JP4757677B2 - Information embedding device, information embedding method, information embedding program, and recording medium - Google Patents

Description

  The present invention relates to an information embedding device, an information embedding method, an information embedding program, and a recording medium, and more particularly to a technique for embedding information in image data in which watermark information is embedded.

  In recent years, a digital watermark technique for embedding information for preventing falsification or copying of image data or document data has been developed. Several techniques have been proposed for embedding a digital watermark technique in a document output as a paper medium in a format that is not visually noticeable to the user.

  For example, Patent Document 1 proposes a technique for embedding secret information by arranging a dot pattern.

  By using such technology, security information for preventing forgery and tampering of the printed document with respect to the recording paper, electronic information indicating the contents described in the printed document, and the printed document It is possible to embed URL information or the like indicating a Web site that guides the contents related to. Thereby, a new added value can be provided for the printed document.

JP 2003-101762 A

  However, as disclosed in Patent Document 1, when watermark information is already embedded in image data, it is difficult to add new information because a dot pattern is arranged on the entire surface.

  In the case of such a conventional technique, once embedded information is extracted, a bit string in which information added to the extracted information is connected is generated, and watermark information generated from the bit string is embedded again. In this case, there is a problem that it takes time to restore the embedded information, or information cannot be added depending on the amount of information already embedded.

  The present invention has been made in view of the above, and an information embedding apparatus, an information embedding method, an information embedding method, and the like, which can easily embed additional information in image data in which watermark information is already embedded. It is an object to provide an embedded program and a recording medium.

In order to solve the above-described problems and achieve the object, the invention according to claim 1 is an image acquisition unit that acquires image data in which information is embedded by an image pattern group composed of a plurality of image patterns; Additional information acquisition means for acquiring additional information, which is information to be further embedded, with respect to the image data acquired by the image acquisition means, and the image pattern attached to the image data acquired by the image acquisition means A position specifying means for specifying the position of the image pattern constituting the group, and an image pattern existing in a region specified by a predetermined rule from the image pattern group whose position is specified by the position specifying means; by dot size or color without changing the position of the dot pattern is processed into different forms and the additional information to the image data Characterized by comprising the additional information embedding means for writing fit, a.

The invention according to claim 2 is the invention according to claim 1 , wherein the position specifying means specifies the position of the embedding block indicating the area including each of the image patterns, and then specifies the specified position. A set block including a plurality of embedded blocks is specified, and the additional information embedding means includes the image pattern included in the embedded block specified by the predetermined rule among the embedded blocks included in the set block. The additional information is embedded by processing the form.

The invention according to a third aspect is the invention according to the first or second aspect , wherein the additional information embedding means sets a dot larger than the dot size of the image pattern without changing a position of the dot of the image pattern. The additional information is embedded by processing into the used form.

According to a fourth aspect of the present invention, there is provided an image acquisition unit that acquires image data in which information is embedded by an image pattern group composed of a plurality of image patterns, and the image data acquired by the image acquisition unit. Further, additional information acquisition means for acquiring additional information, which is information to be embedded, and the position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquisition means a position specifying unit, a position is specified by the position specifying means, from the image pattern group that includes the line patterns, the images pattern that exists in the specified region by a predetermined rule, the position of the line of the image pattern the length of the line without changing, is processed into a form that the width or color is different, the additional information embedding means for embedding the additional information Characterized by comprising a.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , wherein the image acquisition means processes the form of the partial image pattern included in the image pattern group. The position specifying means specifies an area of the image pattern group that is not processed in the form of the image pattern, and the additional information embedding means includes the position information. The additional information is embedded by processing a part of the image pattern in the image pattern group included in the area specified by the specifying unit.

The invention according to claim 6 is the invention according to any one of claims 1 to 5 , further comprising image correction means for performing image correction processing on the image data acquired by the image acquisition means. It is characterized by that.

The invention according to claim 7 is the invention according to any one of claims 1 to 6 , wherein the image acquisition unit acquires the image data by scanning a recording sheet. .

The invention according to claim 8, an image acquisition step of acquiring image data in which information has been embedded by the formed image pattern group from a plurality of image patterns, with respect to the image data acquired by the image acquisition step Further, an additional information acquisition step for acquiring additional information, which is information to be embedded, and a position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquisition step are specified. From the position specifying step and the image pattern group whose position is specified by the position specifying step , an image pattern existing in an area specified by a predetermined rule is changed without changing the dot position of the image pattern. by size or color is processed into different forms and additional information embedding the additional information into the image data And having a buried step.

The invention according to claim 9 is the invention according to claim 8 , wherein the position specifying step specifies the position of the embedding block that indicates the area including each of the first image patterns, and then specifies the position. A set block including a plurality of the embedded blocks, and the additional information embedding step is included in the embedded block specified by the predetermined rule among the embedded blocks included in the set block. The additional information is embedded by processing the form of the image pattern.

According to a tenth aspect of the present invention, in the invention according to the eighth or ninth aspect , the additional information embedding step does not change a dot position of the first image pattern. The additional information is embedded by processing into a form using dots larger than the dot size.

According to an eleventh aspect of the present invention, there is provided an image acquisition step of acquiring image data in which information is embedded by an image pattern group composed of a plurality of image patterns, and the image data acquired by the image acquisition step. Further, an additional information acquisition step for acquiring additional information, which is information to be embedded, and a position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquisition step are specified. position identification step, the position by the position specifying step is identified from the first image pattern group that includes the line patterns, the images pattern that exists in the specified area by the predetermined rule, the image pattern By changing the length, width or color of the line without changing the position of the line, And additional information embedding step of embedding the pressure information, and having a.

According to a twelfth aspect of the present invention, in the invention according to any one of the eighth to eleventh aspects, the image acquisition step is performed after processing a form of the partial image pattern included in the image pattern group. The position specifying step further specifies a region of the image data group that is not processed in the form of the image pattern in the image data, and the additional information embedding step includes: The additional information is embedded by processing a part of the image pattern of the image pattern group included in the region specified by the position specifying step.

