JP4884305B2 - Image processing apparatus, image forming apparatus, computer program, and recording medium - Google Patents

Description

The present invention, document images processor you determine whether the allocation document assigned a plurality of image, the image forming apparatus, a computer program, and a recording medium.

  Conventionally, as a method of reducing the number of printed sheets, there is a method called a Nin1 function (or Nup function) that allocates and prints two originals or four originals on one sheet of paper, and copies an original image or electronic data It is used when printing a document created on a computer or created on a computer.

  For example, in Patent Document 1, when the independent page mode is selected in which the spread left and right pages of a bookbinding document are divided and transferred onto individual transfer sheets, the read image of the binding portion of the independent pages is transferred to the binding portion side of the transfer sheet. Describes that printing is forcibly overlapped. As a result, it is possible to eliminate image missing due to a shift in the divided position of the left and right pages of the read image data in the independent page mode due to a shift between the detected binding portion position and the actual binding portion position.

In Patent Document 2, a two-page divided reading / transmission mode is provided for a document of a specific size (for example, A3 size), and when the document information of a specific size is transmitted, the right half of the document information is read and converted into vertical and horizontal directions. Are transmitted, followed by reading the left half of the document information, converting the image to portrait and landscape, and transmitting.
JP-A-9-166938 JP-A-10-190895

  However, in the above-described prior art, when copying a two-sided original document one by one, it is necessary to provide an image mode such as an independent page mode (Patent Document 1) and a two-page divided reading / transmitting mode (Patent Document 2).

  For this reason, there is a problem that a method of providing an image mode cannot cope with a case where an unallocated document and an allocated document are mixed, and the allocated document is printed for each area.

The present invention has been made in view of such circumstances, and calculates feature amounts representing the characteristics of each line for a plurality of lines along the main scanning direction and the sub-scanning direction, and the feature amount of each line is determined in advance. The layout is determined by comparing with a threshold and determining whether or not a line determined to have no feature value satisfies a predetermined condition and is a layout document. even if the original and the usual original are mixed, particular processing mode setting can be Ru images processing device to determine whether the N-up document without the image forming apparatus, a computer It is an object to provide a program and a recording medium.

An image processing apparatus according to the present invention includes a unit for binarizing the image and a main scanning of the binarized image in the image processing apparatus for determining the type of the document based on an image obtained by reading the document. Scanning in the direction and the sub-scanning direction, and the feature amount representing the characteristics of each line for a plurality of lines along the main scanning direction and the sub-scanning direction is inverted from one of the binary values to the other on each scanned line. The means for extracting the number of times is compared with a feature value of each extracted line and a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature value is determined to be equal to or less than the threshold value is determined in the main scanning direction and Means for counting each in the sub-scanning direction, and means for determining whether or not the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition. Said article When it is determined that meet, characterized in that the document are to be determined that the allocation document assigned a plurality of images in one page.

  In the present invention, a feature amount representing a feature of each line is calculated for a plurality of lines along the main scanning direction and the sub-scanning direction, the feature amount of each line is compared with a predetermined threshold value, and the feature amount is calculated. Since it is determined whether or not a line that is determined to be nonexistent exists by satisfying a predetermined condition, it is determined whether or not it is an allocated document. Is mixed, it is determined whether the document is an allocated document without setting a specific processing mode.

  In the present invention, it is possible to determine an assigned document by using the number of times of reversal as a feature amount that is generally used rather than a special parameter.

An image processing apparatus according to the present invention scans the image in the main scanning direction and the sub-scanning direction in the image processing apparatus that determines the type of the document based on an image obtained by reading the document, and performs the main scanning. Means for detecting an edge of an image on each line for a plurality of lines along the direction and the sub-scanning direction, and an edge for which a feature amount representing the characteristic of each line in the main scanning direction and the sub-scanning direction is detected for each line And a feature value of each extracted line is compared with a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature value is determined to be equal to or less than the threshold value is determined in the main scanning direction. And a means for counting each in the sub-scanning direction, and a means for determining whether or not the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition. If the number of is determined to the condition is satisfied, wherein the document are to be determined that the allocation document assigned a plurality of images in one page.

  In the present invention, it is possible to determine a document to be assigned by using the number of edges as a feature quantity that is generally used rather than a special parameter.

An image processing apparatus according to the present invention scans the image in the main scanning direction and the sub-scanning direction in the image processing apparatus that determines the type of the document based on an image obtained by reading the document, and performs the main scanning. Means for calculating a feature amount representing a feature of each line for a plurality of lines along the direction and the sub-scanning direction as an average value of pixel values of pixels included in each line, and a predetermined feature amount for each line Means for counting the number of blank areas in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value are counted in each of the main scanning direction and the sub-scanning direction, and the counted main scanning direction And means for determining whether or not the number of blank areas in the sub-scanning direction satisfies a predetermined condition, and when it is determined that the number of blank areas satisfies the condition, the document includes a plurality of images. Characterized in that you have to be determined that the allocation document allocated to the page.

  According to the present invention, it is possible to determine a document to be allocated using an average value of pixel values as a feature value that is generally used rather than a special parameter.

An image processing apparatus according to the present invention scans the image in the main scanning direction and the sub-scanning direction in the image processing apparatus that determines the type of the document based on an image obtained by reading the document, and performs the main scanning. Means for calculating a feature amount representing a feature of each line for a plurality of lines along the direction and the sub-scanning direction as variations in pixel values of pixels included in each scanned line; A means for counting a number of blank areas in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value are compared for each of the main scanning direction and the sub-scanning direction, and the counted main scanning Means for determining whether or not the number of blank areas in the direction and the sub-scanning direction satisfies a predetermined condition, and when it is determined that the number of blank areas satisfies the condition, the document is duplicated. Characterized in that the image are to be determined that the allocation document allocated to the first page.

  In the present invention, it is possible to determine a document to be assigned using not a special parameter but a variation (dispersion value) of pixel values as a commonly used feature amount.

