JP2009302974A - Image processing method, image processing apparatus, image forming apparatus, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect a copy-protection pattern described in a remarkably unnoticeable state on a copy-protected document. <P>SOLUTION: The image processing apparatus detects the copy-protection pattern of specific color and specific shape included in image data. Therefore, the image processing apparatus includes a first specific color-detecting part 1 for detecting image data of the specific color about the copy-protection pattern of a relatively low concentration from the image data to output its binary data, a second specific color-detecting part 2 for detecting the image data of specific color about the copy-protection pattern of a relatively high concentration from the image data to output its binary data, and a specific shape detecting part 3, a detecting result adding part 4 and a positional relationship calculating part 5 for outputting data about existence or non-existence of the copy-protection pattern by detecting the specific shape of the copy-protection pattern from the binary data supplied from at least one of the first and second specific color detecting parts 1, 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image processing method, an image processing apparatus, an image forming apparatus, a program, and a recording medium for detecting a copy prohibition pattern included in an image of a document that should be prohibited from being copied, such as banknotes, securities, and confidential documents. It is.

  In recent years, color copying apparatuses can reproduce a copied image with high fidelity with respect to an original image as copying performance is improved. Along with this, color copying apparatuses are required to have a high prevention function against the act of copying copy-prohibited originals such as banknotes, securities, and confidential documents, especially the act of copying and forging a large amount.

  In the conventional copy apparatus, copy prevention technology includes image data (read image data) obtained by reading an image of a document to be printed on a recording sheet by an image reading apparatus, and copy prevention objects registered in advance in the copying apparatus. It is known that the image data of a specific image (registered image data) is compared to determine whether to print the read image data. Further, in this technique, when it is determined that printing of the read image data is not performed, a process of simply stopping printing or changing the read image data to image data different from the read image data and performing printing is performed. Is called.

  Patent Document 1 and Patent Document 2 are known as specific conventional techniques of this type. In the technique described in Patent Document 1, a specific pattern made of a barcode formed on the peripheral edge of a document, or a specific pattern made of two diagonal lines that extend from corner to corner of the document and cross each other. When the image of the original is read and the specific pattern is detected by the detection unit, the copying function of the copying machine is stopped by the detection signal from the detection unit.

In the technique described in Patent Document 2, the image processing apparatus includes first and second color extraction blocks, an OR circuit, a storage device, a mark detection unit, a document cutout unit, and a matching unit. In this image processing apparatus, the input image data is individually binarized with black and red by the first and second color extraction blocks, and these two data are combined into one data by an OR circuit. And store it in the storage device. Next, the mark detection unit detects a square mark included in the input image data using the template, the image cutout unit cuts out a mark surrounded by the square mark, and the copy prohibition determination mark (specific mark) of the cut out mark ) Is determined by the matching unit, and the result is output.
JP 54-32322 (published March 9, 1979) JP-A-9-16043 (published January 17, 1997)

  Copy prohibition patterns written on copy prohibition manuscripts such as banknotes, securities and confidential documents that are prohibited from being copied are very inconspicuous in order to prevent tampering. In addition, the paper quality and the copy density of the copy prohibition pattern vary depending on the original. That is, noise is likely to occur in the signal for detecting the copy prohibition pattern due to the difference in paper quality, and it is difficult to detect the copy prohibition pattern with uniform accuracy due to the density of the print density of the copy prohibition pattern. For this reason, a high function is also required in the detection of the copy prohibition pattern.

  In such a situation, the technique described in Patent Document 1 detects a specific pattern clearly described, and therefore cannot accurately detect the above-described copy prohibition pattern.

  Note that the technique described in Patent Document 1 is effective in managing a barcode by printing it on a document when the specific pattern is, for example, a barcode. However, in any of the above specific patterns, the specific patterns are very conspicuous, and it is easily known that they are copy-inhibited patterns. Therefore, the copy-prohibited document can be easily copied by making some alterations to the specific marks so that they are not detected.

  Further, the technique described in Patent Document 2 can detect two color copy prohibition determination marks (specific marks) by having two color filters. In addition, the circuit scale can be reduced by combining two detection signals of two colors by the OR circuit.

  However, although the two color filters can detect specific marks of different colors, as in the technique described in Patent Document 1, since the two color filters cannot cope with noise due to a difference in paper quality and the density of the print density of the specific marks, The copy prohibition pattern cannot be accurately detected.

  Therefore, the present invention accurately detects a copy prohibition pattern written in a very inconspicuous state with respect to a copy prohibition original even if there is a difference in the paper quality of the copy prohibition original or the density of the copy prohibition pattern. An object of the present invention is to provide an image processing apparatus and an image processing method that can be used.

  In order to solve the above-described problems, an image processing apparatus according to the present invention is an image processing apparatus that detects a copy prohibition pattern having a specific color and a specific shape included in image data. A first specific color detecting means for detecting image data of a specific color for the light copy prohibition pattern and outputting the image data as binary data; and the copy prohibition pattern having a relatively high density from the image data At least one of the second specific color detecting means for detecting the image data of the specific color and outputting the image data as binary data, and the first specific color detecting means and the second specific color detecting means A specific shape of the copy prohibition pattern is detected from the binary data input from the image data, and the presence or absence of the copy prohibition pattern in the image data is detected. It is characterized in that an output means for outputting that information.

  Further, the image processing method of the present invention is an image processing method for detecting a copy prohibition pattern having a specific color and a specific shape included in the image data, the copy prohibition pattern having a relatively low density from the image data. A first specific color detection step of detecting image data of a specific color and outputting the image data as binary data; and image data of a specific color for the copy prohibition pattern having a relatively high density from the image data. The second specific color detection step of detecting and outputting the image data as binary data, and the two specific colors obtained from at least one of the first specific color detection step and the second specific color detection step An output process for detecting a specific shape of the copy prohibition pattern from the value data and outputting information on the presence or absence of the copy prohibition pattern in the image data It is characterized in that it comprises and.

