JP5104401B2 - Image processing apparatus, image processing method, and image forming apparatus - Google Patents

Description

  The present invention relates to an image processing apparatus, an image processing method, and an image forming apparatus such as an MFP.

  A technique for applying a digital watermark to an image of a document using human visual characteristics is used in the field of image formation. By inserting a digital watermark, it is possible to confirm the originality of the document, to display a copy prohibition warning, to add various auxiliary information, or to control the device.

  Conventionally, in a multi-function copying machine called a multi-function peripheral or MFP (Multi Function Peripherals), additional information is created using a plurality of types of dots of different sizes, and this additional information is combined with an image of a document. Embedding is done. For example, two types of dots having different sizes are used, a background is formed by small dots, and an embedded character is formed by large dots. The background and embedded characters by these two types of dots are synthesized as a background pattern for the image of the document.

  In recent years, in order to prevent a confidential document from being illegally copied, the above-described background pattern or predetermined additional information is added to the confidential document.

  For example, when the additional information of the original is read by the determination means and the original is determined to be a confidential document, the control means controls the copy operation of the original such as outputting a blank sheet, thereby An image processing apparatus capable of preventing outflow has been proposed (Patent Document 1).

  In addition, when copying a confidential paper document with a tint block printed in color mode, by eliminating the background part of the tint block, the latent image part of the tint block can be clearly revealed, and the effect of suppressing duplication of the tint block can be achieved. An image forming apparatus capable of performing the above has been proposed (Patent Document 2).

Furthermore, even when the background removal process for removing the background pattern as the background is set off by the user, the latent image pattern made up of character strings, patterns, etc. can be distinguished from the background pattern so that it can be easily seen. A possible image forming apparatus has been proposed (Patent Document 3).
Japanese Patent Laid-Open No. 6-20027 JP 2006-295857 A JP 2007-19734 A

  However, in the methods as described in Patent Documents 1 to 3, the copy of the original and the copy of the copy obtained by the copy (grandchild copy), the pattern of the secret information is formed. When the shape deteriorates, it becomes difficult to detect the secret information. As a result, it is impossible to accurately determine whether or not the manuscript or the copy includes confidential information.

  In view of such a problem, an object of the present invention is to enable accurate detection of secret information.

An image processing apparatus according to an aspect of the present invention is an image processing apparatus that performs image processing on image data generated by reading a document having secret information composed of dots. Pattern detecting means for detecting a specific pattern indicating that information exists, secret information detecting means for detecting the secret information from an area where the specific pattern detected by the pattern detecting means exists, and the secret information Storage means for storing dot data and pattern data respectively corresponding to the dot and the specific pattern, and an image based on the image data for the dot and the specific pattern of the secret information detected by the secret information detection means The dots and the specifics that are caused by repeatedly printing on the paper A deterioration preventing correction means for performing the deterioration prevention correction process for preventing the turn of degradation, the said area of the specific pattern is present, the specific dot is a dot of a predetermined shape representing that should perform the deterioration preventing correction Specific dot detection means for detecting whether each of the areas is present, and the deterioration preventing correction means is the area where the specific dots are detected by the specific dot detection means. The deterioration prevention correction process is performed on the dot and the specific pattern in the dot, and the deterioration prevention correction process is performed by the dot data stored in the storage unit at the original position of the dot and the specific pattern of the secret information. Write a dot based on the pattern and a specific pattern based on the pattern data. Including the conversion to the process.

  According to the present invention, it is possible to accurately detect confidential information from a document even when a generation copy is performed. Therefore, it is possible to accurately determine whether or not the document includes confidential information.

  According to the image processing apparatus according to the present embodiment, even when a copy of a manuscript and a copy of a copy obtained by the copy (these may be collectively referred to as “generation copies”), a password, etc. It is possible to prevent the deterioration of the pattern constituting the secret information. Thereby, it is possible to accurately determine whether or not the document includes confidential information. Hereinafter, a configuration for obtaining such an effect will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an example of the configuration of the image processing apparatus 1 according to the present embodiment, FIG. 2 is a block diagram showing an example of the configuration of the detection correction processing unit 4 in FIG. 1, and FIG. 3 shows secret information HJ. It is a figure for demonstrating the example of the detection area KR.