  The image processing apparatus according to the present invention further includes means for reducing the resolution of an image to be scanned.

  In the present invention, the data amount can be reduced without degrading the determination accuracy. Since the blank area for determining whether or not the document is an allocated document is wide, the determination accuracy is not decreased even if the resolution is decreased.

When the image processing apparatus according to the present invention determines that the image is an allocated document, the image processing apparatus extracts each of the allocated images, and forms each of the extracted images one page at a time. And image processing means for performing predetermined processing on the image.
The image forming apparatus according to the present invention is characterized by comprising said image processing apparatus, and means for the image subjected to processing by the image processing means the image processing apparatus has formed on the sheet.

  In the present invention, since it is automatically determined whether or not the document is a layout document, it is possible to provide an easy-to-use image forming apparatus that saves the user from setting the image mode.

A computer program according to the present invention causes a computer to execute the steps in a computer program to determine the type of the document based on an image obtained by reading a document, a computer, for binarizing the image, binarization the image obtained by by scanning in a main scanning direction and the sub-scanning direction, a feature quantity representing the feature of each line for a plurality of lines along the main scanning direction and the sub-scanning direction, the binary on each line was scanned A blank area in which a predetermined number of lines in which a feature amount is determined to be equal to or less than the threshold value by comparing the extracted feature amount of each line with a predetermined threshold value by comparing the step of extracting the number of inversions from one to the other and causing the number of counted for each of the main scanning direction and the sub-scanning direction, the main scanning direction and the sub scanning direction of the blank territory was counting A step number of causes is determined whether or not the condition that a predetermined, before Symbol if the number of blank area is determined with the condition is satisfied, the allocation document the document is allocated a plurality of images in one page And a step of determining that there is.
According to another aspect of the present invention, there is provided a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original, and for causing the computer to display the image in the main scanning direction and the sub-scanning direction. Scanning and detecting an edge of an image on each line for a plurality of lines along the main scanning direction and the sub-scanning direction, and a feature amount representing a feature of each line in the main scanning direction and the sub-scanning direction The step of extracting as the number of edges detected for each line and the feature amount of each extracted line are compared with a predetermined threshold value, and a predetermined number of consecutive lines for which the feature amount is determined to be equal to or less than the threshold value A step of counting the number of areas in each of the main scanning direction and the sub-scanning direction; A step of determining whether or not the number of blank areas in the inspection direction satisfies a predetermined condition, and when it is determined that the number of blank areas satisfies the condition, the document allocates a plurality of images in one page. And a step of determining that the document is an assigned document.
According to another aspect of the present invention, there is provided a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original, and for causing the computer to display the image in the main scanning direction and the sub-scanning direction. Scanning, and calculating a feature value representing a feature of each line for a plurality of lines along the main scanning direction and the sub-scanning direction as an average value of pixel values of pixels included in each line; Comparing the feature amount of each line with a predetermined threshold value, and counting the number of blank regions in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value are counted in each of the main scanning direction and the sub-scanning direction. And a step for determining whether or not the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition. If the flop, the number of the blank area is determined that the condition is satisfied, characterized in that to execute a step of determining and the document is allocated document assigned a plurality of images in one page.
According to another aspect of the present invention, there is provided a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original, and for causing the computer to display the image in the main scanning direction and the sub-scanning direction. Scanning, and calculating a feature amount representing a feature of each line for a plurality of lines along the main scanning direction and the sub-scanning direction as variations in pixel values of pixels included in each scanned line; The feature amount of each line is compared with a predetermined threshold value, and the number of blank areas where a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value is counted in each of the main scanning direction and the sub-scanning direction. Step and whether the counted number of blank areas in the main scanning direction and sub-scanning direction satisfy a predetermined condition A step of, when the number of the blank area is determined with the condition is satisfied, characterized in that to execute a step of determining and the document is allocated document assigned a plurality of images in one page.

  In the present invention, the computer can read and execute an image processing method for determining whether or not the document is a layout document, and this image processing method can be general-purpose.

A recording medium according to the present invention is recorded with the computer program according to any one of the above-described inventions .

  In the present invention, the image processing apparatus can be realized on a computer by an image processing program read from a recording medium.

  In the case of the present invention, the feature amount representing the feature of each line is calculated for a plurality of lines along the main scanning direction and the sub-scanning direction, the feature amount of each line is compared with a predetermined threshold value, and the feature amount is calculated. Since it is determined whether or not a line that is determined to be nonexistent satisfies a predetermined condition, it is determined whether or not it is an allocated document. Even in the case where the document is mixed, it is possible to determine whether the document is an allocated document without setting a specific processing mode.

  In the case of the present invention, it is possible to determine an assigned document using not a special parameter but a generally used feature amount, for example, the number of inversions, the number of edges, an average value or a variance value of pixel values, etc. It becomes.

  According to the present invention, the amount of data can be reduced without reducing the determination accuracy. Since the blank area for determining whether or not the document is an allocated document is wide, the determination accuracy is not decreased even if the resolution is decreased.

  According to the present invention, since it is automatically determined whether or not it is a layout document, it is possible to provide an easy-to-use image forming apparatus that saves the user from setting an image mode.

  According to the present invention, the computer can read and execute an image processing method for determining whether or not the document is a layout document, and this image processing method can be general-purpose.

  According to the present invention, the image processing apparatus can be realized on a computer by an image processing program read from a recording medium.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
Embodiment 1 FIG.
FIG. 1 is a block diagram illustrating the internal configuration of the image processing apparatus according to the present embodiment. The image processing apparatus according to the present embodiment includes a signal conversion unit 521, a resolution conversion unit 522, a main scanning direction feature quantity calculation unit 523, a main scanning direction feature quantity analysis unit 524, a sub scanning direction feature quantity calculation unit 525, and a sub scanning. A direction feature quantity analysis unit 526 and a determination unit 527 are provided.