The invention according to claim 13 is the invention according to any one of claims 8 to 12 , further comprising an image correction step of performing an image correction process on the image data acquired by the image acquisition step. It is characterized by that.

According to a fourteenth aspect of the present invention, in the invention according to any one of the eighth to thirteenth aspects, the image acquiring step acquires the image data by scanning a recording sheet. .

The invention according to claim 15 is characterized in that the information embedding method according to any one of claims 8 to 14 is executed by a computer.

The invention according to claim 16 is a computer-readable recording medium storing the information embedding program according to claim 15 .

According to the first aspect of the present invention, information that has already been embedded because the position has not been changed by processing the dot in the size or the color in a different form without changing the dot position of the image pattern. Can be extracted and additional information can be embedded.

According to the invention of claim 2 , watermark information can be extracted from the image pattern by processing the form of the image pattern included in the embedded block specified by the predetermined rule for each aggregate block. Therefore, it is possible to embed additional information in the image data in which watermark information is already embedded.

Further, according to the invention of claim 3 , if the dot size is changed to a larger dot size, the image pattern can be processed without deleting the already applied image pattern, so that additional information is embedded. There exists an effect that processing becomes easy.

According to the invention of claim 4 , since the position is not changed by processing into a form in which the length, width or color of the line is different without changing the position of the line of the image pattern, it is already embedded. It is possible to extract the information that has been stored and to embed additional information.

Further, according to the invention of claim 5 , there is an effect that the additional information can be embedded in the image data a plurality of times.

According to the invention of claim 6 , since the image correction process is performed, the quality of the image data is improved, and the accuracy when information is embedded is improved.

According to the seventh aspect of the invention, additional information can be further added to the paper-medium document, so that the convenience is improved.

Further, according to the invention according to claim 8 , since the positions of the dots are not changed by changing the size or color of the dots without changing the positions of the dots of the image pattern, the dots are already embedded. This makes it possible to extract the information and to easily embed additional information in the image data in which the information is already embedded .

According to the invention of claim 9 , watermark information can be extracted from the image pattern by processing the form of the image pattern included in the embedded block specified by the predetermined rule for each aggregate block. Therefore, it is possible to embed additional information in the image data in which watermark information is already embedded.

According to the tenth aspect of the present invention, if the dot size is changed to a larger dot size, the image pattern can be processed without deleting the already attached image pattern, so that additional information is embedded. There exists an effect that processing becomes easy.

According to the eleventh aspect of the present invention, since the positions of the lines in the image pattern are not changed, and the positions are not changed by processing the lines in different forms in length, width, or color, so that the positions have not been changed. It is possible to extract the information that has been stored and to embed additional information.

Further, according to the twelfth aspect of the present invention, there is an effect that additional information can be embedded in image data a plurality of times.

According to the thirteenth aspect of the present invention, since the image correction process is performed, the quality of the image data is improved, and the accuracy in embedding information is improved.

According to the fourteenth aspect of the present invention, additional information can be further added to a paper medium document, so that the convenience is improved.

According to the invention of claim 15 , the information embedding method according to any one of claims 8 to 14 can be realized by using a computer by causing the computer to read and execute the information. The same effects as those of the information embedding methods are achieved.

The invention according to claim 16 is a recording medium storing the information embedding program according to claim 15 , and the information embedding program is executed by causing the computer to read the recording medium. There is an effect that is possible.

  Exemplary embodiments of an information embedding device, an information embedding method, an information embedding program, and a recording medium according to the present invention will be explained below in detail with reference to the accompanying drawings.

(First embodiment)
As an embodiment of the present invention, an example in which the information embedding device of the present invention is applied to a printer will be described. This printer is connected to the PC 50 and accepts input of document image data in which watermark information is embedded (hereinafter referred to as first watermarked embedded document image data) from the PC. In the present embodiment, the image data to which the watermark information is attached is not limited to the document image data in which the document is described, and any image data may be used.

  FIG. 1 is a block diagram showing a configuration of a PC 50, a printer 100, and an information extraction device 150 according to the first embodiment of the present invention. As shown in the figure, the PC 50 includes a document generation unit 51, an information acquisition unit 52, an information embedding unit 53, and an output processing unit 54. The first watermarked document image data is transferred to the printer 100. Process to output to.

  The document generation unit 51 generates document data based on information input from a user using an input device (not shown) or the like.

  FIG. 2 is an explanatory diagram showing an example of document data generated by the document generation unit 51. Watermark information is embedded in the document data shown in this figure.

  Returning to FIG. 1, the information acquisition unit 52 acquires the embedding target information to be embedded as a watermark in the document data. The embedding target information may be any information, but may be, for example, original digital data indicating document data, text information included in the document data, or link information for accessing the digital data.

  The information embedding unit 53 performs processing for embedding information to be embedded in the document data for the generated document data. Specifically, the information embedding unit 53 generates watermark image data in which a bit string indicating embedding target information is embedded as a dot pattern. Thereafter, the information embedding unit 53 performs a process of superimposing the generated watermark image data as the background of the document data.

  A procedure for generating watermark image data in the information embedding unit 53 will be described. First, the information embedding unit 53 performs a process of dividing the watermark image data having the same display area size as the document data into blocks each having a predetermined size (hereinafter referred to as an embedding block). Then, the information embedding unit 53 arranges a dot pattern indicating each bit information of the bit string of the embedding target information for each embedding block.

  Next, the arranged dot pattern will be described. FIG. 3A is a diagram illustrating an example of a dot pattern indicating '0' bits. FIG. 3B is a diagram illustrating an example of a dot pattern indicating '1' bits. These dot patterns are arranged for each embedded block. These dot patterns correspond to the first image pattern in other words.

