Watermarking method and apparatus for a watermark carrier

Abstract

The present disclosure relates to a watermark processing method and device for a watermark carrier, and a computer storage medium, and relates to the technical field of computers. The watermark processing method for a watermark carrier comprises: generating a watermark image reflecting the identity of a user browsing the watermark carrier according to the identity of the user; acquiring a positioning image, the positioning image comprising a positioning texture for positioning the position of the watermark image in the watermark carrier in a watermark extraction process; embedding the watermark image into the positioning image to obtain a composite image, the composite image comprising the positioning texture; and superimposing the composite image into the watermark carrier. According to the present disclosure, the difficulty of watermark extraction can be reduced, and the accuracy of watermark extraction can be improved.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of computers, and in particular, to a watermark processing method and device for a watermark carrier, and a computer storage medium. BACKGROUND

[0002] Watermarks have important and extensive applications in copyright protection, leakage tracing, and the like of watermark carriers such as web pages, pictures, and documents.

[0003] In the related art, a watermark image is directly embedded into a watermark carrier. SUMMARY

[0004] In the related art, in a case where relevant information of a watermark carrier cannot be acquired in advance, watermark adding and extraction are difficult, and accuracy is poor.

[0005] To address the foregoing technical problems, the present disclosure provides a solution that can reduce the difficulty of watermark adding and extraction, and improve the accuracy of watermark extraction.

[0006] According to a first aspect of the present disclosure, a watermark processing method for a watermark carrier is provided, including: generating a watermark image reflecting an identifier of a user browsing the watermark carrier according to the identifier; acquiring a positioning image including a positioning texture for positioning a position of the watermark image in the watermark carrier in a watermark extraction process; embedding the watermark image into the positioning image to obtain a composite image, the composite image including the positioning texture; and superimposing the composite image into the watermark carrier.

[0007] In some embodiments, superimposing the composite image into the watermark carrier includes: performing enhancement processing on the composite image according to an overlay transparency required for superimposing the composite image, which is preset by the user; and superimposing the composite image after the enhancement processing into the watermark carrier with the overlay transparency.

[0008] In some embodiments, the enhancement processing on the composite image includes: for each pixel point of the composite image, determining a target pixel value of the each pixel point in the composite image according to a first pixel value of the each pixel point in the positioning image, a second pixel value of the each pixel point in the composite image, and the overlay transparency.

[0009] In some embodiments, for the each pixel point: the target pixel value is negatively correlated with the first pixel value, and positively correlated with the second pixel value; in a case where the second pixel value is greater than the first pixel value, the target pixel value is negatively correlated with the overlay transparency; in a case where the second pixel value is less than the first pixel value, the target pixel value is positively correlated with the overlay transparency; and in a case where the second pixel value is equal to the first pixel value, the target pixel value is equal to the first pixel value.

[0010] In some embodiments, determining the target pixel value of each pixel point in the composite image comprises: calculating a difference value between the second pixel value and the first pixel value of each pixel point; calculating a ratio value of the difference value and the superimposition transparency; and calculating the target pixel value of each pixel point according to a sum of the ratio value and the first pixel value.

[0011] In some embodiments, superimposing the composite image into the watermark carrier comprises: modifying a pixel value of a pixel point in the composite image with a pixel value less than a truncation threshold to the truncation threshold to perform pixel value truncation on the composite image; and superimposing the composite image after the pixel value truncation into the watermark carrier.

[0012] In some embodiments, superimposing the composite image into the watermark carrier comprises: obtaining a first pixel value of a positioning texture in the positioning image; restoring a second pixel value of the positioning texture in the composite image to the first pixel value; and superimposing the composite image with the second pixel value of the positioning texture restored to the first pixel value into the watermark carrier.

[0013] In some embodiments, generating a watermark image reflecting the identity of the user browsing the watermark carrier comprises: determining a digital code corresponding to the identity of the user browsing the watermark carrier, the digital code comprising one or more digits, each digit having a value ranging from 0 to 9; obtaining a blank image carrying the digital code; determining position coordinates of a pixel block in the blank image for carrying each digit of the digital code; and setting a pixel value of the pixel block in the blank image for carrying each digit of the digital code to a preset pixel value according to the determined position coordinates of the pixel block for each digit, the preset pixel value having an absolute value of a difference from a pixel value of a pixel block other than the pixel block carrying each digit in the blank image greater than a pixel block threshold.

[0014] In some embodiments, the width of the blank image is positively correlated with the size of the pixel block and the number of digits of the digital code, respectively, and the height of the blank image is determined according to the size of the pixel block.

[0015] In some embodiments, the number of digits of the digital code is positively correlated with the width and height of the positioning image, respectively.

[0016] In some embodiments, superimposing the composite image into the watermark carrier comprises: superimposing the composite image into the watermark carrier in a tiled manner.

[0017] In some embodiments, the positioning texture comprises at least one of text content and graphic content.

[0018] According to a second aspect of the present disclosure, a watermark processing method for a watermark carrier is provided, wherein the watermark carrier is superimposed with a composite image in which a watermark image is embedded in a positioning image, the watermark image is generated according to an identification of a user browsing the watermark carrier and reflects the identification of the user, the positioning image and the composite image both include a positioning texture for locating a position of the watermark image in the watermark carrier in a watermark extraction process, the watermark processing method comprises: obtaining an image of at least a part of the watermark carrier as a to-be-processed image; locating a position of the composite image in the watermark carrier by using the positioning texture in the positioning image and a positioning texture in the to-be-processed image, so as to locate a position of the watermark image in the watermark carrier; and extracting the watermark image from the to-be-processed image according to the position of the composite image in the watermark carrier.