  The signal conversion unit 521 performs processing for converting an RGB signal input from the outside into a luminance signal Y by the following equation.

  Y = 0.3R + 0.59G + 0.11B

For example, in the case of 8 bits (256 gradations), Y = 0 represents black and Y = 255 represents white. In addition, a brightness signal may be used instead of the luminance signal. For example, a signal of uniform color space L ^* a ^* b ^* signal (the CIE International Commission on Illumination 1976 defined L ^* a ^* b ^* signal (CIE: Commission International de l'Eclairage , L *: lightness, a ^*, b ^* : chromaticity)) or L ^* u ^* v ^* signal (L ^* u ^* v ^* signal (L ^* : lightness, u ^* , v ^* : chromaticity)) defined in CIE International Lighting Commission 1976) May be.

  The signal conversion unit 521 is not necessarily provided inside the image processing apparatus. For example, a G signal may be used instead of the above-described luminance signal and lightness signal.

  The resolution conversion unit 522 performs processing for reducing the resolution of image data. For example, 1200 dpi is converted to 150 dpi, 600 dpi is converted to 75 dpi, and the like. As a resolution conversion method, a nearest neighbor method in which the value of an existing pixel closest to the pixel to be interpolated or in a predetermined positional relationship with the pixel to be interpolated is used as the value of the interpolated pixel, and the pixels to be interpolated are surrounded The average of the weighted values in proportion to the distance of the four existing pixels is obtained, the bilinear method using the value as the interpolation pixel, the four points surrounding the pixel to be interpolated, and the 12 points surrounding them are added. Any of the bicubic methods for performing an interpolation operation using the values of a total of 16 pixels can be used.

  The main scanning direction feature amount calculation unit 523 scans the image in the main scanning direction, and calculates a feature amount for each scanned line. As the feature amount, the number of inversions from white to black or from black to white can be used. In this case, the main scanning direction feature quantity calculation unit 523 binarizes the luminance signal Y output from the signal conversion unit 521. Then, of the two values “0” or “1”, the total number of times of changing from “0” to “1” and the number of times of changing from “1” to “0” is obtained to obtain the number of inversions. For the binarization of the luminance signal, a method of simply binarizing using a preset threshold value (for example, 128) or a block (for example, 3 × 3) composed of a plurality of pixels centering on the target pixel. ), An average value of pixel values of the block is obtained, and a method of binarizing using the average value as a threshold value can be used.

  Further, the edge of the image may be detected for each scanned line, and the number of detected edges may be used as the feature amount. In this case, the main scanning direction feature amount calculation unit 523 obtains an absolute value of a difference between the target pixel and the right adjacent pixel or the left adjacent pixel adjacent to the target pixel, and the absolute value is equal to or greater than a threshold value (for example, 50). When an edge is detected, it counts. Further, instead of using a difference value between adjacent pixels, a known edge detection direction such as a Sobel filter or a secondary differential filter may be used to detect the edge by performing threshold processing on the detection result.

  Furthermore, an average value of pixel values may be calculated for each scanned line, and the calculated average value may be used as a feature amount. In this case, the main scanning direction feature quantity calculation unit 523 adds pixel values in line units, and divides by the total number of pixels included in the line to calculate an average value of pixel values.

  Furthermore, the variation (dispersion) of the pixel value for each scanned line may be calculated, and the calculated variation of the pixel value may be used as the feature amount. That is, since the variance value increases in the image area and decreases in the non-image area, it can be used as an image feature amount. In this case, the main scanning direction feature quantity calculation unit 523 calculates the average value of the pixel values by adding the pixel values in units of lines and dividing the result by the total number of pixels included in the line. The sum of squares of deviation from the average value is calculated.

  A sub-scanning direction feature amount calculation unit 525 scans an image in the sub-scanning direction, and calculates a feature amount for each scanned line. As a feature amount calculation method, a method similar to that in the main scanning direction feature amount calculation unit 523 can be used.

  The main scanning direction feature quantity analysis unit 524 obtains the feature of the document in the main scanning direction from the feature quantity distribution in the main scanning direction, and the sub scanning direction feature quantity analysis unit 526 performs the sub scanning from the feature quantity distribution in the sub scanning direction. Find the characteristics of the original in the direction.

  The determination unit 527 determines whether or not the read document is an allocated document in which a plurality of images are allocated within one page based on the analysis results by the main scanning direction feature value analysis unit 524 and the sub-scanning direction feature value analysis unit 526. Judgment is made.

  Hereinafter, processing executed by the main scanning direction feature quantity analysis unit 524 and the sub scanning direction feature quantity analysis unit 526 will be described. 2 to 5 are explanatory diagrams for explaining analysis examples of distribution of feature amounts in the main scanning direction and the sub-scanning direction.

  In the example shown in FIG. 2, the result of reading a horizontally-written original image in which characters are written over a plurality of lines and analyzing it by the main scanning direction feature quantity analysis unit 524 and the sub-scanning direction feature quantity analysis unit 526 is obtained. Show. The histograms of the feature amounts in the main scanning direction and the sub-scanning direction shown in the figure are simulated. In the case of such a document, since there is a space between lines, when the number of times of reversal is counted in the main scanning direction, a distribution in which the number of times of reversal appears at intervals corresponding to the space between the lines. On the other hand, since the character spacing is narrower than the line spacing, when the number of inversions is counted in the sub-scanning direction, the distribution is almost continuous. Strictly speaking, there is a discontinuous distribution because there is a slight space between characters, but when a feature amount is obtained in units of lines without reducing the resolution, the distribution is almost continuous. As shown in FIG. 3, when a distribution in which no blank area exists in the middle of the main scanning direction and the sub-scanning direction is obtained, it can be determined that the document to be determined is a normal document without an assigned image. it can.