  As shown in FIG. 1, the image processing apparatus 1 includes a first scanner image processing unit 3, a detection correction processing unit 4, a second scanner image processing unit 5, a compression / decompression processing unit 6, a printer image processing unit 7, and a tint block pattern generation. 8, a password generation unit 9, a data storage unit 11, and the like. Note that a reading unit 2 including a CCD (Charge-Coupled Device), a mirror, a platen glass, and the like, and the printer 10 are provided as a part of an image forming apparatus HK described later.

  The image processing apparatus 1 is constituted by, for example, a CPU, a memory, and other circuit elements. In some cases, all or a part of these CPUs are used as LSIs as microcomputers or ASICs (Application Specific Integrated Circuits).

  The memory of the image processing apparatus 1 incorporates a computer program for realizing various functions of the image processing apparatus 1. Such a program can be installed from a portable recording medium BT including a recording medium BT1 such as a CD-ROM or DVS-ROM in which the program is recorded and a recording medium BT2 such as a semiconductor memory. It is also possible to download a program from a server via a network.

  The reading unit 2 reads a document and generates image data GD. The first scanner image processing unit 3 performs shading correction, interline correction, chromatic aberration correction, and the like on the image data GD generated by the reading unit 2.

  By the shading correction, so-called scanner unevenness (sensitivity variation of each pixel of the CCD, uneven light distribution, etc.) is corrected for the image data GD. By the inter-line correction, the phase shift of the R, G, B color image signals (data) caused by the positional shift between the R, G, B lines of the CCD is corrected. In this case, correction is performed by delaying the R and G image data GD using the field memory. By the chromatic aberration correction, the phase shift caused by the chromatic aberration of the lens system is corrected for the image data GD.

  The detection correction processing unit 4 detects a specific pattern for the image data GD, and corrects the image data GD based on the detection result. Details will be described later.

  The specific pattern is composed of a tint block pattern constituting secret information such as a password for authenticating an authorized user, a security level, and user information. The copy-forgery-inhibited pattern is a pattern provided to prevent unauthorized copying, and is therefore sometimes called an unauthorized copy code.

  The second scanner image processing unit 5 performs processes such as resolution conversion, area determination, color conversion, character edge correction, and error diffusion on the processed image data GD.

  By resolution conversion, resolution conversion is performed on the image data GD in accordance with a display unit (liquid crystal display) 21a of the operation panel 21 (to be described later) according to the setting state of the imaging mode in this apparatus. In resolution conversion, the resolution is reduced by thinning out the image data GD, and the resolution is increased by interpolating the image data GD.

  By the area determination, the image data GD is divided into areas corresponding to attributes such as characters, photographs, halftone dots, and edges. The color conversion converts the R, G, B image data GD into yellow (Y), magenta (M), cyan (C), and black (K) image data GD.

  Further, the edge of the character is emphasized by the character edge correction. By the error diffusion process, a halftone original image such as a photographic image is reproduced with a reduced value. In the error diffusion process, the gradation level of the original image is reduced to the reduced data by a certain threshold, and the error between the data value (luminance value) of the target pixel and the corresponding luminance value of the reduced data is constant. A plurality of peripheral pixels in the range are weighted and distributed.

  The compression / decompression processing unit 6 compresses the image data GD in a predetermined format, and stores the compressed image data GD in a memory (not shown). The compression / decompression processing unit 6 reads the image data GD stored in the memory and decompresses (decompresses) the image data GD.

  The printer image processing unit 7 performs predetermined image correction, image composition, screen control, delay control, and PWM control on the image data GD. By the image composition, the background pattern generated by the background pattern generation unit 8 and the password generated by the password generation unit 9 are combined with the image data GD.

