JP3078447B2 - Image processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus used for a digital copying machine, a facsimile machine, a scanner, an image filing apparatus, and the like. To an image processing apparatus.

[0002]

2. Description of the Related Art In recent years, with the improvement of image processing technology and image forming technology, it has become possible to copy a banknote copied by a digital color copying machine and an actual banknote so precisely that it cannot be easily distinguished. For this reason, a digital color copying machine has been put to practical use in which a special document, such as a bill or a securities, for which copying is prohibited is discriminated, and illegal copying is prohibited in the case of a special document.

[0003] As a method of discriminating such special manuscripts such as bills and securities, input image data is compared with a specific mark (pattern data) registered in advance by a pattern matching method. If there is a document, how to determine that the document is a special document,
As disclosed in Japanese Patent Application Laid-Open No. Hei 4-54681, a method of comparing and discriminating the shapes of histograms based on hue distribution has been proposed.

[0004] On the other hand, in a corporate office or the like, even for general documents other than special manuscripts such as banknotes and securities, copying is prohibited from the viewpoint of the importance of the contents of the document and confidentiality. Documents (hereinafter referred to as copy prohibited documents). Generally, such a copy-prohibited document is stamped with a confidential seal, a copy-prohibited mark, or the like, so as to be distinguished from a document that can be copied.

[0005]

However, in the prior art,
A confidential seal or a mark of copy prohibition is imprinted on the copy prohibition document, and the user is recognized as a copy prohibition document, and the copy of the copy prohibition document is copied on the assumption that the user observes the prohibition. Since copying is prohibited, copying cannot be substantially prohibited. For example, a user can copy using a copying machine, facsimile sending using a facsimile device, and However, there is a problem that it is also possible to input the data into the image filing device and save it.

It is conceivable to apply the above-mentioned conventional method of discriminating a special original to discrimination of a copy-inhibited document to constitute a device for prohibiting copying of a copy-inhibited document. When a secret seal or a copy prohibition mark is discriminated and copying of a copy prohibition document is prohibited, when a secret seal or a copy prohibition mark is covered with paper or the like and copied. Cannot be discriminated, and copying of a copy-inhibited document cannot be prohibited.

[0007] Further, when the shape of the histogram based on the hue distribution is compared and discriminated, there is a problem that the method cannot be applied to a device that handles image information as black and white binary data, and there are various copy prohibited documents. In addition, since the shapes of the histograms based on the hue distributions are not necessarily common, there is a problem that it is not possible to sufficiently determine the copy-inhibited document.

The present invention has been made in view of the above, and an object of the present invention is to reliably determine a copy-inhibited document and to surely prohibit copying, transfer, storage, and input of image information of the copy-inhibited document. And

[0009]

According to the present invention, in order to achieve the above object, an image processing apparatus according to claim 1 performs a shading correction process, a filter process, a scaling process on input image information. In an image processing apparatus that performs gamma correction processing, gradation processing, and the like, for each pixel data constituting the image information, whether or not the target pixel has a black peak is determined based on the target pixel data and pixel data adjacent thereto. Black peak detecting means for detecting whether the black peak density in a predetermined area centered on the pixel data of interest coincides with the black peak density of a predetermined copy prohibition pattern. Black peak density determining means for determining whether or not to perform the processing, a white background area detecting means for inputting the image information to detect a white background area, and detecting an edge area by inputting the image information And a determination result of the black peak density determination unit and a detection result of the white background region detection unit. The target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is input. A peripheral white area determining means for determining whether a white area of a predetermined size exists around a predetermined distance, a determination result of the black peak density determining means, and a detection result of the edge area detecting means; A halftone graph / halftone character area determining means for determining whether the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is a halftone graph or a halftone character area pixel; The target pixel data is copied based on the determination result of the black peak density determination unit, the determination result of the surrounding white background region determination unit, and the determination result of the halftone graph / shaded character region determination unit. Target pixel data determination means for determining whether or not the pixel data is part of a prohibited pattern;
Based on the number of pixel data determined to be a part of the copy prohibition pattern by the noted pixel data determination means,
A copy-inhibited document determining means for determining whether or not the image information is a copy-inhibited document, wherein the copy-inhibited document is prepared in advance using a paper on which a copy-inhibited pattern is printed or copied over the entire surface of the paper; The copy prohibited document determination means determines whether the document is a copy prohibited document.

According to a second aspect of the present invention, in the image processing apparatus, the copy prohibited document determination means counts the number of pixel data determined to be a part of a copy prohibited pattern existing in one line in the main scanning direction. The count value is set to the first
If the threshold value is equal to or greater than the threshold value, a line determination unit that determines the line as a copy-inhibited pattern line, a determination result of the line determination unit for a predetermined line, and a copy for counting the number of copy-inhibited pattern lines in the predetermined line A prohibition pattern line counting means; and a determination means for determining that the image information is a copy prohibition document if the count value of the copy prohibition pattern line counting means is equal to or greater than a preset second threshold value. is there.