  In addition, the pattern arrange | positioned for every embedding block is not restrict | limited to the dot pattern shown to FIGS. 3-1 and FIGS. 3-2. A modification of the image pattern arranged on the background will be described. FIG. 4A is a diagram illustrating an example of a line pattern indicating a “0” bit according to the present modification. FIG. 4B is a diagram illustrating an example of a line pattern indicating the “1” bit according to the present modification. As described above, the watermark image data may have any shape image pattern as long as it is an image pattern in which bit information can be distinguished. When these line patterns are used, additional information is embedded by changing the line length, width, or color of the line pattern. Other processes are the same as those in the first embodiment, and a description thereof is omitted.

  Returning to the first embodiment, FIG. 5 is an explanatory diagram showing an example of watermark image data generated by the information embedding unit 53. As shown in the figure, the dot pattern described above is arranged on the entire surface of the watermark image data. The information embedding unit 53 can generate a watermark image in which the embedding target information is embedded by arranging the dot pattern in this way. Further, the information embedding unit 53 superimposes the generated watermark image data as the background of the document data. That is, the embedding target information is embedded in the document data as a watermark.

  Returning to FIG. 1, the output processing unit 54 performs processing for outputting the document data on which the watermark is superimposed to the printer 100 together with the print request. Further, before performing the output process, the output processing unit 54 converts the document data into image data when outputting to the printer 100. The image data converted from the document data on which the watermark is superimposed is set as the first watermarked document image data.

  By the output processing of the output processing unit 54, the printing process is performed after the additional information is embedded in the printer 100 described later. The output processing unit 54 also outputs a user ID for identifying a printer. The user ID and the like are embedded as watermark information by the printer 100 described later.

  The printer 100 includes an input receiving unit 101, an additional information acquisition unit 102, an image acquisition unit 103, a position specifying unit 104, an additional information embedding unit 105, and a print processing unit 106. The received first watermarked document image data is further embedded with additional information at the time of printing and is output to a recording sheet.

  Further, the additional information to be embedded may be any information, but in the present embodiment, it is information that identifies the source. Examples of the information specifying the origin include a user ID for identifying a user who has printed, printer information unique to the printer, and a printing date and time.

  The input reception unit 101 receives an input of a user ID for identifying a printed user and first watermarked document image data together with a print request from the PC 50.

  The additional information acquisition unit 102 acquires, as additional information, a user ID (hereinafter referred to as a printer ID) that identifies a user who has printed, printer information unique to the printer 100, and a printing date and time. Further, the printer ID is acquired from the input receiving unit 101.

  Further, as a method for acquiring the printer information, it can be considered to read from an HDD or the like (not shown) in the printer 100. The print date / time acquisition method may include receiving an input from the PC 50, acquiring it from the internal configuration of the printer 100, or acquiring it from a TSA (time certification authority) or the like via a network.

  The image acquisition unit 103 acquires the first watermarked document image data that has been accepted. In some cases, information is not embedded in the document image data input to the printer 100 (a dot pattern is not added to the background). Therefore, the image acquisition unit 103 may determine whether information is embedded in the input document image data. If the information is embedded, the processing described later is performed. In the case where it is not embedded, any processing may be performed. For example, a dot pattern indicating additional information may be added.

  The position specifying unit 104 includes an embedding block position specifying unit 111 and a set block position specifying unit 112, and specifies the positions of set blocks, embedded blocks, and dot patterns necessary for embedding additional information.

  The embedding block position specifying unit 111 specifies the position of the dot of the dot pattern added to the background of the acquired first watermarked document image data and the position of the embedding block including each dot pattern. The embedding block position specifying unit 111 may use any technique for specifying the dot pattern and the position of the embedding block, but for example, specifies the position of the embedding block by using template matching.

  The collective block position specifying unit 112 specifies the position of the collective block composed of the embedded blocks 3 × 3 from the position of the embedded block specified by the embedded block position specifying unit 111.

  The collective block refers to a block obtained by integrating a plurality of embedding blocks set to embed one or more pieces of bit information of additional information. In this embodiment, the collective block is composed of 3 × 3 embedded blocks and stores 1-bit information of additional information.

  FIG. 6 is an explanatory diagram showing an example of a collective block identified from the background of the first watermarked document image data by the collective block position specifying unit 112. As shown in the figure, it can be confirmed that the collective block includes the dot pattern indicating the above-described ‘0’ bit or ‘1’ bit by 3 × 3.

  Returning to FIG. 1, the additional information embedding unit 105 performs a process of embedding bit information of the additional information for each aggregate block whose position is specified. Specifically, the additional information embedding unit 105 embeds additional information by enlarging the dot size of the dot pattern of a predetermined embedding block included in the aggregate block. Next, the position of the embedding block for increasing the dot size will be described.

  Information about the dot pattern before processing is embedded at the dot position. The dot pattern before processing and the dot pattern with the enlarged dot size have a corresponding relationship because the dot position is not changed.

  FIG. 7 is an explanatory diagram showing the position of an embedding block that enlarges the dot size in the aggregate block. As shown in (A) of this figure, when the bit information to be embedded as additional information is ‘0’ bits, the bit size of the embedded block in the upper middle column and the lower middle column of the aggregate block is expanded. As shown in (B) of this figure, when the bit information embedded as additional information is ‘1’ bits, the bit size of the embedded block in the middle stage left column and the middle stage right column of the aggregate block is expanded. In this way, information for each bit is assigned to each aggregate block.

  FIG. 8 is an explanatory diagram showing the process of embedding bit information by the additional information embedding unit 105 for each stage. As shown in the figure, the additional information embedding unit 105 performs processing for converting a printing date and time, a printer ID indicating a printer, and printer information to be embedded as additional information into a bit string. Next, the additional information embedding unit 105 concatenates the printing date and time, the printer ID, and the printer information converted into this bit string to form one bit string. Then, the additional information embedding unit 105 performs a process of expanding the dot size of the dot pattern of the embedding block at the predetermined position described above for each aggregate block for each bit information included in the connected bit string. Do. In addition, the dot pattern in which the dot size is enlarged corresponds to the second image pattern in other words.

