Method and device for embedding digital watermark in interest surface data set and electronic equipment

Abstract

The invention relates to the technical field of geographic information security, and relates to a method and device for embedding a digital watermark in an interest surface data set and electronic equipment, and the method comprises the steps: generating watermark information data based on copyright information and the time for executing a digital watermark embedding operation; determining a reference ray according to a starting point on the interest surface and a far end point farthest from the starting point; calculating an initial distance ratio based on an initial vertical distance between the initial position of the target point and the reference ray and a ratio between the initial point and the far-end point; determining a plurality of target watermark bit groups corresponding to the target point from the watermark information data; obtaining a target distance ratio according to the target watermark bit group and a preset mapping relation; determining a target position between the target point and the reference ray according to the target distance ratio, the starting point and the far-end point; and determining the target position of the target point according to the position relationship between the target point and the starting point as well as between the target point and the far-end point, and the target position, and completing the digital watermark embedding operation.

Description

Technical Field

[0001] The present invention belongs to the field of geographic information security technology, and specifically relates to a method, a device and an electronic device for embedding a digital watermark in an interest surface data set. Background Art

[0002] Interest surface refers to regional geographic entities in map data, such as commercial buildings, residential areas, university campuses, commercial districts, etc. Interest surface data has good expression and computing power for these areas, and can provide rich geographic information to help users perform accurate geographic positioning and analysis. Since interest surface data usually contains a large amount of geographic coordinates and attribute information, it has high commercial and research value, which makes the copyright protection of interest surface data particularly important.

[0003] Digital watermarking is a technology that embeds specific information (such as copyright information, time) into digital products. This information can be used to track and identify the source and ownership of data without affecting the quality of digital products. The robustness of digital watermarking technology means that watermark information can resist various data processing and attacks, thereby providing effective evidence in copyright disputes. In addition, the invisibility of digital watermarks ensures that it will not affect the normal use and display of data when embedded in interest-side data. Therefore, digital watermarks provide an effective technical means for copyright protection of interest-side data.

[0004] In the prior art, embedding digital watermarks into the interest surface data is achieved by one of the following methods: First, the map is divided into blocks according to coordinates, the intensity of the watermark is adaptively modulated according to the classification of vertex density in each block, and then the binary image is embedded into the vertex coordinate values.

[0005] Second, the watermark information is divided into two parts and embedded into the least significant bits of the node coordinates through double mesh partitioning.

[0006] Third, the vector coordinate data is normalized, the normalized value is watermarked, and then the embedded data value is denormalized to achieve resistance to geometric attacks.

[0007] The watermark capacity embedded by the above three methods is small, and it is impossible to embed the complete watermark information into a single interest surface, so it is not applicable to interest surface datasets and cannot resist merging attacks. Summary of the invention

[0008] The embodiment of the present invention provides a method, device and electronic device for embedding a digital watermark in an interest face data set. The method solves the technical problems in the above-mentioned prior art, specifically including: Generate watermark information data based on the copyright information and the time when the digital watermark embedding operation is performed; the watermark information data includes a plurality of watermark bit groups; Determine a reference ray according to a starting point on the surface of interest and a distal point farthest from the starting point; For each target point on the surface of interest, based on the ratio of the initial vertical distance between the initial position of the target point and the reference ray and the distance from the starting point to the far end point, calculate the initial distance ratio of the target point; Determining a plurality of target watermark bit groups corresponding to the target point from the watermark information data; According to the target watermark bit group and the preset mapping relationship, the initial distance ratio is modified to obtain a target distance ratio; Determining a target position between the target point and the reference ray according to the target distance ratio, the starting point, and the distal end point; According to the positional relationship between the target point and the starting point, the remote point, and the target position, the target position of the target point is determined to complete the digital watermark embedding operation.

[0009] Specifically, determining a plurality of target watermark bit groups corresponding to the target point from the watermark information data includes: After deleting the starting point and the far end point, the storage order of the coordinate string in the interest surface is used as a watermark index; According to the watermark index, a plurality of target watermark bit groups corresponding to the target point are extracted from the watermark information data.

