KR20010006644A - Image processing device, pattern detecting method, image processing control method and the storage medium - Google Patents

Abstract

PURPOSE: A pattern detecting method is provided to prohibit an unauthorized copying in a copying machine, etc., without impairing the readability of an original document also while preventing document contents from being easily separated from a pattern by printing a special pattern on the rear face of the original by a method capable of printing the original document by normal monochrome printer or color printer. CONSTITUTION: A specific pattern detecting part(102) detects a specific pattern candidate printed on the rear face of a document from an acquired image and decides whether the document is one on which the specific pattern was printed on the rear face of the document by checking arrangement relation about the pattern candidate, and an image outputting part(103) inhibits operations such as copying, when the specific pattern is printed.

Description

Image processing apparatus, pattern detection method, image processing control method and recording medium {IMAGE PROCESSING DEVICE, PATTERN DETECTING METHOD, IMAGE PROCESSING CONTROL METHOD AND THE STORAGE MEDIUM}

The present invention relates to a pattern detection method for detecting a specific pattern to prevent illegal copying of a confidential document, an image processing control method for controlling an image processing function in accordance with a specific pattern detection, and a recording medium on which an image processing control program is recorded.

Conventionally, as a method of preventing illegal copying, for example, using a special paper which cannot be copied illegally with metallic luster (see Japanese Patent Application Laid-open No. Hei 6-155975), and attaching a seal to prevent printed copying on the printed matter. (See Japanese Patent Application Laid-Open No. Hei 6-259013), or printing characters / background in two colors, each of which has almost the same reproduction density when making black and white copies (see Japanese Patent Application Laid-open No. Hei 7-89215). Printing methods, such as a latent image appearing after copying (refer to Utility Model Publication No. Hei 6-68051), are proposed.

However, when creating a confidential document in an office or the like, a black and white printer is often used, and it is difficult to use a special paper or a special printing method both functionally and costly. In addition, since confidential contents are important, confidential documents are copied in a readable state, except where the seal is attached, even if the seal is attached to a part so that it is not reproduced clearly. .

There is also an apparatus for controlling an image processing process (copy) by identifying a target surface pattern (Japanese Patent Laid-Open No. 60-229572). However, this device is effective when the entire surface pattern is specified, but in general confidential documents, the pattern of the entire surface of the document cannot be specified in advance, and a specific pattern is printed on a blank or the like so as not to impair the readability of the document. Even in this case, it is easy to conceal the part at the time of image reading, and thus, unauthorized copying cannot be prevented.

The present invention prints a special pattern on the back side of a document in a manner that can be printed with a conventional black-and-white printer or a color printer, without damaging the readability of the original document and preventing easy separation of the document content and the pattern. An object of the present invention is to provide a pattern detection method, an image processing control method, and a recording medium capable of prohibiting illegal copying.

1 is a view showing the configuration of an embodiment of the present invention.

2 is a process flow diagram of an embodiment of the present invention.

3 shows an example of a specific pattern.

4 is a diagram showing a developing state of an acquired image;

5 is a diagram illustrating a developing state of an acquired image in the case where a character and a specific pattern overlap.

6 shows a first example of a pattern arrangement;

7 shows an example of pattern candidate detection results.

8 is a diagram illustrating relative position detection of pattern candidates.

9 shows a second example of a pattern arrangement;

10 is a view showing an embodiment using a printing press.

Fig. 11 shows another embodiment used for a printing press.

12 is a view showing still another embodiment of a printing press.

Fig. 13 is a diagram showing an example in which image processing control by specific pattern detection is configured by a program.

Explanation of symbols on the main parts of the drawings

101: image input unit

102: specific pattern detection unit

103: image output unit

104: data storage unit

105: control unit

106: data communication path

107: external notification unit

In order to achieve the above object, the invention described in claim 1 is characterized by detecting a specific pattern printed on the back side of the scanning surface by extracting pixels having a density level within a predetermined range from an image obtained by scanning a document.

The invention described in claim 2 is characterized by detecting a specific pattern printed on the back side of the scanning surface by detecting a change in density from an image obtained by scanning a document.

The invention described in claim 3 is characterized by detecting a specific pattern printed on the back side of the scanning surface by extracting a color pixel of a predetermined range from an image obtained by scanning a document.