[0019] In some embodiments, locating the position of the composite image in the watermark carrier comprises: performing an image feature point matching operation on the positioning image and the to-be-processed image to obtain a plurality of groups of feature point pairs, each group of feature point pairs being a corresponding relationship between pixel position coordinates of a feature-matched pixel point in the positioning image and pixel position coordinates in the to-be-processed image; and locating the position of the composite image in the watermark carrier according to the plurality of groups of feature point pairs.

[0020] In some embodiments, extracting the watermark image from the to-be-processed image comprises: calculating an affine matrix according to the plurality of groups of feature point pairs; performing an alignment operation on the to-be-processed image according to the affine matrix; cutting a to-be-processed sub-image superimposed with one of the composite images from the to-be-processed image after alignment according to the position of the composite image in the watermark carrier; and extracting the watermark image from the to-be-processed sub-image.

[0021] In some embodiments, extracting the watermark image from the to-be-processed sub-image comprises: for each image channel of the to-be-processed sub-image, determining a pixel value range representing a background of the to-be-processed sub-image according to pixel values of respective pixel points in the each image channel; performing enhancement processing on the composite image superimposed in the to-be-processed sub-image according to the pixel value range; and extracting the watermark image from the to-be-processed sub-image after enhancement processing.

[0022] In some embodiments, performing enhancement processing on the composite image superimposed in the to-be-processed sub-image comprises: determining a maximum pixel value and a minimum pixel value in the pixel value range; and for each image channel of the to-be-processed sub-image, updating pixel values of each pixel point according to a size relationship between the pixel values of the each pixel point and the maximum pixel value and the minimum pixel value, so as to increase a contrast between the background of the to-be-processed sub-image and the composite image.

[0023] In some embodiments, the composite image and the to-be-processed sub-image are both grayscale images, and updating the pixel value of each pixel point comprises: for each pixel point in each image channel of the to-be-processed sub-image, if the pixel value of the pixel point is less than the minimum pixel value, updating the pixel value of the pixel point to 0; if the pixel value of the pixel point is greater than the maximum pixel value, updating the pixel value of the pixel point to 255; if the pixel value of the pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, updating the pixel value of the pixel point according to the difference between the maximum pixel value and the minimum pixel value and the pixel value of the pixel point, so that the updated pixel value is greater than the pixel value before the updating.

[0024] In some embodiments, for each pixel point in each image channel of the to-be-processed sub-image, if the pixel value of the pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, the updated pixel value is negatively correlated with the difference and positively correlated with the pixel value before the updating.

[0025] In some embodiments, positioning the position of the composite image in the watermark carrier comprises: pre-processing the to-be-processed image, the pre-processing comprising at least one of histogram equalization and local binarization; and positioning the position of the composite image in the watermark carrier by using the positioning texture in the positioning image and the positioning texture in the pre-processed to-be-processed image.

[0026] In some embodiments, the watermark processing method further comprises: after extracting the watermark image, calculating an average value of pixel values of each pixel point in each pixel block in the extracted watermark image as a pixel block average value; determining positions of pixel blocks in which each digit of the digital code corresponding to the identity of the user is located according to the pixel block average value; determining the digital code according to the determined positions of the pixel blocks in which each digit is located; and determining the identity of the user according to the digital code.

[0027] In some embodiments, the digital code is N digits, N being a positive integer, and determining the positions of the pixel blocks in which each digit of the digital code corresponding to the identity of the user is located comprises: calculating an average value of each pixel block average value corresponding to each pixel block as a reference average value; and determining positions of N pixel blocks with the largest difference from the reference average value from each pixel block average value corresponding to each pixel block as the positions of the pixel blocks in which each digit of the digital code is located.

[0028] According to a third aspect of the present disclosure, a watermark processing apparatus for a watermark carrier is provided, comprising: a generating module configured to generate a watermark image reflecting an identity of a user browsing the watermark carrier according to the identity of the user; an obtaining module configured to obtain a positioning image, the positioning image comprising a positioning texture used to locate a position of the watermark image in the watermark carrier in a watermark extraction process; an embedding module configured to embed the watermark image into the positioning image to obtain a composite image, the composite image comprising the positioning texture; and a superimposing module configured to superimpose the composite image into the watermark carrier.

[0029] According to a fourth aspect of the present disclosure, a watermark processing apparatus for a watermark carrier is provided, wherein the watermark carrier is superimposed with a composite image in which a watermark image is embedded, the watermark image being generated according to an identity of a user browsing the watermark carrier and reflecting the identity of the user, the positioning image and the composite image both comprising a positioning texture used to locate a position of the watermark image in the watermark carrier in a watermark extraction process, the watermark processing apparatus comprising: an obtaining module configured to obtain an image of at least a portion of the watermark carrier as a to-be-processed image; a locating module configured to locate a position of the composite image in the watermark carrier by using the positioning texture in the positioning image and the positioning texture in the to-be-processed image, so as to locate a position of the watermark image in the watermark carrier; and an extracting module configured to extract the watermark image from the to-be-processed image according to the position of the composite image in the watermark carrier.