  According to the above configuration, the first specific color detection means (first specific color detection step) detects image data of a specific color for the copy prohibition pattern having a relatively low density from the image data, and Output image data as binary data. The second specific color detection means (second specific color detection step) detects image data of a specific color for the copy prohibition pattern having a relatively high density from the image data, and uses the image data as binary data. Output. The output means (output step) detects a specific shape of the copy prohibition pattern from binary data input from at least one of the first specific color detection means and the second specific color detection means, and copies the image data. Information relating to the presence or absence of the prohibited pattern, for example, the similarity of the detected copy prohibited pattern to the actual copy prohibited pattern is output.

  Therefore, whether the image data is a banknote printed with a thin copy prohibition pattern or a banknote printed with a dark copy prohibition pattern, the copy prohibition pattern is reliably detected from the image data. can do. In addition, noise components (components such as lines and patterns entangled with the background or copy prohibition pattern) added to the copy prohibition pattern at a lower density can be appropriately eliminated.

  In the above image processing apparatus, the copy prohibition pattern includes a plurality of marks arranged in a predetermined positional relationship, and the output unit outputs binary data output from the first specific color detection unit. From the first specific shape detection unit for detecting the relative positional relationship of the plurality of marks in the copy prohibition pattern and outputting the detection result as position data, and the binary output from the second specific color detection means A second specific shape detection unit that detects a relative positional relationship of the plurality of marks in the copy prohibition pattern from the data and outputs a detection result as position data; and the first specific shape detection unit and the second specific shape detection unit A detection result addition unit for adding the outputs of the shape detection unit, a relative positional relationship between the plurality of marks indicated by the position data output from the detection result addition unit, and actual copying prohibition Comparing the relative positional relationship of the plurality of marks in turn, may be configured to have a positional relationship calculation unit for outputting the judgment result as to whether or not the copying-inhibited pattern in the image data.

  In the image processing method, the copy prohibition pattern includes a plurality of marks arranged in a predetermined positional relationship, and the output step includes binary data output from the first specific color detection unit. A first specific shape detecting step for detecting a relative positional relationship of the plurality of marks in the copy prohibiting pattern and outputting a detection result as position data; and a binary output from the second specific color detecting means A second specific shape detecting step for detecting a relative positional relationship between the plurality of marks in the copy prohibition pattern from the data, and outputting a detection result as position data; and the first specific shape detecting step and the second specific shape A detection result addition step of adding outputs obtained by the shape detection step, and a relative of the plurality of marks indicated by the position data obtained by the detection result addition step A positional relationship calculating step of comparing the positional relationship with the relative positional relationship of a plurality of marks in the actual copy prohibition pattern and outputting the determination result regarding the presence or absence of the copy prohibition pattern in the image data. Also good.

  According to the above configuration, the copy prohibition pattern includes a plurality of marks arranged in a predetermined positional relationship, and the output means (output process) includes the first specific shape detection unit (first specific shape detection process). , A second specific shape detection unit (second specific shape detection step), a detection result addition unit (detection result addition step), and a positional relationship calculation unit (positional relationship calculation step).

  The first specific shape detection unit (first specific shape detection step) detects and detects the relative positional relationship of a plurality of marks in the copy prohibition pattern from the binary data output from the first specific color detection means. The result is output as position data. The second specific shape detection unit (second specific shape detection step) detects and detects the relative positional relationship of the plurality of marks in the copy prohibition pattern from the binary data output from the second specific color detection means. The result is output as position data. The detection result adding unit (detection result adding step) adds the outputs of the first specific shape detecting unit (first specific shape detecting step) and the second specific shape detecting unit (second specific shape detecting step). . The positional relationship calculation unit (positional relationship calculation step) includes a relative positional relationship between a plurality of marks indicated by position data output from the detection result addition unit (detection result addition step) and a relative relationship between the plurality of marks in the actual copy prohibition pattern And a determination result concerning the presence or absence of a copy prohibition pattern in the image data is output.

  Therefore, as described above, whether the image data is a banknote printed with a thin copy prohibition pattern or a banknote with image data printed darkly, the copy prohibition from the image data is prohibited. The pattern can be detected reliably.

  In addition, the specific shape detection unit (specific shape detection step) with a small memory usage includes a first specific shape detection unit (first specific shape detection step) and a second specific shape detection unit (second specific shape detection step). Process), but the output of both of them is combined into one by the detection result adding unit (detection result adding step), and the processing part after the detection result adding unit (detection result adding step) that uses a large amount of memory is 1 It has a configuration with only one. As a result, the memory capacity required as a whole is small and the circuit scale is also small.

  In the image processing apparatus, when the plurality of marks of the copy prohibition pattern are detected from the binary data in the first specific shape detection unit, and in the second specific shape detection unit, the binary data When the plurality of marks of the copy prohibition pattern are detected, a blur correction unit is provided that sets a region from the detection position of the plurality of marks in the binary data to a predetermined range as a mask region that does not output a detection result. It is good also as composition which has.

  According to the above configuration, the blur correction unit detects the plurality of marks when the first specific shape detection unit or the second specific shape detection unit detects a plurality of marks of the copy prohibition pattern from the binary data. An area from the detection position to a predetermined range is set as a mask area where no detection result is output. Therefore, for example, it is possible to prevent a situation in which a plurality of copy prohibition patterns are detected within a predetermined range due to blurring of an image that occurs in an image reading stage of printing or a scanner. Further, although the specific shape detection unit includes the first and second specific shape detection units, the configuration can be simplified by using one blur correction unit.

  In the image forming apparatus, the first specific color detection unit and the second specific color detection unit may be configured such that red density R is equal to or higher than an R lower limit threshold and equal to or lower than an R upper limit threshold and green density G is equal to or higher than a G lower limit threshold And the G density is equal to or less than the G upper limit threshold, the blue density B is equal to or greater than the B lower limit threshold, and the difference between the green density G and the red density R is equal to or greater than the GR lower limit threshold and equal to or less than the GR upper limit threshold. The difference GB between the green density G and the blue density B is not less than the GB lower threshold and not more than the GB upper threshold, and the difference RB between the red density R and the blue density B is not less than the RB lower threshold. In addition, the image data may be binarized by setting the pixel satisfying all the six conditions that are equal to or less than the RB upper limit threshold value to 1 and setting the other pixels to 0.

