JP6460025B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus and an image forming apparatus, and more particularly to a technique for detecting a barcode attached to a document.

  A technique for embedding data in a recording medium such as paper by printing a barcode obtained by encoding data has been put into practical use. The embedded data is extracted by optically reading a recording medium on which a barcode is printed, detecting the barcode, and analyzing the detected barcode.

  Today, various techniques for quickly and accurately reading such barcodes have been proposed. For example, Patent Document 1 below describes that the barcode detection speed is improved by adjusting the barcode printing position. Japanese Patent Application Laid-Open No. 2005-228561 describes that barcode recognition accuracy is improved by allowing a user to specify a position where a barcode is printed with a mouse.

  Further, in Patent Document 3 below, when a barcode (two-dimensional code) photographed by a camera has a curved distortion, it is possible to improve barcode reading accuracy by correcting barcode image data. Have been described.

JP 2011-077620 A Japanese Patent Laid-Open No. 07-262216 JP 2010-045586 A JP 2010-219704 A

  However, with the technique described in the above-mentioned Patent Document 1, the barcode detection time cannot be shortened for a document whose barcode printing position is not adjusted. Further, in the technique described in Patent Document 2, the user needs to specify the barcode printing position on the document, and the user is requested to perform the operation, and time for the operation is required. Therefore, it is not possible to improve the barcode detection speed. Further, with the technique described in Patent Document 3, the barcode reading accuracy can be improved, but the barcode detection time cannot be shortened.

  Further, when the barcode is inclined or barcodes with different inclinations are mixed, the barcode may not be read. In the above-mentioned Patent Document 4, it is described that the inclination of a barcode (symbol image) printed on a document is detected and the inclination of the document is detected from the detected inclination of the barcode. The technique described in Document 4 does not increase the barcode detection speed.

  The present invention has been made in view of the above circumstances, and is necessary for bar code reading without requiring special processing for a manuscript such as adjusting the bar code printing position or requiring a special operation from the user. An object of the present invention is to shorten the time required for the analysis and to analyze the barcode reliably even when the barcode is inclined.

An image reading apparatus according to one aspect of the present invention includes a document reading unit that reads a document,
An image data storage unit for storing image data of the document obtained by reading by the document reading unit;
A reduced image creation unit that creates a reduced image of the document from the image data stored in the image data storage unit;
A position detection unit that detects the position of the barcode in the reduced image from the reduced image created by the reduced image creation unit;
An inclination detection unit that detects an inclination of the barcode detected by the position detection unit;
A position calculating unit that calculates the position of the barcode in the original image of the document based on the position detected by the position detecting unit;
By scanning in the direction of the inclination detected by the inclination detecting unit at the position calculated by the position calculating unit in the original image of the document indicated by the image data stored in the image data storage unit, An analysis unit for analyzing the barcode in the original image ,
The tilt detection unit detects a corner point of the image indicating the barcode detected by the position detection unit, and detects a tilt of a long side of a rectangle formed by the detected corner point as the tilt of the barcode. Is.
An image reading apparatus according to another aspect of the present invention includes a document reading unit that reads a document,
An image data storage unit for storing image data of the document obtained by reading by the document reading unit;
A reduced image creation unit that creates a reduced image of the document from the image data stored in the image data storage unit;
A position detection unit that detects the position of the barcode in the reduced image from the reduced image created by the reduced image creation unit;
An inclination detection unit that detects an inclination of the barcode detected by the position detection unit;
A position calculating unit that calculates the position of the barcode in the original image of the document based on the position detected by the position detecting unit;
By scanning in the direction of the inclination detected by the inclination detecting unit at the position calculated by the position calculating unit in the original image of the document indicated by the image data stored in the image data storage unit, An analysis unit for analyzing the barcode in the original image,
When the inclination detection unit detects a corner point of the image indicating the barcode from the reduced image, and the figure formed by the detected corner point has a convex shape, the long side of the protruding part in the figure The inclination is detected as the inclination of the barcode.

  An image forming apparatus according to an aspect of the present invention includes the image reading device and an image forming unit that forms an image on a recording medium.