  The data storage unit 11 stores dot data and pattern data respectively corresponding to security dots SD and specific patterns TP constituting secret information HJ described later. The detection correction processing unit 4 corrects the image data GD based on the dot data and pattern data stored in the data storage unit 11.

  The copy-forgery-inhibited pattern generation unit 8 generates a copy-forgery-inhibited pattern to be combined with the image data GD in the printer image processing unit 7 based on the dot data and pattern data stored in the data storage unit 11. The password generation unit 9 generates a specific pattern including a password and the like to be combined with the image data GD in the printer image processing unit 7 based on the dot data and pattern data stored in the data storage unit 11. . When the copy-forgery-inhibited pattern and password are added to the image data GD to generate the image data GDp with the specific pattern TP, the above-mentioned copy-forgery-inhibited pattern generation unit 8 and password generation unit 9 are used.

  As shown in FIG. 2, the detection correction processing unit 4 includes a detection unit 50, a frame memory 51, a first correction processing unit 52, a second correction processing unit 53, a selector 54, and the like.

  The detection unit 50 detects the specific pattern TP from the image data GD. Here, as shown in FIG. 3B, the specific pattern TP is constituted by a plurality of pattern dots PD regularly arranged.

  Next, when the specific pattern TP exists, the detection unit 50 detects a plurality of security dots SD arranged between the pattern dots PD. The plurality of security dots SD constitute the secret information (security information including the password PW) HJ in FIG.

  The CPU 20 recognizes an area where the security dot SD detected by the detection unit 50 exists (area where the specific pattern TP exists) as a detection area KR (area surrounded by a broken line in FIG. 3A). That is, the detection area KR includes the pattern dot PD and the security dot SD. Therefore, a region where the specific pattern TP overlaps the content CT1 made up of character images or the like is not recognized as the detection region KR. The CPU 20 is provided as a part of an image forming apparatus HK described later.

  The CPU 20 extracts the password PW from the secret information HJ detected by the detection unit 50. The frame memory 51 holds the image data GD until permission is given by the CPU 20.

  When the CPU 20 can extract the password PW from the secret information HJ, the CPU 20 displays a message indicating the request on the display unit 21a of the operation panel 21 in order to request the user to input the password. The operation panel 21 is provided as a part of an image forming apparatus HK described later.

  Then, when the password input by the user matches the password PW included in the secret information HJ, the CPU 20 allows the image data GD held in the frame memory 51 to be output, assuming that the user is a regular user.

  Here, the detection unit 50 detects whether or not a specific dot TD formed by adding a cross to a dot having a specific shape (specific size) exists in the detection region KR.

  The specific dot TD is a region SR surrounded by a plurality (eight in FIG. 3B) of security dots SD in a region TR surrounded by a plurality (four in FIG. 3B) of pattern dots PD. Arranged inside. The size (size) of the specific dot TD is set larger than the sizes of the pattern dot PD and the security dot SD.

  Based on the detection result of the detection unit 50, the first correction processing unit 52 identifies the specific dot TD, the pattern dot PD, and the security dot SD (hereinafter collectively referred to as “dot”) in the detection region KR where the specific dot TD exists. Deterioration prevention correction processing (detailed later) is performed to prevent these from being deteriorated by repeated copying.

  As described above, the combination of the recognition of the detection region KR and the detection of the specific dot TD makes it possible to accurately determine the region where the deterioration prevention correction process is to be performed. That is, when the specific dot TD does not exist in the detection region KR, the deterioration prevention correction process is not performed.

  The second correction processing unit 53 performs normal correction processing (smoothing processing) on the detection region KR and other regions where the specific dot TD does not exist based on the detection result of the detection unit 50. The density value of each pixel is set so that the change in density between adjacent pixels is smoothed by the smoothing process.

  In this case, the CPU 20 controls the selector 54 so that the image data GD1 after the deterioration prevention correction process and the normal correction process is output.

  On the other hand, even when the password PW is extracted from the secret information HJ, the CPU 20 outputs the image data GD of the frame memory 51 when it does not match the input password or when the password PW does not exist in the secret information HJ. do not do. In this case, other processing such as displaying a message on the display unit 21a may be performed.