[0030] According to a fifth aspect of the present disclosure, a watermark processing apparatus for a watermark carrier is provided, comprising: a memory; and a processor coupled to the memory, the processor being configured to execute a watermark processing method for a watermark carrier according to any one of the above-mentioned embodiments based on instructions stored in the memory.

[0031] According to a sixth aspect of the present disclosure, a computer storage medium is provided, having computer program instructions stored thereon, the instructions being executed by a processor to implement a watermark processing method for a watermark carrier according to any one of the above-mentioned embodiments.

[0032] In the above-mentioned embodiments, the difficulty of watermark adding and extracting can be reduced, and the accuracy of watermark extraction can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0034] The present disclosure can be more clearly understood and appreciated from the following detailed description, taken in conjunction with the following drawings of which:

[0035] Figure 1 Figure 1 is a flowchart illustrating a watermarking method according to some embodiments of the disclosure;

[0036] Figure 2A Figure 2 is a schematic diagram illustrating a watermark image according to some embodiments of the disclosure;

[0037] Figure 2B Figure 3 is a schematic diagram illustrating a positioning image according to some embodiments of the disclosure;

[0038] Figure 2C Figure 4 is a schematic diagram illustrating a composite image according to some embodiments of the disclosure;

[0039] Figure 2D Figure 5 is a schematic diagram illustrating a composite image according to some other embodiments of the disclosure;

[0040] Figure 3A Figure 6 is a schematic diagram illustrating a watermark carrier overlaid with a composite image according to some embodiments of the disclosure;

[0041] Figure 3B Figure 7 is a schematic diagram illustrating a watermark carrier overlaid with a composite image according to some other embodiments of the disclosure;

[0042] Figure 4 Figure 8 is a flowchart illustrating a watermarking method according to some embodiments of the disclosure;

[0043] Figure 5A Figure 9 is a schematic diagram illustrating a to-be-processed image according to some embodiments of the disclosure;

[0044] Figure 5B Figure 10 is a schematic diagram illustrating a to-be-processed sub-image according to some other embodiments of the disclosure;

[0045] Figure 5C Figure 11 is a schematic diagram illustrating a to-be-processed sub-image according to some further embodiments of the disclosure;

[0046] Figure 5D Figure 12 is a schematic diagram illustrating an enhanced to-be-processed sub-image according to some embodiments of the disclosure;

[0047] Figure 5E Figure 13 is a schematic diagram illustrating a watermark image extracted from a to-be-processed sub-image according to some embodiments of the disclosure;

[0048] Figure 6 Figure 14 is a block diagram illustrating a watermarking device according to some embodiments of the disclosure;

[0049] Figure 7 Figure 15 is a block diagram illustrating a watermarking device according to some other embodiments of the disclosure;

[0050] Figure 8 is a block diagram illustrating a watermark processing apparatus according to some embodiments of the present disclosure;

[0051] Figure 9 is a block diagram illustrating a computer system for implementing some embodiments of the present disclosure. DETAILED DESCRIPTION

[0052] Various exemplary embodiments of the present disclosure will now be described in detail herein with reference to the attached drawings. It should be noted that the relative arrangement of components and steps, numerical expressions, and numerical values set forth in these embodiments are not limiting to the scope of the present disclosure unless specifically stated otherwise.

[0053] It should also be understood that the size of the various portions shown in the drawings is not intended to be limiting.

[0054] The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the scope of the present disclosure, its application, or uses.

[0055] Techniques, methods, and devices known to those of ordinary skill in the relevant art can not be discussed in detail herein. However, where appropriate, such techniques, methods, and devices can be considered part of the specification.

[0056] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Thus, other examples of the exemplary embodiments can have different values.

[0057] It should be noted that like numbers and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0058] Figure 1 is a flowchart illustrating a watermark processing method according to some embodiments of the present disclosure.

[0059] As Figure 1As shown, the watermark processing method for the watermark carrier includes: step S110, generating a watermark image reflecting the identity of the user; step S120, obtaining a positioning image; step S130, embedding the watermark image into the positioning image (tile image) to obtain a composite image; and step S140, superimposing the composite image into the watermark carrier. In the case where the related information of the watermark carrier cannot be obtained in advance, by obtaining the positioning image including the positioning texture, embedding the watermark image into the positioning image including the positioning texture to obtain the composite image fused with the watermark information, and superimposing the composite image into the watermark carrier, the difficulty of watermark adding can be reduced. In addition, the positioning texture can assist in positioning the position of the watermark image in the watermark carrier in the watermark extraction process, so that the difficulty of watermark extraction can be reduced and the accuracy of watermark extraction can be improved. For example, the watermark processing method is executed by a watermark processing device.

[0060] In step S110, a watermark image reflecting the identity of the user is generated according to the identity of the user browsing the watermark carrier. In some embodiments, the watermark carrier includes but is not limited to a webpage, a picture, and a document. For example, the identity of the user is a user ID (Identity document).

[0061] In some embodiments, the generation of the watermark image reflecting the identity of the user can be realized in the following manner.

[0062] First, a digital code corresponding to the identity of the user browsing the watermark carrier is determined. The digital code includes one or more digits, and each digit has a value range of 0 to 9. In some embodiments, the digital code corresponding to the identity of the user can be determined by means of hash mapping, md5 (message-digest algorithm 5) mapping, or hard-coded lookup table mapping.