  In the example shown in FIG. 3, an image of an assigned document in which two pages of document images are allocated within one page is read and analyzed by a main scanning direction feature amount analysis unit 524 and a sub scanning direction feature amount analysis unit 526. The results are shown. In this case, since there is a line spacing in the sub-scanning, a distribution in which the number of inversions appears at intervals corresponding to the line spacing. On the other hand, two continuous distributions appear in the main scanning direction. Although it depends on the layout of the original, it is assigned depending on whether or not a line whose number of inversions is equal to or less than a predetermined value (for example, 20) is about 20 mm (about 60 lines when the resolution is 75 dpi) in the distribution of the feature amount. It is determined whether the document is a document. Note that the margin portion around the document is excluded from the determination target. That is, when the first line or the last line is included in a line whose number of inversions is equal to or less than a predetermined value, it is excluded from the determination target.

  In the example shown in FIG. 4, there is no image assignment, and an image of a document in the case where there is a column is read and analyzed by the main scanning direction feature amount analysis unit 524 and the sub scanning direction feature amount analysis unit 526. Is shown. In this case, since there is a line interval in the main scanning direction, a distribution in which the number of inversions appears at intervals corresponding to the line interval. On the other hand, two continuous distributions appear in the sub-scanning direction. In this case, the fact that two continuous distributions appear only in the sub-scanning direction is used as a determination material, and it is determined that the document is not an allocated document.

  In the example shown in FIG. 5, an image of an assigned document in which four pages of document images are allocated within one page is read and analyzed by a main scanning direction feature amount analysis unit 524 and a sub scanning direction feature amount analysis unit 526. The results are shown. In this case, two continuous distributions appear in both the main scanning direction and the sub-scanning direction. In this case as well, as described above, allocation is performed depending on whether or not a line whose number of inversions is equal to or less than a predetermined value (for example, 20) exists about 20 mm (about 60 lines when the resolution is 75 dpi) in the distribution of the feature amount. It is determined whether the document is a document.

  The analysis method using the number of inversions as the feature amount has been described above, but the same applies to the case where the average value of the pixel values is used. That is, the case where the number of assignments is 2 (2-in-1 original document) will be described. In the main scanning direction, two distributions of continuous average values (values between 0 and 255) can be created. Since there is a blank area and there is a line spacing in the sub-scanning direction, an average value appears at every predetermined interval. Note that a blank area between two distributions appearing in the main scanning direction depends on the background color, scanner reading error, noise, and the like, but takes an average value close to 255.

  Hereinafter, the processing procedure for document type determination will be described. 6 and 7 are flowcharts for explaining the procedure of processing executed by the image processing apparatus according to this embodiment. First, the parameter Fm for counting the blank area in the main scanning direction and the value of the parameter Fs for counting the blank area in the sub scanning direction are set to 0 (step S11). Next, the signal conversion unit 521 performs processing for converting the RGB signal into the luminance signal Y (step S12), and performs resolution conversion processing for converting the image data into resolution (step S13).

  Next, a feature amount is calculated for each line in the main scanning direction and the sub-scanning direction of the image (step S14), and an analysis is performed on the distribution of the feature amount in the main scanning direction and the sub-scanning direction (step S15).

  Next, based on the analysis result in step S15, it is determined whether there is one blank area in the main scanning direction that satisfies a predetermined condition (step S16). If there is one blank area that satisfies the predetermined condition in the main scanning direction (S16: YES), the value of Fm is set to 1 (step S17).

  When the value of Fm is set to 1 (S17), or when it is determined that there is no blank area that satisfies the predetermined condition in the main scanning direction (S16: NO), the blank area that satisfies the predetermined condition is in the sub-scanning direction. It is determined whether or not one exists (step S18). If there is one blank area that satisfies the predetermined condition in the sub-scanning direction (S18: YES), the value of Fs is set to 1 (step S19).

  Whether or not Fm = 1 and Fs = 1 when the value of Fs is set to 1 (S19), or when it is determined that there is no blank area that satisfies a predetermined condition in the sub-scanning direction (S18: NO) That is, it is determined whether or not there is a blank area that satisfies a predetermined condition in both the main scanning direction and the sub-scanning direction (step S20). When it is determined that there is a blank area satisfying a predetermined condition in both the main scanning direction and the sub-scanning direction (S20: YES), the document is a 4-in-1 document (an allocated document in which four pages of images are allocated in one page). Is determined (step S21), and the processing according to this flowchart ends.

  If it is determined that one of Fm and Fs is not 1 (S20: NO), it is determined whether Fm = 1 and Fs = 0 (step S22). When it is determined that Fm = 1 and Fs = 0, that is, when it is determined that there is a blank area that satisfies a predetermined condition only in the main scanning direction (S22: YES), a 2-in-1 document (images for two pages) It is determined that the original is an allocated original within one page (step S23), and the processing according to this flowchart ends. Further, when it is determined that Fm = 0 and Fs = 0 or 1, that is, when it is determined that there is no blank area satisfying a predetermined condition in the main scanning direction (S22: NO), a normal document that is not an allocated document is used. It is determined that the document is a document (step S24), and the processing according to this flowchart is terminated.

  Note that the image processing apparatus may execute a predetermined process according to the determination of the document type. For example, the image of the allocated area is enlarged and rotated to form an image one by one. In this case, the center of the blank area existing between the distributions of the feature values is set as the boundary of the assigned image, and the effective image area is determined based on the center line. FIG. 8 is a schematic diagram showing an example of setting an effective image area. When the effective image area data is A4 document size and the allocation number is 2, the data is enlarged by 1.41 times. A known method can be adopted for detecting the document size. For example, a method in which a plurality of photoelectric sensors are provided in the document table according to the document size and detection is performed based on the presence or absence of light detection can be used. When the position of the image of the allocated document is shifted and the effective image area extends beyond the allocated document, the pixel value of the margin part excluding the end of the allocated document may be assigned to the protruding area.