  Furthermore, when the specific pattern TP does not exist in the image data GD, the CPU 20 controls the selector 54 so that the image data GD2 after the normal correction processing by the second correction processing unit 53 is output.

  FIG. 4 is a diagram for explaining an example of a document copying operation by the image forming apparatus HK, and FIG. 5 is a diagram for explaining an example of deterioration prevention correction processing.

  Hereinafter, a case will be described in which the copying operation of the original paper (hereinafter referred to as “security original paper”) S1 as shown in FIG. 4A is performed by an image forming apparatus HK such as an MFP (Multi Function Peripherals). The image forming apparatus HK includes an image processing apparatus 1, a reading unit 2, a printer 10, a CPU 20, an operation panel 21, and the like.

  On the security manuscript paper S1 of FIG. 4A, a manuscript image GG composed of a tint block pattern ZP made of a dot pattern and content CT1 (“ABC... XYZ” in FIG. 4A) is formed. ing.

  When copying the security manuscript paper S1, if the password authentication fails when the specific pattern TP exists in the security manuscript paper S1, or if the password PW does not exist in the secret information HJ, FIG. As shown in B), the copy image HG1 constituted by the black solid image BP is printed on the copy paper S2.

  In the above example, the black solid image BP is printed on the copy sheet S2 when the password authentication fails and the password PW does not exist. However, the image data GD held in the frame memory 51 is erased, A blank sheet may be output, or the message “copy prohibited” may be displayed on the display unit 21a of the operation panel 21 without printing the black solid image BP on the copy sheet S2.

  On the other hand, when the specific pattern TP does not exist on the security manuscript paper S1, as shown in FIG. 4C, the security manuscript paper S1 is composed of the tint block pattern ZP and the content CT2 based on the image data GD2 after the normal correction process (smoothing process). The copied image HG2 is printed on the copy paper S3.

  If the password authentication is successful when the specific pattern TP is present on the security manuscript paper S1, as shown in FIG. 4D, a secret information detection area group KG composed of a plurality of detection areas KR is detected. The normal correction process (smoothing process) described above for the secret information non-detected area group MG (area group in which the content CT1 exists) excluding the secret information detection area group KG is applied. Is given.

  Then, as shown in FIG. 4E, a copy image HG3 composed of the copy-forgery-inhibited pattern ZPH and the content CT2 including dots that do not deteriorate in shape even when copying is repeated is printed on the copy paper S4.

  Here, as deterioration prevention correction processing, processing for enhancing the edge of a dot using an edge enhancement filter (sharpness processing, edge enhancement processing), processing for changing a dot color to a pure color (M, C, K) (pure color processing) ), The error diffusion process described above, the writing process described below, and the dot diameter correction process (dot diameter correction process) such as the closing process, the dilation process, and the erosion process. Implemented in combination.

  In the sharpness processing (edge enhancement processing) described above, the detection region KR is regarded as an edge region regardless of the edge region determination result by the second scanner image processing unit 5, and the edges of the dots in the detection region KR are detected. Is emphasized. Another example of the deterioration prevention correction process is not performing the smoothing process.

  By performing such deterioration prevention correction processing, it is possible to prevent the dot shape from deteriorating even when copying is repeated.

  Hereinafter, the writing process as the deterioration prevention correction process will be described. The writing process is performed on the specific dot TD, the pattern dot PD, and the security dot SD in the detection region KR where the specific dot TD exists. Hereinafter, a case where the writing process is performed on the pattern dot PD will be described. An example will be described.

  When the writing process is performed on the pattern dot PD as shown in FIG. 5A, the pattern dot PD stored in the data storage unit 11 is written at the same position as the original position, and the pattern dot PD The surrounding area WR is converted into a white area. That is, if there is black or gray data in the area WR, it is erased to make it white. Thereby, it is possible to prevent the dot shape from being deteriorated due to the positional deviation or expansion of the dots or color blurring that occurs during color conversion or reading (scanning).