According to a third aspect of the present invention, there is provided an image processing apparatus for performing shading correction processing, filter processing, scaling processing, γ correction processing, gradation processing, and the like on input image information. Black pixel detecting means for detecting whether or not the pixel of interest has a black peak from pixel data of interest and pixel data adjacent thereto for each pixel data constituting image information; A black peak density determining means for inputting a result and determining whether a black peak density in a fixed area centered on the pixel data of interest matches a black peak density of a predetermined copy prohibition pattern; White background area detection means for inputting information to detect a white background area, edge area detection means for inputting the image information to detect an edge area, and black peak density determination means The determination result and the detection result of the white background region detecting means are input, and a white background region of a predetermined size is set around a predetermined distance from the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern. The peripheral white area determining means for determining whether or not the pixel is present, the determination result of the black peak density determining means and the detection result of the edge area detecting means are input, and the pixel is a pixel that matches the black peak density of the copy prohibition pattern. Halftone graph / halftone character area determining means for determining whether or not the target pixel data determined to be a halftone graph or halftone character area pixel; a determination result of the black peak density determining means; Of the target pixel data to determine whether or not the target pixel data is a part of the copy prohibition pattern, based on the determination result of Copy prohibition for judging whether or not the image information is a copy prohibition document based on the number of pixel data judged to be a part of the copy prohibition pattern by the raw data judgment means and the target pixel data judgment means. A document determination unit; and a prohibition unit for prohibiting the output of the image information when the copy prohibition document determination unit determines that the document is a copy prohibition document. Is created using paper printed or copied, and the copy prohibited document determination means determines whether or not the document is a copy prohibited document.

According to a fourth aspect of the present invention, in the image processing apparatus, the prohibiting means prohibits the output of the image information by masking the image information with another image signal to invalidate the image information.

According to a fifth aspect of the present invention, in the image processing apparatus, in the case of image magnification, the black peak detecting means refers to an area to be referred to when detecting whether or not the pixel of interest has a black peak. In the scanner running direction, the area to be referred to when the edge area detecting means detects the edge area is changed in the scanner running direction.

[0014]

The image processing apparatus according to the present invention determines whether or not the target pixel has a black peak based on the target pixel data and pixel data adjacent thereto for each pixel data constituting the image information. Black peak detecting means for detecting
The result of the black peak detecting means is input, and it is determined whether or not the black peak density in a certain area centering on the target pixel data matches the black peak density of a predetermined copy prohibition pattern. Also, the image information is input to detect a white background area, and the image information is input to detect an edge area, and target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern. It is determined whether or not a white background area of a predetermined size exists around a certain distance from the target pixel data. In addition, the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is displayed in a halftone graph or It is determined whether or not the pixel is a shaded character area pixel. Further, whether or not the pixel of interest is a pixel that matches the black peak density of the copy prohibition pattern, whether or not a white background area of a predetermined size exists around a predetermined distance, a halftone graph or a halftone character area Based on whether the pixel
By judging whether or not the image information is a copy-inhibited document, a copy-inhibited document created in advance by using a paper on which a copy-inhibited pattern is printed or copied on the entire surface of the paper is reliably determined.

An image processing apparatus according to the present invention (claim 2)
Counts the number of pixel data determined to be a part of the copy prohibition pattern existing in one line in the main scanning direction, and if the count value is equal to or greater than a preset first threshold, the line is copied. By determining that the line is a prohibited pattern line, counting the number of copy prohibited pattern lines in a predetermined line, and determining that the image information is a copy prohibited document when the count value is equal to or greater than a second threshold value set in advance, A copy-inhibited document created using a paper on which a copy-inhibited pattern has been printed or copied in advance on the entire surface of a sheet is reliably determined.

An image processing apparatus according to the present invention (claim 3)
Determines whether the image information is a copy-inhibited document, and if the document is a copy-inhibited document, prohibits the output of the image information. The copied copy prohibited document is reliably determined, and the creation of the copy prohibited document is prohibited.

Further, an image processing apparatus according to the present invention (claim 4)
In this case, the creation of a copy-inhibited document is prohibited by masking the image information with another image signal to invalidate the image information.

Further, the image processing apparatus of the present invention (claim 5)
Changes the area to be referred to when the black peak detecting means detects whether or not the pixel of interest is a black peak in the scanner running direction when the image is zoomed, and the edge area detecting means By changing the area to be referred to when detecting the image in the scanner traveling direction, the detection of the copy prohibition pattern and the determination of the copy prohibition document can be performed with high accuracy even when the image is scaled.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which an image processing apparatus of the present invention is applied to a digital copying machine will be described in detail in the order of Embodiment 1 and Embodiment 2 with reference to the drawings.

[Embodiment 1] In Embodiment 1, for each piece of pixel data constituting image information, it is detected whether or not the pixel data is a part of a predetermined copy prohibition pattern. Based on the number of pixel data detected as being part of the pattern,
By determining whether or not the image information is a copy-inhibited document, a copy-inhibited document created in advance by using a paper on which a copy-inhibited pattern is printed or copied on the entire surface of a sheet is reliably determined.

Hereinafter, with respect to the digital copying machine of the first embodiment, the overall configuration of the digital copying machine, a copy-inhibited pattern, a copy-inhibited pattern detecting section, a copy-inhibited document determining section, a copy-inhibited document discriminating operation, and a copy-inhibited pattern formation. The operation will be described in the order.

FIG. 1 is a block diagram of a digital copying machine according to a first embodiment, in which image information is read from an original and subjected to A / D conversion (analog / digital conversion). A scanner 101 for outputting (digital signal), and an image processing unit 102 for inputting image information from the scanner 101 and executing various image processing to be described later and copy prohibition document determination processing of the present invention.
A plotter 103 for outputting image information on which image processing has been performed by the image processing unit 102 to recording paper;
2 and an image processing unit 1
02 and an operation display unit 1 for inputting various modes, displaying messages, and the like.
04 and a system controller 10 for controlling the above-described units.
And 5. The copy prohibition pattern synthesizing unit 1
As No. 15, a confidential pattern printing function of a digital copying machine, which is a known technique, can be applied, and a detailed description thereof will be omitted.