The invention as set forth in claim 4 is a method for detecting a specific pattern printed in a lattice shape at a predetermined interval on the back surface of the scanning surface from an image obtained by scanning a document, wherein the predetermined interval is centered around the detected one pattern candidate. It is examined whether or not another pattern candidate exists on the circumference of the radius, and if present, the specific pattern is detected by accumulating the scores for all the pattern candidates detected by giving a score.

According to the fifth aspect of the present invention, when a plurality of different pattern candidates are detected on the circumference of the radius, a high score is given when an angle formed between the candidates with respect to the circle center is a specific angle or a predetermined angle.

The invention described in claim 6 is characterized by giving a high score when another candidate exists at a distance of a constant magnification or an integer multiple of the radius on a line connecting the candidate on the detected circumference with the circle center point.

The invention described in claim 7 is characterized by detecting a specific pattern printed on at least one side by scanning both sides of the document.

The invention as set forth in claim 8 is a method for controlling an image processing operation of a document by reading a document, the method comprising the feature pattern printed on the back side of the document according to claim 1, 2 or 3. Is detected, the image processing operation of the document is controlled.

The invention described in claim 9 is an image processing control method for reading a document and controlling an image processing operation of the document, wherein the plurality of specific pattern arrangement relations and color arrangement relations printed on the back side of the document are set forth in claims 4 and 5. Or when detecting by the method described in claim 6, controlling the image processing operation of the document.

The invention as set forth in claim 10 is an image processing apparatus having an image input unit and a control unit, further comprising a specific pattern detection unit for detecting a specific pattern printed on the back side of the scanning surface from an image obtained by scanning a document with the image input unit. It is characterized by.

The invention as set forth in claim 11, wherein the specific pattern detection unit includes a pixel extraction unit and is printed on the back side of the scanning surface by extracting pixels having a density level within a predetermined range from an image obtained by scanning a document with the image input unit. Detecting a specific pattern.

The invention as set forth in claim 12, wherein the specific pattern detection unit includes a pixel extraction unit and detects a specific pattern printed on the back surface of the scanning surface by detecting a change in density from an image obtained by scanning a document with the image input unit. Characterized in that.

The invention as set forth in claim 13, wherein the specific pattern detection unit includes a pixel extraction unit, and the specific pattern printed unit is printed on the back side of the scanning surface by extracting a predetermined range of color pixels from an image obtained by scanning a document with the image input unit. It is characterized by detecting a pattern.

15. The invention set forth in claim 14, wherein the specific pattern detection unit includes a specific pattern determination unit, and the specific pattern is printed in a lattice form at predetermined intervals on the back surface of the scanning surface from an image obtained by scanning a document with the image input unit. To detect whether or not another pattern candidate exists on the circumference having the detected one pattern candidate as the radius and the predetermined interval as a radius, and if there is, scoring for all the pattern candidates detected. It is characterized by detecting a specific pattern based on the accumulated value.

The invention as set forth in claim 15, wherein the specific pattern determination unit is configured to detect a plurality of different pattern candidates on the circumference of the radius, and, when the angles formed between the candidates with respect to the circle center are a specific angle or a predetermined angle. An image processing apparatus characterized by giving a high score.

16. The invention set forth in claim 16, wherein the specific pattern determination unit scores higher when another candidate is present at a constant magnification or an integer multiple of the radius on a line connecting the candidate on the detected circumference with the circle center point. It is characterized by giving.

17. The invention described in claim 17 is characterized in that the image input unit detects a specific pattern printed on at least one surface by scanning both sides of the document.

The invention as set forth in claim 18 further comprises an image output section and controls image output based on a detection result of the specific pattern detection section.

19. The invention described in claim 19 is characterized in that, when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the image output unit to prohibit image output.

The invention according to claim 20 is characterized in that the control unit controls the image output unit to output an image when the specific pattern detection unit determines that the specific pattern is printed on the document.

The invention set forth in claim 21 is characterized in that the image processing apparatus is a copying machine.

The invention as set forth in claim 22, further comprising an external communication unit, and determining whether or not to transmit image data to the external communication unit based on a detection result of the specific pattern detection unit. It is done.

The invention as set forth in claim 23 is characterized in that, when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the external notification unit to transmit image data to the outside.

The invention as set forth in claim 24 is characterized in that, when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the external notification unit to prevent image data from being transmitted to the outside.