[0063] For example, the number of digits of the digital code is positively correlated with the width and height of the positioning image, respectively. In some embodiments, the digital code includes N digits (codes), and N is a positive integer. For example, N = W1 x H1 / C. W1 is the width of the positioning image, H1 is the height of the positioning image, and C is a constant. Taking an example of a 5x5 pixel block occupied by one digit of the digital code and a DWT-DCT (Discrete Wavelet Transformation-Discrete Cosine Transformation) algorithm as the watermark embedding algorithm for embedding the watermark image into the positioning image, C = 8x5x5x10 = 4000, 8 is determined by the watermark embedding algorithm, 5x5 is the pixel size of the pixel block, and 10 represents that each digit has a value of 0 to 9. For example, the digital code corresponding to the identity of the user is “123456”.

[0064] Secondly, a blank image is obtained to carry the digital encoding. For example, each bit of the digital encoding is carried in a pixel block of the blank image. The size of the pixel block can be pre-set by a user. For example, the size of the pixel block is 5x5.

[0065] In some embodiments, the width of the blank image is positively correlated with the size of the pixel block and the number of bits of the digital encoding, respectively. The height of the blank image is determined according to the size of the pixel block. Taking the digital encoding "123456", the size of the pixel block 5x5, and the value range of each bit of the digital encoding 0-9 as an example, the height H2 of the blank image is 50 pixels, and the width W2 is 5x6=30 pixels.

[0066] Then, the position coordinates of the pixel block for carrying each bit of the digital encoding in the blank image are determined. For example, taking the digital encoding "123456", the size of the pixel block 5x5, and the value range of each bit of the digital encoding 0-9 as an example, in the height direction, each column of the blank image includes 10 pixel blocks, which represent the numbers 0-9 from top to bottom. Each bit of the digital encoding is represented by a column of the blank image. According to this rule, the position coordinates of the pixel block for each bit of the digital encoding "123456" can be determined. For example, the position coordinates of the pixel block for "1" is (1, 1), the position coordinates of the pixel block for "2" is (2, 2), the position coordinates of the pixel block for "3" is (3, 3), the position coordinates of the pixel block for "4" is (4, 4), the position coordinates of the pixel block for "5" is (5, 5), and the position coordinates of the pixel block for "6" is (6, 6).

[0067] Finally, the pixel value of the pixel block for carrying each bit of the digital encoding in the blank image is set to a preset pixel value according to the determined position coordinates of the pixel block for each bit. The absolute value of the difference between the preset pixel value and the pixel value of the pixel block other than the pixel block for carrying each bit in the blank image is greater than a pixel block threshold. For example, the preset pixel value is 0 (black), and the pixel value of the other pixel block is 255 (white).

[0068] For example, for the digital encoding "123456", the watermark image is shown in FIG. 2.

[0069] Figure 2A is a schematic diagram showing a watermark image according to some embodiments of the present disclosure.

[0070] As shown in Figure 2A each dashed small square represents a pixel block, and each column includes 10 pixel blocks, which represent the numbers 0-9 from top to bottom. Each column from left to right represents the position of each bit in the digital encoding. That is, the six bits are arranged from left to right. The dashed lines in the figure only assist in understanding the structure of the watermark image and do not belong to the watermark image.

[0071] Each digit of the numerical code "123456" is located at pixel positions (1,1), (2,2), (3,3), (4,4), (5,5), and (6,6) in the watermark image, with a pixel value of 0, appearing as black. The pixel blocks outside the blocks containing each digit have a pixel value of 255, appearing as white. The watermark image is a binarized image.

[0072] return Figure 1 In step S120, a positioning image is acquired. The positioning image includes a positioning texture used to locate the position of the watermark image within the watermark carrier during the watermark extraction process. In some embodiments, the positioning texture includes at least one of text content and graphic content. For example, the text content may be a message such as "Copyright reserved, piracy will be prosecuted" or "Internal document, do not distribute." The graphic content may be a company logo (logotype, emblem), etc.

[0073] In some embodiments, a positioning image can be generated based on the width W3, height H3, background grayscale value, and positioning texture pre-configured by the user. For example, using a webpage as the watermark carrier, to ensure the coverage density of the watermark image, the values ​​of W3 and H3 range from 150 to 300 mm. For example, the background grayscale value is 230. The grayscale value of the positioning texture is, for example, smaller than the background grayscale value. In some embodiments, the transparency of the positioning texture in the positioning image can also be set according to the transparency of the positioning texture pre-configured by the user.

[0074] Figure 2B This is a schematic diagram illustrating positioning images according to some embodiments of the present disclosure.

[0075] like Figure 2B As shown, the positioning image includes a positioning texture labeled "Internal Document, Do Not Distribute," with a grayscale value of 230. The grayscale value of the positioning texture is less than 230.

[0076] return Figure 1 In step S130, the watermark image is embedded into the positioning image to obtain a composite image. The composite image includes the positioning texture.

[0077] In some embodiments, the watermark image can be embedded into the positioning image by using a digital watermark embedding algorithm. For example, the digital watermark embedding algorithm can be Discrete Cosine Transformation (DCT), Discrete Wavelet Transformation (DWT), Discrete Fourier Transform (DFT), Discrete Wavelet Transformation-Discrete Cosine Transformation (DWT-DCT). In some other embodiments, the background and the positioning texture of the positioning image can be separated, and the watermark image can be embedded into the background layer of the positioning image, and then the layers can be merged.

