JP2015226264A - Image processing apparatus, image formation apparatus with the same, image processing program, and recording medium with recorded program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of precisely detecting multiple documents being fed one over another in reading a plurality of documents, an image formation apparatus with the same, an image processing program, and a recording medium having the program recorded.SOLUTION: An image formation apparatus executes a process of conveying a plurality of documents and generating read image data (steps 400 and 408), presents a request to change the direction of a document from a direction in the first process before executing the second process (step 404), and compares values of two out of one set of the numbers of times of documents, one set of total data sizes, and one set of the total numbers of characters calculated in the two processes and thereby determines whether a plurality of documents are fed one over another together (step 412). Consequently, simultaneous multiple-document feeding can be precisely detected, and a function that a user specifies can be executed using image data generated without the simultaneous multiple-document feeding.

Description

  The present invention relates to an image processing apparatus capable of detecting that two or more originals are conveyed in a superimposed manner when reading a plurality of originals, an image forming apparatus including the image processing apparatus, an image processing program, and the program The present invention relates to a recording medium on which is recorded.

  In recent years, an image forming apparatus (typically a copier) that forms an image on a recording sheet has been introduced into many offices (company, office, etc.). An MFP (Multifunction Peripheral), which is one type of such an image forming apparatus, includes a plurality of printer modes such as a copy mode, a facsimile mode, a communication network (hereinafter simply referred to as a network), and a scanner mode. It has the function of.

  In the copy function of an image forming apparatus, an image input device (scanner or the like) scans a document to generate image data, draws a recording sheet from a paper feed tray, conveys it to an image forming unit, and generates the generated image data. Based on this, an image is formed on the surface of the recording paper (hereinafter also referred to as printing). For example, when an electrophotographic system is used, a toner image carried on a photosensitive drum or a transfer body is transferred onto a conveyed recording paper, and then heated and pressed to fix the image on the recording paper.

  An automatic document feeder is known as a device that automatically conveys a plurality of documents so that they can be scanned by an image input device. The automatic document feeder is designed to take a document set on a tray one by one with a pickup roller and convey it to a scan position of an image input device. However, a plurality of documents may be taken and conveyed at once by the pickup roller (hereinafter referred to as double feeding). In such a case, there is a problem that some pages of the document are not scanned.

  If the number of documents is known in advance, it is possible to know the occurrence of double feeding only by counting the number of times the document has been conveyed. If the number of conveyances coincides with the number of documents, double feeding does not occur, and if they do not coincide, double feeding has occurred. However, it may be difficult to accurately count the number of documents when reading a large number of documents or copying.

  Patent Document 1 below discloses a technique for solving double feeding. In Patent Document 1, in order to detect double feeding of an original without increasing the size of the apparatus, the original is scanned a plurality of times, the total number of pages of the original conveyed in each scan is compared, and the comparison result is shown. A technique for informing the user is disclosed. If the total number of sheets does not match, a double feed of the document has occurred.

JP 2012-50002 A

  However, the technology disclosed in Patent Document 1 does not have sufficient double feed detection accuracy. If the original is scanned a plurality of times and the total number of pages is different, it can be seen that double feeding has occurred. However, even if the total number of pages matches, the possibility that double feeding has occurred still remains.

  Further, when the stapler is removed from the stapled document and the document is scanned, double feeding is likely to occur unless the document is sufficiently separated. Even if a document that has once undergone double feeding is scanned again as it is, there is a high possibility that double feeding will occur at the same position (the same multiple pages will be double fed). Therefore, even if scanning is performed a plurality of times, the total number of pages becomes the same, and there is a high possibility that double feed cannot be detected.

  Similarly to the above, the technique disclosed in Patent Document 1 is also used when reading a book that has been bound, an original that has been pasted at the end, such as a magazine, or an original that is folded at the end of the original. There is a high possibility that double feed cannot be detected.

  Therefore, the present invention provides an image processing apparatus capable of accurately detecting double feeding when reading a plurality of originals, an image forming apparatus including the image processing apparatus, an image processing program, and a recording medium on which the program is recorded. The purpose is to provide.

  The image processing apparatus according to the first aspect of the present invention counts the number of conveyances from the start of conveyance of a plurality of documents by the conveyance device for conveying the set plurality of documents to the completion of conveyance. A counting unit, a data size calculation unit that calculates a total data size of a plurality of image data generated by reading the document by the reading device every time the document is conveyed, and a plurality of generated image data A number-of-characters calculation unit that counts the characters included in all to calculate the total number of characters, a set of transport times obtained by transporting all of a plurality of documents twice, a total data size of one set, and 1 A comparison unit that compares the values of each group with respect to at least two of the total number of characters in the group, and a determination unit that determines whether double feeding has occurred in two transports according to a comparison result by the comparison unit Including.

  As a result, when a plurality of documents are read, it is possible to detect double feeding more accurately than in the past.

  Preferably, the image processing apparatus requests to change the orientation of the document and set the document on the conveyance device before executing the second conveyance of the two conveyances.

  As a result, when the document is set for the second processing, it is possible to detect the double feed of the document with higher accuracy by changing the direction of the document as set by the user and setting the document on the conveying device. it can.

  More preferably, the determination unit determines that double feeding has occurred in two transports if the difference between at least one of the at least two sets compared by the comparison unit is greater than a predetermined value.

  More preferably, the image processing apparatus further includes a color document number calculation unit that determines whether the generated image data corresponds to a color document and calculates the number of color documents corresponding to all of the plurality of image data. Including. The comparison unit compares the number of sets of color documents obtained when all of a plurality of documents are conveyed twice, and the determination unit determines that the difference between the number of sets of color documents is greater than a predetermined value. For example, it is determined that double feeding has occurred in the two transports.

  Thereby, it is possible to detect the double feed of the document with higher accuracy.

  Preferably, the number-of-characters calculation unit calculates the number of characters in the page, which is the number of characters included in the image data generated each time the document is transported, and all the plurality of documents are transported, A vector generation unit that generates a vector having the number of characters in the page as an element while maintaining the calculation order of the number of characters is included. The comparison unit determines whether or not all the differences between the corresponding elements of the two sets of vectors obtained by transporting all of the plurality of originals twice are equal to or less than a predetermined value. The determination unit determines that double feeding has occurred in two transports unless all of the differences between the corresponding elements of the two sets of vectors are equal to or less than a predetermined value.

  By comparing the number of characters in each page in this way, it is possible to detect the double feed of the document with higher accuracy than when comparing only the characteristics of the entire document.

  More preferably, the data size calculation unit calculates a page data size that is a data size of image data generated every time a document is transported, and the page data size is obtained by transporting all of the plurality of documents. And a vector generation unit for generating a vector having the page data size as an element. The comparison unit determines whether or not all the differences between the corresponding elements of the two sets of vectors obtained by transporting all of the plurality of originals twice are equal to or less than a predetermined value. The determination unit determines that double feeding has occurred in two transports unless all of the differences between the corresponding elements of the two sets of vectors are equal to or less than a predetermined value.

  By comparing the data sizes of the pages in this way, it is possible to detect the double feed of the document with higher accuracy than when comparing only the features of the entire document.

  An image forming apparatus according to a second aspect of the present invention includes any one of the image processing apparatuses described above and an image forming unit that forms an image on a recording sheet according to image data.

  Such an image forming apparatus can accurately detect double feeding when reading a plurality of documents, and is designated by a user using image data scanned without double feeding. A function (such as a copy function, a scanner function, or a facsimile machine) can be executed.

  According to a third aspect of the present invention, there is provided an image processing program from the start of conveyance of a plurality of documents to a completion of conveyance by a conveyance device for conveying a plurality of set documents to the image processing apparatus. A counting function for counting the number of times the document is transported, a data size calculating function for calculating the total data size of a plurality of image data generated by reading the document every time the document is transported, and a plurality of generated image data The number-of-characters calculation function for calculating the total number of characters by counting the characters included in all, the number of conveyance times obtained by conveying all of a plurality of documents twice, the total data size of one set, and 1 A comparison function that compares the values of each group with respect to at least two sets of the total number of characters in the group, and a determination function that determines the presence or absence of the occurrence of double feed in two transports according to the comparison result of the comparison function Realization To.

  A recording medium according to a fourth aspect of the present invention is a computer-readable recording medium on which the image processing program is recorded.