[0010] Specifically, the initial distance ratio is modified according to the target watermark bit group and the preset mapping relationship to obtain the target distance ratio, including: According to the preset mapping relationship, determining a target number corresponding to each target watermark bit group; When the original number at the designated position in the decimal place of the initial distance ratio is inconsistent with the target number corresponding to the designated position, the target number is used to replace the original number to obtain the target distance ratio.

[0011] Specifically, determining the target position between the target point and the reference ray according to the target distance ratio, the starting point, and the distal end point includes: Determining a target angle of the target point in space according to a distance relationship between the target point and the starting point or the far end point; Determine the target vertical distance according to the target distance ratio and the distance between the starting point and the far end point; According to the target angle, a position whose vertical distance to the reference ray is equal to the target vertical distance is taken as the target position.

[0012] Specifically, determining the target angle of the target point in space according to the distance relationship between the target point and the starting point or the distal point includes: When the distance between the target point and the starting point is greater than the distance between the target point and the distal end point, the target angle is determined with the distal end point as the vertex angle; When the distance between the target point and the starting point is less than the distance between the target point and the distal end point, the target angle is determined with the starting point as the vertex angle.

[0013] Specifically, the method further includes: After each point in the interest surface has completed the operation of embedding the digital watermark, Calculate the maximum absolute value of the difference between the horizontal coordinate and the vertical coordinate of all embedded points before and after embedding, as well as the root mean square error; If the error is greater than the set precision error, the watermark embedding of the interest surface is cancelled and its coordinates are restored to the original coordinate values.

[0014] The embodiment of the present invention further provides a device for embedding a digital watermark in an interest face data set, the device comprising: A generating module, used to generate watermark information data based on the copyright information and the time when the digital watermark embedding operation is performed; the watermark information data includes a plurality of watermark bit groups; A first determination module is used to determine a reference ray according to a starting point on the interest surface and a distal point farthest from the starting point; A calculation module, configured to calculate, for each target point on the interest surface, an initial distance ratio of the target point based on a ratio of an initial vertical distance between an initial position of the target point and the reference ray and a ratio between the starting point and the distal end point; A second determination module, used to determine a plurality of target watermark bit groups corresponding to the target point from the watermark information data; A first operation module, configured to modify the initial distance ratio according to the target watermark bit group and a preset mapping relationship to obtain a target distance ratio; A third determination module is used to determine the target position between the target point and the reference ray according to the target distance ratio, the starting point and the far end point; The fourth determination module is used to determine the target position of the target point according to the positional relationship between the target point and the starting point, the remote point, and the target position, so as to complete the digital watermark embedding operation.

[0015] The method provided by the embodiment of the present invention can embed complete watermark information into a single interest surface, so it is applicable to interest surface data sets and achieves the purpose of resisting merging attacks. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of a method for embedding a digital watermark in an interest face data set provided by an embodiment of the present invention; Figure 2 This is the effect diagram of the interest face dataset before the watermark information is embedded; Figure 3 This is a diagram showing the effect of the interest face data set after the watermark information is embedded using the method provided by the present invention; Figure 4 A structural diagram of a device for embedding a digital watermark in an interest surface data set provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0017] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0018] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0019] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0020] like Figure 1 As shown, an embodiment of the present invention provides a method for embedding a digital watermark in an interest face data set, the method comprising: Step 11, based on the copyright information and the time when the digital watermark embedding operation is performed, watermark information data is generated; the watermark information data includes multiple watermark bit groups; the specific process in this step is as follows: First, the copyright information and the time of executing the digital watermark embedding operation are converted into binary sequences respectively. Then, the binary information in the operation time is inserted into the copyright information in the order of copyright information first and operation time later to generate a binary sequence. Then, a binary sequence key is generated, and the key is XORed with the above binary sequence to obtain the encrypted watermark information; Step 12, determining a reference ray according to the starting point on the surface of interest and the farthest point from the starting point; the specific process of this step is as follows: Starting point The coordinates of , calculate the Euclidean distance from the starting point to any other point, and record the point farthest from the starting point as the far end point ; calculate and midpoint ,Pass Make it perpendicular to The reference ray of the line segment ; Step 13: for each target point on the interest surface , based on the target point The initial position and the reference ray The initial vertical distance With the starting point To the remote point The ratio between the two is used to calculate the target point The initial distance ratio , refer to formula (1): Formula (1) Step 14, determining multiple target watermark bit groups corresponding to the target point from the watermark information data; the specific process of this step is as follows: The starting point will be deleted with the distal end After that, the storage order of the coordinate strings in the interest surface is used as the watermark index; According to the watermark index, a plurality of target watermark bit groups corresponding to the target point are extracted from the watermark information data. , Depend on It is composed of watermark bits.