  The pure colorization process is performed as the deterioration prevention correction process for the following reason. Document dots are often written in primary colors such as magenta (M), cyan (C), or black (K). This is because color misregistration, discoloration, and the like are less likely to occur, thereby improving detection reliability. Therefore, the dot shape can be prevented from deteriorating by making the dots pure even in the copy.

  In addition, the error diffusion process is performed as the deterioration prevention correction process for the following reason.

  Normally, an image forming apparatus HK such as an MFP performs error diffusion processing to give priority to resolution for character areas and gives priority to reproduction of gradation for photo areas based on the result of area discrimination. For this reason, screen processing is performed. Therefore, error diffusion processing is performed on the dots in the detection area KR, as in the character area. Thereby, deterioration of the shape of a dot can be prevented.

  FIG. 6 is a flowchart for explaining an example of the flow of copying processing by the image processing apparatus 1, FIG. 7 is a flowchart for explaining an example of the flow of correction processing when there is a pattern in the copying processing, and FIG. It is.

  As shown in FIG. 6, first, it is determined whether or not the specific pattern TP exists in the image data GD (# 1). When the specific pattern TP exists (Yes in # 1), the secret information HJ is detected from the specific pattern TP (# 2).

  Then, it is determined whether or not the password PW exists in the detected secret information HJ (# 3). When the password PW exists in the secret information HJ (Yes in # 3), a password input request is made (# 4). In this case, as shown in FIG. 8, a password input request for the user is displayed on the display unit 21 a of the operation panel 21.

  Then, it is determined whether or not the password input by the user matches the password PW of the secret information HJ (# 5). When the password input by the user matches the password PW of the secret information HJ (Yes in # 5), the following pattern correction process is performed on the image data GD (# 6). Thereafter, the processed image data GD1 is output (# 7).

  Here, the procedure of the correction process when the pattern exists is as shown in FIG.

  That is, in FIG. 7, first, the detection region KR is recognized (# 21). Next, the detection process of the specific dot TD in each detection area KR is performed (# 22), and when the specific dot TD exists in the detection area KR (Yes in # 23), the detection that the specific dot TD exists is detected. Deterioration prevention correction processing is performed on the dots in the region KR, and normal correction processing (smoothing processing) is performed on the other regions (# 24).

  On the other hand, when the specific dot TD does not exist in the detection region KR (No in # 23), normal correction processing (smoothing processing) is performed on the detection region KR and other regions (# 25).

  Returning to FIG. 6, when the specific pattern TP does not exist (No in # 1), a correction process when no pattern exists, that is, a normal correction process (smoothing process) is performed on the image data GD (# 8). Thereafter, the processed image data GD2 is output (# 9).

  Furthermore, when the password PW does not exist in the secret information HJ (No in # 3), and when the password input by the user and the password PW of the secret information HJ do not match (No in # 5), the image data GD Is not output (# 10).

(Effect in this embodiment)
As described above, in this embodiment, when the specific pattern TP indicating that the secret information HJ exists in the document or the copy is detected, the deterioration prevention correction process is performed on the dots in the detection region KR. Thereby, even when generation copy is performed, it is possible to prevent the dot shape from deteriorating. This makes it possible to accurately detect the secret information HJ. Therefore, it is possible to accurately and reliably determine whether the document or the copy includes the confidential information HJ.

(Other embodiments)
In the above embodiment, when the password PW of the specific pattern TP matches the password input by the user, the user is authenticated as a legitimate user. However, the present invention is not limited to this, and is input by the user. If the password matches a pre-registered password, or if biometric authentication is performed using a user's voice or fingerprint, the user may be authenticated as a legitimate user.

  Further, the above-described CPU provided for processing in the image processing apparatus 1 and the CPU 20 provided in the image forming apparatus HK may be combined.

  In addition, the configuration of the entire image processing apparatus 1 or each unit, the processing content, the processing order, and the like can be appropriately changed in accordance with the gist of the present invention. In this case, the above-described unique and exceptional effects can be obtained. Is done.