  According to the above configuration, the first specific color detection unit and the second specific color detection unit are not only the three primary color signals but also the maximum and minimum values of six signals including their color difference signals. Thus, the image data of a specific color for the copy prohibition pattern can be detected with high accuracy.

  As described above, according to the configuration of the present invention, for example, image data is either a banknote on which a copy prohibition pattern is printed thinly, or image data is a banknote on which a copy prohibition pattern is printed darkly. However, the copy prohibition pattern can be reliably detected from the image data.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to an embodiment of the present invention. This image processing apparatus has a function of determining whether or not a copy prohibition pattern indicating that the image is of a copy prohibition original exists in the input image. The copy prohibition pattern is included in an image of a manuscript to be prohibited from copying, such as banknotes, securities, and confidential documents. For example, a plurality of marks having a specific color and constituting the copy prohibition pattern are specified. Arranged in a positional relationship. Specific examples of such copy prohibition patterns are shown in FIGS. 2 (a) and 2 (b).

  FIG. 2A is an explanatory diagram showing a copy prohibition pattern 71. The copy prohibition pattern 71 shown in FIG. 2A is, for example, yellow and printed lightly. FIG. 2B is an explanatory diagram showing a state where the copy prohibition pattern 71 is entangled with other thin lines and patterns. The copy prohibition pattern 71 shown in FIG. 2B is, for example, a yellow color and printed darkly. As described above, the lines and patterns are entangled in the copy prohibition pattern 71 because of camouflaging that makes the copy prohibition pattern 71 difficult to understand.

  As shown in FIG. 2A, the copy prohibition pattern 71 has a plurality of marks 71a, and these marks 71a are arranged with a predetermined positional relationship. In FIG. 2A, the copy prohibition pattern 71 has five marks 71a arranged in a straight line. The reason why the copy prohibition pattern 71 is printed in pale yellow is that the printed matter in pale yellow is difficult to see with the naked eye. The copy prohibition pattern 71 is an example, and the shape, number, arrangement interval, and arrangement direction of the marks 71a are not limited to those described above.

  The copy prohibition pattern 71 is written on the document as shown in FIG. 3, for example. FIG. 3 is a plan view showing an example of the original 73 to which the copy prohibition pattern 71 is added. As shown in FIG. 3, a copy prohibition pattern 71 is written in, for example, yellow on the upper portion of the original 73 (the left region in FIG. 3).

  As shown in FIG. 1, the image processing apparatus includes a resolution conversion unit 23, a first specific color detection unit (first specific color detection unit) 1, and a second specific color detection unit (second specific color detection unit) 2. , A specific shape detection unit (output unit) 3, a detection result addition unit (output unit) 4, and a positional relationship calculation unit (output unit) 5.

  The resolution conversion unit 23 converts image data input from an image input device such as a scanner or a digital camera into a fixed resolution, and outputs the image data to the first and second specific color detection units 1 and 2. In the example shown in FIG. 1, RGB 8-bit image data is input to the resolution conversion unit 23 from the scanner. Note that the resolution conversion processing by the resolution conversion unit 23 converts image data from, for example, 600 DPI (Dot Per Inch) to 300 DPI in order to reduce the memory capacity.

  The first and second specific color detection units 1 and 2 detect specific color image data from the image data input from the resolution conversion unit 23, binarize the image data, and output the binarized image data to the specific shape detection unit 3. Here, the image data of the specific color is image data of a copy prohibition pattern having a specific color included in the input image data.

  In this case, the first specific color detection unit 1 detects a light color for the specific color, and the second specific color detection unit 2 detects a dark color for the specific color. For this purpose, the first specific color detection unit 1 includes a color difference calculation unit 6, a comparator 7, and a setting register 8. Similarly, the second specific color detection unit 2 includes a color difference calculation unit 9 and a comparator 10. And a setting register 11.

  The specific shape detection unit 3 detects the specific shape indicating the copy prohibition pattern and its position from the binary image data input from the first and second specific color detection units 1 and 2 and detects it as position data for the specific shape. The result is output to the result adding unit 4. The specific shape detection unit 3 includes a first specific shape detection unit 14, a second specific shape detection unit 17, a blur correction unit 18, and a memory 19.

  The first specific shape detection unit 14 corresponds to the first specific color detection unit 1 and includes a shape identification unit 13 and a memory 12. The shape identification unit 13 detects a specific shape and its position from binary image data of a thin specific color. The memory 12 temporarily stores a plurality of lines of image data when the shape identification unit 13 performs the above processing.

  Similarly, the second specific shape detection unit 17 corresponds to the second specific color detection unit 2 and includes a shape identification unit 16 and a memory 15. The shape identification unit 16 detects a specific shape and its position from binary image data of a dark specific color. The memory 15 temporarily stores a plurality of lines of image data when the shape identification unit 16 performs the above processing. A page synchronization signal and a line synchronization signal are input to the first specific shape detection unit 14 and the second specific shape detection unit 17.

  When the first specific shape detection unit 14 or the second specific shape detection unit 17 detects a specific shape (copy prohibited pattern), the blur correction unit 18 is an image of an area within a predetermined range from the position of the specific shape. Data (pixel) is used as a mask area. This prevents a situation in which a plurality of original specific shapes (copy prohibition patterns) are detected within a predetermined range due to, for example, blurring of an image that occurs in an image reading stage of printing or a scanner. The memory 19 temporarily stores a plurality of lines of image data when the blur correction unit 18 performs the above processing.

  The detection result adding unit 4 is composed of, for example, an OR circuit, adds the detection results of the first specific shape detection unit 14 and the second specific shape detection unit 17, that is, performs an OR operation, and outputs the result to the positional relationship calculation unit 5. To do.