[0078] In step S140, the composite image is superimposed into the watermark carrier.

[0079] In some embodiments, the superimposition of the composite image into the watermark carrier can be achieved in the following manner.

[0080] First, the composite image is enhanced according to the superimposition transparency required by the user for superimposing the composite image.

[0081] For example, for each pixel point of the composite image, the target pixel value of each pixel point in the composite image is determined according to the first pixel value of each pixel point in the positioning image, the second pixel value of each pixel point in the composite image, and the superimposition transparency.

[0082] In some embodiments, for each pixel point: the target pixel value is negatively correlated with the first pixel value, and positively correlated with the second pixel value; in the case that the second pixel value is greater than the first pixel value, the target pixel value is negatively correlated with the superimposition transparency; in the case that the second pixel value is less than the first pixel value, the target pixel value is positively correlated with the superimposition transparency; in the case that the second pixel value is equal to the first pixel value, the target pixel value is equal to the first pixel value.

[0083] In some embodiments, the difference between the second pixel value and the first pixel value of each pixel point is calculated; the ratio of the difference and the superimposition transparency is calculated; and the target pixel value of each pixel point is calculated according to the sum of the ratio and the first pixel value. For example, for a pixel point with coordinates (x, y), the first pixel value is P1, the second pixel value is P2, the target pixel value is P, and the transparency is T. P = (P2-P1) / T+P1.

[0084] Figure 2C FIG. 1 is a schematic diagram showing a composite image according to some embodiments of the present disclosure.

[0085] Figure 2C The image shown is the composite image after enhancement processing. The enhancement processing of the composite image is the enhancement processing of the watermark image embedded in the positioning image.

[0086] Then, the composite image after enhancement processing is superimposed into the watermark carrier with superimposition transparency.

[0087] In the above embodiment, by performing enhancement processing on the composite image according to the superimposition transparency, the difficulty of watermark extraction can be further reduced, and the accuracy of watermark extraction can be further improved.

[0088] In some embodiments, the composite image can also be superimposed into the watermark carrier in the following way.

[0089] First, the pixel value of the pixel point in the composite image whose pixel value is less than the truncation threshold is modified to the truncation threshold, so as to perform pixel value truncation on the composite image. The truncation threshold is a pixel value threshold, for example, 216.

[0090] Then, the composite image after pixel value truncation is superimposed into the watermark carrier.

[0091] In the above embodiment, by performing pixel value truncation on the composite image, denoising is realized, and the user browsing experience can be improved.

[0092] In some embodiments, the composite image can also be superimposed into the watermark carrier in the following way.

[0093] First, the first pixel value of the positioning texture in the positioning image is obtained.

[0094] Then, the second pixel value of the positioning texture in the composite image is restored to the first pixel value.

[0095] Finally, the composite image in which the second pixel value of the positioning texture is restored to the first pixel value is superimposed into the watermark carrier.

[0096] In the above embodiment, by restoring the pixel value of the positioning texture, the clarity of the positioning texture can be increased, the difficulty of watermark extraction can be further reduced, and the accuracy of watermark extraction can be further improved.

[0097] In some embodiments, the composite image can also be superimposed into the watermark carrier after being sequentially subjected to enhancement processing, pixel value truncation, and pixel value restoration.

[0098] Figure 2D is a schematic diagram showing a composite image according to some other embodiments of the present disclosure.

[0099] Figure 2DThe shown image is a composite image after enhancement, pixel value clipping and pixel value restoration in sequence. Compared with Figure 2B the image shown in FIG. 2, the positioning texture is still clear, but other parts except the positioning texture are enhanced, but the noise is less than Figure 2C that in FIG. 2.

[0100] In some embodiments, the composite image can be superimposed into the watermark carrier in a tiled manner. For example, the composite image can be superimposed into the watermark carrier in a superimposed transparency preset by the user.

[0101] Figure 3A FIG. 4 is a schematic diagram showing superimposition of a composite image into a watermark carrier according to some embodiments of the present disclosure. Figure 3A FIG. 5 shows an overlay effect diagram of tiling superimposition of a composite image into a watermark carrier with a transparency of 0.2. “test” is the text of the watermark carrier.

[0102] Figure 3B FIG. 6 is a schematic diagram showing superimposition of a composite image into a watermark carrier according to some other embodiments of the present disclosure. Figure 3B FIG. 7 shows an overlay effect diagram of tiling superimposition of a composite image into a watermark carrier with a transparency that can make the user imperceptible. The transparency that makes the user imperceptible is a transparency that adjusts the gray value of the positioning texture to a difference of less than or equal to 2 from the gray value of the background of the composite image, so that the user cannot see the composite image. “test” is the text of the watermark carrier.

[0103] Figure 4 FIG. 8 is a flowchart showing a watermark processing method according to some embodiments of the present disclosure.

[0104] As shown in Figure 4 FIG. 8, the watermark processing method for a watermark carrier includes steps S410-S430. The watermark carrier is superimposed with a composite image in which a watermark image is embedded in a positioning image. The watermark image is generated according to the identification of a user browsing the watermark carrier and reflects the identification of the user. Both the positioning image and the composite image include a positioning texture for positioning the position of the watermark image in the watermark carrier in a watermark extraction process. For example, the watermark processing method is performed by a watermark processing device.

