters.

  Thereafter, the inclination correction and size correction processing performed by the image forming apparatus 100 is the same as when the data stored in the storage device 104 in association with the input image data is four-point coordinates.

(Embodiment 2)
The image forming apparatus 100 according to the first embodiment disables the tilt correction when the tilt correction function is enabled and the correction angle parameter calculated by the parameter calculation unit 52 is smaller than the correction function cancel angle threshold. I explained that. The image forming apparatus 100 ′ according to the present embodiment can inquire the user whether to enable or disable the tilt correction without automatically invalidating the tilt correction.

  The image forming apparatus 100 ′ will be described with reference to FIGS. FIGS. 15 and 16 show the flow of image data during the printing process and the image transmission process in the image forming apparatus 100 ′ and the image reading apparatus, respectively. As shown in FIGS. 15 and 16, the image forming apparatus 100 ′ and the image reading apparatus according to this embodiment include the display control unit 14 and output image data to be displayed on the image display apparatus 107. 1 has the same configuration as the image forming apparatus 100 and the image reading apparatus.

  The image display device 107 is a liquid crystal display provided in an operation panel (not shown) of the image forming apparatus 100 ′. The image display device 107 is covered with a touch panel, and has a function as an input interface of the image forming apparatus 100 ′. As shown in FIG. 18, the image display device 107 is a GUI (graphical user interface) for inputting various commands such as instructing the image processing device 102 to turn on / off the document size correction function and the inclination correction function. ) And operation guides are displayed.

  The image display device 107 is not limited to a liquid crystal display, and may be a display means other than the liquid crystal display (for example, an organic EL display, a plasma display, etc.).

  When the tilt correction function is enabled, when it is detected that the parameter of the correction angle calculated by the parameter calculation unit 52 is smaller than the correction function cancel angle threshold, the document tilt / size detection unit 5 performs printing or image processing. Along with an instruction to display a preview before transmission, a correction parameter when the inclination correction is invalidated is supplied to the document inclination / size correction unit 6. The document inclination / size correction unit 6 generates display image data corrected based on the output correction parameters. Then, the document inclination / size correction unit 6 supplies the display control unit 14 with an instruction to display the display image (inclination correction cancel image) represented by the display image data on the image display device 107. Then, as shown in FIGS. 17A and 17B, the display control unit 14 selects an interface (an “OK” button and a “OK” button in FIG. 17) to select whether to enable or disable the tilt correction together with the display image. “Inclination correction” button) is displayed on the image display device 107.

  When the image display apparatus 107 receives an instruction from the user, the control unit 106 detects the instruction. When the instruction is an instruction to invalidate the tilt correction, the control unit 106 instructs the document direction detection unit 7 that detects the document direction for the top and bottom correction based on the display image data. The display image data that has not been tilt-corrected is subjected to processing subsequent to the document orientation detection unit 7, and output image data obtained as a result is output.

  On the other hand, when the instruction is an instruction indicating that the inclination correction should be enabled, the control unit 106 instructs the document inclination / size detection unit 5 to perform the inclination correction based on the four-point coordinates recorded in the storage device 104. Is instructed to calculate a correction parameter when. Thereafter, the output image data subjected to the tilt correction is output by the processing after the document tilt / size detection unit 5.

  As described above, the image forming apparatus 100 ′ displays a preview of the output image output when the inclination correction is invalidated when the inclination of the document image is small, and instructs whether to perform the inclination correction. Accept from user. Thereby, the user can determine whether or not to perform inclination correction by checking the output image. Compared to a plain document, the document surrounded by ruled lines and the like feels noticeable when tilted and printed, but the image forming apparatus 100 'is particularly effective when printing such a document.

(Additional notes)
Note that the image transmission processing in the first embodiment may be realized as an image reading device (scanner) including the image input device 500 and the image processing device 112. Further, the image transmission processing in the second embodiment may be realized as an image reading device (scanner) including the image input device 500 and the image processing device 112 ′.

  The operation of the image processing apparatuses 112 and 112 ′ during the image transmission process will be described with reference to FIGS. 2 and 16. FIGS. 2 and 16 show the flow of image data in the image processing apparatuses 112 and 112 ′ when image transmission processing is performed in full color in the image transmission mode, respectively.