  The positional relationship calculation unit 5 includes a memory 20, a vector calculation unit 21, and a similarity calculation unit 22. The vector calculation unit 21 performs vector calculation based on the position data of the specific shape (copy prohibition pattern) input from the detection result addition unit 4, and determines whether or not the position data indicates a copy prohibition pattern. judge. The memory 20 serves as a work area when the vector calculation unit 21 performs the above operation. When the vector calculation unit 21 determines that the position data indicates a copy prohibition pattern, the similarity calculation unit 22 calculates and outputs a similarity to the copy prohibition pattern having the specific shape.

Next, each part of the image processing apparatus will be described in more detail.
FIG. 4 is a block diagram showing a configuration of the resolution conversion unit 23 shown in FIG.

  As shown in FIG. 4, the resolution conversion unit 23 includes a main scan conversion unit 31, a sub scan conversion unit 32, a memory 33, and a setting register 34.

  The main scanning conversion unit 31 converts the resolution in the main scanning direction of the image data into a fixed resolution. For example, image data of 600 DPI RGB each of 8 bits (256 gradations) is converted to 300 DPI by taking an average value of two pixels.

  Similarly, the sub-scanning conversion unit 32 converts the resolution in the sub-scanning direction to a certain resolution for the image data. Similar to the main scanning direction, for example, 600 DPI RGB 8-bit image data is converted to 300 DPI by taking an average value of two pixels. However, in the sub-scanning direction, the image may be scaled by setting the moving speed of the optical system, and the resolution conversion magnification is not constant. Therefore, in the sub-scanning direction, the resolution is scaled according to the magnification set in the setting register 34. The memory 33 temporarily stores data of a plurality of lines in the sub-scanning direction when the sub-scanning conversion unit 32 performs the resolution conversion operation in the sub-scanning direction.

  The first specific color detection unit 1 and the second specific color detection unit 2 have basically the same configuration. Therefore, here, the first specific color detection unit 1 will be described as an example with reference to FIG. FIG. 5 is a block diagram illustrating a configuration of the first specific color detection unit 1.

  The color difference calculation unit 6 of the first specific color detection unit 1 calculates G-R (green and green) from 8-bit image data of R (red), G (green), and B (blue) input from the resolution conversion unit 23. Red color difference), GB (green and blue color difference), and RB (red and blue color difference) are calculated. Since the data (color difference signal) thus obtained may be negative, it becomes 9 bits. Then, the color difference calculation unit 6 outputs six types of data of R, G, B, GR, GB, and RB to the comparator 7.

  The setting register 8 has a maximum density value (upper limit threshold value) and a minimum value for detecting a specific color for each of the six parameters R, G, B, GR, GB, and RB. Set the (lower threshold).

  The comparator 7 compares the six parameters of the image data input from the color difference calculation unit 6 with the maximum value and the minimum value set for each parameter in the setting register 8, and the comparison result is binary data. Output as. That is, 1 is output when all of the 6 parameters are equal to or less than the corresponding maximum value and equal to or greater than the maximum value, and 0 is output otherwise. In this way, by binarizing the output value, the image data of 8 bits for each of RGB becomes 1 bit and the data amount becomes 1/24.

  Here, specific examples of the maximum value and the minimum value set in the setting register 8 will be shown. When 255 is a light color, 0 is a dark color, and the specific color is yellow, in order to detect a specific color, R_min = 160, R_max = 230, G_min = 160, G_max = 215, B_min = 90, B_max = 150, G -R_min = -25, G-R_max = 10, GB-min = 20, GB-max = 105, RB_min = 50, RB_max = 130.

  FIG. 6 shows an example of the maximum value and the minimum value set in the setting register 8 for a plurality of colors. Specifically, the case where the copy prohibition pattern is a light yellow region, a dark yellow region, a red region, a light black region, and a dark black region is shown.

  In the specific shape detection unit 3, the first specific shape detection unit 14 detects a specific shape (copy prohibited pattern) based on the binary data input from the first specific color detection unit 1, and the second specific shape detection unit 17 detects a specific shape (copy prohibited pattern) based on the binary data input from the second specific color detector 2.

  FIG. 7 is an explanatory diagram illustrating an example of a template used by the shape identification units 13 and 16 for template matching. In the specific shape detection operation, the shape identification unit 13 of the first specific shape detection unit 14 and the shape identification unit 16 of the second specific shape detection unit 17 are, for example, 15 (15 pixels in the main scanning direction) as shown in FIG. A template of × 15 (15 lines in the sub-scanning direction) is used.

  FIG. 8 is an explanatory diagram illustrating a specific shape detection operation by template matching of the shape identification units 13 and 16. In the specific shape detection operation, the shape identification units 13 and 16 perform template matching while shifting the template 51 one pixel at a time in the main scanning direction, as shown in FIG. When the processing in the main scanning direction from the left end to the right end is completed, the position of the template 51 is moved down by one line, and template matching is performed in the same manner. An area E in FIG. 8 is an area where a copy prohibition pattern may be detected, and an area F is an area where no copy prohibition pattern is detected.

  In the example of FIG. 8, as data processing for one copy original (300 DPI: H4000 pixels × V9450 pixels), scanning is performed (4000-15) times with a window of 15 pixels in the main scanning direction, and sub-scanning is performed. In the direction, (9450-15) scans are performed in a window of 15 pixels × 15 lines.

  Next, template matching for detecting a specific shape (copy prohibited pattern) by the shape identifying units 13 and 16 will be described in more detail.

  FIGS. 9A to 9E show a plurality of processes set for detecting a copy prohibition pattern in a template 51 of 15 (15 pixels in the main scanning direction) × 15 (15 lines in the sub scanning direction). It is explanatory drawing which shows an area | region. That is, the template 51 includes a peripheral white determination area 51a shown in FIG. 9A, a peripheral count area 51b shown in FIG. 9B, a first central count area 51c shown in FIG. It has the 2nd center part count area | region 51d shown in (d), and the 3rd center part count area | region 51e shown in FIG.9 (e). In the template identification for detecting the copy prohibition pattern, the shape identification units 13 and 16 have the number of 1 of binary data, that is, the number of pixels of a specific color (the number of black pixels in the binary data) in each of these areas. Is counted and compared with a set value to determine whether or not a specific shape (copy prohibited pattern) is included.