Further, the image processing unit 102 includes the scanner 1
01, a shading correction unit 106 for performing shading correction on the input image information, and a filter processing unit 107 for performing various filtering processes on the input image information using a smoothing filter, an edge enhancement filter, and the like.
A scaling unit 108 for scaling the image information; a gamma correction unit 109 for performing the gamma correction process; and a gradation processing unit 110 for converting the image information into preset multi-value data.
A copy prohibition pattern detecting unit for inputting image information from the scanner 101 and detecting whether or not the pixel data is a part of a predetermined copy prohibition pattern for each pixel data constituting the image information A copy-inhibited document determining unit 112 that determines whether or not the image information is a copy-inhibited document based on the number of pixel data 111 that is detected by the copy-inhibited pattern detection unit 111 as being a part of the copy-inhibited pattern. The image information is input from both the white data generator 113 for generating image information composed of white data, and the gradation processing unit 110 and the white data generator 113, and according to the determination result of the copy prohibited document determination unit 112, , The image information input from the gradation processing unit 110 or the image information input from the white data generator 113 (that is, white data) is selected. And a selector 114 for output to the plotter 103 to.

Copy Prohibition Pattern Here, the copy prohibition pattern will be described with reference to FIG. The copy prohibition pattern is a pattern for determining whether or not the image information (that is, the original document) is a copy prohibition document. In the present invention, a document on which the copy prohibition pattern is formed is referred to as a copy prohibition document. judge. Therefore, the copy prohibition document is created using paper on which a copy prohibition pattern has been printed or copied on the entire surface of the paper in advance. For example, as shown in FIG. 2A, on a sheet of paper on which a copy prohibition pattern 201 has been created
By recording a confidential document, a copy-prohibited document can be created. When copying the original document of the confidential document whose copying is prohibited, the copy prohibition pattern can be combined with the copy document using the copy prohibition pattern combining unit 115 to create a copy prohibition document.

As shown in the enlarged view of FIG. 2B, the copy-prohibited pattern 201 by the copy-prohibited pattern synthesizing section 115 is a number composed of halftone dots of about 65 lines (here,
1). As shown in FIG. 2A, for a document in which the copy prohibition pattern 201 is recorded on the entire paper surface,
Although details will be described later, the apparatus of the present invention determines that the document is a copy-prohibited document and performs an operation of prohibiting copying. Conversely, a normal copying operation is performed for other documents.

FIG. 3 shows a block diagram of the copy prohibition pattern detection section 111. For each pixel data constituting image information, FIG.
A black peak detector 301 for detecting whether or not the pixel of interest has a black peak, based on the pixel data of interest and pixel data adjacent thereto, and a detection result of the black peak detector 301 are input, and the pixel data of interest is input. A black peak density determining unit 302 for determining whether or not a black peak density in a certain area at the center coincides with a black peak density of a predetermined copy prohibition pattern; and inputting image information to detect a white background area A white background area detection unit 303, an edge area detection unit 306 that detects an edge area by inputting image information, and a determination result of the black peak density determination unit 302 and a detection result of the white background area detection unit 303 are input to prohibit copying. It is determined whether or not a white background area of a predetermined size exists around a certain distance from the target pixel data determined to be a pixel matching the black peak density of the pattern. The pixel of interest determined by inputting the determination result of the surrounding white background area determination unit 304, the black peak density determination unit 302, and the detection result of the edge region detection unit 306, and determining that the pixel matches the black peak density of the copy prohibition pattern Halftone graph / halftone character area determination unit 307 for determining whether data is a halftone graph or halftone character area pixel
The target pixel data is a part of the copy prohibition pattern based on the determination result of the black peak density determination unit 302, the determination result of the surrounding white background region determination unit 304, and the determination result of the halftone graph / shaded character region determination unit 307. And a target pixel data determination unit 305 for determining whether or not there is a pixel data.

More specifically, the above-mentioned black peak detector 301
As shown in FIG. 4, the pixel data of interest is a central pixel E in a 3 × 3 matrix, the density of the central pixel E is higher than that of the other pixels, and the density of the central pixel E is a predetermined threshold , Black pixel threshold), the pixel data of interest is detected as a black peak pixel.

Further, the black peak density determination unit 302 determines that a certain area (eg, 11 × 1
The black peak density of one matrix) is measured, and it is determined whether or not the peak density of halftone dots of about 65 lines characteristic of the copy prohibition pattern 201 shown in FIG.

Similarly, in the white area detection unit 303,
The presence or absence of a white background in a certain area is detected, and whether or not a white background exists is detected. At this time, detection of the presence or absence of a white background is performed, for example, by binarizing each pixel of an M × M matrix (for example, an 11 × 11 matrix) with a predetermined threshold (hereinafter, referred to as a white background detection threshold), When all the pixels are white, the inside of the M × M matrix is detected as a white background area.

Further, the peripheral white background area determination unit 304
The detection result of the white area detection unit 303 and the black peak detection unit 30
Based on the detection result of No. 1, it is determined whether or not there is a white background area in an area at a certain distance from the pixel detected as the black peak pixel. The determination of the presence or absence of a peripheral white background is performed, for example, by referring to FIG.
As shown in FIG.
Areas 502, 503, and 50 separated by a fixed distance d to the right
When a white background exists at 4,505, the target pixel 501 is determined as a pixel having a peripheral white background region. here,
The determination as to whether or not a white background exists is made in areas 502, 503, 504, and 505 in the four directions of up, down, left, and right. As shown in FIG. Left, right, diagonally upper left, diagonally upper right, diagonally lower right, diagonally lower left eight directions area 50
By looking at 2 to 509, the determination accuracy of the peripheral white background area may be enhanced. Alternatively, in FIG. 5A, the determination can be made only in the regions 502 and 503 in the upper and lower directions, so that the hardware amount can be reduced and the configuration can be simplified.