  In addition, there are cases where the originals are copied, filing, and electronically distributed as they are.In addition, a horizontal document that has multiple columns appears as a blank area in the sub-scanning direction. Since there are cases where it is not possible to distinguish it from 2-in-1 only in the case of two-column writing, the document type determination result is displayed on the display unit of the operation panel 1, and the image of the allocated area is enlarged and rotated. The user may select whether or not to form an image one by one.

Embodiment 2. FIG.
The document type determination method described in the first embodiment can be used in combination with other document type determination methods. Note that an image processing apparatus for realizing such a document type determination method is exactly the same as that of the first embodiment, and thus description of the apparatus configuration is omitted.

  FIG. 9 is a flowchart for explaining the processing procedure of document type determination according to the second embodiment. First, the image processing apparatus executes an assigned document determination process (step S31). Specifically, it is determined whether the document to be determined is an allocated document according to the procedure shown in the flowcharts of FIGS. The determination result is held in a memory not shown in the figure.

  Next, the minimum density value and the maximum density value in the n × m block including the target pixel are calculated (steps S32 and S33), and the maximum density difference is calculated using the calculated minimum density value and the maximum density value (step S34). . Next, the sum of absolute values of density differences between adjacent pixels (that is, the total density busyness) is calculated (step S35).

  Then, the calculated maximum density difference and the maximum density difference threshold are compared, and the calculated total density busyness and the total density busyness threshold are compared. Both the maximum density difference and the total density busyness are compared. It is determined whether it is smaller than the threshold value (step S36). When it is determined that the maximum density difference is smaller than the maximum density difference threshold and the total density busyness is smaller than the total density busyness threshold (S36: YES), it is determined that the target pixel is the background / printing paper area ( Step S37).

  At this time, the maximum density difference is compared with a predetermined threshold (background / printing paper determination threshold) to determine whether the maximum density difference is smaller than the background / photographic paper determination threshold (step S38). If it is determined that the maximum density difference is smaller than the background / photographic paper determination threshold (S38: YES), the target pixel is counted as the background area (step S39), and the maximum density difference is equal to or larger than the background / photographic paper determination threshold. If it is determined (S38: NO), the target pixel is counted as a photographic paper region (step S40).

  On the other hand, if it is determined in step S36 that either the maximum density difference or the total density busyness is greater than or equal to the threshold value to be compared (S36: NO), it is determined that the target pixel is a character / halftone dot region ( Step S41).

  At this time, the total density busyness is compared with a product with a predetermined threshold (character / halftone dot determination threshold) to determine whether the total density busyness is smaller than the product value (step S42). When it is determined that the total density busyness is smaller than the product value (S42: YES), the target pixel is counted as a character area (step S43), and when the total density busyness is determined to be equal to or greater than the product value (S42). : NO), the target pixel is counted as a halftone dot region (step S44).

  Next, it is determined whether or not all the pixels have been processed (step S45). If it is determined that the processing has not ended (S45: NO), the process returns to step S32. If it is determined that all pixels have been processed (S45: YES), the document type is determined based on the count results in steps S39 and S40 and steps S43 and S44 (step S46). A threshold value is set for each of the background area, the photographic paper area, the halftone dot area, and the photographic paper area, and the document type can be determined by comparing the threshold value with the count result of each area.

  For example, 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). Also, assuming that the detection accuracy is higher in the order of characters, halftone dots, and photographic paper photographs, when the ratio of the character area is 30% of the total number of pixels, the ratio of the character original and the halftone area is 20% of the total number of pixels. In this case, when the ratio of the halftone dot original (printed photo original) and the photographic paper photo area is 10% of the total number of pixels, it is determined that the image is a photographic paper photo original. In this case, the document type is determined to be a character document, a character printed photo document, a printed photo document, a photographic paper photo document, or a character photographic paper photo document. The document type determination may be performed using image data temporarily stored in a storage unit such as a hard disk instead of performing pre-scanning.

  Thus, by using two types of document determination methods in combination, a 2-in-1 character document, a character-printed photo document, and the like can be determined. In the present embodiment, the area determination is performed after the assigned document determination process in step S31. However, it goes without saying that both may be performed in parallel.

Embodiment 3 FIG.
In the following, an embodiment in which the present invention is applied to an image forming apparatus such as a printer device or a digital multifunction peripheral will be described.

  FIG. 10 is a block diagram illustrating the internal configuration of the image forming apparatus according to the present embodiment. The image forming apparatus according to the present embodiment includes an operation panel 1, an image input device 3, an image processing device 5, and an image output device 7.

  The operation panel 1 is an interface for accepting an operation by a user, and includes an operation unit such as various switches and buttons, and a display unit that displays information to be notified to the user, an image, and the like.

  The image input device 3 is a unit that optically reads an image of a document, and includes a light source that irradiates light to a document for reading, an image sensor such as a CCD (Charge Coupled Device), and the like. In the image input device 3, a reflected light image from a document set at a predetermined reading position is formed on the image sensor, and RGB (R: Red, G: Green, B: Blue) analog electrical signals are output. . The analog electrical signal output from the image input device 3 is input to the image processing device 5.

  The image processing device 5 converts the analog electrical signal output from the image input device 3 into a digital electrical signal, performs appropriate processing, and outputs the obtained image signal to the image output device 7. The internal configuration and operation of the image processing apparatus 5 will be described in detail later.

  The image output device 7 is a means for forming an image on a sheet such as paper or an OHP film based on the image signal output from the image processing device 5. For this reason, the image output device 7 is a charger for charging the photosensitive drum to a predetermined potential, and laser writing for generating an electrostatic latent image on the photosensitive drum by emitting laser light in accordance with image data received from the outside. An apparatus, a developing device that supplies toner to the electrostatic latent image formed on the surface of the photosensitive drum to make it visible, a transfer device that transfers the toner image formed on the surface of the photosensitive drum onto paper (not shown), etc. And an image desired by the user is formed on a sheet by electrophotography. In addition to image formation by an electrophotographic method using a laser writing apparatus, an image formation may be performed by an inkjet method, a thermal transfer method, a sublimation method, or the like.