  FIG. 10A is an explanatory diagram showing a peripheral white determination region 51a of the template 51, and FIG. 10B is a peripheral white using the peripheral white determination region 51a in the shape identification units 13 and 16. It is explanatory drawing which shows the specific structure for determination operation | movement. As shown in FIG. 10B, the shape identifying units 13 and 16 include a NOR circuit 52 for the peripheral white determination operation. In this peripheral white determination operation, the condition of having a specific shape (copy prohibition pattern) is satisfied when the number of pixels of a specific color (the number of black pixels in binary data) is, for example, 0 in the peripheral white determination region 51a.

  FIG. 11A is an explanatory diagram showing a peripheral count area 51b of the template 51, and FIG. 11B shows a peripheral count operation using the peripheral count area 51b in the shape identification sections 13 and 16. It is explanatory drawing which shows the specific structure for this. As shown in FIG. 11B, the shape identifying units 13 and 16 include a counter 53 and a comparator 54 for the peripheral portion counting operation. In this peripheral portion counting operation, when the number of pixels of a specific color (the number of black pixels in binary data) A counted by the counter 53 in the peripheral portion count area 51b is, for example, a register set value B or less, a specific shape (copy prohibited) The pattern) is met.

  12A is an explanatory diagram showing the first center count area 51c of the template 51, and FIG. 12B shows the first center count area 51c in the shape discriminating sections 13 and 16 used. It is explanatory drawing which shows the specific structure for 1 center part count operation | movement. As shown in FIG. 12B, the shape identifying units 13 and 16 include a counter 55 and a comparator 56 for the first central portion counting operation. In this first center counting operation, when the number of pixels of a specific color (the number of black pixels in binary data) A counted by the counter 55 in the first center count area 51c is, for example, a register setting value B or less, the specific shape Satisfies the condition of (copy prohibited pattern).

  FIG. 13A is an explanatory view showing the second center count area 51d of the template 51, and FIG. 13B shows the second center count area 51d in the shape identification sections 13 and 16. It is explanatory drawing which shows the specific structure for 2 center part count operation | movement. As shown in FIG. 13B, the shape identifying units 13 and 16 include a counter 57 and a comparator 58 for the second central portion counting operation. In this second center count operation, the number of pixels of a specific color (the number of black pixels in binary data) A counted by the counter 57 in the second center count area 51d is, for example, not more than the register set value B and the register set value C. In the above case, the condition of having a specific shape (copy prohibited pattern) is satisfied.

  FIG. 14A is an explanatory diagram showing the third central part count area 51e of the template 51, and FIG. 14B shows the third central part count area 51e in the shape discriminating units 13 and 16 using the third central part count area 51e. It is explanatory drawing which shows the specific structure for 3 center part count operation | movement. As shown in FIG. 14B, the shape identifying units 13 and 16 include a counter 59 and a comparator 60 for the third central portion counting operation. In the third center counting operation, the specific shape is obtained when the number of pixels of a specific color (the number of black pixels in binary data) A counted by the counter 59 in the third center count area 51e is equal to or greater than the register set value B, for example. Satisfies the condition of (copy prohibited pattern).

  In the shape identification units 13 and 16, there is a specific shape (copy prohibition pattern) in all the operations of the peripheral white determination, the peripheral count, the first center count, the second center count, and the third center count. When the above condition is satisfied, it is determined that there is a specific shape (copy prohibited pattern) in the image data.

  When the template matching is established, that is, when it is determined that there is a specific shape (copy prohibited pattern) in the image data, the specific shape detection unit 3 sets the coordinate of the upper left pixel position of the template 51 to 1 at that time. Is output to the detection result adding unit 4. This data is further output from the detection result adder 4 to the positional relationship calculator 5.

  FIG. 15 is an explanatory diagram of the operation of the blur correction unit 18. When the specific shape (copy prohibited pattern) is detected by the first specific shape detection unit 14 or the second specific shape detection unit 17, the blur correction unit 18 describes the position of the copy prohibition pattern as a template matching point. Then, from this template matching point, for example, the back 14 pixels and the back 14 lines in the sub-scanning direction are set as a mask area. Thereby, even if a specific shape (copy prohibited pattern) is detected in the mask area from the first specific shape detection unit 14 or the second specific shape detection unit 17, the specific shape (copying) is detected with respect to the detection result adding unit 4. Detection result (position data) with prohibition pattern) is not output. As a result, it is possible to prevent a situation where one copy prohibition pattern is originally detected as a plurality of copy prohibition patterns within a predetermined area.

  FIG. 16 is an explanatory diagram of the template 72 used by the positional relationship calculation unit 5. In the present embodiment, as shown in FIG. 2A, the copy prohibition pattern 71 has marks 71a arranged in a straight line. Therefore, the positional relationship calculation unit 5 uses a template 72 of 101 (number of pixels in the main scanning direction) × 101 (number of pixels in the sub scanning direction) as shown in FIG. In this template 72, the positions of the five marks 71a of the copy prohibition pattern 71 are P0, P1, P2, P3, and P4, and the position 4 passes through the positions P0, P1, P3, and P4. It has a ring pattern.

  The vector calculation unit 21 of the positional relationship calculation unit 5 uses the template 72, and the position data input from the detection result addition unit 4 is centered on one mark 71a and the other four marks 71a are 4 in number. It is determined whether or not the condition located on each ring is met. Next, when the position data meets the above condition, a vector operation is performed on the position data, and the mark indicated by the position data (corresponding to the mark 71a) conforms to the condition in which the mark is linearly arranged. Judge whether to do. If this condition is met, the similarity calculation unit 22 calculates the similarity of the specific shape indicated by the position data with respect to the copy prohibition pattern 71, and the calculation result is shown in the mechanical control unit (shown in FIG. 17). Output to the print control unit 84).