  Further, the order of expansion is as follows: for each bit from the first bit of the bit string, the dot size of the dot pattern of the embedded block at the above-mentioned position of the aggregate block is sequentially changed from the left end of the top stage of the aggregate block to the right. The process of embedding is performed by enlarging. When the embedding process is performed up to the right end of the corresponding stage of the aggregate block, the embedding process is sequentially performed from the left end of the next stage. As a result, document image data in which additional information is embedded is generated. The document image data in which the additional information is embedded is referred to as second watermarked document image data.

  FIG. 9 shows a data flow until the first watermarked document image data output from the PC 50 is printed on the recording paper as the second watermarked document image data by the printer 100 in this embodiment. FIG.

  As shown in the figure, the PC 50 outputs document image data in which watermark information is embedded by attaching a dot pattern having the same dot size. Then, the printer 100 embeds additional information by enlarging the dot size of the dot pattern added to the input first document image data. That is, the second watermarked document image data printed from the printer 100 has two types of dot sizes. When the printer 100 performs such processing, since the dot position is not changed, the watermark information embedded by the PC 50 is not added, changed, or deleted. That is, the printer 100 can embed additional information without performing processing such as analysis on already embedded watermark information.

  Further, the printer 100 can embed additional information without analyzing the watermark information already attached to the first watermarked document image data and rearranging the background dot pattern. As a result, processing load such as analysis for the printer 100 is reduced.

  The print processing unit 106 performs print processing of the second watermarked document image data in which the additional information is embedded. That is, since the origination information is embedded in the recording paper on which the second watermarked document image data is output, the source of the outflow can be specified when the information is leaked, and thus the safety is improved. Thus, since the second watermarked document image data printed on the recording paper can be acquired, the convenience is improved.

  The information extraction device 150 includes a document image acquisition unit 151, an image correction unit 152, a watermark image extraction unit 153, a determination unit 154, a first information extraction unit 155, a second information extraction unit 156, and a display processing unit. 157 and a resolution conversion unit 158, and after reading the second watermarked document image data printed by the printer 100, the embedded information is extracted and displayed on a monitor (not shown) together with the image data I do.

  The document image acquisition unit 151 performs processing for acquiring the second watermarked document image data via the scanner 10. Note that the method of acquiring the second watermarked document image data is not limited to that using the scanner 10, and may be acquired via a public network, for example.

  The image correction unit 152 performs processing for correcting the acquired second watermarked document image data. For example, since the image data read by the scanner 10 generally has noise or distortion, the image correction unit 152 performs correction suitable for performing the processing described later.

  The watermark image extraction unit 153 performs a process of separating the background portion from the second watermarked document image data and extracting the watermark image data. In addition, with such processing, document image data to which watermark image data is not added can be acquired.

  Any method may be used as the data restoration method in the region where the background dot pattern and the characters described in the document are overlapped, regardless of a known technique.

  The determination unit 154 determines whether the first information can be extracted from the extracted watermark image data. The determination unit 154 determines whether or not the dot pattern embedded by the PC 50 can be read in the acquired watermark image data.

  In other words, since the size of the dot pattern embedded in the PC 50 is very small, when the second watermarked document image data printed from the printer 100 is copied by another multifunction device, it is embedded in the PC 50 by background processing or the like. The dot pattern may be erased.

  Therefore, the determination unit 154 determines whether or not the dot pattern can be read. In the present embodiment, processing described later is made different depending on a difference in determination indicating whether or not a dot pattern can be read. In the printer 100 according to the present embodiment, the dot size of the dot pattern in which the additional information is embedded is enlarged. For this reason, it is assumed that the dot pattern whose dot size has been confirmed remains without falling below the limit of the image reproduction capability. In the following, a dot pattern that has not been enlarged by the printer 100 is referred to as a dot pattern having a minute dot size.

  When it is determined by the determination unit 154 that the information embedded by the PC 50 can be extracted, the first information extraction unit 155 uses the minute dot size dot pattern and the enlarged dot size dot pattern from the watermark image data. The information embedded by the PC 50 is extracted. Any technique may be used as the technique for extracting the first information. For example, it has been described in Japanese Patent Application No. 2005-050593 “Information Extraction Method, Information Extraction Apparatus, Information Extraction Program, and Storage Medium”. Technology or the like can be used. Note that since the additional information is embedded, the minute dot size and the enlarged dot size are mixed. Therefore, the first information extraction unit 155 performs template matching or the like with the dot patterns of the respective dot sizes. By performing such processing, the first information extraction unit 155 can extract the first information.

  The second information extraction unit 156 extracts additional information embedded from the printer 100 by different processing depending on whether the determination unit 154 determines that the information embedded by the PC 50 can be extracted. These processes will be described below.

  First, a case will be described in which the second information extraction unit 156 extracts additional information from watermark image data in which a minute size dot pattern representing only information embedded from the PC 50 is not erased.

  FIG. 10 is an explanatory diagram showing an example of watermark image data in a case where a minute size dot pattern is not removed. As shown in the figure, in the watermark image data, a dot pattern having a minute dot size and a dot pattern having an enlarged dot size are described.

  Then, the second information extraction unit 156 specifies the above-described embedding block position using a technique such as template matching. Then, the second information extracting unit 156 identifies the aggregate block by integrating the identified embedded blocks 3 × 3.

  Further, the second information extraction unit 156 extracts bit information of additional information from each aggregate block. Specifically, the second information extraction unit 156 can extract the bit information of the additional information by determining whether the dot size of the embedded block at which position of the aggregate block is large.

  In addition, the determination whether the dot size performed by the second information extraction unit 156 is large or not may be performed by any method, for example, by determining the number of black pixels in the embedding block. Also good.

  As a result, the second information extraction unit 156 can identify the position of the embedded block in which the enlarged dot size is arranged in the aggregate block, and thus can acquire the bit information of the additional information.

  Next, a case where the second information extraction unit 156 extracts additional information from watermarked document image data in which the dot pattern representing only the information embedded by the PC 50 has disappeared will be described.