  In the present invention, the barcode position in the original image of the document is calculated, and the barcode in the original image is analyzed by scanning the calculated position with respect to the original image. That is, according to the present invention, when the barcode is analyzed, the original image only needs to be scanned at the calculated specific location, so that scanning at an unnecessary location can be omitted.

  In the present invention, the barcode position in the original image is not directly detected from the original image, but is calculated from the barcode position in the reduced image detected from the reduced image. Can be reduced, and the barcode detection speed can be increased.

  As a result, according to the present invention, the time required to read the barcode can be shortened even if the document is not specially processed. Further, since the inclination of the barcode in the reduced image is detected, the barcode can be reliably analyzed even if the barcode is inclined.

1 is a functional block diagram schematically showing a main internal configuration of an image forming apparatus according to a first embodiment of the present invention. (A) shows a barcode attached to a document, (B) shows an image obtained by performing reduction processing and interpolation processing on the barcode, and (C) shows interpolation processing and correction processing performed on the barcode. The image is shown. (A) is an example of an image obtained by converting a barcode into a simple figure, (B) shows corner points forming a simple figure, and (C) shows the inclination of the barcode. (A) is an example of an image obtained by converting a barcode into a simple figure, (B) shows corner points forming a simple figure, and (C) shows the inclination of the barcode. 3 is a flowchart illustrating a first embodiment of barcode analysis processing by the image forming apparatus. FIG. 6 is a diagram illustrating an example of a document in which barcodes having different inclinations are mixed. FIG. 6 is a functional block diagram schematically illustrating a main internal configuration of an image forming apparatus according to a second embodiment. (A), (B) is explanatory drawing for demonstrating the midpoint of the short side in the rectangle which shows the barcode converted into the simple figure. 6 is a flowchart illustrating a second embodiment of barcode analysis processing by the image forming apparatus.

Hereinafter, an image reading apparatus and an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a functional block diagram schematically showing the main internal configuration of the image forming apparatus according to the first embodiment of the present invention. The image forming apparatus 1 is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function, and includes a control unit 10, a document feeding unit 6, a document reading unit 5, an image, and the like. The image forming apparatus includes a forming unit 12, an image memory 32, an HDD (Hard Disk Drive) 92, a fixing unit 13, a paper feeding unit 14, an operation unit 47, a facsimile communication unit 71, and a network interface unit 91.

  The document feeding unit 6 feeds a document to be read to the document reading unit 5.

The document reading unit 5 includes a reading mechanism (not shown) having a light irradiation unit, a CCD (Charge Coupled Device) sensor, and the like under the control of the control unit 100 constituting the control unit 10. Irradiates a document using a light irradiator and receives the reflected light by a CCD sensor, thereby reading an image from the document. Image data obtained by reading the document by the document reading unit 5 is stored in the image memory 32.

  The image forming unit 12 forms a toner image of an image to be printed on a sheet (recording medium).

  The image memory 32 is an area for temporarily storing image data of a document obtained by reading by the document reading unit 5 and temporarily storing data to be printed by the image forming unit 12. . The image memory 32 is an example of an image data storage unit in the claims.

  The HDD 92 is a large-capacity storage device that stores document images and the like read by the document reading unit 5.

  The fixing unit 13 fixes the toner image on the paper to the paper by thermocompression bonding.

  The paper supply unit 14 includes a paper supply cassette (not shown), and picks up and conveys the paper stored in the paper supply cassette.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guidance to the operator. The display unit 473 is a touch panel, and the operator can operate the image forming apparatus 1 by touching buttons and keys displayed on the screen.

  The facsimile communication unit 71 includes an encoding / decoding unit, a modulation / demodulation unit, an NCU (Network Control Unit), and the like (not shown), and performs facsimile communication using a public telephone line network.

The network interface unit 91 includes a communication module such as a LAN (Local Area Network) board, and is connected to the network interface unit 91.
Various data are transmitted / received to / from an external device 20 such as a personal computer (PC) in a local area or on the Internet via N or the like.

The control unit 10 includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a dedicated hardware circuit. The control unit 10 includes a control unit 100, a reduced image creation unit 101, a position detection unit 102, an inclination detection unit 103, a position calculation unit 104, an analysis unit 105, and a reduced image data storage unit 106. ing.