  This mechanical control unit controls a printing operation (copying operation) in an image forming apparatus such as a copying machine provided with the image processing apparatus of the present embodiment. Depending on the degree, processing such as stopping the copying operation of the image forming apparatus, displaying a warning on the operation panel, and erasing the target image data stored in the image memory is performed.

  In the above configuration, in the image processing apparatus according to the present embodiment, when image data read from the document 73 including the copy prohibition pattern 71 is input, the image data is processed by the resolution conversion unit 23, and the data amount Decrease.

  Next, the image data processed by the resolution conversion unit 23 is input to the first specific color detection unit 1 and the second specific color detection unit 2, and the first specific color detection unit 1 or the second specific color detection unit. 2, image data of a specific color corresponding to the copy prohibition pattern 71 is output as binary data.

  In this case, when the copy prohibition pattern 71 is printed thinly on the original 73, the copy prohibition pattern 71 is detected by the first specific color detection unit 1, and the binary data is detected by the first specific color detection unit 1. Is output from. On the other hand, when the copy prohibition pattern 71 is printed dark on the document 73, the copy prohibition pattern 71 is detected by the second specific color detection unit 2, and the binary data is received from the second specific color detection unit 2. Is output.

  That is, the light copy prohibition pattern 71 is detected by the first specific color detection unit 1 because the density is within the range of the minimum value and the maximum value of the setting register 8 in the first specific color detection unit 1. . The dark copy prohibition pattern 71 is detected by the second specific color detection unit 2 because the density is in the range between the minimum value and the maximum value of the setting register 8 in the second specific color detection unit 2. . In this case, thin lines, patterns, or noise components entangled in the copy inhibition pattern 71 for camouflaging are eliminated.

  The binary data output from the first specific color detection unit 1 is input to the first specific shape detection unit 14 of the specific shape detection unit 3, and the binary data output from the second specific color detection unit 2 is specified. It is input to the second specific shape detection unit 17 of the shape detection unit 3. When the first specific shape detection unit 14 and the second specific shape detection unit 17 detect a specific shape (copy prohibited pattern) from the binary data by template matching, the position data of the specific shape is output to the detection result addition unit 4. To do. This position data includes the relative positional relationship of the marks 71a constituting the copy prohibition pattern 71.

  In the detection result addition unit 4, the position data output from the first specific shape detection unit 14 and the second specific shape detection unit 17 are added to form one data and output to the positional relationship calculation unit 5. Therefore, the position data output from the detection result adding unit 4 includes the position data of the copy prohibition pattern 71 detected by the first specific shape detection unit 14 or the second specific shape detection unit 17.

  In the positional relationship calculation unit 5, when the vector calculation unit 21 determines that the relative positional relationship between the marks indicated by the position data input from the detection result addition unit 4 is that of the copy prohibition pattern 71, the similarity calculation unit 22. However, based on the determination result of the vector calculation unit 21, for example, the similarity to the copy prohibition pattern 71 having a specific shape indicated by the position data is calculated.

  As described above, in the image processing apparatus according to the present embodiment, the first specific color detection unit 1 that detects a light color copy prohibition pattern and the second specific color detection unit 2 that detects a dark color copy prohibition pattern 71; Therefore, the copy prohibition pattern 71 can be reliably detected regardless of whether the copy prohibition pattern 71 is printed lightly or darkly on a banknote, for example. Further, it is possible to appropriately eliminate noise components added to the copy prohibition pattern 71 at a lower density.

  The specific shape detection unit 3 includes the first specific shape detection unit 14 and the second specific shape detection unit 17, but includes only one blur correction unit 18, and the first specific shape detection unit 14 and Since the output of the second specific shape detection unit 17 is added by the detection result addition unit 4 to form one data, the configuration is simplified.

  Further, two specific shape detection units, ie, a first specific shape detection unit 14 and a second specific shape detection unit 17, have a small memory usage (for 14 lines in the present embodiment), and a large amount of memory is used. (101 lines in the present embodiment) Since only one positional relationship calculation unit 5 is provided, the required memory capacity is reduced as a whole.

  FIG. 17 is a block diagram showing a configuration of an image forming apparatus 80 such as a copying machine provided with the image processing apparatus 81 of the present embodiment. The image forming apparatus 80 includes a color scanner 82, an image processing apparatus 81, an operation unit 83, a print control unit 84, an image processing unit 85, and a printing unit 86.

  The image processing unit 85 inputs image data (RGB data) of a document read by the color scanner 82 via the image processing device 81 and processes it into image data for printing. The printing unit 86 has a function as a printer, and prints the image data output from the image processing unit 85 on a sheet.

  As described above, the image processing apparatus 81 determines the presence / absence of the specific shape (copying prohibition pattern 71) in the image data. The similarity with respect to the registered copy prohibition pattern 71 for the specific shape included in the resulting image is output to the print control unit 84.

  The print control unit 84 controls the operations of the image processing unit 85 and the printing unit 86, determines whether or not image data can be printed based on the similarity input from the image processing device 81, and the image processing unit 85. The image data processing operation in the printing unit 86 is controlled. For example, when the similarity is greater than or equal to a predetermined value, the processing of the image data by the image processing unit 85 and the printing of the image data by the printing unit 86 are prohibited. Further, the print control unit 84 deletes all the data related to the image data stored in the HDD (hard disk drive) 87 and the memory 88 of the image processing unit 85.

  FIG. 18 is a flowchart showing the operation of the image forming apparatus 80 shown in FIG. As shown in FIG. 18, in the image forming apparatus 80, various modes are set by a user operation on the operation unit 83 (S1). In this mode setting, the image forming apparatus 80 is set to a monochrome mode, a full color mode, or an automatic mode. The automatic mode automatically determines whether the document read by the color scanner 82 is a monochrome document or a full-color document, and performs the operation in the monochrome mode or the full-color mode according to the determination result. is there.

  Next, when the start key of the operation unit 83 is turned on (S2), the color scanner 82 starts scanning the original image (S3).