25. The invention as set forth in claim 25 is characterized in that the image processing apparatus is a scanner.

The invention according to claim 26 is characterized in that the image processing apparatus is a facsimile.

The invention as set forth in claim 27 is characterized in that, when the specific pattern detection unit determines that the specific pattern is printed on the document, the communication unit notifies the information to the outside.

The invention as set forth in claim 28 has a computer readable recording program for realizing a function of detecting a specific pattern printed on the back side of a document and a function of prohibiting or permitting image output of the document in accordance with the detection of the specific pattern. It is characterized in that it is a possible recording medium.

Example

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

1 shows an embodiment configuration of the present invention. In the drawing, reference numeral 101 denotes an image input unit such as a scanning unit, 102 denotes a specific pattern detection unit which is one of the characteristics of the present invention, 103 an image output unit which draws and prints an image obtained by scanning, and 104 an image data obtained by scanning and during each processing. A data storage unit for storing respective data and the like, 105 is an overall processing control unit, 106 is a data communication path, and 107 is an external notification means for communicating with an external device or the like via a network or the like.

2 is a process flowchart of the present invention. Hereinafter, an embodiment will be described with reference to FIG. 2. First, the image input unit 101 optically scans a document to acquire an image (step 201). The image signal is black and white multivalue or RGB full color. Next, the specific pattern detection unit 102 detects a candidate of the specific pattern from the acquired image (step 202).

In the first embodiment, a specific pattern is printed in black on the back side of the document (paper) to be scanned. 3 shows an example of a specific pattern. Among the image signals obtained by scanning the surface of the document on which the specific pattern is printed on the back side of the document, the specific pattern on the back side appears as a signal of medium density.

For example, when the acquired image signal is a black and white multivalue of 0 (white) to 255 (black), it becomes an intermediate density signal of level 50 (FIG. 4). 4 shows a state where the concentration is shallow. This level value depends on the paper quality or the characteristics of the image input unit 101. However, if a copy-prohibited document is intentionally printed, the paper quality can be selected to some extent even from plain paper, and the characteristics of the image input unit are determined in advance. As a result, the expected level value can be within a predetermined range.

Therefore, if the pixel having the density level value is extracted from the entire document image, and matches with the template of the specific pattern, it is detected that the specific pattern is printed on the back side of the document. In order to increase the matching accuracy, it is better to make the specific pattern as non-directional as possible. Also, if a certain amount of rotation invariant is taken by using a known method such as [Fourier Descriptor] or [Moment Method], it is not influenced by some rotation. Therefore, combination of patterns is possible.

In addition, you may detect the above-mentioned specific pattern using the relative difference with the level value of a background (usually white) instead of the absolute value of a density value.

In the case where the document image obtained by scanning as described above is full color, it may be simply converted to a luminance component and then subjected to a template matching process as described above. In addition, color information (e.g., a predetermined range of Color pixels).

Furthermore, in the above example, the surface (one side) of the document is scanned, but by scanning both sides of the document, a specific pattern printed on at least one side may be detected.

Next, the specific pattern detection unit 102 makes a determination based on the relative position of the specific pattern candidate (step 203). Text is printed on the surface of the document regardless of the pattern position on the back side. Therefore, as shown in FIG. 5, it is expected that the letters on the surface and the patterns on the back surface overlap. If the overlap is large, no matching may be taken. In addition, if there is a part printed at a medium density on the surface of the document, there is a possibility that an error is detected as part of the pattern.

Then, it is determined whether the document is a specific pattern print document by the relative positional relationship of the detected plurality of specific pattern candidates. For example, a specific pattern is printed at a distance d interval as shown in FIG. 6, and the result of detecting the pattern (pattern candidate) is as shown in FIG.

Here, as shown in Fig. 8, whether the other candidate exists locally at the position of the radius d of one of the pattern candidates is checked locally, and if one exists there, the point = 1 is assigned to the pattern candidate. If two candidates exist and they are at a symmetrical position of 180 degrees, or if they are at a position that forms an angle of 90 degrees, points = 3 are given to the pattern candidate to calculate the points. Moreover, when another candidate exists in the distance of the constant magnification or integer multiple of d on the line which connects a circle center and a detected candidate, you may give a high point.

These point calculation processes are performed on all detected candidates, and finally, the total number of points exceeds a threshold (absolute value), or the value obtained by normalizing the total number of points to the number of detection pattern candidates exceeds a threshold value. The document determines that a specific pattern is printed on the reverse side.