  The control unit 10 operates in accordance with a control program installed in the HDD 92 to control the control unit 100, the reduced image creation unit 101, the position detection unit 102, the tilt detection unit 103, the position calculation unit 104, the analysis unit 105, and the reduction unit. It functions as the image data storage unit 106. However, the control unit 100 and the like can also be configured by hardware circuits independently of the operation according to the control program by the control unit 10. The same applies to each embodiment unless otherwise specified.

  The control unit 100 governs overall operation control of the image forming apparatus 1. The control unit 100 includes a document feeding unit 6, a document reading unit 5, an image forming unit 12, an image memory 32, an HDD 92, a fixing unit 13, a sheet feeding unit 14, an operation unit 47, a facsimile communication unit 71, and a network interface unit 91. Are connected, and drive control of these parts is performed.

  The reduced image creation unit 101 includes an interpolation processing unit 101a and a correction processing unit 101b, and creates and creates a reduced image of a document from image data stored in the image memory 32 obtained by reading by the document reading unit 5. The reduced image data is stored in the reduced image data storage unit 106.

  The interpolation processing unit 101a performs an interpolation process on the original image subjected to the above-described reduction process by, for example, B-Spline interpolation or the like, and smoothes the density in the barcode. The correction processing unit 101b performs correction for emphasizing a dark part of the reduced image after the interpolation processing by, for example, gamma correction. By the processing by the interpolation processing unit 101a and the correction processing unit 101b, an image showing a barcode is converted into an image showing a simple figure as shown below.

  2A shows a barcode attached to the document, FIG. 2B shows an image obtained by performing reduction processing and interpolation processing on the barcode, and FIG. 2C shows interpolation processing and correction processing on the barcode. The applied image is shown.

  Examples of the interpolation processing include a method using an interpolation algorithm by spline interpolation such as the B-Spline interpolation. When spline interpolation is performed on the original image, the original image is reduced, and the bar code P1 composed of black lines and white lines is gray with white lines adjacent to each other, and black lines are adjacent to adjacent white lines. It turns gray and the barcode density is smoothed.

  When the gray level of black and white is expressed by 2 8 (= 256 gradations), the pixel value “200 to 255” is black, and the pixel value “0 to 50” is white, when spline interpolation is performed, While the image is reduced, for example, the pixel value of the barcode becomes “125 to 200”, and the barcode becomes a blurred image P2 as shown in FIG.

Examples of the correction processing include the gamma correction described above. For example, correction that emphasizes a dark portion is performed so that pixels having a pixel value “125” or more have a pixel value “200 to 255 (black)”. As a result, as shown in FIG. 2C, the barcode is a simple figure (similar to a blackened rectangle).
Image P3).

  The position detection unit 102 detects the barcode position from the reduced image indicated by the reduced image data stored in the reduced image data storage unit 106. The position detection unit 102 stores a pattern prepared by performing in advance the same processing as the above-described processing by the interpolation processing unit 101a and the correction processing unit 101b on an image showing a barcode. The position detection unit 102 collates the reduced image with the prepared pattern, detects a barcode from the reduced image by pattern matching or the like, and detects the position of the detected barcode in the reduced image. The pattern stored in the position detection unit 102 is an image showing a figure in which a barcode is simplified by the above processing.

  The inclination detection unit 103 detects the inclination of the barcode detected by the position detection unit 102 from the reduced image indicated by the reduced image data stored in the reduced image data storage unit 106. For example, the inclination detection unit 103 obtains a contour line of the figure from the rapid change in brightness in the area around the barcode position detected by the position detection unit 102, and further detects a corner point representing a feature point on the image. Then, the inclination of the long side of the rectangle formed by the detected corner points is detected as the inclination of the barcode.

  FIG. 3A is an example of an image obtained by converting a barcode into a simple figure, FIG. 3B shows corner points forming a simple figure, and FIG. 3C shows the inclination of the barcode. ing. The image P4 is rectangular, the image P4 is formed by corner points C1 to C4, and the arrow A1 indicates the inclination of the image P4.