  FIG. 11 is an explanatory view showing an example of watermarked document image data when a minute size dot pattern is removed. As shown in the figure, in the watermarked document image data, only a dot pattern having an enlarged dot size is described. In the present embodiment, the resolution conversion unit 158 performs resolution conversion before the second information extraction unit 156 extracts additional information.

  The resolution conversion unit 158 performs processing for converting the watermarked document image data to a predetermined resolution lower than the resolution of the original image data.

  FIG. 12 is an explanatory diagram showing a process of converting the resolution to a predetermined resolution performed by the resolution conversion unit 158. (A) in this figure is watermarked document image data before conversion, and (B) in this figure is watermarked document image data after conversion. As shown in the figure, the predetermined resolution converted by the resolution conversion unit 158 is a resolution at which the above-described embedded block becomes one dot. In the present embodiment, the predetermined resolution is set to such a value. However, the resolution is not limited to this value, and may be any resolution that facilitates template matching described later.

  At this time, when the resolution conversion unit 158 converts a predetermined resolution, if there are a plurality of black dots in the embedding block, a conversion to black dots is performed, and if there are not, a conversion to white dots is performed. Do. Thereby, the information extraction apparatus 150 of this Embodiment can acquire the low resolution image data shown to (B) of FIG.

  Then, the second information extraction unit 156 extracts additional information from the watermarked document image data whose resolution is converted by the resolution conversion unit 158. The second information extraction unit 156 performs template matching when extracting additional information.

  FIGS. 13A and 13B are diagrams illustrating templates used by the second information extraction unit 156 for template matching. FIG. 13A is a template showing the ‘0’ bit, and FIG. 13B is a template showing the ‘1’ bit. The second information extraction unit 156 can acquire the bit information of the additional information by performing the matching process using the template described above on the block corresponding to the aggregate block.

  Returning to FIG. 1, the display processing unit 157 displays the contents of the document image data on a monitor (not shown) and also displays the origin information embedded as additional information. In addition, when the original digital data embedded by the PC 50 can be extracted, the display processing unit 157 may display the original digital data describing the content in an editable state instead of the document image data. .

  Next, from the reception of the input of the first watermarked document image data in the printer 100 according to the present embodiment configured as described above, the second watermarked document image data further embedded with additional information is printed. The process up to will be described. FIG. 14 is a flowchart illustrating a procedure of the above-described processing in the printer 100 according to the present embodiment.

  First, the input receiving unit 101 receives a print request from the PC 50 and a user ID for identifying a printed user and first watermarked document image data (step S1101).

  Next, the additional information acquisition unit 102 acquires a printer ID embedded as additional information, printer information unique to the printer 100, and a printing date and time (step S1102).

  Then, the image acquisition unit 103 acquires the first watermarked document image data received by the input receiving unit 101 (step S1103).

  Next, the embedding block position specifying unit 111 specifies the dot pattern and the position of the embedding block in the background of the first watermarked document image data (step S1104).

  Then, the collective block position specifying unit 112 specifies the position of the collective block made up of 3 × 3 embedded blocks from the specified position of the embedded block (step S1105).

  Next, the additional information embedding unit 105 enlarges the dot size of the dot pattern of the predetermined embedding block for each aggregate block whose position is specified, and embeds the additional information in the document image data (step S1106). As a result, the second watermarked document image data in which the additional information is embedded is generated.

  Then, the print processing unit 106 outputs the generated second watermarked document image data to a recording sheet (step S1107).

  The processing procedure described above allows the user to obtain a recording sheet in which additional information is embedded. The above-described processing procedure is an example of a printing processing procedure for the second watermarked document image data in which additional information is further embedded from the reception of the input of the first watermarked document image data according to the present embodiment. However, the present invention is not limited to this processing procedure.

  Next, processing from the acquisition of the second watermarked document image data to the display processing of the document image data and the extracted information in the information extracting apparatus 150 according to the present embodiment configured as described above will be described. FIG. 15 is a flowchart showing the above-described processing procedure in the information extraction apparatus 150 according to the present embodiment.

  First, the document image acquisition unit 151 performs processing for acquiring second watermarked document image data via the scanner 10 or the like (step S1201).

  Next, the image correction unit 152 performs a process of correcting the acquired second watermarked document image data (step S1202). This corrects image noise reduction, distortion, and the like that often occur when image data is acquired by reading a printed document on a paper medium.

  Then, the watermark image extraction unit 153 extracts background watermark image data from the second watermarked document image data (step S1203). At this time, document image data from which the background has been removed is also acquired.

  Next, the determination unit 154 determines whether or not a dot pattern showing only information embedded by the PC 50 can be read from the extracted watermark image data (step S1204).

  If the determination unit 154 determines that it can be read (step S1204: Yes), the first information extraction unit 155 identifies the position of the embedded block from the extracted watermark image data, and determines the level of each embedded block. Bit information is acquired from the dot pattern, and information embedded by the PC 50 is extracted (step S1205).

  Next, the second information extraction unit 156 integrates the embedded blocks 3 × 3 specified by the first information extraction unit 155, specifies the position of the aggregate block, and acquires bit information of additional information for each aggregate block Then, additional information embedded in the printer 100 is extracted (step S1206).

  If the determination unit 154 determines that it cannot be read (step S1204: NO), the resolution conversion unit 158 performs processing for converting the extracted watermark image data to a low resolution (step S1207).

  Next, the second information extraction unit 156 performs template matching on the watermark image data converted into the low resolution, acquires bit information of the additional information for each aggregate block, and extracts the additional information (step) S1208).

  Then, the display processing unit 157 performs processing for displaying the extracted information together with the document image data (step S1209).

  With the processing procedure described above, it is possible to confirm information embedded as a watermark. The processing procedure described above shows an example of the processing procedure from the acquisition of the second watermarked document image data to the display of the document image data according to this embodiment, and the present invention is limited to this processing procedure. Not what you want.