  Next, the internal configuration of the image processing apparatus 5 will be described. The AD conversion unit 50 converts RGB analog signals input from the image input device 3 into digital signals. The shading correction unit 51 performs a process for removing various distortions generated in the illumination system, the imaging system, and the imaging system of the image input device 3 on the digital RGB signal output from the AD conversion unit 50. The RGB signal subjected to the shading correction is output to the document type determination unit 52.

  The document type determination unit 52 uses RGB (RGB reflectance signal) from which various distortions have been removed by the shading correction unit 51 and the color balance has been adjusted, such as a density signal, and is used in a color image processing apparatus. The signal is converted into a signal that can be easily handled by the system, and the document type is determined. In the present embodiment, it is determined whether or not the document is an allocated document in which a plurality of images are allocated within one page. As the determination method, the method described in the first embodiment or the second embodiment is used.

  The input tone correction unit 53 performs image quality adjustment processing such as background density removal and contrast. The region separation processing unit 54 performs processing for separating each pixel in the input image into one of a character region, a halftone dot region, and a photographic region from the RGB signals. Based on the separation result, the region separation processing unit 54 sends a region identification signal indicating to which region the pixel belongs to the subsequent black generation and under color removal unit 56, the spatial filter processing unit 57, and the gradation reproduction processing unit 59. In addition to the output, the input signal output from the input tone correction unit 53 is output to the subsequent color correction unit 55 as it is.

  The color correction unit 55 performs processing for removing color turbidity based on the spectral characteristics of the CMY color material including unnecessary absorption components in order to faithfully reproduce color reproduction. The color-corrected RGB signal is output to the subsequent black generation and under color removal unit 56.

  The black generation and under color removal unit 56 generates black (K) signals from the CMY three-color signals after color correction, and generates a new CMY signal obtained by subtracting the K signal obtained by black generation from the original CMY signals. Generate the process. By this processing, the CMY three-color signal is converted into a CMYK four-color signal.

  As an example of the black generation process, there is a method of generating black using skeleton black. In this method, the input / output characteristic of the skeleton curve is y = f (x), the input data is C, M, Y, the output data is C ′, M ′, Y ′, K ′, the UCR rate (UCR) : Under Color Removal) α (0 <α <1), the black generation under color removal processing is expressed by the following equation.

K ′ = f {min (C, M, Y)}
C ′ = C−αK ′
M ′ = M−αK ′
Y ′ = Y−αK ′

  The spatial filter processing unit 57 performs spatial filter processing by a digital filter on the image data of the CMYK signal input from the black generation and under color removal unit 56 based on the region identification signal, thereby correcting the spatial frequency characteristics. Processing is performed to prevent blurring and particulate deterioration of the output image.

  For example, in the region separated into characters by the region separation processing unit 54, in order to improve the reproducibility of black characters or color characters in particular, the sharpness enhancement processing in the spatial filter processing by the spatial filter processing unit 57 has a high frequency enhancement amount. Increased. At the same time, the gradation reproduction processing unit 59 selects binarization or multi-value processing on a high-resolution screen suitable for high-frequency reproduction. Further, with respect to the region separated into halftone dot regions by the region separation processing unit 54, the spatial filter processing unit 57 performs low-pass filter processing for removing the input halftone component. The output tone correction unit 58 performs output tone correction processing for converting a signal such as a density signal into a halftone dot area ratio that is a characteristic value of the color image output device, and then the tone reproduction processing unit 59 performs the final processing. Specifically, gradation reproduction processing is performed in which an image is separated into pixels and processed so that each gradation can be reproduced. In addition, regarding the region separated into the photograph by the region separation processing unit 54, the binarization or multi-value processing on the screen with an emphasis on gradation reproducibility is performed.

  The image data subjected to the above-described processes is temporarily stored in storage means (not shown), read at a predetermined timing, and output to the image output device 7.

  In addition to the above-described configuration, the digital color multifunction peripheral having a copy function, a printer function, a facsimile function, an e-mail transmission / reception function, and the like further includes a communication device including a modem and a network card. When sending a facsimile, if the modem is ready for transmission by the transmission procedure with the other party, the image data compressed in a predetermined format (image data read by the scanner) is stored in the memory. The data is read from the data, and the necessary processing such as changing the compression format is performed, and the data is sequentially transmitted to the other party via the communication line.

  When receiving a facsimile, the communication device receives the image data transmitted from the other party and inputs it to the image processing device while performing the communication procedure, and the image processing device receives the received image data (not shown). The compression / decompression processing unit performs decompression processing. The decompressed image data is subjected to rotation processing and resolution conversion as necessary, subjected to output tone correction and tone reproduction processing, and is output from the image output device.

  In addition, data communication is performed with a computer or other digital multi-function peripheral connected to the network via a network card or a LAN cable.

  In the above description, the color multifunction peripheral has been described, but it goes without saying that it may be a monochrome multifunction peripheral.

Embodiment 4 FIG.
In this embodiment, an embodiment in which the present invention is applied to an image reading apparatus such as a flatbed scanner will be described.

  FIG. 11 is a block diagram illustrating the internal configuration of the image reading apparatus according to the present embodiment. The image reading apparatus according to the present embodiment includes a color image reading unit 110 and a color image processing unit 120. The color image processing unit 120 includes an AD conversion unit 121, a shading correction unit 122, and a document type determination unit 123.

The color image reading unit 110 is configured by a scanner unit including, for example, a CCD (Charge Coupled Device), and the reflected light image from the document is converted into an CCD (R: red, G: green, B: blue) analog signal as a CCD. And input to the color image processing unit 120.

  The analog signal read by the color image reading unit 110 is sent through the color image processing unit 120 in the order of the AD conversion unit 121, the shading correction unit 122, and the document type determination unit 123.