[0021] Step 15, modifying the initial distance ratio according to the target watermark bit group and the preset mapping relationship to obtain a target distance ratio; this step specifically includes the following contents: A preset mapping relationship between each watermark bit group in the watermark information data and a number (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) is established, so that each number has at least one corresponding watermark bit group; for example, the preset mapping relationship is that the number 1 corresponds to 000, the number 2 corresponds to 010, the number 3 corresponds to 001, the number 4 corresponds to 100, the numbers 5 and 6 correspond to 110, the numbers 7 and 8 correspond to 111, and the numbers 9 and 0 correspond to 011. Therefore, according to the preset mapping relationship, each target watermark bit group extracted in step 14 Each of them corresponds to a number, and the determined number is used as the target number; When the initial distance ratio The decimal places in the specified position If the original number of is inconsistent with the target number corresponding to the specified position, the target number is used to replace the original number to obtain the target distance ratio, for example, No. The original number is 2, but the watermark bit group to be embedded is 000, so the first The number is changed to 1, and the target distance ratio is obtained. ; Step 16: according to the target distance ratio , the starting point and the distal end point , determine the target position between the target point and the reference ray; this step specifically includes: Step 1: According to the target point To the starting point or the distal end The distance relationship between the target points is determined to determine the target angle of the target point in space; this step specifically includes: When the target point To the starting point The distance between the target point To the remote point When the distance between the two ends is , the target angle is determined by taking the distal end point as the vertex angle. ; When the target point To the starting point The distance between the target point is less than To the remote point When the distance between the starting point and the target angle is determined, the starting point is taken as the vertex angle. ; Step 2: Determine the target vertical distance based on the target distance ratio and the distance between the starting point and the far end point. ; According to formula (1), due to the target distance ratio Known, arrive The distance is constant, so the vertical distance of the target can be obtained ; Step 3: According to the target angle, the position whose vertical distance to the reference ray is equal to the vertical distance to the target is taken as the target position. For example: When the target angle is When the ray Find the vertical distance on the ray The point is the target position; When the target angle is When the ray Find the vertical distance on the ray The point is the target position; Step 17, according to the positional relationship between the target point and the starting point, the remote point, and the target position, the target position of the target point is determined to complete the digital watermark embedding operation.

[0022] Furthermore, after completing the above steps, it can also further include: when each point in the interest surface has completed the operation of embedding the digital watermark, calculating the maximum absolute value of the difference between the horizontal coordinate and the vertical coordinate of all embedded points before and after embedding and the root mean square error; if the error is greater than the set accuracy error, canceling the watermark embedding of the interest surface and restoring its coordinates to the original coordinate values.

[0023] Interested in points, and the coordinates of each point before embedding the watermark are , the coordinates after embedding the watermark are , calculate the absolute value of the difference between the horizontal and vertical coordinates of each point according to formula (2) and formula (3): Formula (2) Formula (3) According to formula (4), the root mean square error of the coordinates is calculated: Announcement (4) If any one of the conditions in formula (5) is satisfied, the watermark embedding of the surface of interest is canceled and its coordinates are restored to the original coordinate values: Formula (5) The above method can embed the complete watermark information into a single interest face, which is suitable for interest face datasets and can resist merging attacks. Figure 2 To complete the effect diagram of the interest face dataset before embedding the watermark information, Figure 3 This is a diagram showing the effect of the interest surface data set after watermark information is embedded using the method provided by the present invention.

[0024] According to the above process, the embodiment of the present invention can also detect the watermark information of the interest surface, and the specific process is as follows: Calculate the detection starting point of the interest surface The Euclidean distance to other points on the surface is recorded as ; calculate and midpoint ,Pass perpendicular to the line segment Detection of vertical rays ; Calculate any point on the interest surface To detect vertical rays Detection vertical distance , and then calculate the detection distance ratio according to formula (1) ; extract The decimal part According to the mapping relationship between the watermark bit group and the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, the detection watermark bit group embedded at the point is extracted. ; Remove points from the surface of interest , The other points except the last point are processed in sequence, and the extracted detection watermark bit groups are spliced ​​in sequence to obtain the extracted detection watermark information ,until When the length of is the same as the length of the watermark information when embedded, the extraction is stopped; Repeat the above steps to process each interest face in the interest face data set to obtain all watermark information in the data set.