The edge area detecting section 306 determines whether or not the target pixel is a pixel in the edge area. The edge pixel area determination is performed using an N × N pixel reference matrix. In this embodiment, the following description will be made using a 5 × 5 pixel block as a reference matrix for edge determination. As the elements of the reference matrix, values obtained by binarizing each pixel with a threshold value for edge pixel determination in advance are set. FIG. 6 shows a schematic diagram of the edge pixel determination. In the edge judgment, the projection in the x and y directions of a 5 × 5 pixel matrix is taken, and xs
[], Ys [].

As an example, xs [] which is an element of xs []

[0] is shown in Equation 1 below, and a schematic diagram is shown in FIG. Here, each element of the 5 × 5 pixel matrix is represented as dxy.

[0033]

(Equation 1)

That is, in FIG. 7, the logical sum of the shaded pixel group is calculated. Similarly, each element of xs [] and ys [] is calculated.

Using xs [] and ys [] calculated thereafter, the continuity of projection in the X and y directions is determined by the following equation (2). The continuity determination results xs and ys are the logical product of the elements, as is apparent from Equation 2.

[0036]

(Equation 2)

Next, it is determined whether or not the center pixel X in FIG. 6 is an edge pixel. The determination of the edge pixel is a logical sum of the continuity determination results xs and ys as shown in Expression 3.

[0038]

(Equation 3)

Next, the configuration of the halftone graph / shaded character area determination unit 307 will be described with reference to FIG. The halftone graph / shaded character area determination unit 307 includes an edge detection unit 80 in the halftone image.
1, a halftone image left edge detection unit 802, a halftone image right edge detection unit 803, and a halftone character area determination unit 804.
, A halftone graph area determination unit 805, and an OR circuit 806.

Here, the edge detection unit 801 in the halftone image,
As shown in FIGS. 9A to 9C, the halftone image left edge detection unit 802 and the halftone image right edge detection unit 803 respectively perform an edge pixel in the halftone image and an edge existing on the left side of the halftone image. Pixels and edge pixels existing on the right side of the halftone dot image are detected.

In each detection, when the pixel of interest is an edge area pixel, a copy prohibition pattern having a predetermined black peak density in a fixed area centered on the pixel of interest data in the left and right WDTH pixels in the main scanning direction. The presence or absence of a pixel determined to match the black peak density of
If it exists on both the left and right sides, it is detected as an edge pixel in the halftone image. If it exists only on the right side of the edge pixel, it is detected as the left edge pixel of the halftone image. It is detected as an image right edge pixel.

Next, when the target pixel is determined to be equal to the black peak density of the copy prohibition pattern by the halftone character area determination unit 804 and there is an edge pixel in the halftone image nearby, the target pixel is determined. It is determined as a shaded character area pixel.

Further, the halftone graph area determining unit 805 determines that the pixel of interest is determined to match the black peak density of the copy prohibition pattern, and the halftone image left edge pixel exists in the nearest neighborhood in the left LNGTH. And right LNG
When a halftone image right edge pixel exists in the nearest vicinity in TH, the pixel of interest is determined to be a halftone graph area pixel.

Finally, an OR circuit 806 calculates the logical sum of the shaded character area determination result and the halftone graph area determination result for each pixel. By doing so, it is possible to determine a shaded character area and a halftone graph area having characteristics similar to the black peak of the copy prohibition pattern.

The target pixel data determination unit 305 shown in FIG.
Are the black peak density determination unit 302 and the surrounding white background region determination unit 3
04 and the result of the halftone graph / shaded character area determination unit 307, it is determined that the target pixel matches the black peak density of the copy prohibition pattern, and it is a peripheral white area pixel.
When it is determined that the target pixel data is not a halftone graph / shaded character area pixel, the target pixel data is determined to be a copy prohibition pattern pixel, and a copy prohibition pattern determination result is output.

FIG. 10 is a block diagram of the copy-inhibited document determination unit 112. The copy-inhibited document determination unit 112 determines each pixel data from the target pixel data determination unit 305 of the copy inhibition pattern detection unit 111. A copy prohibition pattern determination result for each is input, the number of pixel data determined to be a part of the copy prohibition pattern existing in one line in the main scanning direction is counted, and the count value is set to a first threshold value set in advance. If TH1 or more, the line determination unit 1001 that determines that line is a copy-inhibited pattern line, and the determination results of the line determination unit 1001 are held for N lines, and the number of copy-inhibited pattern lines in the N lines (count value M ), And a copy-inhibited pattern line counting unit 1002
If the count value M (M ≦ N) is equal to or greater than the second threshold value TH2 set in advance, the determination unit 10 determines that the image information is a copy-inhibited document and outputs a white data selection signal “1”.
03.

Operation of Discrimination Process of Copy-Forbidden Document In the above configuration, the operation of discrimination process of copy-inhibited document will be described in detail with reference to the flowcharts of FIGS. 11 (a) to 11 (c) and FIG.

The user sets a document (original document) to be copied at a predetermined position of the scanner 101 and operates the operation display unit 10.
When a copy start key (not shown) is pressed, image information of the document is read by the scanner 101, and A
After the / D conversion, the digital signal is input to the image processing unit 102 as a digital signal.