  The AD conversion unit 121 converts RGB analog signals into digital signals, and the shading correction unit 122 applies the illumination system of the color image reading unit 110 to the digital RGB signals sent from the AD conversion unit 121. The image forming system and the imaging system are subjected to processing for removing various distortions. The shading correction unit 122 adjusts the color balance. Further, the shading correction unit 122 converts the RGB reflectance signal into a density signal.

  In the document type determination unit 123, an image used in the color image processing unit 120, such as a density signal, is an RGB signal (RGB reflectance signal) from which various distortions have been removed by the shading correction unit 122 and the color balance has been adjusted. It is converted into a signal that can be easily handled by the processing system, and whether it is an allocated document, or whether it is a character document, a printed photo document, or a character-printed photo document in which characters and printed photos are mixed The document type such as “K” is determined.

  The image data and the document type determination signal output from the image reading apparatus are transmitted to a printer, a multifunction peripheral, or a computer via a network.

Embodiment 5 FIG.
In the above-described embodiment, each process is realized by hardware. However, the present invention may be realized by software processing.

  FIG. 12 is a block diagram for explaining the internal configuration of the image processing apparatus in which the program code (execution format program, intermediate code program, source program) of the computer program of the present invention is installed. In the figure, reference numeral 200 denotes an image processing apparatus according to the present embodiment, specifically a personal computer, a workstation, or the like. The image processing apparatus 200 includes a CPU 201, and hardware such as a ROM 203, a RAM 204, a hard disk 205, an external storage unit 206, an input unit 207, a display unit 208, and a communication port 209 is connected to the CPU 201 via the bus 202. Yes. The CPU 201 controls each part of the hardware described above according to the program code of the control program stored in advance in the ROM 203.

  The RAM 204 is a volatile memory that temporarily stores various data generated during execution of the control program described above or the computer program according to the present invention. The hard disk 205 is a storage unit having a magnetic recording medium, and stores the program code of the computer program of the present invention, image data to be processed, and the like. The external storage unit 206 includes a reading device for reading a computer program from the recording medium M on which the program code of the present invention is recorded. As the recording medium M, an FD (Flexible Disk), a CD-ROM, or the like can be used. The program code read by the external storage unit 206 is stored in the hard disk 205. The CPU 201 implements the image processing method according to the present invention as described in the first embodiment by loading the program code according to the present invention stored in the hard disk 205 onto the RAM 204 and executing it.

  The input unit 207 functions as an interface for acquiring image data from the outside. For example, a color scanner device or the like is connected to the input unit 207. The display unit 208 functions as an interface for displaying image data to be processed, image data during image processing, image data after image processing, and the like. The display unit 208 may be configured to display an image data by connecting an external display device such as a liquid crystal display device, or the display unit 208 may include a display device and display the image data. The communication port 209 is an interface for connecting the printer 300 to the outside. When printing image data that has undergone image processing by the printer 300, the image processing apparatus 200 generates print data that can be decoded by the printer 300 based on the image data, and transmits the generated print data to the printer 300. .

  In the present embodiment, the CPU 201 performs various calculations. However, a dedicated chip for performing calculations related to image processing may be provided separately, and calculations may be performed according to instructions from the CPU 201.

  As the recording medium M for recording the computer program according to the present invention, in addition to the FD and CD-ROM described above, optical recording media such as MO, MD, DVD, magnetic recording media such as hard disks, IC cards, memory cards, It is also possible to use a semiconductor memory such as a card-type recording medium such as an optical card, mask ROM, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), flash ROM, or the like. Further, since the system configuration is such that a communication network including the Internet can be connected, the program code according to the present invention may be downloaded from the communication network. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  In addition, the computer program of the present invention may be provided as a single application program or utility program, or may be incorporated into another application program or utility program and provided as a partial function of the program. May be. For example, as one form, a form provided by being incorporated in a printer driver is conceivable. In this case, the document type is determined based on the image data obtained by reading the document image, subjected to image processing according to the determination result, and then translated into a printer language and transmitted to the target printer device. Is called.

It is a block diagram explaining the internal structure of the image processing apparatus which concerns on this Embodiment. It is explanatory drawing explaining the example of analysis of distribution of the feature-value in a main scanning direction and a subscanning direction. It is explanatory drawing explaining the example of analysis of distribution of the feature-value in a main scanning direction and a subscanning direction. It is explanatory drawing explaining the example of analysis of distribution of the feature-value in a main scanning direction and a subscanning direction. It is explanatory drawing explaining the example of analysis of distribution of the feature-value in a main scanning direction and a subscanning direction. It is a flowchart explaining the procedure of the process which the image processing apparatus which concerns on this Embodiment performs. It is a flowchart explaining the procedure of the process which the image processing apparatus which concerns on this Embodiment performs. It is a schematic diagram which shows the example of a setting of an effective image area | region. 10 is a flowchart illustrating a document type determination processing procedure according to the second embodiment. 1 is a block diagram illustrating an internal configuration of an image forming apparatus according to an embodiment. 1 is a block diagram illustrating an internal configuration of an image reading apparatus according to an embodiment. It is a block diagram explaining the internal structure of the image processing apparatus in which the program code (execution format program, intermediate code program, source program) of the computer program of this invention was installed.