In the case of operating as printing the specific pattern on the back side of the copy prohibition document, when it is determined in step 203 that the specific pattern is printed, the image output unit 103 controls not to print (copy) the image ( Step 204). Not only the copy printing of the document may be performed but also the subsequent copying operation may be stopped again until any processing proceeds, and the illegal copying operation is notified from the external notification unit 107 to another device or the like via the network. You may do so.

On the contrary, in the case where the specific pattern is printed and operated on the back side of the copy permission document, the image output unit 103 prints (copys) the image only when the specific pattern is detected in step 203. Control (step 204).

In Fig. 1, the scanned image is stored in the temporary data storage section 104. However, this may save the entire document front image, and extracts the pattern candidate from the specific pattern detection section 102 every time a part of the image is taken and stored. You may take a method of investigating the whole arrangement relationship later.

The second embodiment is an embodiment in which a specific pattern is printed in color on the back side of a document. Individual pattern candidates (pixels of a specific color are detected by printing individual specific patterns in one color other than black or some predetermined color, and using color information as well as density values or density differences as in the first embodiment. Whether or not it is detected. Furthermore, when examining the whole arrangement relationship, not only the pattern candidate arrangement but also the color arrangement of the pattern candidates (for example, patterns of a specific color are arranged in a specific direction as shown in FIG. 9), such a color pattern is applied to the document. Determine if it is on the back.

The above embodiment is an example applied to a copier which controls the copying operation by detecting the presence or non-existence of a specific pattern printed on the back side of the document, but the present invention is not limited to this, but can also be applied to a scanner. That is, the image output unit is a mechanism for transmitting an image to the outside instead of printing, and the scanner for controlling the image reading operation or the image transmission operation by detecting the presence or absence of a specific pattern printed on the back side of the document. This is an example.

Moreover, the specific pattern for determining copy prohibition or permission can also be applied to a printing machine which prints on the back of the document printing surface. For example, as shown in Fig. 10, a confidential document print command is sent from the host computer together with the document data. Using a duplex printing mechanism, a specific pattern is printed first on one side and original document data on the other side for a confidential document print command. In addition, as shown in Fig. 11, a print driver software (not shown) of the host computer creates a print command in which a document data is placed on the surface and a specific pattern is placed on the back side and sent to a printer. In addition, as shown in FIG. 12, when there is no duplex printing mechanism, the mode which prints a specific pattern is provided previously, and a specific pattern is printed on one surface in this mode. [Specific mode] may be a command by a computer, or may be designated by a printer scanning panel. Since a sheet printed with a specific pattern is set upside down in the paper feed tray and a confidential document print command is fed from this feed tray, a confidential document with a specific pattern printed on the back side can be printed. This can prevent unauthorized copying by a copying machine or the like.

In addition, the present invention is not limited to a specific hard configuration, and the specific pattern detection unit which is the subject of the present invention can also be realized by a program. 13 is an example in which image processing control by specific pattern detection is configured by a program. As shown in the figure, a specific pattern detection program and an image output control program are stored in a recording medium such as a CD-ROM, and are installed in a system from a CD-ROM drive or downloaded from the network. As a specific pattern is detected from the input document image, it controls to prohibit or permit image output.

As described above, according to the present invention, a specific pattern printed on the back side of a document can be detected with high accuracy by a normal printing method without damaging the readability of the document. In addition, by printing such a specific pattern on the back side of a document such as a document that is prohibited from copying, and when attempting to print a copy-protected document by using a copying machine or a scanner, a specific pattern can be detected to prevent unauthorized copying.

Claims (28)