  In the first embodiment, the case where the color of the dot pattern is black has been described. However, the color of the dot pattern is not limited. That is, any color may be used for the dot pattern as long as the information extraction device 150 can extract information embedded as a watermark. For example, a color that approximates the output destination paper may be used as the color of the dot pattern.

  As a result, the user does not care about the dot pattern attached to the background, and can easily grasp the contents of the document image data printed on the paper. That is, the visibility for the user is improved, and the appearance deterioration of the watermarked document image data can be suppressed.

  The printer 100 according to the above-described embodiment can easily add additional information to the first watermarked document image data in which information is already embedded without affecting the information already embedded. Can be embedded. Moreover, since it is not necessary to analyze the embedded information, the processing load at the time of embedding can be reduced.

  FIG. 16 is a diagram illustrating a hardware configuration of a PC that executes a program for realizing the functions of the printer 100. The printer 100 according to the present embodiment includes a control device such as a CPU (Central Processing Unit) 1501, a storage device such as a ROM (Read Only Memory) 1502 and a RAM (Random Access Memory) 1503, an HDD (Hard Disk Drive), An external storage device 1504 such as a CD (Compact Disk) drive device, a display device 1505 such as a display device, an input device 1506 such as a keyboard and a mouse, a communication I / F 1507, and a bus 1508 for connecting them are provided. The hardware configuration uses a normal computer.

  The information embedding program executed by the printer 100 according to the present embodiment is a file in an installable or executable format, such as a CD-ROM, a flexible disk (FD), a CD-R, a DVD (Digital Versatile Disk), or the like. The program is provided by being recorded on a computer-readable recording medium.

  In addition, the information embedding program executed by the printer 100 of the present embodiment may be stored on a computer connected to a network such as the Internet and provided by being downloaded via the network. Further, the information embedding program executed by the printer 100 of the present embodiment may be provided or distributed via a network such as the Internet.

  Further, the information embedding program of this embodiment may be provided by being incorporated in advance in a ROM or the like.

  The information embedding program executed by the printer 100 according to the present embodiment includes the above-described units (input receiving unit, additional information acquiring unit, image acquiring unit, position specifying unit, additional information embedding unit, and print processing unit). It has a module configuration, and as the actual hardware, the CPU reads the information embedding program from the recording medium and executes the information embedding unit to be loaded onto the main storage device, the input receiving unit, the additional information acquiring unit, An image acquisition unit, a position specifying unit, an additional information embedding unit, and a print processing unit are generated on the main storage device.

(Second Embodiment)
In the first embodiment described above, an example in which the information embedding device is applied to the printer 100 has been described. However, the electronic device to which the information embedding device is applied is not limited to the printer 100. Therefore, in the second embodiment, a case where the information embedding device is applied to a multifunction machine will be described.

  FIG. 17 is a block diagram illustrating a configuration of the multifunction peripheral 1300 and the information extraction device 150 according to the second embodiment of the present invention. The MFP 1300 is different from the printer 100 according to the first embodiment described above in that a software configuration related to information embedding has the input receiving unit 101 deleted and the input processing unit 1301 added. The image correction unit 1302 is added, and the authentication unit 1303 is added. In the following description, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted. The information extraction apparatus 150 is the same as that in the first embodiment, and a description thereof will be omitted.

  The input processing unit 1301 performs input processing of first watermarked document image data read from a paper document by a scanner (not shown) provided in the multifunction peripheral 1300.

  The image correction unit 1302 performs processing for correcting the first watermarked document image data acquired by the image acquisition unit 103. For example, since the image data read by the scanner has noise, distortion, or dirt or dust is attached, the image correction unit 1302 performs image correction as preprocessing. . Accordingly, it is possible to improve the accuracy of processing executed by the multifunction machine 1300, such as specifying the position by the position specifying unit 104.

  Examples of correction processing actually performed by the image correction unit 1302 include processing for facilitating dot pattern recognition and embedding block position specification such as distortion correction and noise removal, Repair processing (such as repair of missing dots or equalization of dot size) can be considered.

  The authentication unit 1303 performs processing for authenticating a user who prints. Any method may be used for this authentication method. For example, it is conceivable to perform personal authentication using a non-contact type IC card (a more detailed example is a FeliCa card). Then, the user ID acquired from the authenticated non-contact type IC card is output to the additional information acquisition unit 102 as the printer ID. Thereby, the printer ID can be embedded as additional information.

  FIG. 18 is a diagram illustrating a data flow when a multifunction printer 1300 copies a recording sheet on which the first watermarked document image data is printed by a printer or the like connected in advance to a PC in the present embodiment. FIG.

  As shown in the figure, on the recording paper on which the first watermarked document image data held before copying by the user is printed, watermark information is embedded with a dot pattern of equal dod size. Then, the recording paper is copied by the multifunction machine 1300, so that the recording paper on which the second watermarked document image data is printed is output. In the background of the recording paper, as in the first embodiment, the dot size of the dot pattern at a predetermined position is changed.

  In the multi-function device 1300, additional information can be embedded during copying by such processing. The details of the additional information are the same as those in the first embodiment.

  Next, the second watermarked document image data in which additional information is further embedded is printed from the input process of the first watermarked document image data in the MFP 1300 according to the present embodiment configured as described above. The process up to will be described. FIG. 19 is a flowchart showing a procedure of the above-described processing in the multifunction machine 1300 according to the present embodiment.

  First, the authentication unit 1303 performs processing for authenticating a user who prints (step S1601). Then, the processing described later is executed when the authentication is successful, and the processing is ended when the authentication fails.

  Next, the input processing unit 1301 performs input processing of the first watermarked document image data read by the scanner (step S1602).

  Then, the additional information acquisition unit 102 acquires the printer ID embedded as additional information, the MFP information unique to the MFP 1300, and the printing date and time (step S1603). For example, the printer ID is the above-described authentication unit 1303, the MFP information is information read from the HDD of the MFP 1300, and the printing date and time is information acquired from a TSA (Time Certification Authority) over the network. To do.

  Then, the image acquisition unit 103 acquires the first watermarked document image data received by the input receiving unit 101 (step S1604).