  As shown in FIG. 3B, the inclination detection unit 103, when the image P4 has four corner points C1 to C4, the long side of the image P4 (the line connecting the corner point C1 and the corner point C4). Min, or the slope of the line segment connecting the corner point C2 and the corner point C3), and the slope of the long side (arrow A1) of the calculated image P4 is detected as the slope of the barcode.

  FIG. 4A shows another example in which the barcode is converted into a simple graphic, FIG. 4B shows the corner points forming the simple graphic, and FIG. 4C shows the inclination of the barcode. ing. The image P5 is convex, the image P5 is formed by corner points C11 to C18, and the arrow A2 indicates the inclination of the image P5.

  The simple figure of the barcode becomes convex as shown in the image P5, for example, when the characters are written in the lower part of the barcode like the barcode shown in FIG. . The rectangle formed from the corner points C11 to C14 is a region indicating a barcode, and the rectangle formed from the corner points C15 to C18 is a region indicating a character string described in the lower part of the barcode.

  As shown in FIG. 4B, the inclination detection unit 103 calculates distances from different corner points for all corner points C11 to C18 when the image P5 has eight corner points. The length of the rectangle formed from the remaining four corner points C11 to C14 by excluding the four corner points C15 to C18 (that is, the corner points forming the region indicating the character string) where different corner points exist nearby The inclination of the side (arrow A2) is detected as the inclination of the barcode.

  The position calculation unit 104 calculates the barcode position in the original image of the document based on the barcode position in the reduced image detected by the position detection unit 102.

Based on the image data stored in the image memory 32, the analysis unit 105 detects the inclination detected by the inclination detection unit 103 at the position calculated by the position calculation unit 104 with respect to the original image indicated by the image data. By scanning in the direction, the barcode in the original image is detected. Further, the analysis unit 105 analyzes the detected barcode and extracts (decodes) the meaning of the data associated with the barcode. The analysis unit 105 can perform this decoding by a known method.

  The image reading apparatus according to the embodiment of the present invention includes at least the document reading unit 5, the image memory 32, the reduced image creation unit 101, the position detection unit 102, the inclination detection unit 103, and the position calculation unit. 104 and an analysis unit 105. In the image forming apparatus 1 according to the embodiment of the invention, the image reading apparatus further includes at least the image forming unit 12.

  Next, a first embodiment of barcode analysis processing by the image forming apparatus 1 will be described with reference to FIG.

  First, when a document reading instruction is input by the operation of the operation unit 47 by the user, the control unit 100 causes the document reading unit 5 to read the document (S1), and the image data obtained by the reading is stored in the image memory 32. Save (S2).

  Subsequently, the reduced image creating unit 101 performs image reduction processing on the original image of the document indicated by the image data obtained by reading by the document reading unit 5 and stored in the image memory 32. At that time, The spline interpolation is performed (S3), and the density in the barcode is smoothed. Further, the reduced image creating unit 101 performs, for example, gamma correction to emphasize the dark part of the interpolated reduced image (S4), thereby making the barcode a simple figure. The reduced image creation unit 101 stores the reduced image data created in this way in the reduced image data storage unit 106 (S5).

  Subsequently, the position detection unit 102 collates the reduced image indicated by the reduced image data stored in the reduced image data storage unit 106 with the prepared pattern (an image showing a simplified bar code figure). By doing so, a barcode is detected from the reduced image (S6).

  When the position detection unit 102 detects a barcode from the reduced image (YES in S7), the position detection unit 102 detects the position of the detected barcode in the reduced image (S8). Subsequently, the inclination detection unit 103 detects the corner point of the barcode detected by the position detection unit 102 (S9), and detects the inclination of the barcode as described above based on the detected corner point (S10). ). Further, the position calculation unit 104 calculates the position of the barcode in the original image of the document based on the position of the barcode in the reduced image detected by the position detection unit 102 (S11). If the position detection unit 102 cannot detect a barcode from the reduced image (NO in S7), the process ends.