[0105] In step S410, an image of at least a part of the watermark carrier is obtained as a to-be-processed image. For example, the watermark carrier is a webpage, and the to-be-processed image is a screenshot of the webpage.

[0106] In step S420, the position of the composite image in the watermark carrier is located by using the positioning texture in the positioning image and the positioning texture in the to-be-processed image, so as to locate the position of the watermark image in the watermark carrier.

[0107] In some embodiments, the to-be-processed image can be pre-processed first. The pre-processing includes at least one of histogram equalization and local binarization. Then, the position of the composite image in the watermark carrier is located by using the locating texture in the locating image and the locating texture in the pre-processed to-be-processed image. For example, the size of the sliding window of the local binarization is 50*50 mm, the step length is 50 mm, and the local binarization algorithm is the OTSU (maximum inter-class variance) algorithm. Through the pre-processing, the difficulty of watermark extraction can be further reduced, and the accuracy of watermark extraction can be further improved.

[0108] Figure 5A is a schematic diagram showing a to-be-processed image according to some embodiments of the present disclosure. Figure 5A is a to-be-processed image with Figure 3A a watermark carrier, and the to-be-processed image after histogram equalization. It can be seen that Figure 5A the texture is enhanced compared with Figure 3A .

[0109] Figure 5B is a schematic diagram showing a to-be-processed image according to some other embodiments of the present disclosure. Figure 5B is a to-be-processed image after image binarization of Figure 5A the to-be-processed image. It can be seen that Figure 5B the locating texture becomes clearer compared with Figure 5A .

[0110] In some embodiments, image feature point matching operations are performed on the locating image and the to-be-processed image, to obtain a plurality of groups of feature point pairs. Each group of feature point pairs is a corresponding relationship between the pixel position coordinates of the feature-matched pixel points in the locating image and the pixel position coordinates in the to-be-processed image. According to the plurality of groups of feature point pairs, the position of the composite image in the watermark carrier is located.

[0111] For example, image feature point matching operations can also be performed on the locating image and the to-be-processed image after histogram equalization and local binarization, to obtain a plurality of groups of feature point pairs. The image feature point matching can adopt SIFT (Scale-invariant feature transform) algorithm, FAST (Features from accelerated segment test) algorithm, AKAZE algorithm, etc.

[0112] Returning to Figure 4 , in step S430, according to the position of the composite image in the watermark carrier, a watermark image is extracted from the to-be-processed image.

[0113] In some embodiments, the extraction of the watermark image from the to-be-processed image can be realized in the following manner.

[0114] First, according to the multiple sets of feature point pairs obtained by the image feature point matching operation, an affine matrix is calculated.

[0115] Second, according to the affine matrix, an alignment operation (affine transformation) is performed on the to-be-processed image.

[0116] Then, according to the position of the composite image in the watermark carrier, a to-be-processed sub-image in which one composite image is superimposed is cropped from the aligned to-be-processed image. For example, Figure 5C The to-be-processed sub-image is cropped from the watermark carrier in Figure 3A .

[0117] Finally, the watermark image is extracted from the to-be-processed sub-image. For example, a digital watermark extraction algorithm opposite to a digital watermark embedding algorithm can be used to extract the watermark image from the to-be-processed sub-image.

[0118] In some embodiments, for each image channel of the to-be-processed sub-image, a pixel value range representing the background of the to-be-processed sub-image can be determined according to the pixel values of the respective pixel points in each image channel; the composite image superimposed in the to-be-processed sub-image can be enhanced according to the pixel value range; and then the watermark image can be extracted from the to-be-processed sub-image after the enhancement processing. Through the enhancement processing, the difficulty of watermark extraction can be further reduced, and the accuracy of watermark extraction can be further improved.

[0119] For example, Figure 5D The to-be-processed sub-image in which the composite image superimposed in the to-be-processed sub-image of 5C is enhanced is shown. It can be seen that, compared with Figure 5C , Figure 5D The texture of the to-be-processed sub-image shown is stronger. For example, Figure 5E The watermark image extracted from the to-be-processed sub-image in Figure 5D is shown.

[0120] For example, the composite image superimposed in the to-be-processed sub-image can be enhanced in the following manner.

[0121] First, the maximum pixel value and the minimum pixel value in the pixel value range representing the background of the to-be-processed sub-image are determined.

[0122] Then, for each image channel of the to-be-processed sub-image, the pixel value of each pixel point is updated according to the size relationship between the pixel value of each pixel point and the maximum pixel value and the minimum pixel value, so as to increase the contrast between the background of the to-be-processed sub-image and the composite image.

[0123] For example, the composite image and the to-be-processed sub-image are both grayscale images, and updating the pixel value of each pixel point includes: for each pixel point in each image channel of the to-be-processed sub-image, in a case where the pixel value of each pixel point is less than the minimum pixel value, updating the pixel value of each pixel point to 0; in a case where the pixel value of each pixel point is greater than the maximum pixel value, updating the pixel value of each pixel point to 255; in a case where the pixel value of each pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, updating the pixel value of each pixel point according to the difference between the maximum pixel value and the minimum pixel value and the pixel value of each pixel point, so that the updated pixel value is greater than the pixel value before the update.