  According to the present invention, when reading a plurality of documents, the image processing apparatus can detect double feeding more accurately than in the past even if the number of documents is not known in advance. In addition, an image forming apparatus provided with such an image processing apparatus uses a function (copy function, scanner function, facsimile machine, or the like) designated by a user using image data scanned without occurrence of double feeding. Can be executed.

  In particular, when a document is set for the second processing, it is possible to detect the double feed of the document with higher accuracy by changing the direction of the document as set by the user and setting it in the automatic document feeder. Can do.

1 is a block diagram showing a configuration of an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a block diagram illustrating a signal flow in an image processing unit when copying is performed in the image forming apparatus of FIG. 1. FIG. 2 is a block diagram illustrating a signal flow in an image processing unit when performing Scan to e-mail in the image forming apparatus of FIG. 1. 3 is a flowchart illustrating a control program for detecting double feed, which is executed in the image forming apparatus of FIG. 1. FIG. 10 is a diagram showing a screen including a message for instructing scanning while changing the orientation of a document. FIG. 4 is a plan view showing the orientation of a document set on an automatic document reader. It is a block diagram which shows the structure of a character recognition part. It is a flowchart which shows the data comparison process of FIG. FIG. 9 is a flowchart in which the file size comparison is prioritized over the character number comparison in FIG. 8. 10 is a flowchart illustrating a data comparison process of a control program for detecting double feeding, which is executed in an image forming apparatus according to a second embodiment of the present invention. It is a figure for demonstrating the process which compares the number of characters of each page performed in the image forming apparatus which concerns on the 3rd Embodiment of this invention. 10 is a flowchart illustrating a data comparison process of a control program for detecting double feed, which is executed in an image forming apparatus according to a third embodiment of the present invention. 10 is a flowchart illustrating a data comparison process of a control program for detecting double feeding, which is executed in an image forming apparatus according to a fourth embodiment of the present invention. In FIG. 13, it is the flowchart changed so that a several comparison process could be performed in series. It is a block diagram which shows the structure of a scanner apparatus.

  In the following embodiments, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

(First embodiment)
The image forming apparatus according to the first embodiment of the present invention is a digital multifunction peripheral having a plurality of functions such as a copy function, a scanner function, a facsimile function, and a printer function. Referring to FIG. 1, the image forming apparatus 100 includes an automatic document feeder (conveyance device) 114, a document reading unit 116, an image forming unit 118, an image processing unit 120, an image memory 122, and an operation unit 124. .

  The image forming apparatus 100 includes a CPU 102 that controls the entire image forming apparatus 100, a ROM (Read Only Memory) 104 for storing programs, a RAM (Random Access Memory) 106 that is a volatile storage device, HDD (Hard Disk Drive) 108, which is a non-volatile storage device that retains data even when the disk is shut off. The ROM 104 stores programs and data necessary for controlling the operation of the image forming apparatus 100.

  The image forming apparatus 100 further includes a transmission / reception unit 110 and a bus 112. The CPU 102, ROM 104, RAM 106, HDD 108, transmission / reception unit 110, automatic document feeder 114, document reading unit 116, image forming unit 118, image processing unit 120, image memory 122, and operation unit 124 are connected to the bus 112. Data (including control information) is exchanged between the units via the bus 112.

  The CPU 102 reads a program from the ROM 104 onto the RAM 106 via the bus 112, and executes the program using a part of the RAM 106 as a work area. That is, the CPU 102 controls each part of the image forming apparatus 100 according to a program stored in the ROM 104, and realizes each function of the image forming apparatus 100.

  The operation unit 124 includes a touch panel display and operation keys (both not shown). The operation unit 124 receives an input such as an instruction to the image forming apparatus 100 by the user.

  The transmission / reception unit 110 includes a NIC (Network Interface Card) and a FAX modem (both not shown). The NIC is an interface through which the image forming apparatus 100 communicates with an external device via a network, connected to an external network (not shown) by wire or wirelessly. The FAX modem is an interface that is connected to an external telephone line (not shown) and allows the image forming apparatus 100 to perform FAX communication with an external apparatus via the telephone line.

  The CPU 102 monitors user operations on the touch panel display and operation keys provided in the operation unit 124, and executes a copy function, a printer function, a scanner function, and a facsimile function in accordance with the user operations. Depending on the function to be executed, the document reading unit 116 is used to generate image data from the document.

  The document reading unit 116 includes a CCD (Charge Coupled Device) for reading an image, and reads the document conveyed by the automatic document feeder 114 to generate image data. Image data is temporarily stored in the image memory 122. The image processing unit 120 performs various image processing on the generated image data. The image forming unit 118 prints an image on a recording sheet according to the image data. The recording paper is held in the paper feeding unit, and the recording paper pulled out from the paper feeding unit is conveyed inside the image forming unit 118 by the conveying roller, and then an image is printed. The recording paper on which the image is formed is discharged to a paper discharge tray. The image data is stored in the HDD 108 as necessary.

  With reference to FIG. 2, a process when the user operates the operation unit 124 to select the copy function will be described in detail. The document reading unit 116 color-separates the light reflected from the conveyed document into R, G, and B (R: red, G: green, B: blue) by the automatic document feeder 114 by the CCD line sensor. Convert to electrical signal. A color image signal (RGB analog signal) input by the CCD line sensor is converted into a digital signal by an A / D (analog / digital) converter, and an illumination system of the original reading unit 116 and an image are formed by a shading correction unit. Various distortions generated in the image pickup system and the image pickup system are removed. Thereafter, γ correction processing and the like are performed on each of the RGB signals in the input processing unit. Further, the CPU 102 (counting means) counts the number of documents input (read) by the document reading unit 116 and holds it in a storage unit (including the ROM 104, the RAM 106, and the HDD 108 in FIG. 1).

  Data output from the input processing unit is delivered to the storage unit and managed as filing data. At this time, the image data is compressed into a JPEG code in a compression processing unit based on, for example, a JPEG compression algorithm and stored in a storage unit (for example, HDD 108). In the compression processing unit (data size calculating means), the data size of the compressed image data (file size when managed as a file) is obtained.

  The output data of the input processing unit is also input to the character recognition unit, and is subject to character recognition. The character recognition by the character recognition unit will be described later. The output data of the input processing unit may also be input to the automatic document discrimination unit.

  When executing the copy output operation or the print output operation, the JPEG code is read from the HDD 108 and delivered to the decompression unit, the decoding process is executed, and the RGB data is converted.

  The automatic document determination unit performs various determination processes based on the input image data, and outputs the result as document determination data. The determination process includes, for example, a process of determining whether the read document is a color document or a monochrome document (automatic color determination process (ACS)), whether or not the document is a blank document (plain color). Whether the document type is a character document, a printed photo document, or a document in which characters and a printed photo are mixed (hereinafter also referred to as a character printed photo document). Processing for determining, processing for determining how dark the background exists in the document (background detection), and the like are included.

  In the region separation unit, processing for determining what kind of region each pixel of the input image data belongs to is executed. For example, it is determined which pixel belongs to which region, such as a black character, a color character, or a halftone dot. A region separation signal that is an output signal representing the region separation result is input to a black generation / undercolor removal unit, a spatial filter unit, and a halftone generation unit.

  In the background removal processing unit, the background removal processing is executed based on the determination result in the automatic document determination unit or the background removal removal level input by the operation of the operation unit 124 by the user.

  In the color correction unit, a CMY (C: cyan, M: magenta, Y: yellow) signal that is a complementary color of the RGB signal is generated and a process for improving color reproducibility is executed, and the black generation / under color removal unit It is converted into a CMYK (K: black) 4-color signal. The spatial filter unit executes enhancement processing or smoothing processing on the CMYK signal.

  The scaling processing unit executes scaling processing according to a magnification specified by the user or according to a predetermined magnification such as a page aggregation function (2 in 1, 4 in 1, etc.) or borderless printing. However, depending on the scaling factor, there is a case where the processing unit does not execute processing (through).

  The output tone correction unit executes an output γ correction process for outputting to a recording medium such as recording paper. In the halftone generation unit, gradation reproduction processing for outputting an image is executed.

  The CMYK signal output from the halftone processing unit is delivered to the image forming unit 118, and an output image is formed. The image forming unit 118 is, for example, an electrophotographic printer or an inkjet printer.