  Next, the image correcting unit 1302 performs processing for correcting the acquired first watermarked document image data (step S1605).

  Then, similarly to steps S1104 to S1107 in FIG. 11 of the first embodiment, the processing from the specification of the position of the dot pattern, the embedding block, and the collective block to the printing of the second watermarked document image data is performed. This is performed (steps S1606 to S1609).

  The processing procedure described above allows the user to obtain a recording sheet in which additional information is embedded. The above-described processing procedure shows an example of the printing processing procedure for the second watermarked document image data in which additional information is further embedded from the input processing of the first watermarked document image data according to the present embodiment. However, the present invention is not limited to this processing procedure.

  In the MFP 1300 according to the present embodiment, the quality of the second watermarked document image data can be improved by performing image correction. Further, since the document image data is corrected before the additional information is embedded, it is possible to appropriately perform the embedding process, and the accuracy of the embedded information is improved.

  Further, since the MFP 1300 according to the present embodiment performs the authentication process, it is possible to prevent unauthorized third parties from copying the second watermarked document image data. Further, since the origin information is embedded when copying, the copy source can be easily specified.

(Modification)
Moreover, it is not limited to each embodiment mentioned above, The various deformation | transformation which is illustrated below is possible.

(Modification 1)
In the above-described embodiment, the case where the dot size of the dot pattern is changed as the process of embedding additional information has been described. However, the process of embedding additional information is not limited to such a change in dot size.

  Therefore, in this modification, an example in which the color of the dot pattern or line pattern is changed when embedding additional information is used. The procedure for specifying the position of the dot pattern whose color is to be changed is the same as that for specifying the position of the dot pattern for changing the dot size in the above-described embodiment, and a description thereof will be omitted. Thereby, in the information extraction device, additional information can be extracted by identifying the color of the dot pattern when extracting the information.

(Modification 2)
In the above-described embodiment, the case has been described in which additional information is embedded in document image data in which information has already been embedded. However, the embedding of the additional information is not limited to one time, and the additional information may be embedded a plurality of times.

  In other words, if additional information is embedded once with a printer or multifunction device having the function of an information embedding device, there is an area where the dot size attached to the background is not changed if the amount of embedded additional information is small Will do. Therefore, when the second watermarked document image data in which the additional information is embedded is copied again by the multifunction peripheral, the second additional information can be further embedded. In this case, after acquiring the second watermarked document image data, the multi-function peripheral specifies a region in which the dot pattern dot size is not changed in the background of the second watermarked document image data. The positions of the dot pattern, embedded block and aggregate block included in the area are specified. Then, the additional information embedding unit performs the same processing as in the above-described embodiment, so that additional information can be embedded.

  Accordingly, even when copying is performed a plurality of times, information can be additionally embedded, so that convenience is improved. In addition, since additional information such as source information can be embedded each time copying is performed, safety is improved. For example, if the origin information described above is additionally embedded many times, the history copied from the watermark information can be grasped. Further, in the embedding process performed at the time of copying, it is not necessary to analyze already embedded information, so that the processing load can be reduced.

  As described above, the information embedding device, the information embedding method, the information embedding program, and the recording medium according to the present invention are useful for a technique for embedding information in image data, and in particular, image data in which information is already embedded. It is suitable for the technology of additionally embedding information.

It is a block diagram which shows the structure of PC concerning 1st Embodiment, a printer, and an information extraction device. It is explanatory drawing which showed the example of the document data produced | generated by the document production | generation part of PC concerning 1st Embodiment. It is the figure which showed the example of the dot pattern which showed 0 bit among the dot patterns arrange | positioned at image data by PC of 1st Embodiment. It is the figure which showed the example of the dot pattern which showed 1 bit among the dot patterns arrange | positioned at image data by PC of 1st Embodiment. It is the figure which showed the example of the dot pattern which showed 0 bit among the dot patterns arrange | positioned at the image data by the modification different from 1st Embodiment. It is the figure which showed the example of the dot pattern which showed 1 bit among the dot patterns arrange | positioned at the image data by the modification different from 1st Embodiment. It is explanatory drawing which showed the example of the watermark image data produced | generated by the information embedding part of PC of 1st Embodiment. It is explanatory drawing which showed the example of the collective block specified from the background of the 1st watermarked document image data by the collective block position specific | specification part of the printer of 1st Embodiment. It is explanatory drawing which showed the position of the embedding block which expands dot size among assembly blocks. It is explanatory drawing which showed the additional information embedding part of the printer of 1st Embodiment for every step which embeds bit information. Explanatory drawing which showed the data flow until the 1st watermarked document image data output from PC is printed on a recording paper as 2nd watermarked document image data in a printer in 1st Embodiment. It is. It is explanatory drawing which showed the example of the watermark image data in case the micro size dot pattern is not removed. It is explanatory drawing which showed the example of the document image data with a watermark when a micro size dot pattern is removed. It is explanatory drawing which showed the process which carries out the resolution conversion to the predetermined | prescribed resolution which the resolution conversion part of the information extraction device concerning 1st Embodiment performs. It is the figure which showed the template which specifies the '0' bit used by the 2nd information extraction part of the information extraction device concerning a 1st embodiment by template matching. It is the figure which showed the template which specifies the '1' bit used by the 2nd information extraction part of the information extraction device concerning a 1st embodiment by template matching. 9 is a flowchart showing a processing procedure from reception of input of first watermarked document image data to printing of second watermarked document image data in which additional information is further embedded in the printer according to the first embodiment. is there. It is a flowchart which shows the procedure of a process from acquisition of the 2nd watermarked document image data in the information extracting device concerning 1st Embodiment to a display process of document image data and the extracted information. It is a figure showing hardware constitutions of PC which executed a program for realizing a function of a printer concerning a 1st embodiment. It is a block diagram which shows the structure of the multifunctional device concerning 2nd Embodiment, and an information extraction device. FIG. 10 is an explanatory diagram showing a data flow when a recording sheet on which first watermarked document image data is printed by a printer connected in advance to a PC or the like in the second embodiment is copied by a multifunction peripheral. . 9 is a flowchart showing a processing procedure from input processing of first watermarked document image data to printing processing of second watermarked document image data in which additional information is further embedded in the multi-function peripheral according to the second embodiment. is there.