  Next, it is determined whether the mode setting in S1 is monochrome mode, full color mode or automatic mode (S4). If the mode setting is automatic mode or full color mode, the copy inhibition pattern detection function of the image processing apparatus 81 is enabled. (S5). On the other hand, in the monochrome mode, the copy prohibition pattern detection function of the image processing apparatus 81 is disabled (S8), and the process proceeds to S9.

  In S5, the image processing apparatus 81 detects the specific shape (copy prohibition pattern), and the image processing apparatus 81 sends a print control unit 84 of the image forming apparatus 80 to the copy prohibition pattern of the specific shape in the processing target image. Similarity is output.

  The print controller 84 determines whether or not the similarity is greater than or equal to a threshold value (S6). If the similarity is greater than or equal to the threshold value, a copy prohibition pattern detection command is issued and the scanning operation in the color scanner 82 is stopped. (S7).

  Next, the image processing unit 85 determines whether or not a copy prohibition pattern detection command is received from the print control unit 84 (S9). When the image processing unit 85 receives the copy prohibition pattern detection command, the processing for the processing target image data is interrupted, and the processing target image data stored in the HDD 87 and the memory 88 is deleted (S10).

  On the other hand, if the image processing unit 85 does not receive the copy prohibition pattern detection command from the print control unit 84 in S9, the image processing unit 85 stores the image data input from the color scanner 82 via the image processing device 81 in the HDD 87 and also stores it. The read image data is read (S11).

  Next, it is determined whether the document (image data to be processed) is color or monochrome (S12). If it is color, color image processing for printing is performed (S13). If it is monochrome, printing is performed. Monochrome image processing is performed (S14). Thereafter, the image data processed by the image processing unit 85 is sent to the printing unit 86 and printed as a visible image on the paper.

  FIG. 19 is a schematic diagram illustrating a configuration of an image forming system 90 including the image forming apparatus 80. As shown in FIG. 19, an image forming system 90 includes an image forming apparatus 80, a digital camera 92, a notebook personal computer (hereinafter referred to as a notebook PC) 93, and a personal computer (hereinafter referred to as a PC) 94. Connected through.

  The image forming apparatus 80 includes processing objects such as an image read by the color scanner 82, an image taken by the digital camera 92, and an image taken into the notebook PC 93 or PC 94 via a computer network such as the Internet. Images are input via the network 91 and printed as appropriate upon request. In this case, the image forming apparatus 80 determines whether or not there is a copy prohibition pattern in the processing target image by using a copy prohibition pattern detection function (an image pattern presence / absence determination function similar to the copy prohibition pattern) of the image processing apparatus 81. For a processing target image determined to have a prohibited pattern, printing is prohibited and the image data is deleted. This prevents counterfeiting banknotes and securities and copying confidential documents.

  Finally, each block of the image processing apparatus 81, particularly the first specific color detection unit 1, the second specific color detection unit 2, the specific shape detection unit 3, the detection result addition unit 4, and the positional relationship calculation unit 5, Or may be realized by software using a CPU as follows.

  That is, the image processing apparatus 81 includes a CPU (central processing unit) that executes instructions of a control program that implements each function, a ROM (read only memory) that stores the program, and a RAM (random access memory) that expands the program. And a storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is to provide a recording medium on which a program code (execution format program, intermediate code program, source program) of a control program of the image processing apparatus 81, which is software that realizes the functions described above, is recorded in a computer-readable manner. This can also be achieved by supplying the image processing apparatus 81 and reading and executing the program code recorded on the recording medium by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  Further, the image processing apparatus 81 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

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

It is a block diagram which shows the structure of the image processing apparatus of embodiment of this invention. 2A is an explanatory diagram showing a copy prohibition pattern that is thinly written on the original shown in FIG. 3, and FIG. 2B is another thin line on the copy prohibition pattern that is darkly shown on the original shown in FIG. It is explanatory drawing which shows the state in which the pattern is entangled. FIG. 6 is a plan view illustrating an example of a document to which a copy prohibition pattern is added. It is a block diagram which shows the structure of the resolution conversion part shown in FIG. It is a block diagram which shows the structure of the 1st specific color detection part shown in FIG. It is explanatory drawing which shows the example of the maximum value and minimum value which are set to the setting register | resistor shown in FIG. 5 about several colors. It is explanatory drawing which shows an example of the template which the shape identification part shown in FIG. 1 uses for template matching. It is explanatory drawing which shows the specific shape detection operation by the template matching of the shape identification part shown in FIG. FIG. 9A is an explanatory diagram showing the peripheral white determination region of the template shown in FIG. 7, FIG. 9B is an explanatory diagram showing the peripheral count region of the template, and FIG. FIG. 9D is an explanatory diagram showing the second center count area of the template, and FIG. 9E is a third center count of the template. It is explanatory drawing which shows an area | region. FIG. 10A is an explanatory diagram showing the peripheral white determination region of the template shown in FIG. 7, and FIG. 10B is a periphery using the peripheral white determination region in the shape identification unit shown in FIG. It is explanatory drawing which shows the specific structure for part white determination operation | movement. 11A is an explanatory view showing the peripheral count area of the template shown in FIG. 7, and FIG. 11B is a peripheral count using the peripheral count area in the shape identification section shown in FIG. It is explanatory drawing which shows the specific structure for an operation | movement. 12A is an explanatory view showing the first central part count area of the template shown in FIG. 7, and FIG. 12B uses the first central part count area in the shape identification part shown in FIG. It is explanatory drawing which shows the specific structure for the 1st center part count operation | movement which performed. 13A is an explanatory diagram showing the second center part count area of the template shown in FIG. 7, and FIG. 13B uses the second center part count area in the shape identification part shown in FIG. It is explanatory drawing which shows the specific structure for the 2nd center part count operation | movement which performed. FIG. 14A is an explanatory diagram showing the third center count area of the template shown in FIG. 7, and FIG. 14B uses the third center count area in the shape identification section shown in FIG. It is explanatory drawing which shows the specific structure for 3rd center part count operation | movement which performed. It is explanatory drawing of the operation | movement which the blur correction | amendment part shown in FIG. 1 performs. It is explanatory drawing of the template which the positional relationship calculation part shown in FIG. 1 uses. 1 is a block diagram illustrating a configuration of an image forming apparatus such as a copying machine including an image processing apparatus according to an embodiment of the present invention. 18 is a flowchart illustrating an operation of the image forming apparatus illustrated in FIG. It is a schematic diagram which shows the structure of the image forming system provided with the image forming apparatus shown in FIG.