  With reference to FIG. 3, processing when the user operates the operation unit 124 and selects the scan to e-mail function will be specifically described. The scan to e-mail function is a function for transmitting image data obtained by scanning a document attached to an e-mail.

  Similarly to the case where the copy function is selected, the document reading unit 116 uses the CCD line sensor and the automatic document feeder 114 to reflect the light reflected from the conveyed document R, G, B (R: red, G: The electrical signal is separated into green and B: blue). An A / D conversion unit, a shading correction unit, an input processing unit, and a compression processing unit execute each process on the generated RGB signal.

  The difference from the case where the copy function is selected is that the processing of the color correction unit is different, and the black generation / under color removal unit and the halftone generation unit do not process the input image data. (Hereinafter, also referred to as “through”), the image data is directly output to the subsequent block. Since the black generation / under color removal unit is passed, the image data of R′G′B ′ is output from the halftone generation unit.

  In the color correction unit, the input RGB image data is converted into R′G′B ′ image data (for example, sRGB data) suitable for display characteristics of a display device that is generally popular, and the spatial filter unit. Spatial filter processing (enhancement processing, smoothing processing, etc.) using a digital filter is performed based on the region separation signal. In the output tone correction unit, for example, correction using the optimum gamma curve is performed for each of the character region or the region other than the character. The R′G′B ′ image data output from the halftone generation unit is changed to a file format such as PDF format in the formatting processing unit, and attached to the e-mail in the mail processing unit (not shown). . The e-mail is output from the transmission / reception unit 110 to the communication network and transmitted to the other party.

  Note that the above processing is executed under the control of the CPU 102. If the image forming apparatus 100 includes a DSP (Digital Signal Processor) (not shown), the above processing may be controlled by the DSP.

  Hereinafter, a control program for detecting double feeding executed in the image forming apparatus 100 will be described with reference to FIG. This program is executed when the operation unit 124 is operated by the user, and a function (for example, a copy function, a scanner function, a facsimile function, or a scan to e-mail function) using the automatic document reader 114 is selected. It is executed in response to an instruction to execute after the condition is set.

  In step 400, as the first process, the CPU 102 controls the automatic document reader 114 to convey the documents one by one, controls the image processing unit 120, and has been described with reference to FIG. Of the series of processes, the process up to the compression processing unit is executed for the entire document. At this time, as described above, the compression processing unit generates image data compressed in units of pages of the document, and after the entire document is scanned, it is stored in the HDD 108 as one file.

  Further, the CPU 102 detects a document to be conveyed by a sensor or the like, and counts the number of document conveyance (hereinafter also referred to as the number of documents for convenience). After all the originals are scanned, the number of originals (total number of original conveyance times) is determined. The CPU 102 (character number calculation means) obtains the number of characters included in each image data (hereinafter also referred to as the number of characters for each page for convenience) by OCR by the character recognition unit, and obtains the accumulated value. After all the originals are scanned, the total number of characters of the whole original is determined.

  In step 402, the CPU 102 stores the processing result in step 400 in the RAM 106 or the HDD 108. The processing results are the number of documents, the file size, and the number of characters. As described above, the number of documents is the total number of times the document is conveyed, the file size is the total data size of one entire file stored in the HDD 108, and the number of characters is the total number of characters of the entire document.

  In step 404, the CPU 102 (request presenting means) requests that the same document be set again in the automatic document reader 114 while changing the orientation of the document. For example, the CPU 102 displays a screen 500 including a message as shown in FIG. 5 on the display panel of the operation unit 124. In a region 502 of the screen 500, a message requesting to set the original with its orientation changed is displayed.

  If the image forming apparatus 100 includes an audio output device, it may be requested to change the orientation of the document and set it again in the automatic document reader 114 by voice.

  Normally, the orientation of the document set on the automatic document reader 114 is one of four types as shown in FIG. 6A to 6D, the document transport direction is the same (for example, the left direction). When the original is set in the arrangement shown in FIG. 6A in the first process (step 400), the arrangement in which the orientation of the original is changed is opposite to the arrangement shown in FIG. 6B. An arrangement rotated 90 degrees clockwise, an arrangement rotated 180 degrees as shown in FIG. 6C, or an arrangement rotated 270 degrees counterclockwise as shown in FIG. 6D. means.

  In step 406, the CPU 102 determines whether or not an original is set on the automatic document reader 114 and execution is instructed. Specifically, the CPU 102 determines whether or not an OK button 504 on the screen 500 displayed on the operation unit 124 has been pressed. If it is determined that execution has been instructed, control proceeds to step 408. Otherwise, step 406 is repeated.

  In step 408, the CPU 102 executes the second process as in step 400. At this time, the conditions (for example, resolution) regarding the scanning of the document are the same as those in the first process.

  In step 410, as in step 402, the CPU 102 stores the processing result in step 408 in the RAM 106 or HDD 108. The processing results are the number of documents, the file size, and the number of characters.

  In step 412, the CPU 102 (comparison means) executes processing for comparing the data stored in steps 402 and 410 (hereinafter referred to as data comparison processing). The data comparison process will be described later. By the data comparison process, it is determined which of the files obtained by the first process or the file obtained by the second process is to be used.

  In step 414, the CPU 102 presents the result of the data comparison process. As a result of the data comparison process, the CPU 102 uses any file out of the file obtained by the first process or the file obtained by the second process as the data used for executing the selected function. For example, it is displayed on the display panel of the operation unit 124. Thereafter, the program ends.

  After the end of the program, the processing after the processing by the decompressing unit in the series of processing described with reference to FIG. 2 or 3 is executed on the image file determined in step 412.

  The character recognition unit will be described with reference to FIG. The character recognition unit includes a signal conversion unit, a binarization processing unit, an inclination detection unit, an inclination correction unit, an OCR processing unit, and a layout analysis unit.

The signal conversion unit converts RGB color image data into a luminance signal, for example, by the following equation.
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 binarization processing unit binarizes the image data and generates binary image data. Specifically, each pixel value is binarized by comparing the density (pixel value) of each pixel in the image data with a preset threshold value. For example, when the image data is 8-bit data, the threshold value is set to 128. Further, an average value of density (pixel value) in a block composed of a plurality of pixels (for example, 5 pixels × 5 pixels) may be used as a threshold value used for binarization of the block.

  The resolution conversion unit lowers the resolution of the binarized image data. For example, image data generated by reading a document under conditions of 1200 dpi or 600 dpi is converted into image data of 300 dpi. A known method may be used as the resolution conversion method. For example, a nearest neighbor method, a bilinear method, a bicubic method, or the like can be used. The resolution conversion unit inputs 300 dpi image data to the tilt detection unit, and inputs 75 dpi image data to the layout analysis unit. In order for the layout analysis unit to determine the layout, low-resolution image data may be used.

  The inclination detection unit detects the inclination of each page using, for example, a method described in Japanese Patent Application Laid-Open No. 7-19086. In this method, a plurality of boundary points between black pixels and white pixels are extracted from the binarized image data, and coordinate data of a sequence of points at each boundary point is obtained. For the boundary between the black pixel and the white pixel, for example, the coordinates of the white / black boundary point at the upper end of each character are obtained and stored in the memory (RAM 106).

  A regression line is obtained from the point sequence coordinate data with reference to the point sequence coordinate data, and the regression coefficient b is calculated by b = Sxy / Sx and stored in the memory (RAM 106).

  Here, Sx and Sy are the residual sum of squares of the variables x and y, respectively, and Sxy is the sum of the products of the residual of x and the residual of y. That is, Sx, Sy, and Sxy are expressed by the following equations.

回帰係数ｂを用いて、画像の傾き角度（スキュー角度）θを、ｔａｎθ＝ｂ から算出する。

An inclination angle (skew angle) θ of the image is calculated from tan θ = b using the regression coefficient b.

  The inclination correction unit corrects the inclination of the document using the following equation. (X, Y) and (X ′, Y ′) respectively represent coordinates before correction and coordinates after correction, and θ represents a counterclockwise rotation angle around the origin.

なお、画素の座標は、読込まれた画像データの左端且つ上端の位置を原点として求める。

Note that the coordinates of the pixel are obtained using the positions of the left end and the upper end of the read image data as the origin.