Explanation of symbols

10 Scanner 50 PC
DESCRIPTION OF SYMBOLS 51 Document generation part 52 Information acquisition part 53 Information embedding part 54 Output processing part 100 Printer 101 Input reception part 102 Additional information acquisition part 103 Image acquisition part 104 Position specification part 105 Additional information embedding part 106 Print processing part 111 Embedding block Position specifying unit 112 Collective block position specifying unit 150 Information extracting device 151 Document image acquiring unit 152 Image correcting unit 153 Image extracting unit 154 Judging unit 155 First information extracting unit 156 Second information extracting unit 157 Display processing unit 158 Resolution converting unit 1300 MFP 1301 Input processing unit 1302 Image correction unit 1303 Authentication unit 1501 CPU
1502 ROM
1503 RAM
1504 External storage device 1505 Display device 1506 Input device 1507 Communication interface 1508 Bus

Claims (16)

Image acquisition means for acquiring image data in which information is embedded by an image pattern group composed of a plurality of image patterns;
Additional information acquisition means for acquiring additional information, which is information to be further embedded, with respect to the image data acquired by the image acquisition means;
Position specifying means for specifying the position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquiring means;
From the image pattern group whose position is specified by the position specifying means, an image pattern existing in an area specified by a predetermined rule is changed in size or color without changing the position of the dot of the image pattern. Additional information embedding means for embedding the additional information in the image data by processing into different forms,
An information embedding device comprising: The position specifying means specifies a position of an embedding block indicating an area including each of the image patterns, and then specifies a collective block including a plurality of the specified embedding blocks;
The additional information embedding unit embeds the additional information by processing the form of the image pattern included in the embedded block specified by the predetermined rule among the embedded blocks included in the aggregate block. thing,
The information embedding device according to claim 1 . The additional information embedding unit embeds the additional information by processing into a form using dots larger than the dot size of the image pattern without changing the position of the dots of the image pattern.
The information embedding device according to claim 1, wherein Image acquisition means for acquiring image data in which information is embedded by an image pattern group composed of a plurality of image patterns;
Additional information acquisition means for acquiring additional information, which is information to be further embedded, with respect to the image data acquired by the image acquisition means;
Position specifying means for specifying the position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquiring means;
Position is specified by the position specifying means, from the image pattern group that includes the line patterns, the images pattern that exists in the specified region by a predetermined rule, without changing the position of the line of the image pattern Additional information embedding means for embedding the additional information by processing the line in a different form in length, width or color ;
Information embedding apparatus comprising the. The image acquisition means acquires the image data after processing a form of the partial image pattern included in the image pattern group,
The position specifying means specifies an area of the image pattern group that is not processed in the form of the image pattern in the image data;
The additional information embedding unit embeds the additional information by processing a part of an image pattern in the image pattern group included in the region specified by the position specifying unit;
Information embedding apparatus according to any one of claims 1 to 4, characterized in. Information embedding apparatus according to any one of claims 1 to 5, characterized in that the image correcting means for performing image correction processing on the image data acquired by the image acquisition unit, further comprising. Said image acquisition means scans the recording sheet, wherein obtaining the image data, the information embedding apparatus according to any one of claims 1 to 6, wherein. An image acquisition step of acquiring image data in which information is embedded by an image pattern group composed of a plurality of image patterns;
An additional information acquisition step for acquiring additional information, which is information to be further embedded, with respect to the image data acquired by the image acquisition step ;
A position specifying step for specifying a position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquiring step;
From the image pattern group whose position is specified by the position specifying step, an image pattern existing in an area specified by a predetermined rule is changed in size or color without changing the position of the dot of the image pattern. An additional information embedding step for embedding the additional information in the image data by processing into a different form;
An information embedding method comprising: In the position specifying step, after specifying the position of an embedding block indicating an area including each of the first image patterns, an assembly block including a plurality of the specified embedding blocks is specified,
The additional information embedding step embeds the additional information by processing a form of the image pattern included in the embedded block specified by the predetermined rule among the embedded blocks included in the aggregate block. thing,
The information embedding method according to claim 8 . The additional information embedding step embeds the additional information by processing into a form using dots larger than the dot size of the first image pattern without changing the positions of the dots of the first image pattern. thing,
10. The information embedding method according to claim 8 or 9 , An image acquisition step of acquiring image data in which information is embedded by an image pattern group composed of a plurality of image patterns;
An additional information acquisition step for acquiring additional information, which is information to be further embedded, with respect to the image data acquired by the image acquisition step;
A position specifying step for specifying a position of the image pattern constituting the image pattern group attached to the image data acquired by the image acquiring step;
Position by the position specifying step is identified from the first image pattern group that includes the line patterns, the images pattern that exists in the area specified by the predetermined rule, the position of the line of the image pattern An additional information embedding step for embedding the additional information by processing into a form in which the length, width or color of the line is different without changing,
An information embedding method comprising: The image acquisition step acquires the image data after processing a form of the partial image pattern included in the image pattern group,
The position specifying step further specifies an area of the image pattern group that is not processed in the form of the image pattern in the image data,
The additional information embedding step embeds the additional information by processing a part of the image pattern in the image pattern group included in the region specified by the position specifying step.
The information embedding method according to any one of claims 8 to 11 . The image correction step of performing image correction processing on the image data acquired by the image acquisition step, further information embedding method according to any one of claims 8 to 12, characterized in that with. The image acquisition step, by scanning the recording sheet, information embedding method according to any one of claims 8 to 13, characterized in that, for acquiring the image data. An information embedding program for causing a computer to execute the information embedding method according to any one of claims 8 to 14 . A computer-readable recording medium storing the information embedding program according to claim 15 .

Images