The image processing unit 102 performs shading correction on image information as a digital signal by the shading correction unit 106 and inputs the image information to both the filter processing unit 107 and the copy prohibition pattern detection unit 111. The image information input to the filter processing unit 107 is
7. After being subjected to predetermined image processing in the scaling unit 108, the γ correction unit 109, and the gradation processing unit 110, the image data is transferred to the selector 114.

On the other hand, the image information input to the copy prohibition pattern detecting section 111
At 11, for each pixel data constituting the image information, it is detected whether or not the pixel data is a part of a predetermined copy prohibition pattern.

FIG. 11 shows a copy prohibition pattern detecting section 111.
7A is an operation flowchart of the white background region detection unit 303 and the peripheral white background region determination unit 304, and FIG. 6B is an edge region detection unit 306 and a halftone graph / shaded character region determination unit 307. FIG. 3C shows a black peak detector 301, a black peak density determiner 302, and a target pixel data determiner 305.
4 is an operation flowchart of FIG. These three operation flowcharts are executed simultaneously by parallel processing.

As shown in the flowchart of FIG. 7A, first, the white area detection unit 303 detects the presence or absence of a white background in a certain area, and detects whether or not a white background exists (S1).
101). Next, the surrounding white background area determination unit 304 receives the detection result of the black peak density determination unit 302 and determines the black peak density (S1102). The presence / absence of a white background area in an area at a certain distance from a pixel detected as a pixel having a black peak density matching the detection result is determined, and the determination result is output to the target pixel data determination unit 305 (S1103). on the other hand,
If it is not a black peak density matching pixel, the processing for the pixel data of interest ends, and the flow returns to S1101.

As shown in the flowchart of FIG. 13B, first, the edge area detection unit 306 detects projections in the x and y directions in the reference matrix to detect an edge area (S1104). Next, it is determined whether the pixel is an edge pixel (S1105).
Check the result of peak density determination in DTH (S110)
6). If there is an area where the black peak density on either or both sides matches the black peak density of the copy prohibition pattern, whether the corresponding edge pixel is a halftone dot left edge, a halftone dot left edge, or a halftone dot right edge Is checked (S1107,
S1108) Next, it is checked whether or not it is a halftone graph / shaded character area, and the determination result is determined by the target pixel data determination unit 30.
5 (S1109). If it is not an edge pixel or if there is no black peak density matching pixel, the processing for the target pixel data is terminated, and the flow returns to S1104.

As shown in the flowchart of FIG. 11C, first, the presence or absence of a black peak pixel is detected by the black peak detecting unit 301 (S1110), and then the black peak density determining unit 302 is detected.
To determine the black peak density (S1111), and determine the black peak density (S1112). Here, if the density does not match the black peak density of the copy prohibition pattern, it is determined that the pattern is not a part of the copy prohibition pattern (S1116).

On the other hand, if they match, it is determined whether or not there is a peripheral white background pixel area (S1113). If it is not a peripheral white background pixel, it is determined that it is not a part of the copy prohibition pattern (S1116). If the pixel is a surrounding white background pixel, it is determined whether or not the pixel is a halftone graph / shaded character area (S1114). If the pixel is a halftone graph / shaded character area, it is not part of the copy prohibition pattern. (S
1116). If it is not a halftone graph / shaded character area, it is determined that it is a part of the copy prohibition pattern (S111).
5) Then, the processing for the target pixel is completed.

The steps S1101 to S1116 are executed for each pixel data of the image information and finally executed for the entire input image information.

FIG. 12 is a flowchart showing the operation of the copy-inhibited document judging section 112. First, the line determination unit 1001
The result of the determination of the copy prohibition pattern for each pixel data is input to step S1201, and the number of pixel data determined to be a part of the copy prohibition pattern existing in one line in the main scanning direction is counted (S1201). Next, the count value is compared with the first threshold value TH1 (S1202). If the count value is equal to or greater than TH1, the line is determined to be a copy prohibition pattern line (S120).
3) If the count value is less than TH1, it is determined that the line is a general line that is not a copy prohibition pattern line (S1).
204).

Subsequently, the copy prohibition pattern line counting unit 1
In step 002, the determination result of the line determination unit 1001 is held for N lines, and the number of copy prohibition pattern lines (count value M) in the N lines is counted (S1205). Then, the count value M
Is compared with the second threshold value TH2 (S1206). If the count value M ≧ TH2, it is determined that the image information is a copy-inhibited document, and the white data selection signal “1” is output (S120).
7). On the other hand, if the count value M <TH2, the white data selection signal “0” is output (S1208), and the process ends.

As described above, image information is transferred to the selector 114 from both the gradation processing unit 110 and the white data generator 113. When the white data selection signal is “1”, the selector 114 selectively selects the white data input from the white data generator 113 according to the determination result (white data selection signal) of the copy prohibited document determination unit 112. Output to the plotter 103. Also, the white data selection signal “0”
In the case of, the image information input from the gradation processing unit 110 is selectively output to the plotter 103.

Accordingly, the copy prohibition pattern is detected by the above processing, and if it is determined that the document is a copy prohibition document, the image information is replaced with white data. It is not output to the document 103, in other words, the selector 114 prohibits the copying of the image information that is the copy-inhibited document.