The layout analysis unit performs layout analysis processing for analyzing whether the direction of the characters included in the image data is vertical writing or horizontal writing based on the binary image data with reduced resolution. Specifically, the circumscribed rectangle of the character is obtained. Whether vertical writing or horizontal writing is determined based on a distance between circumscribed rectangles. The circumscribed rectangle of the character is obtained by the following processes (1) to (4).
(1) The first line (the first line) is set as the target line, and the black pixels are labeled.
(2) The target line is moved down by one line, and a label different from the above line is set for the black pixel.
(3) The connected state of the target line and the black pixel of the line above it is determined, and when connected, it is determined that the pixel is connected, and the connected black pixel in the line above is connected Replace with the same label as
(4) The processes of (1) to (3) are sequentially performed for each line, and characters are extracted based on the labeling result of each line. A circumscribed rectangle is extracted based on pixel positions (pixel coordinates) at the upper end, lower end, left end, and right end of the extracted character.

  The OCR processing unit executes character recognition processing using the binary image data subjected to resolution conversion and the layout analysis result, and calculates additional information related to character recognition (for example, the number of characters included in each page). Specifically, based on the binary image data and the layout analysis result, a character feature amount included in the image data is extracted, and the character recognition process is performed by comparing the extraction result with the character feature amount included in the dictionary data. The character code corresponding to the similar character is detected. Then, text data is generated based on the detection result of the character code.

  With reference to FIG. 8, the data comparison processing in step 412 shown in FIG. 4 will be described. In step 430 of the data comparison process, the CPU 102 determines whether or not to compare the number of originals. Here, as an initial setting of the image forming apparatus 100, it is assumed that which of the number of documents, the file size, and the number of characters is to be compared is set in advance. If it is set to compare the number of documents, the control proceeds to step 432. Otherwise, control passes to step 438.

  In step 432, the CPU 102 determines whether there is a difference in the number of documents stored in steps 402 and 410 (whether the number of documents is different). If it is determined that there is a difference, control proceeds to step 434. Otherwise (if it is determined that there is no difference), control passes to step 436.

  In step 434, the CPU 102 (determination means) determines the number of documents out of the files stored in the first process (step 400 in FIG. 4) and the files stored in the second process (step 408 in FIG. 4). The file with the larger number is determined as the final output data (image file that is the execution target of the selected function). The reason why the file with the larger number of documents is determined as the final output data is that the smaller number of documents means that the documents are double-fed and a part of the document is not scanned. Such a file lacks image data corresponding to a page that was not scanned. Thereafter, control proceeds to step 414 in FIG.

  When it is determined in step 432 that there is no difference, in step 436, the CPU 102 determines the file stored by the first process or the second process as final output data. If there is no difference in the number of documents, it is considered that double feeding has not occurred. Therefore, since the files stored by the first process and the second process are not superior or inferior, any of them may be used. Thereafter, control proceeds to step 414 in FIG.

  If it is not set to compare the number of originals, in step 438, the CPU 102 determines whether or not to compare the number of characters. If it is set to compare the number of characters, control passes to step 440. Otherwise, control passes to step 444.

  In step 440, the CPU 102 determines whether or not the difference in the number of characters stored in steps 402 and 410 is equal to or less than a predetermined value. If the difference in the number of characters is equal to or smaller than the predetermined value, it is considered that double feeding has not occurred, and the control shifts to step 436 and the above-described processing is executed. Otherwise (if the difference in the number of characters is greater than the predetermined value), it is considered that double feeding has occurred, and control proceeds to step 442.

The difference D1 in the number of characters is, for example, that the number of characters obtained by the first processing is Text1, and the number of characters obtained by the second processing is Text2.
D1 = abs (Text1-Text2) / avage (Text1, Text2)
Ask for. Here, abs (x) is an operator for obtaining an absolute value of x, and avgage (x, y) is an operator for obtaining an average value of x and y.

  In this case, in step 440, it is determined whether or not D1 ≦ TEXT. TEXT is, for example, 0.1. TEXT is not limited to this value, and an appropriate value can be used as appropriate.

  In step 442, the CPU 102 selects the file having the larger number of characters among the file stored in the first process (step 400 in FIG. 4) and the file stored in the second process (step 408 in FIG. 4). Are determined as final output data. Thereafter, control proceeds to step 414 in FIG.

  If D1 ≦ TEXT is not satisfied, the file with the smaller number of characters is double-fed, and it is considered that the number of characters has decreased due to missing pages. Therefore, as described above, the file with the larger number of characters is used as the final output data. Determine as.

  If it is not set to compare the number of characters, in step 444, the CPU 102 determines whether or not the difference between the file sizes stored in step 402 and step 410 is equal to or less than a predetermined value. If it is determined that the difference between the file sizes is equal to or smaller than the predetermined value, it is considered that double feeding has not occurred, and the control shifts to step 436 and the above-described processing is executed. Otherwise (if the difference is greater than the predetermined value), it is considered that a double feed has occurred and control passes to step 446.

The file size difference D2 is, for example, that the file size obtained by the first process is Size1, and the file size obtained by the second process is Size2.
D2 = abs (Size1-Size2) / avage (Size1, Size2)
Ask for.

  In this case, in step 444, it is determined whether or not D2 ≦ SIZE. SIZE is, for example, 0.1. SIZE is not limited to this value, and an appropriate value can be used as appropriate.

  In step 446, the CPU 102 has the larger file size of the file stored in the first process (step 400 in FIG. 4) and the file stored in the second process (step 408 in FIG. 4). Determine the file as the final output data. Thereafter, control proceeds to step 414 in FIG.

  If D2 ≦ SIZE is not satisfied, the file with the smaller file size is double-fed, and it is considered that the file size has decreased due to missing pages. Therefore, as described above, the file with the larger file size is Determine as final output data.

  4 and 8, the image forming apparatus 100 performs the scanning process twice on the same document, and compares the number of documents, the number of characters, or the file size, thereby double-feeding documents. The function designated by the user can be executed using the image file scanned without causing double feed. In particular, when a document is set for the second processing, the orientation of the document is changed and set in the automatic document feeder 114 as instructed by the user, thereby detecting the document double feed more accurately. be able to.

  In the present embodiment, the same document may be scanned twice without changing the orientation of the document, and the number of documents, the number of characters, or the file size may be compared. That is, as described above, when the first scanning process is completed, in step 404, a request to change the orientation and set the document is presented (see FIG. 5), but the user is presented. It is not always the case that the original is set in a different direction. Even if the original is set in the same direction as the original at the time of the first scan process and the second scan process is executed, the number of documents, the number of characters, or the file obtained by executing the second scan process By comparing the sizes, it is possible to detect the double feed of the document and execute the function designated by the user by using the image file scanned without the double feed. Therefore, the presentation in step 404 is optional.

  In the above description, a case has been described in which it is determined whether or not to compare the number of characters if the number of documents is not set to be compared. However, the present invention is not limited to this. For example, as shown in FIG. 9, if it is not set to compare the number of originals, it may be determined whether to compare the file sizes. FIG. 9 differs from FIG. 8 in that step 438 in FIG. 8 is replaced with a new step 450, steps 440 and 444 are replaced, and steps 442 and 446 are replaced. In FIG. 9, the process with the same reference number as FIG. 8 is the same as FIG.

  If it is determined in step 430 that the number of originals is not compared, in step 450, the CPU 102 determines whether or not the file size is set to be compared. If the file sizes are set to be compared, control proceeds to step 444, where it is determined whether the difference in file sizes is less than or equal to a predetermined value, and step 436 or step 446 is performed depending on the result. Executed. If the file sizes are not set to be compared, control proceeds to step 440 where it is determined whether the difference in the number of characters is less than or equal to a predetermined value and step 436 or step 442 is executed depending on the result. Is done.

  By the processing shown in FIG. 9, as in FIG. 8, it is possible to detect a double feed of a document and execute a function specified by the user using a scanned image file without occurrence of double feed. . In particular, by performing the second process by changing the orientation of the document, it is possible to detect the document double feed more accurately.

  In the above, when the difference in the number of characters or the file size is equal to or smaller than the predetermined value, it is considered that double feeding has not occurred in any of the two processes, and the file stored by the first process or the second process is stored. Has been described as the final output data (step 434), but the file having the larger number of characters or file size may be determined as the final output data.