It is a block diagram which shows the example of a structure of the image processing apparatus which concerns on this embodiment. It is a block diagram which shows the example of a structure of the detection correction process part of FIG. It is a figure for demonstrating the example of the detection area | region where secret information exists. FIG. 6 is a diagram for explaining an example of a document copying operation by the image forming apparatus. It is a figure for demonstrating the example of a deterioration prevention correction process. 10 is a flowchart for explaining an example of the flow of copying processing by the image processing apparatus. It is a flowchart explaining the example of the flow of a correction process at the time of the pattern in a copying process. It is a figure which shows the example of an operation panel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image processing apparatus 2 Reading part (reading means)
4 Detection correction processing unit (pattern detection means, secret information detection means, deterioration prevention correction means)
5 Second scanner image processing unit (edge area discrimination means)
10 Printer (printing means)
11 Data storage (storage means)
20 CPU (authentication means)
50 detection unit (pattern detection means, secret information detection means, specific dot detection means)
52 1st correction process part (deterioration prevention correction means)
GD Image data HJ Confidential information HK Image forming apparatus KR Detection area (area)
PD pattern dot SD security dot (dot)
TD specific dot TP specific pattern

Claims (9)

An image processing apparatus that performs image processing on image data generated by reading a document having secret information composed of dots,
Pattern detection means for detecting a specific pattern indicating that the secret information exists from the image data;
Secret information detection means for detecting the secret information from an area where the specific pattern detected by the pattern detection means exists;
Storage means for storing dot data and pattern data respectively corresponding to the dot and the specific pattern of the secret information;
For the dots and the specific pattern of the secret information detected by the secret information detection means, the deterioration of the dots and the specific pattern caused by repeatedly printing an image based on the image data on paper is prevented. Deterioration preventing correction means for performing deterioration preventing correction processing for
Specific dot detection means for detecting, for each region, whether or not there is a specific dot that is a dot of a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction unit performs the deterioration prevention correction process on the dot and the specific pattern in the region where the specific dot is detected by the specific dot detection unit,
In the deterioration prevention correction process, the dot based on the dot data stored in the storage unit and the specific pattern based on the pattern data are written and written to the original position of the dot and the specific pattern of the secret information. Including processing to convert the area around the dot to a white area,
An image processing apparatus. An image processing apparatus that performs image processing on image data generated by reading a document having secret information composed of dots,
Pattern detection means for detecting a specific pattern indicating that the secret information exists from the image data;
Secret information detection means for detecting the secret information from an area where the specific pattern detected by the pattern detection means exists;
For the dots and the specific pattern of the secret information detected by the secret information detection means, the deterioration of the dots and the specific pattern caused by repeatedly printing an image based on the image data on paper is prevented. In order to achieve this, a deterioration prevention correction process including a pure color process for purifying the dot of the secret information and the color of the specific pattern with one color of magenta (M), cyan (C), or black (K) is performed. Deterioration preventing correction means to be applied;
Specific dot detection means for detecting, for each region, whether or not there is a specific dot that is a dot of a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction unit performs the deterioration prevention correction process on the dot and the specific pattern in the region where the specific dot is detected by the specific dot detection unit.
An image processing apparatus. Authentication means for authenticating whether or not the document is a legitimate user;
The deterioration prevention correction unit performs the deterioration prevention correction process when the authentication unit authenticates the user as a legitimate user.
The image processing apparatus according to claim 1 . The deterioration prevention correction process includes a sharpness process that emphasizes the dots of the secret information and the edges of the specific pattern.
The image processing apparatus according to claim 1. Having an area determination means for determining an edge area for the image data;
The deterioration prevention correction unit regards the region as the edge region regardless of the determination result by the region determination unit for the region where the specific pattern exists, and sets the dot and the specific pattern of the secret information in the region. Applying the sharpness treatment,
The image processing apparatus according to claim 4 . An image forming apparatus that prints an image based on image data generated by reading a document having secret information composed of dots on a sheet,
Reading means for reading the original and generating image data;