Next, a copy-prohibited pattern forming operation using the copy-prohibited pattern synthesizing section 115 will be described. When forming a copy prohibition pattern on the recording paper output from the plotter 103, in other words, when creating a copy prohibition document, first, a predetermined key of the operation display unit 104 is depressed, and the operation of forming the copy prohibition pattern is performed. Is specified. When the system controller 105 receives the formation signal of the copy prohibition pattern from the operation display unit 104, it outputs a synthesis instruction signal to the copy prohibition pattern synthesis unit 115 of the image processing unit 102. The copy prohibition pattern synthesizing section 115 synthesizes the image signal output from the selector 114 with the copy prohibition pattern shown in FIG. 2 based on the synthesis signal, and outputs the image signal to the plotter 103. As a result, the recording paper (copy-inhibited document) on which the copy-inhibited pattern is formed is output from the plotter 103.

As described above, in the first embodiment, when the black peak pixel (pixel of interest) has a black peak density characteristic of the copy prohibition pattern and a white background exists in a region separated by a certain distance, the pixel of interest is Since the data is determined to be a pixel of the copy prohibition pattern, the presence of the copy prohibition pattern can be accurately and easily detected.

In addition, it is determined whether or not each line is a copy-inhibited pattern line, and if the number M of copy-inhibited pattern lines in N lines exceeds a predetermined value, it is determined that the document is a copy-inhibited pattern. , It is possible to determine a copy-inhibited document without erroneous determination.

It is determined whether each line is a copy-inhibited pattern line. If the number M of copy-inhibited pattern lines in N lines exceeds a predetermined value, it is determined that the document is a copy-inhibited document. , The portion determined as a copy-inhibited document can be reliably erased even from the middle of the page by the white data generator 113 and the selector 114.

Further, in the first embodiment, the copy prohibition pattern can be synthesized by the copy prohibition pattern synthesizing section 115 and output to the recording paper via the plotter 103 to create a copy prohibition document. When a document is read on its own machine, the copy prohibition pattern is reliably recognized,
Since the document is determined to be a copy-inhibited document, the copy-inhibited document is reliably determined, and the image information of the copy-inhibited document is copied, transferred,
Saving and inputting can be reliably prohibited.

In the first embodiment, an example in which the image processing apparatus of the present invention is applied to a digital copying machine has been described. However, the present invention is not particularly limited to this. Facsimile transmission can be prohibited. When the present invention is applied to an image filing apparatus, filing of a copy-inhibited document can be prohibited by the same processing. Further, when the present invention is applied to a scanner, reading of a copy-inhibited document can be prohibited by the same processing.

In the first embodiment, an example is shown in which the image information of the copy-inhibited document is replaced with white data.
It may be replaced with black data or replaced with data having a predetermined pattern.

[Second Embodiment] In a second embodiment, it is determined whether or not to perform line thinning in the sub-scanning direction via the operation display unit 104, and the parameters of internal processing in the copy prohibition pattern detection unit 111 are determined. By performing the switching, the determination of the copy-inhibited document can be reliably performed even at the time of zooming. Note that the configuration and operation of the second embodiment are almost the same as those of the first embodiment, and only different parts will be described.

FIG. 13 shows the structure of the copy prohibition pattern detecting section 1301 of the second embodiment, in which a sub-scanning line thinning section 1302 is added to the copy prohibition pattern detecting section 111 of the first embodiment. In the sub-scanning line thinning unit 1302,
Lines are thinned out in accordance with the magnification at the time of enlargement, and a line synchronizing signal to be used in the copy prohibition pattern detection unit 1301 and the copy prohibition document determination unit 112 is generated.

For example, when the magnification is 200%, the signal obtained by thinning out one line into two lines by the sub-scanning line thinning unit 1302 is output from the copy prohibition pattern detecting unit 130.
1 is output. The line synchronization signal generated at that time is twice as large as the line synchronization signal of the image information input to the sub-scanning line thinning unit 1302. FIG. 14 shows the line thinning and the generation of the line synchronizing signal when the magnification is 200%. FIG. 14A shows the sub-scanning line thinning unit 1302.
FIG. 4B shows a line synchronization signal of input image information to
Indicates a double line synchronizing signal generated by the sub-scanning line thinning unit 1302, which is a copy prohibition pattern detecting unit 13
01 and the line synchronization signal used in the copy-inhibited document determination unit 112. FIG. 14C shows the lines of the image information input to the sub-scanning line thinning unit 1302.
On the other hand, when the magnification is 200%, one line is thinned out of two lines, and the line of image information is output from the sub-scanning line thinning unit 1302 as shown in FIG.

Next, a copy prohibition pattern detection unit 1301
Changes the detection matrices of the black peak detection unit 301 and the edge area detection unit 306 according to the magnification. First, when the sub-scanning line thinning unit 1302 does not perform line thinning during enlargement, the black peak detecting unit 301
When the detection is performed by using the 3 × 5 matrix shown in FIG. 15 instead of the 3 × 3 matrix shown in FIG. 4, and the line is thinned out in the sub-scanning line thinning unit 1302, the black peak detecting unit 301 Detection is performed using the 3 × 3 matrix shown in FIG. This processing is performed in the first embodiment.
However, the operation is the same except that the pixel positions of A to I other than E are different.

In the edge area detection unit 306, the edge pixel area is determined by using an N × N pixel reference matrix. In this embodiment, the reference matrix for edge determination is determined by using a 5 × 5 pixel block as follows. Give an explanation. As the elements of the reference matrix, values obtained by binarizing each pixel with a threshold value for edge pixel determination in advance are set. FIG. 16 is a schematic diagram of the edge pixel determination. The edge determination is performed by projecting a 5 × 5 pixel matrix in the x and y directions and setting them as xs [] and ys [].