Explanation of symbols

1 1st specific color detection part (1st specific color detection means)
2 Second specific color detection unit (second specific color detection means)
3 Specific shape detector (output means)
4 Detection result adder (output means)
5 Positional relationship calculation unit (output means)
6 color difference calculation unit 7 comparator 8 setting register 9 color difference calculation unit 10 comparator 11 setting register 13 shape identification unit 14 first specific shape detection unit 16 shape identification unit 17 second specific shape detection unit 18 blur correction unit 21 vector Calculation unit 22 Similarity calculation unit 23 Resolution conversion unit 31 Main scan conversion unit 32 Sub scan conversion unit 34 Setting register 51 Template 51a Peripheral white determination region 51b Peripheral count region 51c First central portion count region 51d Second central portion count Area 51e Third center count area 71 Copy prohibition pattern
71a to 71d Mark 72 Template 73 Document 80 Image forming apparatus 81 Image processing apparatus 82 Color scanner 84 Print control section 85 Image processing section 86 Printing section

Claims (9)

In an image processing apparatus for detecting a copy prohibition pattern having a specific color and a specific shape included in image data,
First specific color detection means for detecting image data of a specific color for the copy prohibition pattern having a relatively low density from the image data, and outputting the image data as binary data;
Second specific color detection means for detecting image data of a specific color for the copy prohibition pattern having a relatively high density from the image data, and outputting the image data as binary data;
The copy prohibition pattern in the image data is detected by detecting a specific shape of the copy prohibition pattern from the binary data input from at least one of the first specific color detection unit and the second specific color detection unit. An image processing apparatus comprising: output means for outputting information on the presence or absence of the image. The copy prohibition pattern includes a plurality of marks arranged in a predetermined positional relationship,
The output means includes
A first specific shape detection unit that detects a relative positional relationship between the plurality of marks in the copy prohibition pattern from binary data output from the first specific color detection unit, and outputs a detection result as position data; ,
A second specific shape detection unit for detecting a relative positional relationship between the plurality of marks in the copy prohibition pattern from binary data output from the second specific color detection unit and outputting a detection result as position data; ,
A detection result addition unit for adding outputs of the first specific shape detection unit and the second specific shape detection unit;
The copy prohibition pattern in the image data is compared by comparing the relative positional relationship of the plurality of marks indicated by the position data output from the detection result adding unit with the relative positional relationship of the plurality of marks in the actual copy prohibition pattern. The image processing apparatus according to claim 1, further comprising: a positional relationship calculation unit that outputs the determination result regarding the presence or absence of the image.   When the plurality of marks of the copy prohibition pattern are detected from the binary data in the first specific shape detection unit, and when the mark of the copy prohibition pattern is detected from the binary data in the second specific shape detection unit When a plurality of marks are detected, a blur correction unit is provided that sets a region from the detection position of the plurality of marks in the binary data to a predetermined range as a mask region that does not output a detection result. The image processing apparatus according to claim 2.   The first specific color detection unit and the second specific color detection unit are configured such that red density R is greater than or equal to R lower limit threshold and less than or equal to R upper limit threshold, green density G is greater than or equal to G lower limit threshold and less than or equal to G upper limit threshold, blue Density B is greater than or equal to the B lower limit threshold and less than or equal to the B upper limit threshold, and the difference GR between the green density G and the red density R is greater than or equal to the GR lower limit threshold and less than or equal to the GR upper limit threshold. The difference G−B of the density B is not less than the GB lower limit threshold and not more than the GB upper limit threshold, and the difference RB between the red density R and the blue density B is not less than the RB lower limit threshold and not more than the RB upper limit threshold. 4. The image processing according to claim 1, wherein the image data is binarized by setting a pixel satisfying all six conditions of 1 to 1 and setting other pixels to 0. 5. apparatus.   An image forming apparatus comprising: the image processing apparatus according to claim 1; and a printing unit that performs printing based on image data. In an image processing method for detecting a copy prohibition pattern having a specific color and a specific shape included in image data,
A first specific color detection step of detecting image data of a specific color for the copy prohibition pattern having a relatively low density from the image data, and outputting the image data as binary data;
A second specific color detecting step of detecting image data of a specific color for the copy prohibition pattern having a relatively high density from the image data, and outputting the image data as binary data;
From the binary data obtained from at least one of the first specific color detection step and the second specific color detection step, a specific shape of the copy prohibition pattern is detected, and the copy in the image data is performed. An image processing method comprising: an output step of outputting information on the presence or absence of a prohibited pattern. The copy prohibition pattern includes a plurality of marks arranged in a predetermined positional relationship,
The output step includes
A first specific shape detection step of detecting a relative positional relationship of the plurality of marks in the copy prohibition pattern from binary data output from the first specific color detection means, and outputting a detection result as position data; ,
A second specific shape detecting step of detecting a relative positional relationship between the plurality of marks in the copy prohibition pattern from binary data output from the second specific color detecting means and outputting a detection result as position data; ,
A detection result addition step of adding outputs obtained by the first specific shape detection step and the second specific shape detection step;
The copy prohibition pattern in the image data is compared by comparing the relative positional relationship of the plurality of marks indicated by the position data obtained by the detection result adding step with the relative positional relationship of the plurality of marks in the actual copy prohibition pattern. The image processing method according to claim 6, further comprising a positional relationship calculation step of outputting the determination result relating to the presence or absence of the image.   The program for functioning a computer as said each means of the image processing apparatus of any one of Claim 1 to 4.   A computer-readable recording medium on which the program according to claim 8 is recorded.

Images