  The image processing apparatuses 112 and 112 ′ include an A / D conversion unit 2, a shading correction unit 3, an input processing unit 4, a document inclination / size detection unit 5, a document inclination / size correction unit 6, a document direction detection unit 7, and a document. A direction correction unit 8 is provided. Further, the image processing apparatus 112 ′ includes a display control unit 14. The processing contents of the respective processing units of the image processing apparatuses 112 and 112 ′ are the same as those of the image processing apparatuses 102 and 102 ′ constituting the image forming apparatuses 100 and 100 ′, respectively.

  The RGB image signal after the above processing is performed in the image processing devices 112 and 112 'is output to a computer, a hard disk, a network, or the like.

  In the image processing apparatus 112 ′, the display control unit 14 performs resolution conversion, confirmation image generation, and gamma correction processing, and outputs the image data to the image display apparatus 107 that displays an image such as a display. The image reading apparatus may include a display on the main body. In this case, the display control unit 14 displays an image on the display provided on the main body.

  In the image forming apparatuses 100 and 100 ′, when the image input device 500 is provided with a document size detection mechanism, and tilt correction or size correction is enabled, the result of the document size detection mechanism is displayed. If the document is scanned within a predetermined range (for example, A3 size, A4 size) without reference, and tilt correction and size correction are disabled, refer to the result of the detection mechanism. Scans the document within the detected range. Here, the document size detection mechanism is a method of detecting the document size in the main scanning direction and the sub-scanning direction placed on the document table by a photoelectric conversion element such as a phototransistor disposed in the image input device. In addition, there is a method in which the control unit detects the document size selected by the user from the operation panel.

  In the case of the image forming apparatuses 100 and 100 ′ in which the image input apparatus 500 is not provided with a document size detection mechanism, reading is performed for a preset range (for example, A3 size, A4 size).

(Program, recording medium)
According to the present invention, there is provided program code (execution format program, program for causing a computer to execute an image processing method for performing the above-described document inclination, size, and orientation determination, and performing document inclination, size, and top / bottom correction according to the detection result. It can also be realized as a computer-readable recording medium on which an intermediate code program and a source program are recorded. As a result, it is possible to portablely provide a recording medium on which a program for performing an image processing method for correcting the inclination, size, and direction of the original is determined according to the detection result. .

  In the present embodiment, as the recording medium, a memory (not shown) such as a ROM itself may be a program medium because processing is performed by a microcomputer. However, it may be a program medium provided with a program reading device as an external storage device and readable by inserting a recording medium therein.

  In any case, the stored program code may be configured to be accessed and executed by the microprocessor, or in any case, the program code is read and the read program code is the microcomputer. The program code may be downloaded to a program storage area (not shown) and executed. It is assumed that this download program is stored in the main device in advance.

  Here, the program medium is a recording medium configured to be separable from the main body, such as a tape system such as a magnetic tape or a cassette tape, a magnetic disk such as a flexible disk or a hard disk, a CD-ROM / MO / MD / DVD, or the like. Semiconductors such as optical discs, IC cards (including memory cards) / optical cards, etc., or mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash ROM, etc. It may be a medium that carries a fixed program code including a memory.

  In the present embodiment, since the system configuration is such that a communication network including the Internet can be connected, a medium that dynamically carries the program code so as to download the program code from the communication network may be used. When the program code is downloaded from the communication network in this way, the download program may be stored in the main device in advance, or may be installed from another recording medium. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission. The recording medium is read by a program reading device provided in a digital color image forming apparatus or a computer system, whereby the above-described image processing method is executed.

  The computer system includes an image input device such as a flatbed scanner, a film scanner, and a digital camera, a computer that performs various processes such as the above image processing method by loading a predetermined program, and a CRT display that displays the processing results of the computer. An image display device such as a liquid crystal display and a printer that outputs the processing results of the computer to paper or the like. Furthermore, a network card, a modem, and the like are provided as communication means for connecting to a server or the like via a network.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the embodiments can be obtained by appropriately combining the respective technical means disclosed in the above-described embodiments. The form is also included in the technical scope of the present invention.

  The image processing apparatus of the present invention can be used for an apparatus that handles image data, but is particularly suitable for a multifunction machine, a copying machine, a printer, and a facsimile machine.