Here, since xs [] operates in the same manner as in the first embodiment, description thereof will be omitted. ys [] is shown in FIG.
As shown in (1), the operation is performed by selecting A, B or C in FIG. Each determination formula performs the same operation as that of the first embodiment except that the size is different. For example, 50%
A is used at the time of reduction. This is because, as a result of reading an image with variable speed in the sub-scanning direction and changing the scanning speed of the scanner, the reading length of the original in the sub-scanning direction per pixel is longer than that of the original, which is corrected. This is because, by using A in the same figure, the same length on the document is always used.

Also, at the time of enlargement, when line subsampling is performed in the sub-scanning line subsampling unit 1302, the copy inhibition pattern detection unit 1301 is equivalent to apparently input reduced image information. Is what you do.

[0075]

As described above, the image processing apparatus according to the present invention (claim 1) uses the target pixel data and the pixel data adjacent thereto for each pixel data constituting the image information. Black peak detecting means for detecting whether or not a pixel has a black peak; inputting the result of the black peak detecting means; and determining a black peak density in a fixed area centered on the target pixel data in advance. It is determined whether or not the density is the same as the black peak density of the copy prohibition pattern, and the image information is input to detect a white background area. It is determined whether or not a white background area of a predetermined size exists around a predetermined distance from the target pixel data determined to be a pixel matching the black peak density of the pattern. It is determined whether or not the target pixel data determined to be a pixel matching the degree is a halftone graph or a shaded character area pixel, and if the target pixel is a pixel matching the black peak density of the copy prohibition pattern. The image information is a copy-forbidden document based on whether or not there is a white background area of a predetermined size around a certain distance, and whether or not it is a halftone graph or a halftone character area pixel. To determine whether or not there is, a copy-inhibited document created by printing or copying a copy-inhibited pattern over the entire surface of the paper in advance can be reliably determined, and the image information of the copy-inhibited document can be copied, transferred, stored, and input. Can be reliably prohibited.

An image processing apparatus according to the present invention (claim 2)
Counts the number of pixel data determined to be a part of the copy prohibition pattern existing in one line in the main scanning direction, and if the count value is equal to or greater than a preset first threshold, the line is copied. The image information is determined to be a prohibited pattern line, the number of copy prohibited pattern lines in a predetermined line is counted, and if the count value is equal to or greater than a preset second threshold value, the image information is determined to be a copy prohibited document. A copy-prohibited document created by printing or copying a copy-prohibited pattern over the entire surface of a sheet can be reliably determined, and copying, transfer, storage, and input of image information of a copy-prohibited document can be reliably prohibited.

An image processing apparatus according to the present invention (claim 3)
Is created using a paper on which a copy prohibition pattern has been printed or copied in advance on the entire paper to determine whether the image information is a copy prohibition document and to prohibit the output of the image information in the case of a copy prohibition document. It is possible to reliably discriminate the copy-inhibited document and to surely prohibit the copying, transfer, storage, and input of the image information of the copy-inhibited document.

The image processing apparatus according to the present invention (claim 4)
Is invalidated by masking the image information with another image signal by the prohibition means, so that the creation of a copy prohibition document is prohibited.

An image processing apparatus according to the present invention (claim 5)
Changes the area to be referred to when the black peak detecting means detects whether or not the pixel of interest is a black peak in the scanner running direction when the image is zoomed, and the edge area detecting means By changing the area to be referred to when detecting the image in the scanner traveling direction, it is possible to accurately detect the copy prohibition pattern and determine the copy prohibition document even when the image is scaled.

[Brief description of the drawings]

FIG. 1 is a block diagram of a digital copying machine according to a first embodiment.

FIG. 2 is an explanatory diagram showing a copy prohibition pattern.

FIG. 3 is a block diagram illustrating a copy prohibition pattern detection unit according to the first embodiment.

FIG. 4 is an explanatory diagram illustrating an example of a black peak detection method in a black peak detection unit.

FIG. 5 is an explanatory diagram illustrating a method of determining a white background area by a peripheral white background area determination unit.

FIG. 6 is a schematic diagram of edge pixel determination according to the first embodiment.

FIG. 7 is a schematic diagram of edge pixel determination according to the first embodiment.

FIG. 8 is an explanatory diagram illustrating a configuration of a halftone graph / shaded character area determination unit.

FIG. 9 is an explanatory diagram showing detection of an edge pixel in a halftone image image edge detection unit, a halftone image left edge detection unit, and a halftone image right edge detection unit.

FIG. 10 is a block diagram illustrating a copy-inhibited document determining unit according to the first embodiment.

FIG. 11 is an operation flowchart of a copy prohibition pattern detection unit according to the first embodiment.

FIG. 12 is an operation flowchart of a copy-inhibited document determining unit according to the first embodiment.

FIG. 13 is an explanatory diagram illustrating a configuration of a copy prohibition pattern detection unit according to the second embodiment.

FIG. 14 is an explanatory diagram showing line thinning and generation of a line synchronization signal when the magnification is 200%.

FIG. 15 is an explanatory diagram illustrating a 3 × 5 matrix used in a black peak detection unit according to the second embodiment.

FIG. 16 is a schematic diagram of edge pixel determination in Embodiment 2.