Explanation of symbols

52 Document type determination unit 521 Document conversion unit 522 Resolution conversion unit 523 Main scanning direction feature value calculation unit 524 Main scanning direction feature value analysis unit 525 Sub-scanning direction feature value calculation unit 526 Sub-scanning direction feature value analysis unit 527 Determination unit

Claims (12)

In the image processing apparatus for determining the type of the document based on the image obtained by reading the document,
Means for binarizing the image, and a feature that represents the characteristic of each line for a plurality of lines along the main scanning direction and the sub-scanning direction by scanning the binarized image in the main scanning direction and the sub-scanning direction. The means for extracting the amount as the number of times of reversal from one of the binary values to the other on each scanned line is compared with the feature value of each extracted line and a predetermined threshold value, and the feature value is determined to be equal to or less than the threshold value. Means for counting the number of blank areas in which a predetermined number of lines continue in each of the main scanning direction and the sub-scanning direction, and a condition in which the number of blank areas counted in the main scanning direction and the sub-scanning direction is predetermined. Means for determining whether or not to satisfy,
An image processing apparatus, wherein when it is determined that the number of blank areas satisfies the condition, the document is determined to be an allocated document in which a plurality of images are allocated within one page. In the image processing apparatus for determining the type of the document based on the image obtained by reading the document,
Means for scanning the image in the main scanning direction and the sub-scanning direction and detecting an edge of the image on each line for a plurality of lines along the main scanning direction and the sub-scanning direction; and the main scanning direction and the sub-scanning A means for extracting the feature amount representing the feature of each line in the direction as the number of edges detected for each line, and comparing the feature amount of each extracted line with a predetermined threshold value, and the feature amount is equal to or less than the threshold value Means for counting the number of blank areas in which the determined lines continue for a predetermined number in each of the main scanning direction and the sub-scanning direction, and the number of blank areas counted in the main scanning direction and the sub-scanning direction are predetermined conditions Means for determining whether or not
An image processing apparatus , wherein when it is determined that the number of blank areas satisfies the condition, the document is determined to be an allocated document in which a plurality of images are allocated within one page . In the image processing apparatus for determining the type of the document based on the image obtained by reading the document,
The image is scanned in the main scanning direction and the sub-scanning direction, and the feature amount representing the characteristic of each line for a plurality of lines along the main scanning direction and the sub-scanning direction is calculated by the pixel value of the pixel included in each line. The means for calculating as an average value is compared with the calculated feature value of each line and a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature value is determined to be equal to or less than the threshold value is determined in the main scanning direction And means for counting each in the sub-scanning direction, and means for determining whether or not the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition,
An image processing apparatus , wherein when it is determined that the number of blank areas satisfies the condition, the document is determined to be an allocated document in which a plurality of images are allocated within one page . In the image processing apparatus for determining the type of the document based on the image obtained by reading the document,
By scanning the image in the main scanning direction and the sub scanning direction, the pixels of the pixels included a feature amount for a plurality of lines along the main scanning direction and the sub-scanning direction representing the characteristics of each line, each line scanned The means for calculating the value variation is compared with the calculated feature value of each line and a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature value is determined to be equal to or less than the threshold value is continued in the main scanning. Means for counting each of the direction and the sub-scanning direction, and means for determining whether or not the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfy a predetermined condition,
An image processing apparatus , wherein when it is determined that the number of blank areas satisfies the condition, the document is determined to be an allocated document in which a plurality of images are allocated within one page . The image processing apparatus according to any one of claims 4 the image to be scanned from claim 1, characterized by further comprising means for low resolution. When it is determined that the image is an allocated document, a predetermined process is performed on each of the images in order to form each page of the extracted images and a means for extracting each of the allocated images. the image processing device according to claim 1, characterized in that it comprises an image processing unit to any one of claims 5 to perform. An image forming apparatus comprising: the image processing apparatus according to claim 6 ; and a unit that forms an image processed by an image processing unit included in the image processing apparatus on a sheet. In a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original,
On the computer,
Binarizing the image;
The image was binarized is scanned in the main scanning direction and the sub-scanning direction, the main scanning direction and the feature amount representing the feature of each line for a plurality of lines along the sub-scanning direction, each line on which were scanned And extracting the binary number as the number of times of reversal from one to the other ,
The feature amount of each extracted line is compared with a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value is determined for each of the main scanning direction and the sub-scanning direction. A step of counting ;
A step number of counting is not said main scanning direction and the sub scanning direction of the blank area to determine whether or not the condition that a predetermined,
If the number of previous SL blank area is determined with the condition is satisfied, a computer program for executing the step of determining said original is a allocation document assigned a plurality of images in one page. In a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original,
On the computer,
Scanning the image in the main scanning direction and the sub-scanning direction, and detecting an edge of the image on each line for a plurality of lines along the main scanning direction and the sub-scanning direction;
Extracting a feature amount representing a feature of each line in the main scanning direction and the sub-scanning direction as the number of edges detected for each line;
The feature amount of each extracted line is compared with a predetermined threshold value, and the number of blank areas in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value is determined for each of the main scanning direction and the sub-scanning direction. A step of counting;
Determining whether the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition;
Determining that the number of blank areas satisfies the condition satisfies the document as an allocated document in which a plurality of images are allocated within one page;
A computer program for running. In a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original,
On the computer,
The image is scanned in the main scanning direction and the sub-scanning direction, and a feature amount representing a feature of each line for a plurality of lines along the main scanning direction and the sub-scanning direction is calculated based on the pixel value of the pixel included in each line. Calculating as an average value;
The calculated feature amount of each line is compared with a predetermined threshold value, and the number of blank regions in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value is determined for each of the main scanning direction and the sub-scanning direction. A step of counting;
Determining whether the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition;
Determining that the number of blank areas satisfies the condition satisfies the document as an allocated document in which a plurality of images are allocated within one page;
A computer program for running. In a computer program for causing a computer to determine the type of the original based on an image obtained by reading the original,
On the computer,
The image is scanned in the main scanning direction and the sub-scanning direction, and the feature amount representing the characteristics of each line for a plurality of lines along the main scanning direction and the sub-scanning direction is displayed. Calculating as a variation in value;
The calculated feature amount of each line is compared with a predetermined threshold value, and the number of blank regions in which a predetermined number of lines whose feature amount is determined to be equal to or less than the threshold value is determined for each of the main scanning direction and the sub-scanning direction. A step of counting;
Determining whether the counted number of blank areas in the main scanning direction and the sub-scanning direction satisfies a predetermined condition;
Determining that the number of blank areas satisfies the condition satisfies the document as an allocated document in which a plurality of images are allocated within one page;
A computer program for running. A computer-readable recording medium on which the computer program according to any one of claims 8 to 11 is recorded.

Images