  In the above description, if there is no difference in the number of documents, it is considered that double feeding has not occurred, and the file stored by the first process or the second process is determined as the final output data (step 434). However, the number of characters or the file size may be compared to determine the file with the larger value as the final output data. That is, the number of documents is set as a comparison target (the number of characters and the file size are not set as comparison targets), and if there is no difference in the number of documents, the number of characters or the file size is compared.

  In the above, if the difference in the number of characters or the difference in file size is larger than the predetermined value, the file with the larger value is considered to have been generated without double feed, and the file with the larger value is finally output. Although the case of determining as data (step 442 or step 446) has been described, the user may be presented with re-reading.

  In the above description, the case where the inclination correction unit executes the inclination correction of the document when the number of characters is calculated by the character recognition unit has been described. However, the present invention is not limited to this. The document skew correction need not be executed. In that case, the character recognition unit can be configured by removing the tilt detection unit and the tilt correction unit from FIG.

  Even if there is a certain amount of skew in the image generated by scanning the document, the OCR processing unit can execute the character recognition process, and the accuracy of the double feed detection process described above is greatly affected. There is no. The fact that the original skew correction is not executed means that the skew angle of the original is taken into consideration in the process of determining the file obtained by the first process or the file obtained by the second process as final data. . That is, as the skew angle increases, the character recognition rate decreases and the number of recognized characters decreases. Therefore, when selecting the final output data, by selecting data with a large number of characters, image data with less skew can be selected, and the function designated by the user can be executed with higher quality.

  In the above description, a case has been described in which a program for detecting double feeding is executed when a user selects a function and instructs execution, but the present invention is not limited to this. For example, when the user selects and performs a mode such as the preliminary scan mode with the operation unit 124, a program for detecting double feeding may be executed.

  In the above description, a case has been described in which which of the number of originals, the file size, and the number of characters is set in advance. However, the user may be able to select which one is compared at the time of execution.

(Second Embodiment)
In the first embodiment, one of the items of the number of originals scanned twice, the file size, and the number of characters is compared, whereas in the second embodiment, the number of originals, A plurality of items are compared among the file size and the number of characters.

  The image forming apparatus according to the present embodiment is configured similarly to the image forming apparatus according to the first embodiment shown in FIGS. In addition, the image forming apparatus according to the present embodiment has a function of operating an operation unit by a user and using an automatic document reader (for example, a copy function, a scanner function, a facsimile function, or a scan to e-mail function). 4 is selected, and when the execution condition is set, the control program for detecting the double feed shown in FIG. 4 is executed. Hereinafter, description will be made with reference to the reference numerals in FIGS.

  In the present embodiment, a data comparison process (step 412 in FIG. 4) different from that in the first embodiment is executed. Specifically, the data comparison process shown in FIG. 10 is executed.

  In the data comparison process of FIG. 10, all of the number of documents, the file size, and the number of characters are to be compared. Therefore, the configuration of the data comparison processing program in FIG. 10 is different from that in the first embodiment (FIG. 8) in that the determination processing in step 430 and step 438 is not included, and steps 432, 444 and 440 are performed. It is configured so that it can be executed in series, and step 442 and step 446 are replaced with a new step 452. In FIG. 10, the process with the same reference number as FIG. 8 is the same as FIG.

  In step 432, the CPU 102 determines whether or not there is a difference in the number of documents stored in the two processes (step 400 and step 408 in FIG. 4). If there is a difference in the number of documents, in step 434, the CPU 102 outputs the file having the larger number of documents among the files stored in the two processes as the final output data (image file to be executed by the selected function). Determine as. This is because the small number of documents means that the documents are double-fed and a part of the document is not scanned.

  If there is no difference in the number of documents, the control proceeds to step 444, and the CPU 102 determines whether or not the difference in file size is equal to or smaller than a predetermined value. If the difference between the file sizes is not less than or equal to the predetermined value, in step 452, the CPU 102 presents that it is recommended to set the document on the automatic document feeder 114 again and instruct execution. For example, the CPU 102 displays that fact on the display panel of the operation unit 124.

  When the difference in file size is larger than a predetermined value, it is considered that the difference in file size is caused by the occurrence of double feeding. Here, since the number of documents is the same, it is not considered that double feeding has occurred in either one of the first processing or the second processing, and double feeding has occurred in both. Therefore, it is preferable to scan the document again.

  If the difference in file size is equal to or smaller than the predetermined value, the control proceeds to step 440, and the CPU 102 determines whether or not the difference in the number of characters is equal to or smaller than the predetermined value. If the difference in the number of characters is not less than the predetermined value, the control moves to step 452 and the above processing is executed.

  When the difference in the number of characters is larger than a predetermined value, the difference in the number of characters is considered to be caused by the occurrence of double feeding. Here, since the number of documents is the same, it is not considered that double feeding has occurred in either one of the first processing or the second processing, and double feeding has occurred in both. Therefore, it is preferable to scan the document again.

  If the difference in the number of characters is equal to or smaller than the predetermined value, in step 436, the CPU 102 determines the file stored by the first process (step 400 in FIG. 4) as the final output data.

  After step 434, step 436, or step 452 is executed, control passes to step 414 in FIG.

  When the control returns to step 414 after step 434 or step 436 is executed, the data used for the execution of the selected function is obtained as the data comparison processing result, as in the first embodiment. Presented.

  When the control returns to step 414 after step 452 is executed, if the message is displayed on the display panel of the operation unit 124 in step 452, the data comparison processing result is presented while maintaining the display. When step 452 is executed, the CPU 102 displays, for example, on the display panel of the operation unit 124 that the data used for executing the selected function has not been determined as the data comparison processing result.

  4 and 10, the image forming apparatus 100 scans the same document twice and sequentially compares the number of documents, the file size, and the number of characters, thereby double-feeding the documents. The function designated by the user can be executed using the image file scanned without occurrence of double feeding. In particular, when a document is set for the second processing, the orientation of the document is changed and set in the automatic document feeder 114 as instructed by the user, thereby detecting the document double feed more accurately. be able to.

  There is a possibility that the user does not change the orientation of the document as instructed. That is, the user may set the document in the same direction as the first time and press the OK button. Even in that case, by comparing the file size and the number of characters in addition to the comparison of the number of originals, it is possible to detect double feeding of the originals more accurately than in the case of comparing only the number of originals. For example, when double feeding occurs in the scanning process of two originals and different pages are double fed, it is not possible to detect double feeding even if only the number of originals is compared. By comparing the file size or the number of characters, double feeding can be detected.

  Note that it may be determined whether the orientation of the document set for the second time is different from the orientation set for the first time. For example, if the document width is stored when the first process is executed, the detected document width is the stored value (1 when the second process execution receives an instruction. If it is the same as the width of the document detected when the second process is executed, a message for confirming whether or not the document has been set may be displayed. As a result, it is possible to increase the possibility that the document will be set by changing the direction of the document, and to further increase the detection accuracy of the double feed.

  In the above description, the case where Step 444 (Character Number Comparison Processing) can be executed after Step 440 (File Size Comparison Processing) is executed has been described. However, the present invention is not limited to this. Step 440 may be executed after step 444 is executed.

  In the above description, the case where the document number comparison process, the file size comparison process, and the character number comparison process can all be executed in series has been described. However, the present invention is not limited to this. It suffices to execute at least two comparison processes: a document number comparison process, a file size comparison process, and a character count comparison process. Further, the plurality of comparison targets may be sequentially compared in time series or may be simultaneously compared in parallel by multitasking.

(Third embodiment)
In the first and second embodiments, the number of characters of the entire document scanned twice is compared, while in the third embodiment, the number of characters for each page of the document is compared. .

  The image forming apparatus according to the present embodiment is configured similarly to the image forming apparatus according to the first embodiment shown in FIGS. In addition, the image forming apparatus according to the present embodiment has a function of operating an operation unit by a user and using an automatic document reader (for example, a copy function, a scanner function, a facsimile function, or a scan to e-mail function). 4 is selected, and when the execution condition is set, the control program for detecting the double feed shown in FIG. 4 is executed. Hereinafter, description will be made with reference to the reference numerals in FIGS.