  Based on the position calculated by the position calculation unit 104, the analysis unit 105 determines a scanning range on the original image (S12), and image data stored in the image memory 32 is stored in the determined scanning range. A bar code is detected by scanning the original image of the document shown (S13). The analysis unit 105 analyzes the barcode according to a known decoding procedure, and extracts data associated with the barcode (S14). At this time, the analysis unit 105 analyzes the barcode using the direction indicated by the inclination detected in S10 as the scanning direction.

In the first embodiment, the barcode position is detected from the reduced image, and the barcode position in the original image of the document is calculated from the reduced image. Therefore, the barcode position is detected from the document image. The scanning range and the pattern matching range become smaller. In addition, by scanning the calculated position and detecting a barcode with respect to the original image, it is possible to omit processing for a portion that is not useful for the detection. In addition, since the barcode is detected from the reduced image by comparing the reduced image with the prepared pattern (an image showing a simplified barcode), the time required for barcode detection Can be shortened. For this reason, it is possible to increase the speed required to detect the barcode from the original image obtained by reading by the document reading unit 5.

  As a result, according to the first embodiment, the time required for reading the barcode can be saved without requiring special processing for the original such as adjusting the barcode printing position or requiring a special operation from the user. Can be shortened. Further, since the barcode inclination in the reduced image is detected and the barcode is analyzed with the direction indicated by the inclination as the scanning direction, the barcode can be reliably analyzed even if the barcode is inclined. For example, as shown in FIG. 6, even if barcodes B1 to B3 having different inclinations are mixed in the document D1, the barcodes B1 to B3 can be reliably read.

  In the first embodiment, when the simple figure of the barcode is convex (see FIG. 4), the inclination of the long side of the rectangle indicating the barcode area is detected as the inclination of the barcode. As another example of the first embodiment, the inclination detection unit 103 uses the inclination of the long side of a rectangle indicating a character string area (that is, the protrusion formed by the corner points C15 to C18) as the inclination of the barcode. You may make it detect.

  FIG. 7 is a functional block diagram schematically showing the main internal configuration of the image forming apparatus according to the second embodiment of the present invention. Components similar to those of the image forming apparatus 1 according to the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted here. The first embodiment is different from the first embodiment in that the short side detection unit 107 is provided, and the configuration of the position calculation unit 104 and the analysis unit 105 is different.

  The short side detection unit 107 detects the short side of the rectangle formed by the corner points detected by the inclination detection unit 103, and further detects the midpoint of the detected short side.

  For example, as shown in FIG. 8A, the short-side detection unit 107, when the image P4 has four corner points, the rectangular short side indicated by the image P4 (the line segment connecting the corner points C1 and C2). Or a line segment connecting the corner point C3 and the corner point C4), and as shown in FIG. 8B, when the corner point is an image P5 having eight corner points, the corner points C11 to C14 are The middle point M2 of the short side of the rectangle shown (the line segment connecting the corner point C11 and the corner point C12 or the line segment connecting the corner point C13 and the corner point C14) is detected.

  Based on the position detected by the position detector 102 and the midpoint of the short side detected by the short side detector 107, the position calculator 104 calculates the scanning start position for the barcode in the original image of the document.

  Based on the image data stored in the image memory 32, the analysis unit 105 detects the original image indicated by the image data from the scan start position calculated by the position calculation unit 104 by the inclination detection unit 103. The barcode in the original image is detected by scanning in the direction of the tilt. Further, the analysis unit 105 analyzes the detected barcode and extracts (decodes) the meaning of data associated with the barcode by a known analysis method.

  Next, a second embodiment of barcode analysis processing by the image forming apparatus 1 will be described based on the flowchart shown in FIG. This processing operation is performed when reading a document. Description of the same processing as that of the first embodiment described with reference to FIG. 5 is omitted.

  The short side detection unit 107 detects the short side of the rectangle formed by the corner points detected by the inclination detection unit 103, and detects the midpoint of the detected short side (S31). Based on the position detected by the position detection unit 102 and the midpoint of the short side detected by the short side detection unit 107, the position calculation unit 104 calculates the scan start position for the barcode in the original image of the document (S32). ).