[Explanation of symbols]

Reference Signs List 101 Scanner 102 Image processing unit 103 Plotter 104 Operation display unit 105 System controller 106 Shading correction unit 107 Filter processing unit 108 Magnification processing unit 109 γ correction unit 110 Gradation processing unit 111 Copy prohibited pattern detection unit 112 Copy prohibited document determination unit 113 White data generator 114 Selector 115 Copy prohibition pattern synthesizing unit 301 Black peak detecting unit 302 Black peak density determining unit 303 White background region detecting unit 304 Peripheral white background region determining unit 305 Target pixel data determining unit 306 Edge region detecting unit 307 Network graph / network Halftone character area determination unit 801 Halftone image middle edge detection unit 802 Halftone image left edge detection unit 803 Halftone image right edge detection unit 804 Halftone character area determination unit 805 Halftone graph area determination unit 806 OR circuit 1001 Down determining unit 1002 copying-inhibited pattern line counting unit 1003 determination unit 1301 copying-inhibited pattern detecting unit 1302 subscanning line thinning section

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-90188 (JP, A) JP-A-2-83571 (JP, A) JP-A-5-219353 (JP, A) 70134 (JP, A) JP-A-6-217122 (JP, A) JP-A-7-36317 (JP, A) JP-A-7-123254 (JP, A) JP-A-7-87309 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/40-1/409 G03G 21/04 G06T 7/00

Claims (5)

(57) [Claims] A shading correction process, a filtering process, a scaling process, a gamma correction process,
In an image processing apparatus that performs gradation processing or the like, it is detected whether or not the target pixel has a black peak from each target pixel data and pixel data adjacent thereto for each pixel data constituting the image information. A black peak detecting means and a result of the black peak detecting means are inputted, and whether or not a black peak density in a certain area centering on the target pixel data coincides with a predetermined black peak density of a copy prohibition pattern is determined. A black background density determining unit for determining the black peak density; a white background region detecting unit for detecting the white background region by inputting the image information; an edge region detecting unit for detecting the edge region by inputting the image information; The determination result of the determination means and the detection result of the white background area detection means are input, and the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is obtained. A peripheral white background area determining unit that determines whether a white background region of a predetermined size exists around a fixed distance, a determination result of the black peak density determining unit, and a detection result of the edge region detecting unit. A halftone graph / halftone character area determining means for determining whether the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is a halftone graph or a halftone character area pixel; Based on the judgment result of the black peak density judging means, the judgment result of the surrounding white background area judging means and the judgment result of the halftone graph / shaded character area judging means, it is determined whether or not the target pixel data is a part of the copy prohibition pattern. Based on the number of pixel data determined to be a part of the copy prohibition pattern by the target pixel data determining means and the target pixel data determining means. And a determining copy inhibited document determining unit configured to determine whether a copy-inhibited document, the copying-inhibited document is created using a paper previously printed or copied a copy prohibition pattern throughout the paper,
An image processing apparatus, wherein the copy prohibition document determination unit determines whether the document is a copy prohibition document. 2. The copy-inhibited document judging means counts the number of pixel data judged to be a part of a copy-inhibited pattern existing in one line in the main scanning direction, and the counted value is set to a predetermined first value. If the threshold value is equal to or greater than the threshold value, a line determination unit that determines the line as a copy-inhibited pattern line, a determination result of the line determination unit for a predetermined line, and a copy for counting the number of copy-inhibited pattern lines in the predetermined line Prohibition pattern line counting means, and determination means for determining that the image information is a copy prohibition document if the count value of the copy prohibition pattern line counting means is equal to or greater than a second threshold value set in advance. The image processing apparatus according to claim 1, wherein: 3. Shading correction processing, filtering processing, scaling processing, gamma correction processing,
In an image processing apparatus that performs gradation processing or the like, it is detected whether or not the target pixel has a black peak from each target pixel data and pixel data adjacent thereto for each pixel data constituting the image information. A black peak detecting means and a result of the black peak detecting means are inputted, and whether or not a black peak density in a certain area centering on the target pixel data coincides with a predetermined black peak density of a copy prohibition pattern is determined. A black background density determining unit for determining the black peak density; a white background region detecting unit for detecting the white background region by inputting the image information; an edge region detecting unit for detecting the edge region by inputting the image information; The determination result of the determination means and the detection result of the white background area detection means are input, and the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is obtained. A peripheral white background area determining unit that determines whether a white background region of a predetermined size exists around a fixed distance, a determination result of the black peak density determining unit, and a detection result of the edge region detecting unit. A halftone graph / halftone character area determining means for determining whether the target pixel data determined to be a pixel matching the black peak density of the copy prohibition pattern is a halftone graph or a halftone character area pixel; Based on the judgment result of the black peak density judging means, the judgment result of the surrounding white background area judging means and the judgment result of the halftone graph / shaded character area judging means, it is determined whether or not the target pixel data is a part of the copy prohibition pattern. Based on the number of pixel data determined to be a part of the copy prohibition pattern by the target pixel data determining means and the target pixel data determining means. A copy prohibition document determining unit for determining whether the document is a copy prohibition document; and a prohibition unit for prohibiting the output of the image information when the copy prohibition document determination unit determines that the document is a copy prohibition document. The copy-inhibited document is created in advance by using a paper on which a copy-inhibited pattern is printed or copied on the entire surface of the paper, and the copy-inhibited document determining means determines whether the document is a copy-inhibited document. Image processing device. 4. The image processing apparatus according to claim 3, wherein the prohibition unit prohibits the output of the image information by masking the image information with another image signal to invalidate the image information. 5. In the case of image scaling, said black peak detecting means changes an area to be referred to when detecting whether said pixel of interest is a black peak in the scanner running direction and said edge area. The image processing apparatus according to claim 1, wherein the detection unit changes an area to be referred to when detecting the edge area in the scanner traveling direction.