5 Document tilt / size detector (recording means)
6 Document skew / size correction unit (correction means)
7 Document Direction Detection Unit 8 Document Direction Correction Unit 9 Area Separation Unit 10 Color Correction Unit 11 Black Generation / Under Color Removal Unit 12 Spatial Filter Unit 13 Halftone Generation Unit 14 Display Control Unit (Display Control Unit)
51 Edge detection processing unit 52 Parameter calculation unit 100 Image forming apparatus 100 ′ Image forming apparatus 102 Image processing apparatus 102 ′ Image processing apparatus 103 Image output apparatus 104 Storage device (storage unit)
105 communication device 106 control unit (setting accepting means, instruction accepting means)
107 Image Display Device 112 Image Processing Device 112 ′ Image Processing Device 500 Image Input Device

Claims (13)

An image processing apparatus for processing image data of an input image generated by reading an area including an entire original image by an image reading apparatus,
Setting accepting means for accepting a setting relating to whether or not to perform at least one of inclination correction for correcting the inclination of the original image and size correction for correcting the size of the input image to the size of the original image;
Regardless of the content of the setting received by the setting receiving means, the area information of the original image used for the inclination correction and the size correction is generated, and the area information and the input image are associated and recorded in the storage unit. Recording means to
When the setting accepting unit accepts a setting for performing at least one of the corrections, the input image is set according to the setting based on the area information recorded in the storage unit in association with the input image. An image processing apparatus comprising correction means for performing correction.   2. The correction unit according to claim 1, wherein the correction unit performs the correction on the input image and performs a top-and-bottom correction on the corrected image for correcting the orientation of the document image included in the corrected image obtained by the correction. The image processing apparatus described.   When the setting accepting unit accepts the setting for performing the tilt correction and the size correction, the correcting unit determines that the leftmost coordinate on the document image, the width and height of the document image are based on the region information. The image processing apparatus according to claim 1, further comprising: generating correction information including information about an inclination angle of the document image and correcting the input image based on the correction information. .   When the setting accepting unit accepts a setting that only tilt correction is performed, the correcting unit uses, as information, the width and height of the input image and the tilt angle of the document image based on the region information. The image processing apparatus according to claim 1, wherein the image processing apparatus generates correction information including correction and corrects the input image based on the correction information.   When the setting accepting unit accepts a setting that only size correction is performed, the correcting unit receives the leftmost coordinates on the document image, the width of the document image, and the height of the document image based on the region information. 5. The image processing apparatus according to claim 1, wherein the image processing apparatus generates correction information including information as to information, and corrects an input image based on the correction information.   When the setting accepting unit accepts a setting indicating that neither the tilt correction nor the size correction is performed, the correcting unit generates parameters representing the width and height of the input image, and based on the parameters The image processing apparatus according to claim 1, wherein an output image is generated from the input image.   5. The correction unit according to claim 3, wherein the correction unit performs the inclination correction on the input image only when an angle included as information in the correction information is a predetermined value or more. Image processing device. Display control means for displaying the input image as a display image on a display unit when the setting accepted by the setting accepting means is a setting for performing the tilt correction;
An instruction receiving means for receiving from the user an instruction as to whether or not to perform the tilt correction on the input image;
The display control means displays the display image on the display unit and the instruction receiving means only when the angle included as information in the correction information generated by the correction means is less than a predetermined value. Accepts the above instructions from the user,
5. The image processing apparatus according to claim 3, wherein when the instruction received by the instruction receiving unit indicates that the tilt correction is performed, the input image is tilt corrected. The area information generated by the recording means includes
a) Coordinates of the four vertices of the original image b) Coordinates of any three vertices of the four vertices of the original image c) Coordinates of two opposite vertices of the four vertices of the original image, and the original image D) Any one of the coordinates of any of the four vertices of the original image, the width of the original image, the height of the original image, and the inclination angle of the original image is any one of a) to d). The image processing apparatus according to claim 1, wherein the image processing apparatus is included as information.   An image forming apparatus comprising the image processing apparatus according to claim 1 and an image reading apparatus. An image processing method of an image processing apparatus for processing image data of an input image generated by reading an area including an entire original image by an image reading apparatus,
A setting acceptance step for accepting a setting regarding whether or not the setting accepting unit performs at least one of an inclination correction for correcting the inclination of the original image and a size correction for correcting the size of the input image to the size of the original image. When,
Regardless of the settings received by the setting receiving means, the recording means generates area information of the original image used for the inclination correction and the size correction, and associates the area information with the input image. A recording process for recording in the storage unit;
When the setting accepting unit accepts a setting for performing at least one of the corrections, the correcting unit adds the input image to the input image based on the area information recorded in the storage unit in association with the input image. And a correction step of performing correction according to the setting.   A program for operating the image processing apparatus according to any one of claims 1 to 9, wherein the image processing program causes a computer to function as each of the means.   A computer-readable recording medium in which the image processing program according to claim 12 is recorded.

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