  By comparing the total number of characters in the original as in the first or second embodiment, there are cases where double feed cannot be detected. This problem will be described with reference to FIG. In FIG. 11, the leftmost column indicates that the document is composed of four pages, and the center column and the rightmost column indicate the results of the first and second scan processes, respectively. In the first scanning process, the second page of the document is double-fed with the first page of the document, indicating that it has not been scanned. In the second scanning process, the third page of the document is double-fed with the second page of the document, indicating that the document has not been scanned.

As a result of the first and second scan processes, the number of documents is both 3, and the total number of characters of the document is 33 characters for the first time and 36 characters for the second time. Therefore, as in the first embodiment,
D1 = abs (Text1-Text2) / avage (Text1, Text2)
Thus, when the difference D1 in the number of characters is calculated, D1 = 3 / 34.5≈0.09. If TEXT = 0.1, D1 ≦ TEXT is satisfied. Therefore, in the flowchart of FIG. 8, in the flowchart of FIG. 8, the process is a process when double feed does not occur even though double feed has actually occurred. 436 is executed.

  In order to cope with this, in the present embodiment, the number of characters for each page of the document is compared in the data comparison process (step 412 in FIG. 4). Specifically, the data comparison process shown in FIG. 12 is executed.

  The control structure of the data comparison processing program in FIG. 12 is different from the control structure of the data comparison processing program in the FIG. 8 (first embodiment) only in that steps 452 and 460 are added. . In FIG. 12, the process with the same reference number as FIG. 8 is the same as FIG.

  Here, in step 400 (first scan processing) and step 408 (second scan processing) in FIG. 4, the added value (cumulative value) of the number of characters obtained as a result of the character recognition processing executed for each page of the document. ) As well as the number of characters in each page in correspondence with the order in which it was calculated. As a result, two vectors are stored. In the example shown in FIG. 11, the vector (16, 9, 8) is stored by the first scanning process, and the vector (16, 12, 8) is stored by the second scanning process.

  As in the first embodiment, as a result of determination in step 430, it is determined that the number of originals is not set to be compared, and as a result of determination in step 438, the number of characters is set to be compared. If it is determined that the difference is found, it is determined in step 440 whether or not the difference in the total number of characters of the document is equal to or less than a predetermined value. If the difference in the total number of characters in the document is not less than the predetermined value, step 442 is executed, and the file with the larger total number of characters in the document is determined as the final output data.

  If the difference in the total number of characters of the document is equal to or smaller than the predetermined value, in step 460, the CPU 102 determines whether or not the number of characters for each corresponding page calculated in each of the first and second scan processes matches. judge. Specifically, the CPU 102 determines whether or not the two stored vectors match. If they match, that is, if all the vector components (number of characters per page) match, control passes to step 436. Otherwise, ie, if the number of characters on the page differs by at least one, control passes to step 452.

  In the example shown in FIG. 11, (16, 9, 8) and (16, 12, 8) are compared. Since these vectors are different in the second component (number of characters of the second stored page), the control shifts to step 452.

  Here, since step 460 is executed when determination is not made based on the number of documents, the case where the number of elements of two generated vectors is different (when the number of scanned documents is different) is also included. In that case, it is determined that the two vectors do not match.

  In step 452, since there is a possibility that double feeding has occurred, the CPU 102 presents that it is recommended to set the document on the automatic document feeder 114 again and instruct execution. For example, the CPU 102 displays that fact on the display panel of the operation unit 124.

  After step 434, step 436, step 442, step 446, or step 452 is executed, control passes to step 414 in FIG.

  When the control returns to step 414 after step 434, step 436, step 442 or step 446 is executed, the selected function is executed as the data comparison processing result as in the first embodiment. The data used for is presented.

  On the other hand, when the control returns to step 414 after step 452 is executed, if the message is displayed on the display panel of the operation unit 124 in step 452, the display is maintained and the data comparison processing result is obtained. For example, the fact that the data used to execute the selected function has not been determined is displayed on the display panel of the operation unit 124, for example.

  4 and 12, the image forming apparatus 100 scans the same document twice and compares the number of documents, the file size, or the number of characters, thereby double-feeding the documents. The function specified by the user can be executed using the image file that has been determined and scanned without causing double feed. In particular, when a document is set for the second processing, the orientation of the document is changed and set in the automatic document feeder 114 as instructed by the user, thereby detecting the document double feed more accurately. be able to.

  In the present embodiment, the same document may be scanned twice without changing the orientation of the document, and the number of documents, the number of characters, or the file size may be compared. That is, the presentation in step 404 is arbitrary.

  Further, when the difference in the total number of characters in the document is equal to or smaller than a predetermined value, the occurrence of double feeding can be detected with higher accuracy by further comparing the number of characters on each page. That is, if the number of characters (vector) for each series of pages obtained by the first scan process and the second scan process is not the same, the occurrence of double feed can be presented to the user.

  Note that information on a page where there is a possibility of double feeding may be presented. That is, when the N-th component of the two vectors is different, there is a possibility that double feed has occurred in the Nth and subsequent pages, so a message such as “Multiple feed occurred after N pages” is presented. be able to. As a result, the user can execute the scanning process again after taking measures to prevent the double feed from occurring on the presented page.

  In the above description, the case where it is determined whether or not the number of characters on each page is the same value has been described. However, the present invention is not limited to this. Considering the error of character recognition processing, it is determined whether or not the difference in the number of characters on each page is less than or equal to a predetermined value, that is, whether or not all the differences between the components of the two vectors are less than or equal to a predetermined value. Also good. In that case, if the differences between the components of the two vectors are all equal to or less than the predetermined value, it is determined that the two vectors match, and step 436 is executed.

  Although the case where the number of characters of each page is compared was demonstrated above, it is not limited to this. You may compare the data size of each page. In that case, the data size of each page may be calculated during the scanning process, and stored in correspondence with the calculated order (for example, stored as a vector). Further, when the data size of each page is not calculated during the scanning process, the data size of each page may be calculated from the final file. Thereby, when the difference between the file sizes of the originals is equal to or less than a predetermined value, the data sizes of the respective pages can be compared. In that case, in consideration of an error in the data size of each page, if the difference in the data size of each page is equal to or smaller than a predetermined value, that is, if all the differences in the components of the two vectors are equal to or smaller than the predetermined value, 2 It may be determined that the two vectors are equal.

  In the above description, when the difference in the total number of characters in the document is equal to or less than a predetermined value, it is determined whether or not the number of characters in each page matches, but without comparing the difference in the total number of characters in the document, You may make it determine whether the number of characters corresponds. Similarly, for the data size of each page, it may be determined whether or not the data size of each page matches without comparing the difference in the total data size of the originals.

  In the above description, the process of comparing the number of characters of each page is added to the flowchart of FIG. 8, but the process of comparing the number of characters of each page may be added to the flowchart of FIG. 9 or 10. For example, step 460 and step 452 in FIG. 12 may be added after step 440 in FIG. 9 or FIG.

(Fourth embodiment)
In the first to third embodiments, the number of documents, the file size, and the number of characters are compared. In the fourth embodiment, the output data (document discrimination data) of the automatic document discrimination unit is used. Use.

  The image forming apparatus according to the present embodiment is configured similarly to the image forming apparatus according to the first embodiment shown in FIGS. In addition, the image forming apparatus according to the present embodiment has a function of operating an operation unit by a user and using an automatic document reader (for example, a copy function, a scanner function, a facsimile function, or a scan to e-mail function). 4 is selected, and when the execution condition is set, the control program for detecting the double feed shown in FIG. 4 is executed. Hereinafter, description will be made with reference to the reference numerals in FIGS.

  In the present embodiment, as in the first to third embodiments, in addition to comparing the number of documents, the file size, and the number of characters, the data of the automatic document discrimination unit (see FIGS. 2 and 3) is also used. The result of automatic color discrimination processing is used. Specifically, the number of pages determined as color by the automatic color determination process executed by the automatic document determination unit (color document number calculation means) (hereinafter also referred to as the number of color documents) is compared. The difference in the number of color originals between the two data is obtained, and if there is a difference, it is determined that the original has been lost due to double feeding, and the data with the larger number of color originals is adopted as the final output data.