  Subsequently, the analysis unit 105 determines the inclination detected by the inclination detection unit 103 from the scanning start position calculated by the position calculation unit 104 with respect to the original image of the document indicated by the image data stored in the image memory 32. A bar code is detected by scanning in the direction (S33). The analysis unit 105 analyzes the barcode according to a predetermined decoding procedure, and extracts data associated with the barcode (S34).

  According to the second embodiment, unlike the first embodiment, since the scanning start position is specified instead of the scanning range, the barcode detection can be started quickly and is necessary for the barcode detection. The time required can be further shortened compared to the first embodiment.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. In the above embodiment, the image reading apparatus according to an embodiment of the present invention has been described using a multifunction peripheral. However, this is only an example, and other electronic devices such as a copy function, a printer function, Other image reading apparatuses having a scanner function and a facsimile function may be used.

  Moreover, in the said embodiment, the structure and process which were shown by the said embodiment using FIG. 1 thru | or FIG. 9 are only one Embodiment of this invention, and are not the meaning which limits this invention to the said structure and process.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 5 Document reading part 10 Control unit 32 Image memory 100 Control part 101 Reduced image creation part 102 Position detection part 103 Inclination detection part 104 Position calculation part 105 Analysis part 106 Reduced image data storage part 107 Short side detection part

Claims (6)

A document reading section for reading a document;
An image data storage unit for storing image data of the document obtained by reading by the document reading unit;
A reduced image creation unit that creates a reduced image of the document from the image data stored in the image data storage unit;
A position detection unit that detects the position of the barcode in the reduced image from the reduced image created by the reduced image creation unit;
An inclination detection unit that detects an inclination of the barcode detected by the position detection unit;
A position calculating unit that calculates the position of the barcode in the original image of the document based on the position detected by the position detecting unit;
By scanning in the direction of the inclination detected by the inclination detecting unit at the position calculated by the position calculating unit in the original image of the document indicated by the image data stored in the image data storage unit, An analysis unit for analyzing the barcode in the original image ,
The tilt detection unit detects a corner point of the image indicating the barcode detected by the position detection unit, and detects a tilt of a long side of a rectangle formed by the detected corner point as the tilt of the barcode. Image reading device. The reduced image creation unit performs an interpolation process on the created reduced image to smooth the density, and performs correction to emphasize the dark part of the reduced image,
The position detection unit detects the position of the barcode in the reduced image by comparing the reduced image with a pattern prepared in advance by performing the interpolation processing on the image indicating the barcode. The image reading apparatus according to claim 1. The image reading apparatus according to claim 2 , wherein the reduced image creating unit performs B-Spline interpolation as the interpolation processing and performs gamma correction as the correction. A short side detection unit for detecting a short side of a rectangle formed by the corner points detected by the inclination detection unit;
The position calculation unit calculates a scanning start position for the barcode in the original image of the document based on the position detected by the position detection unit and the short side detected by the short side detection unit;
In the original image of the original indicated by the image data stored in the image data storage unit, the analysis unit moves in the direction of the inclination detected by the inclination detection unit from the scanning start position calculated by the position calculation unit. The image reading apparatus according to claim 1 , wherein the barcode in the original image is analyzed by scanning. A document reading section for reading a document;
An image data storage unit for storing image data of the document obtained by reading by the document reading unit;
A reduced image creation unit that creates a reduced image of the document from the image data stored in the image data storage unit;
A position detection unit that detects the position of the barcode in the reduced image from the reduced image created by the reduced image creation unit;
An inclination detection unit that detects an inclination of the barcode detected by the position detection unit;
A position calculating unit that calculates the position of the barcode in the original image of the document based on the position detected by the position detecting unit;
By scanning in the direction of the inclination detected by the inclination detecting unit at the position calculated by the position calculating unit in the original image of the document indicated by the image data stored in the image data storage unit, An analysis unit for analyzing the barcode in the original image,
When the inclination detection unit detects a corner point of the image indicating the barcode from the reduced image, and the figure formed by the detected corner point has a convex shape, the long side of the protruding part in the figure images reader you detect inclination as the slope of the bar code. An image reading apparatus according to any one of claims 1 to 5 ,
An image forming apparatus comprising: an image forming unit that forms an image on a recording medium.