[0025] This method takes each region of interest as a watermark information embedding unit, constructs a watermark bit group to increase the embedding capacity of each region of interest, and embeds the watermark bit group into geometric features, enabling this method to achieve watermark embedding and detection and resistance to the merging attack on the region of interest dataset. In addition, since this method embeds the watermark information into the distance ratio with rotation, scaling, and translation invariance, this method can resist almost all common types of attacks.

[0026] As Figure 4 shown, an embodiment of the present invention provides a device for embedding a digital watermark in a region of interest dataset. The device includes: A generation module 41, configured to generate watermark information data based on copyright information and the time of performing the digital watermark embedding operation; the watermark information data includes a plurality of watermark bit groups; A first determination module 42, configured to determine a reference ray according to a starting point on the region of interest and a distal point farthest from the starting point; A calculation module 43, configured to calculate an initial distance ratio of each target point on the region of interest based on a ratio of an initial perpendicular distance between an initial position of the target point and the reference ray to a distance between the starting point and the distal point; A second determination module 44, configured to determine a plurality of target watermark bit groups corresponding to the target point from the watermark information data; A first operation module 45, configured to modify the initial distance ratio according to the target watermark bit group and a preset mapping relationship to obtain a target distance ratio; A third determination module 46, configured to determine a target position between the target point and the reference ray according to the target distance ratio, the starting point, and the distal point; A fourth determination module 47, configured to determine a target position of the target point according to a positional relationship between the target point, the starting point, and the distal point, and the target position, and complete the digital watermark embedding operation.

[0027] The second determination module 44 is specifically configured to use the storage order of the coordinate string in the region of interest after deleting the starting point and the distal point as a watermark index; and extract a plurality of target watermark bit groups corresponding to the target point from the watermark information data according to the watermark index.

[0028] The first operation module 45 is specifically configured to determine a target number corresponding to each target watermark bit group according to the preset mapping relationship; when an original number at a specified position in the decimal part of the initial distance ratio is inconsistent with the target number corresponding to the specified position, replace the original number with the target number to obtain the target distance ratio.

[0029] The third determination module 46 is specifically used to determine the target angle of the target point in space according to the distance relationship between the target point and the starting point or the distal end point; determine the target vertical distance according to the target distance ratio and the distance between the starting point and the distal end point; and according to the target angle, take the position whose vertical distance to the reference ray is the target vertical distance as the target position. Determining the target angle of the target point in space according to the distance relationship between the target point and the starting point or the distal end point includes: When the distance between the target point and the starting point is greater than the distance between the target point and the distal end point, the target angle is determined with the distal end point as the vertex angle; when the distance between the target point and the starting point is less than the distance between the target point and the distal end point, the target angle is determined with the starting point as the vertex angle.

[0030] The device also includes a second operation module 48 for calculating the maximum absolute value of the difference between the horizontal coordinate and the vertical coordinate of all embedded points before and after the embedding and the root mean square error after the digital watermark embedding operation is completed for each point in the interest surface; if the error is greater than the set precision error, the watermark embedding of the interest surface is cancelled and its coordinates are restored to the original coordinate values.

[0031] An embodiment of the present invention provides an electronic device, which includes a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction is executed by the processor to perform the steps of the above-mentioned method for obtaining a human behavior recognition signal.

[0032] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0033] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0034] It should be noted that if an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may also be a centered element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a centered element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method. The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the various technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0035] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for embedding a digital watermark in an interest face dataset, characterized in that: The method comprises: Generate watermark information data based on the copyright information and the time when the digital watermark embedding operation is performed; the watermark information data includes a plurality of watermark bit groups; Determine a reference ray according to a starting point on the surface of interest and a distal point farthest from the starting point; For each target point on the surface of interest, based on the ratio of the initial vertical distance between the initial position of the target point and the reference ray and the distance from the starting point to the far end point, calculate the initial distance ratio of the target point; Determining a plurality of target watermark bit groups corresponding to the target point from the watermark information data; According to the target watermark bit group and the preset mapping relationship, the initial distance ratio is modified to obtain a target distance ratio; Determining a target position between the target point and the reference ray according to the target distance ratio, the starting point, and the distal end point; According to the positional relationship between the target point and the starting point, the remote point, and the target position, the target position of the target point is determined to complete the digital watermark embedding operation.