  Specifically, the data comparison process shown in FIG. 13 is executed. The configuration of the data comparison processing program of FIG. 13 differs from the configuration of the data comparison processing program of FIG. 9 in the following points. That is, Steps 600 and 602 are added to FIG. 9, Steps 436 and 446 of FIG. 9 are replaced with Steps 604 and 452, respectively, and Step 452 is executed when the determination result of Step 440 is NO. In FIG. 13, the process with the same reference number as FIG. 9 is the same as FIG.

  Here, as an initial setting of the image forming apparatus 100, it is assumed that any of the number of documents, the file size, the number of color documents, and the number of characters is set in advance. Further, in step 400 (first scan processing) and step 408 (second scan processing) in FIG. 4, the number of pages determined to be color by the automatic color determination processing is stored.

  If it is determined in step 430 that the number of documents is set to be compared, it is determined in step 432 whether there is a difference between the number of documents stored in step 402 and step 410. If it is determined that there is a difference in the number of documents, control proceeds to step 434. Otherwise (if it is determined that there is no difference in the number of documents), control proceeds to step 604.

  If it is determined in step 430 that the number of documents is not set to be compared, in step 450, the CPU 102 determines whether or not the file size is set to be compared. If it is set to compare file sizes, control proceeds to step 444, and if it is not set to compare file sizes, control proceeds to step 600.

  In step 444, the CPU 102 determines whether or not the difference between the file sizes stored in steps 402 and 410 is equal to or smaller than a predetermined value. If it is determined that the difference between the file sizes is equal to or smaller than the predetermined value, the control proceeds to step 604. Otherwise (if the file size difference is greater than a predetermined value), control passes to step 452.

  In step 600, the CPU 102 determines whether or not it is set to compare the number of color originals. If it is set to compare the number of color originals, the control proceeds to step 602. Otherwise, control passes to step 440.

  In step 602, the CPU 102 determines whether or not the difference in the number of color originals is equal to or less than a predetermined value. If the difference in the number of color originals is equal to or smaller than the predetermined value, the control proceeds to step 604. Otherwise, control passes to step 452.

  If it is not set to compare the number of color originals, in step 440, the CPU 102 determines whether or not the difference in the number of characters stored in step 402 and step 410 is equal to or smaller than a predetermined value. If it is determined that the difference in the number of color originals is equal to or smaller than the predetermined value, the control proceeds to step 604. Otherwise (if the difference in the number of color originals is greater than a predetermined value), the control proceeds to step 452.

  In step 604, the CPU 102 has a large number of characters or file size among the files stored in the first process (step 400 in FIG. 4) and the files stored in the second process (step 408 in FIG. 4). This file is determined as final output data (an image file to be executed by the selected function). Thereafter, control proceeds to step 414 in FIG.

  In step 452, since there is a possibility that double feeding has occurred, the CPU 102 presents that it is recommended to set the document on the automatic document feeder 114 again and instruct execution. For example, the CPU 102 displays that fact on the display panel of the operation unit 124.

  After step 434, step 452, or step 604 is executed, control passes to step 414 in FIG.

  When the control returns to step 414 after step 434 or step 604 is executed, data used for execution of the selected function is obtained as a data comparison processing result, as in the first embodiment. Presented.

  On the other hand, when the control returns to step 414 after step 452 is executed, if the message is displayed on the operation unit 124 in step 452, it is used to execute the selected function while maintaining the display. That the data to be determined has not been determined is displayed on the display panel of the operation unit 124.

  4 and 13, the image forming apparatus 100 executes the scan process twice for the same document, and compares the number of documents, the file size, the number of color documents, or the number of characters. The function specified by the user can be executed by determining whether or not the document is double-fed and using the image file scanned without the double-fed. In particular, when a document is set for the second processing, the orientation of the document is changed and set in the automatic document feeder 114 as instructed by the user, thereby detecting the document double feed more accurately. be able to.

  In the present embodiment, the same document may be scanned twice without changing the orientation of the document, and the number of documents, the number of characters, the number of color documents, or the number of characters may be compared. That is, the presentation in step 404 is arbitrary.

  Further, when the difference in file size, the difference in the number of color originals, or the difference in the number of characters is large, the fact is presented to the user, so the user should take measures to avoid double feeding such as handling the originals. Can do.

  In the above description, a case has been described in which any one of the number of originals scanned twice, the file size, the number of color originals, and the number of characters is compared. However, the present invention is not limited to this. As in the second embodiment, a plurality of items may be compared among the number of documents, the file size, the number of color documents, and the number of characters. For example, a data comparison process as shown in FIG. 14 may be used.

  In the data comparison process of FIG. 14, all of the number of documents, the file size, the number of color documents, and the number of characters are to be compared. Therefore, the difference between the program configuration of the data comparison process of FIG. 14 and the program configuration of the data comparison process of FIG. 13 does not include the determination process of step 430, step 450, and step 600, but step 432, step 444, step 602 and step 444 are configured to be executed in series. In FIG. 14, the process with the same reference number as FIG. 13 is the same as FIG.

  As shown in FIG. 14, by comparing all of the number of documents, the file size, the number of color documents, and the number of characters, the orientation of the document is determined by the user in the second scanning process, as in the second embodiment. Even if no change is made, it is possible to detect double feeding of documents with higher accuracy than when only the number of documents is compared.

  For example, the following method can be used as the automatic color discrimination process. For example, the maximum value and the minimum value of the RGB signal are compared with a threshold value THa (for example, 20) to determine whether the pixel is chromatic or achromatic. Then, the pixels determined to be chromatic are counted for the entire document. For example, if the chromatic pixels are 7000 or more, it is determined that the document is a color document. The above threshold value is used as an absolute number, not as a ratio (%) of chromatic pixels to the entire document, so that even a large A3 size document can determine a partially stamped document as a color document. It is to make it.

  In addition, as a method for determining whether a pixel is chromatic or achromatic, a known method such as a method of obtaining an absolute value of a difference between each color component of an RGB signal and comparing the value with a threshold value is used. Also good.

  In the above description, a color document or a monochrome document is determined by comparing the value of counting chromatic pixels with a threshold value. However, the present invention is not limited to this. You may use the method currently disclosed by Unexamined-Japanese-Patent No. 4-282968. This method discriminates whether each pixel is a color pixel or a monochrome pixel, and if the presence of a predetermined number or more of continuous color pixels is detected in the given pixel order, the continuous color pixel portion is detected as a color block. If a predetermined number or more of color blocks exist in one line, the line is counted as a color line. If a predetermined number or more of color lines exist in the document, it is determined as a color image, and otherwise, it is determined as a monochrome image. What is necessary is just to set appropriately the reference | standard which determines whether it is a color block, and the number of the color lines in a document depending on how many color pixels are contained in a document and it determines with a color document.

  In the above description, the case where the number of color originals obtained from the result of the automatic color discrimination process is used as the output data of the automatic original discrimination unit has been described, but the result of other discrimination processes may be used. For example, the number of character originals, the number of printed photo originals, the number of character printed photo originals, or the number of photographic paper photo originals obtained from the determination result of the type of original may be compared.

As a method for discriminating the type of document, for example, the method described in Japanese Patent Laid-Open No. 2002-232708 can be used. In this method, the type of document is determined by the following (1) to (7).
(1) The minimum density value and the maximum density value in a block of n pixels × m pixels (for example, 7 pixels × 15 pixels) including the target pixel are calculated.
(2) The difference between the calculated minimum density value and the maximum density value is calculated, and the value is set as the maximum density difference.
(3) The total density busyness (for example, the sum of values calculated in the main scanning direction and the sub-scanning direction), which is the sum of absolute values of density differences between adjacent pixels, is calculated.
(4) The calculated maximum density difference is compared with the maximum density difference threshold, and the calculated total density busyness is compared with the total density busyness threshold. If the target pixel satisfies the conditions of maximum density difference <maximum density difference threshold and total density busyness <total density busyness threshold, it is determined that the target pixel belongs to the background / photographic paper photograph region. If the target pixel does not satisfy this condition, it is determined that the target pixel belongs to the character / halftone dot region.
(5) For a pixel determined to belong to the background / printing paper photo area, if the target pixel satisfies the condition of maximum density difference <background / printing paper photo determination threshold, the target pixel is determined to be the background pixel. If the target pixel does not satisfy this condition, it is determined that the target pixel is a photographic paper photograph (continuous tone region) pixel.
(6) For a pixel determined to belong to the character / halftone dot region, if the target pixel satisfies the condition that the total density busyness <the maximum density difference multiplied by the character / halftone determination threshold, the target pixel is a character It is determined that it is a pixel. If the target pixel does not satisfy this condition, it is determined that the target pixel is a halftone pixel.
(7) Count the number of pixels classified into a background area, a photographic paper photograph area, a character area, or a halftone dot area. Each count value and a predetermined background area, a photographic paper photograph area, and a halftone dot area are counted. The document type is determined by comparing the threshold value for the character area. For example, assuming that the detection accuracy is higher in the order of characters, halftone dots, and photographic paper photographs, the ratio of the text original and halftone areas is 20% of the total number of pixels when the ratio of the character areas is 30% or more of the total number of pixels. In the above case, when the ratio of the halftone original (printed photo original) and the photographic paper photo area is 10% or more of the total number of pixels, it is determined that the image is a photographic paper photo original. Further, when the ratio of the character area and the ratio of the halftone dot area are equal to or greater than the threshold value, respectively, it is determined that the character / halftone original (character-printed photo original).