And detecting a specific pattern printed on the back side of the scanning surface by extracting pixels having a density level within a predetermined range from an image obtained by scanning a document. A specific pattern printed on the back side of the scanning surface is detected by detecting a change in density from an image obtained by scanning a document. A specific pattern printed on the back side of the scanning surface is detected by extracting a color pixel of a predetermined range from an image obtained by scanning a document. A method of detecting a specific pattern printed in a lattice form at a predetermined interval on a back surface of the scanning surface from an image obtained by scanning a document, the method comprising: detecting another pattern on a circumference centering on one detected pattern candidate and setting the predetermined interval as a radius; And detecting a specific pattern based on a cumulative value of all scores for all detected pattern candidates. The pattern detection method according to claim 4, wherein when a plurality of different pattern candidates are detected on the circumference of the radius, a high score is given when an angle formed between the candidates with respect to a circle center is a specific angle or a predetermined angle. The pattern detection method according to claim 4, wherein a high score is given when another candidate exists at a distance of a constant magnification or an integer multiple of the radius on a line connecting the candidate on the detected circumference and the circle center point. The pattern detection method according to any one of claims 1, 2, 3 or 4, wherein a specific pattern printed on at least one surface is detected by scanning both sides of the document. An image processing control method for reading a document and controlling an image processing operation of the document, wherein the specific pattern printed on the back side of the document is detected by the method described in claim 1, 2 or 3. Controlling the image processing operation of the image processing control method. An image processing control method for reading a document and controlling an image processing operation of the document, wherein the plurality of specific pattern arrangement relations and color arrangement relations printed on the back side of the document are described in claims 4, 5 or 6. An image processing control method characterized by controlling an image processing operation of a document when detected by the method. An image processing apparatus comprising an image input unit and a control unit, further comprising a specific pattern detection unit to detect a specific pattern printed on the back side of the scanning surface from an image obtained by scanning a document with the image input unit. . 11. The method of claim 10, wherein the specific pattern detecting unit includes a pixel extracting unit and detects a specific pattern printed on the back side of the scanning surface by extracting pixels having a density level within a predetermined range from an image obtained by scanning a document with the image input unit. Image processing device. The image processing apparatus according to claim 10, wherein the specific pattern detecting unit includes a pixel extracting unit and detects a specific pattern printed on the back side of the scanning surface by detecting a change in density from an image obtained by scanning a document with the image input unit. The image of claim 10, wherein the specific pattern detection unit includes a pixel extraction unit and detects a specific pattern printed on the back side of the scanning surface by extracting a predetermined range of color pixels from an image obtained by scanning a document with the image input unit. Processing unit. 12. The apparatus of claim 10, wherein the specific pattern detection unit includes a specific pattern determination unit and detects a specific pattern printed in a lattice form at predetermined intervals on the back surface of the scanning surface from an image obtained by scanning a document with the image input unit. Investigate whether other pattern candidates exist on the circumference centered on the dog pattern candidates and having the predetermined interval as a radius, and if present, scores are given and based on accumulated values of scores for all detected pattern candidates. An image processing apparatus for detecting a specific pattern. 15. The method of claim 14, wherein when the plurality of different pattern candidates are detected on the circumference of the radius, the specific pattern determination unit gives a high score when the angle formed between the candidates with respect to the circle center is a specific angle or a predetermined angle. Image processing apparatus. The image processing according to claim 14, wherein the specific pattern determination unit gives a high score when another candidate exists at a distance of a constant magnification or an integer multiple of the radius on a line connecting the candidate on the detected circumference and the circle center point. Device. The image processing apparatus according to any one of claims 10 to 16, wherein the image input unit detects a specific pattern printed on at least one surface by scanning both sides of the document. The image processing apparatus according to any one of claims 10 to 16, further comprising an image output unit and controlling image output based on a detection result of the specific pattern detection unit. 19. The image processing apparatus according to claim 18, wherein when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the image output unit to prohibit image output. 19. The image processing apparatus according to claim 18, wherein when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the image output unit to permit image output. An image processing apparatus according to claim 18, wherein said image processing apparatus is a copying machine. The image processing apparatus according to any one of claims 10 to 16, further comprising an external communication unit, and determining whether to transmit image data to the external communication unit based on a detection result of the specific pattern detection unit. The image processing apparatus according to claim 22, wherein when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the external communication unit to permit transmission of image data to the outside. The image processing apparatus according to claim 22, wherein when the specific pattern detection unit determines that the specific pattern is printed on the document, the control unit controls the external communication unit to prohibit image data from being transmitted to the outside. The image processing apparatus according to claim 22, wherein the image processing apparatus is a scanner. The image processing apparatus according to claim 22, wherein the image processing apparatus is a facsimile. The image processing apparatus according to claim 22, wherein when the specific pattern detection unit determines that the specific pattern is printed on the document, the communication unit notifies the information to the outside. A computer-readable recording medium having recorded thereon a program for realizing a function of detecting a specific pattern printed on the back side of a document and a function of prohibiting or permitting image output of the document by detecting the specific pattern. .