[0124] For example, for each pixel point in each image channel of the to-be-processed sub-image, in a case where the pixel value of each pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, the updated pixel value is negatively correlated with the difference value and positively correlated with the pixel value before the update. For example, the updated pixel value P_new=(P-P_new)×255 / (P_max-P_min), P is the pixel value before the update, P_max is the maximum pixel value, and P_min is the minimum pixel value.

[0125] In some embodiments, after the watermark image is extracted, an average value of the pixel values of each pixel point in each pixel block in the extracted watermark image is calculated as a pixel block average value; a position of a pixel block in which each digit of a digital code corresponding to the identity of the user is located is determined according to the pixel block average value; the digital code is determined according to the determined position of the pixel block in which each digit is located; and the identity of the user is determined according to the digital code. For example, through the corresponding relationship between the digital code and the identity of the user, the identity of the user can be determined, and the leakage traceability is realized.

[0126] For example, the digital code is N digits, and N is a positive integer. Determining the position of the pixel block in which each digit of the digital code corresponding to the identity of the user is located includes: calculating an average value of each pixel block average value corresponding to each pixel block as a reference average value; and determining the positions of N pixel blocks with the largest difference from the reference average value from each pixel block average value corresponding to each pixel block as the positions of the pixel blocks in which each digit of the digital code is located.

[0127] For example, the watermark image is generated Figure 2A For example, the watermark image is generated Figure 5E For example, the watermark image is generated Figure 5E For example, the watermark image is generated For each column after the pixel blocks are divided, the maximum difference between the pixel block average value and the average value of the pixel block average values of each pixel block in the column is selected as the digit in the corresponding digital code position.

[0128] In the above embodiments, the position of the watermark image in the watermark carrier can be located by the locating texture of the watermark image and the locating texture in the locating image, so that the watermark image can be extracted, the difficulty of watermark extraction can be reduced, and the accuracy of watermark extraction can be improved.

[0129] Figure 6 is a block diagram illustrating a watermark processing apparatus according to some embodiments of the present disclosure.

[0130] As shown in Figure 6 , the watermark processing apparatus 6 for a watermark carrier includes a generating module 61, an obtaining module 62, an embedding module 63, and a superimposing module 64.

[0131] The generating module 61 is configured to generate a watermark image reflecting the identity of a user browsing the watermark carrier according to the identity of the user, for example, performing step S110 as shown in Figure 1 .

[0132] The obtaining module 62 is configured to obtain a locating image, for example, performing step S120 as shown in Figure 1 . The locating image includes a locating texture for locating the position of the watermark image in the watermark carrier in a watermark extraction process.

[0133] The embedding module 63 is configured to embed the watermark image into the locating image to obtain a composite image, for example, performing step S130 as shown in Figure 1 .

[0134] The superimposing module 64 is configured to superimpose the composite image into the watermark carrier, for example, performing step S140 as shown in Figure 1 .

[0135] Figure 7 is a block diagram illustrating a watermark processing apparatus according to some embodiments of the present disclosure. A watermark carrier is superimposed with a composite image in which a watermark image is embedded, the watermark image is generated according to the identity of a user browsing the watermark carrier and reflects the identity of the user, and the locating image and the composite image both include a locating texture for locating the position of the watermark image in the watermark carrier in a watermark extraction process.

[0136] As shown in Figure 7 , the watermark processing apparatus 7 for a watermark carrier includes an obtaining module 71, a locating module 72, and an extracting module 73.

[0137] The obtaining module 71 is configured to obtain an image of at least a portion of the watermark carrier as a to-be-processed image, for example, performing step S410 as shown in Figure 4 .

[0138] The positioning module 72 is configured to position the position of the composite image in the watermark carrier by using the positioning texture in the positioning image and the positioning texture in the image to be processed, to position the position of the watermark image in the watermark carrier, for example, to perform the step S420 as shown in Figure 4

[0139] The extraction module 73 is configured to extract the watermark image from the image to be processed according to the position of the composite image in the watermark carrier, for example, to perform the step S430 as shown in Figure 4

[0140] Figure 8 is a block diagram illustrating a watermark processing apparatus according to some embodiments of the present disclosure.

[0141] As shown in Figure 8 The watermark processing apparatus 8 for a watermark carrier includes a memory 81 and a processor 82 coupled to the memory 81. The memory 81 is configured to store instructions for performing corresponding embodiments of the watermark processing method. The processor 82 is configured to perform the watermark processing method in any of some embodiments of the present disclosure based on the instructions stored in the memory 81. The watermark processing apparatus 8 can have the same or similar functions as at least one of the watermark processing apparatus 6 and the watermark processing apparatus 7.

[0142] Figure 9 is a block diagram illustrating a computer system for implementing some embodiments of the present disclosure.

[0143] As shown in Figure 9 The computer system 90 can be in the form of a general-purpose computing device. The computer system 90 includes a memory 910, a processor 920, and a bus 900 connecting different system components.

[0144] The memory 910 may, for example, include system memory, non-volatile storage media, and the like. The system memory, for example, stores an operating system, application programs, a boot loader, and other programs, and the like. The system memory can include volatile storage media, such as random access memory (RAM) and / or cache memory. The non-volatile storage media, for example, stores instructions for performing corresponding embodiments of at least one of the watermark processing methods. The non-volatile storage media includes, but is not limited to, magnetic disk storage media, optical storage media, flash memory, and the like.