  In the first to fourth embodiments, the order of priority of each comparison target is the highest in the number of documents, and decreases in the order of file size, number of characters, or number of color documents. Even if double feeding does not occur, the file size may change slightly due to the influence of paper dust or slight document inclination (about several kilobytes). Since the difference in file size includes such variation factors, the priority order is lower than the difference in the number of documents.

  The number of characters can be used when the document type determination result is a character document, a character-printed photo document, or a character photographic paper photo document (a document in which characters and photographic paper-printed photos are mixed). The number of color originals is effective when a color original is included in the original discrimination result. Thus, since the number of characters and the number of color originals depend on the type of original, the priority order is lowered.

  Table 1 shows the priorities of the above-described comparison targets for the document type discrimination result. Even in an image forming apparatus that does not include an automatic document discrimination unit, the priority order of each comparison target decreases in the order of the number of documents, the file size, the number of characters, or the number of color documents. Also in this case, since there is a possibility that the character document and the color document are not included, the priority order of the number of characters and the number of color documents is lowered.

上記では、画像形成装置において原稿の搬送時に発生する重送を検出する場合を説明したが、これに限定されない。図１５に示したスキャナ装置等にも、本発明は適用することができる。伸張部より出力されたＲＧＢの画像データは、パーソナルコンピュータ又はサーバコンピュータ等に送信される。図１５に示した各部の動作は、画像形成装置と同じであるので説明を繰返さない。

In the above description, a case has been described in which double feeding that occurs during document conveyance in the image forming apparatus is detected, but the present invention is not limited thereto. The present invention can also be applied to the scanner device shown in FIG. The RGB image data output from the decompression unit is transmitted to a personal computer or a server computer. Since the operation of each unit shown in FIG. 15 is the same as that of the image forming apparatus, description thereof will not be repeated.

  In the above description, a case has been described in which double feed is detected by a program stored in a ROM built in the image forming apparatus, but the present invention is not limited to this. The program for detecting double feeding may be recorded on a computer-readable portable recording medium. The program code to be recorded is arbitrary. It may be any of an executable program, an intermediate code program, or a source program. Thereby, the recording medium which recorded the program which detects double feeding can be provided freely.

  If a ROM is mounted by providing a socket on a control board on which a CPU or the like is mounted, the above-described ROM can also be realized as a portable by a service person or the like.

  Computer-readable recording media are recording media that can be attached to and detached from the main body of the apparatus, such as tape systems such as magnetic tapes and cassette tapes, magnetic disks (flexible disks, hard disks, etc.) and optical disks (CD-ROM, MO, MD, and DVD) Etc.), disk systems such as IC cards (including memory cards) and optical cards, etc., or mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (registered trademark) (Electrically Erasable Programmable Read Only Memory) , And a medium carrying a fixed program code such as a semiconductor memory system such as a flash ROM.

  If the image forming apparatus can be connected to a communication network including the Internet, a program code for detecting double feeding may be downloaded via the communication network. In this case, the download program may be stored in the image forming apparatus in advance, or may be installed in the image forming apparatus from another recording medium.

  The embodiment disclosed herein is merely an example, and the present invention is not limited to the above-described embodiment. The scope of the present invention is indicated by each claim of the claims after taking into account the description of the detailed description of the invention, and all modifications within the meaning and scope equivalent to the wording described therein are included. Including.

100 Image forming apparatus 102 CPU
104 ROM
106 RAM
108 HDD
110 Transmission / Reception Unit 112 Bus 114 Automatic Document Feeder 116 Document Reading Unit 118 Image Forming Unit 120 Image Processing Unit 122 Image Memory 124 Operation Unit

Claims (9)

A counting means for counting the number of conveyance times from the start of conveyance of a plurality of the originals by a conveyance device for conveying a plurality of set originals to completion of conveyance;
A data size calculating unit that calculates a total data size of the plurality of image data generated by reading the document by the reading unit each time the document is conveyed;
A character number calculating means for calculating the total number of characters by counting characters included in all of the plurality of generated image data;
With respect to at least two sets of one set of the number of conveyance times, one set of the total data size, and one set of the total number of characters obtained by conveying all of the plurality of originals twice, each set A comparison means for comparing values;
An image processing apparatus including: a determination unit configured to determine whether or not a double feed has occurred in the two transports according to a comparison result by the comparison unit;   2. The apparatus according to claim 1, further comprising request presentation means for requesting to change the orientation of the document and set the document on the transport device before executing the second transport of the two transports. Image processing apparatus.   The determination unit determines that a double feed has occurred in the two transports if a difference between at least one of the at least two sets compared by the comparison unit is greater than a predetermined value. The image processing apparatus according to 1 or 2. A color document number calculating means for determining whether the generated image data corresponds to a color document and calculating the number of color documents corresponding to all of the plurality of image data;
The comparing means compares the number of sets of color originals obtained by conveying all of the plurality of originals twice.
4. The determination unit according to claim 1, wherein if the difference in the number of sheets of the one set of color originals is larger than a predetermined value, it is determined that double feeding has occurred in the two transports. 5. Image processing apparatus. The number-of-characters calculating means calculates the number of characters in the page, which is the number of characters included in the image data generated every time the document is conveyed, and the plurality of the documents are conveyed, Maintaining a calculation order of the number of characters in the page, including vector generation means for generating a vector having the number of characters in the page as an element;
The comparing means determines whether or not all of the differences between corresponding elements of the two sets of vectors obtained by transporting all of the plurality of documents twice are equal to or less than a predetermined value;
5. The determination unit according to claim 1, wherein the determination unit determines that double feeding has occurred in the two transports unless all of the differences between corresponding elements of the two sets of vectors are equal to or less than a predetermined value. The image processing apparatus according to item. The data size calculating means calculates a page data size that is a data size of the image data generated every time the document is transported, and the page data size is determined by transporting all of the plurality of documents. Vector generation means for generating a vector having the page data size as an element while maintaining the size calculation order,
The comparing means determines whether or not all of the differences between corresponding elements of the two sets of vectors obtained by transporting all of the plurality of documents twice are equal to or less than a predetermined value;
5. The determination unit according to claim 1, wherein the determination unit determines that double feeding has occurred in the two transports unless all of the differences between corresponding elements of the two sets of vectors are equal to or less than a predetermined value. An image processing apparatus according to 1. An image processing apparatus according to any one of claims 1 to 6,
An image forming apparatus comprising: an image forming unit that forms an image on recording paper according to the image data. In the image processing device,
A counting function for counting the number of conveyances from the start of conveyance of the plurality of documents by a conveyance device for conveying a plurality of set documents to completion of conveyance;
A data size calculation function for calculating a total data size of the plurality of image data generated by reading the document every time the document is conveyed;
A number-of-characters calculation function for calculating the total number of characters by counting characters included in all of the plurality of generated image data;
With respect to at least two sets of one set of the number of conveyance times, one set of the total data size, and one set of the total number of characters obtained by conveying all of the plurality of originals twice, each set A comparison function to compare values;
An image processing program that realizes a determination function that determines whether or not double feeding has occurred in two transports according to a comparison result by the comparison function. A computer-readable recording medium on which the image processing program according to claim 8 is recorded.

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