Pattern detection means for detecting a specific pattern indicating that the secret information exists from the image data generated by the reading means;
Secret information detection means for detecting the secret information from an area where the specific pattern detected by the pattern detection means exists;
Storage means for storing dot data and pattern data respectively corresponding to the dot and the specific pattern of the secret information;
For the dots and the specific pattern of the secret information detected by the secret information detection means, the deterioration of the dots and the specific pattern caused by repeatedly printing an image based on the image data on paper is prevented. Deterioration preventing correction means for performing deterioration preventing correction processing for
Printing means for printing an image based on the image data after processing by the deterioration prevention correction means on paper;
Specific dot detection means for detecting, for each region, whether or not there is a specific dot that is a dot of a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction unit performs the deterioration prevention correction process on the dot and the specific pattern in the region where the specific dot is detected by the specific dot detection unit,
In the deterioration prevention correction process, the dot based on the dot data stored in the storage unit and the specific pattern based on the pattern data are written and written to the original position of the dot and the specific pattern of the secret information. Including processing to convert the area around the dot to a white area,
An image forming apparatus. An image forming apparatus that prints an image based on image data generated by reading a document having secret information composed of dots on a sheet,
Reading means for reading the original and generating image data;
Pattern detection means for detecting a specific pattern indicating that the secret information exists from the image data generated by the reading means;
Secret information detection means for detecting the secret information from an area where the specific pattern detected by the pattern detection means exists;
For the dots and the specific pattern of the secret information detected by the secret information detection means, the deterioration of the dots and the specific pattern caused by repeatedly printing an image based on the image data on paper is prevented. In order to achieve this, a deterioration prevention correction process including a pure color process for purifying the dot of the secret information and the color of the specific pattern with one color of magenta (M), cyan (C), or black (K) is performed. Deterioration preventing correction means to be applied;
Printing means for printing an image based on the image data after processing by the deterioration prevention correction means on paper;
Specific dot detection means for detecting, for each region, whether or not there is a specific dot that is a dot of a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction unit performs the deterioration prevention correction process on the dot and the specific pattern in the region where the specific dot is detected by the specific dot detection unit.
An image forming apparatus. An image processing method for performing image processing on image data generated by reading a document having secret information composed of dots,
Detecting a specific pattern indicating that the secret information exists from the image data;
Detecting the secret information from an area where the detected specific pattern exists;
Deterioration prevention correction for preventing deterioration of the dot and the specific pattern caused by repeatedly printing an image based on the image data on the detected data with respect to the dot and the specific pattern of the secret information Processing steps,
A specific dot detection step for detecting, for each region, whether or not there is a specific dot that is a dot having a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction process is performed on the dot and the specific pattern in the region where the specific dot is detected in the specific dot detection step,
In the deterioration prevention correction process, a dot based on the dot data stored in the storage unit and a specific pattern based on the pattern data stored in the storage unit at the original position of the dot and the specific pattern in the secret information are added. Including the process of writing and converting the area around the written dot to a white area,
An image processing method. An image processing method for performing image processing on image data generated by reading a document having secret information composed of dots,
Detecting a specific pattern indicating that the secret information exists from the image data;
Detecting the secret information from an area where the detected specific pattern exists;
In order to prevent the dot and the specific pattern from being deteriorated by repeatedly printing an image based on the image data on the paper with respect to the detected dot and the specific pattern of the secret information. Performing a deterioration prevention correction process including a pure color process for purifying the color of the dot of the information and the color of the specific pattern with one of magenta (M), cyan (C), or black (K);
A specific dot detection step for detecting, for each region, whether or not there is a specific dot that is a dot having a specific shape indicating that the deterioration prevention correction processing should be performed in the region where the specific pattern exists; Have
The deterioration prevention correction process is performed on the dot and the specific pattern in the region where the specific dot is detected in the specific dot detection step.
An image processing method.

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