2. The method according to claim 1, characterized in that The step of determining a plurality of target watermark bit groups corresponding to the target point from the watermark information data comprises: After deleting the starting point and the far end point, the storage order of the coordinate string in the interest surface is used as a watermark index; According to the watermark index, a plurality of target watermark bit groups corresponding to the target point are extracted from the watermark information data.

3. The method according to claim 1, characterized in that The modifying the initial distance ratio according to the target watermark bit group and the preset mapping relationship to obtain the target distance ratio includes: According to the preset mapping relationship, determining a target number corresponding to each target watermark bit group; When the original number at the designated position in the decimal place of the initial distance ratio is inconsistent with the target number corresponding to the designated position, the target number is used to replace the original number to obtain the target distance ratio.

4. The method according to claim 1, characterized in that The step of determining a target position between the target point and the reference ray according to the target distance ratio, the starting point, and the distal end point includes: Determining a target angle of the target point in space according to a distance relationship between the target point and the starting point or the far end point; Determine the target vertical distance according to the target distance ratio and the distance between the starting point and the far end point; According to the target angle, a position whose vertical distance to the reference ray is equal to the target vertical distance is taken as the target position.

5. The method according to claim 4, characterized in that The step of determining a target angle of the target point in space according to a distance relationship between the target point and the starting point or the distal end point includes: When the distance between the target point and the starting point is greater than the distance between the target point and the distal end point, the target angle is determined with the distal end point as the vertex angle; When the distance between the target point and the starting point is less than the distance between the target point and the distal end point, the target angle is determined with the starting point as the vertex angle.

6. The method according to claim 1, characterized in that The method further comprises: After each point in the interest surface has completed the operation of embedding the digital watermark, Calculate the maximum absolute value of the difference between the horizontal coordinate and the vertical coordinate of all embedded points before and after embedding, as well as the root mean square error; If the error is greater than the set precision error, the watermark embedding of the interest surface is cancelled and its coordinates are restored to the original coordinate values.

7. A device for embedding a digital watermark in an interest face data set, characterized in that: The device comprises: A generating module, used to generate watermark information data based on the copyright information and the time when the digital watermark embedding operation is performed; the watermark information data includes a plurality of watermark bit groups; A first determination module is used to determine a reference ray according to a starting point on the interest surface and a far end point farthest from the starting point; A calculation module, configured to calculate, for each target point on the interest surface, an initial distance ratio of the target point based on a ratio of an initial vertical distance between an initial position of the target point and the reference ray and a ratio between the starting point and the distal end point; A second determination module, used to determine a plurality of target watermark bit groups corresponding to the target point from the watermark information data; A first operation module, configured to modify the initial distance ratio according to the target watermark bit group and a preset mapping relationship to obtain a target distance ratio; A third determination module is used to determine the target position between the target point and the reference ray according to the target distance ratio, the starting point and the far end point; The fourth determination module is used to determine the target position of the target point according to the positional relationship between the target point and the starting point, the remote point, and the target position, so as to complete the digital watermark embedding operation.

8. The device according to claim 7, characterized in that The second determining module is specifically used for: After deleting the starting point and the far end point, the storage order of the coordinate string in the interest surface is used as a watermark index; According to the watermark index, a plurality of target watermark bit groups corresponding to the target point are extracted from the watermark information data.

9. The device according to claim 8, characterized in that The first operating module is specifically used for: According to the preset mapping relationship, determining a target number corresponding to each target watermark bit group; When the original number at the designated position in the decimal place of the initial distance ratio is inconsistent with the target number corresponding to the designated position, the target number is used to replace the original number to obtain the target distance ratio.

10. An electronic device, characterized in that: The electronic device includes a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction is executed by the processor to perform the steps of any one of the methods for embedding a digital watermark in a face of interest data set in claims 1-6.

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