[0145] ​​The processor 920 can be implemented with a general-purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, etc. discrete hardware component. Accordingly, each module such as the determination module and the determination module can be implemented by a central processing unit (CPU) running instructions in the memory to perform corresponding steps, or by a special circuit performing corresponding steps.

[0146] The bus 900 can use any of a variety of bus structures. For example, the bus structure includes but is not limited to an industry standard architecture (ISA) bus, a micro channel architecture (MCA) bus, a peripheral component interconnect (PCI) bus.

[0147] The computer system 90 can also include an input / output interface 930, a network interface 940, a storage interface 950, etc. These interfaces 930, 940, 950 and the memory 910 and the processor 920 can be connected through the bus 900. The input / output interface 930 can provide a connection interface for display, mouse, keyboard, etc. Input / output devices. The network interface 940 provides a connection interface for various networking devices. The storage interface 950 provides a connection interface for external storage devices such as floppy disks, U disks, SD cards, etc.

[0148] Here, various aspects of the present disclosure are described with reference to flowcharts and / or block diagrams of methods, apparatuses and computer program products according to embodiments of the present disclosure. It should be understood that each block of the flowchart and / or block diagram can be implemented by computer readable program instructions.

[0149] These computer readable program instructions can be provided to a processor of a general purpose computer, a special purpose computer, or other programmable device to produce a machine, so that the instructions executed by the processor produce the device specified in one or more blocks of the flowchart and / or block diagram.

[0150] These computer readable program instructions can also be stored in a computer readable storage medium, which makes the computer work in a specific way, so as to produce a product, including instructions to implement the functions specified in one or more blocks of the flowchart and / or block diagram.

[0151] The present disclosure can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects.

[0152] Through the watermark processing method and device for the watermark carrier in the above embodiment, the computer storage medium, the difficulty of watermark adding and extracting can be reduced, and the accuracy of watermark extraction can be improved.

[0153] So far, the watermark processing method and device for a watermark carrier, the computer storable medium according to the present disclosure have been described in detail. In order to avoid obscuring the concept of the present disclosure, some details known in the art are not described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein according to the above description.

Claims

1. A method for watermark processing of a watermark carrier, comprising: generating a watermark image reflecting an identity of a user browsing the watermark carrier according to the identity of the user; obtaining a positioning image, the positioning image comprising a positioning texture for locating a position of the watermark image in the watermark carrier in a watermark extraction process; embedding the watermark image into the positioning image to obtain a composite image, the composite image comprising the positioning texture; superimposing the composite image into the watermark carrier so as to add the watermark image into the watermark carrier; wherein superimposing the composite image into the watermark carrier comprises: obtaining a first pixel value of the positioning texture in the positioning image; restoring a second pixel value of the positioning texture in the composite image to the first pixel value; superimposing the composite image with the second pixel value of the positioning texture restored to the first pixel value into the watermark carrier so as to increase a definition of the positioning texture.

2. The watermark processing method of claim 1, wherein, superimposing the composite image into the watermark carrier comprises: enhancing the composite image according to an overlay transparency required for superimposing the composite image preset by the user; superimposing the enhanced composite image into the watermark carrier with the overlay transparency.

3. The watermark processing method of claim 2, wherein, enhancing the composite image comprises: for each pixel point of the composite image, determining a target pixel value of the each pixel point in the composite image according to the first pixel value of the each pixel point in the positioning image, a second pixel value of the each pixel point in the composite image and the overlay transparency.

4. The watermark processing method of claim 3, wherein, for the each pixel point: the target pixel value is negatively correlated with the first pixel value and positively correlated with the second pixel value; in a case that the second pixel value is greater than the first pixel value, the target pixel value is negatively correlated with the overlay transparency; in a case that the second pixel value is less than the first pixel value, the target pixel value is positively correlated with the overlay transparency; in a case that the second pixel value is equal to the first pixel value, the target pixel value is equal to the first pixel value.

5. The watermark processing method of claim 4, wherein, determining the target pixel value of the each pixel point in the composite image comprises: calculating a difference value of the second pixel value and the first pixel value of the each pixel point; calculating a ratio value of the difference value and the overlay transparency; calculating the target pixel value of the each pixel point according to a sum of the ratio value and the first pixel value.

6. The watermark processing method of claim 1, wherein, superimposing the composite image into the watermark carrier comprises: modifying a pixel value of a pixel point in the composite image with a pixel value less than a truncation threshold to the truncation threshold to perform pixel value truncation on the composite image; superimposing the composite image after the pixel value truncation into the watermark carrier.

7. The watermark processing method of claim 1, wherein, generating the watermark image reflecting the identity of the user browsing the watermark carrier according to the identity of the user comprises: determining a digital code corresponding to the identity of the user browsing the watermark carrier, the digital code comprising one or more digits, each digit having a value ranging from 0 to 9; obtaining a blank image carrying the digital code; determining position coordinates of a pixel block in the blank image for carrying each digit of the digital code; According to the determined position coordinates of the pixel block of each digit, pixel values of the pixel block of each digit in the blank image for carrying the digital code are set as preset pixel values, and an absolute value of a difference between the preset pixel values and pixel values of other pixel blocks in the blank image except the pixel block of each digit is greater than a pixel block threshold.

8. The watermark processing method of claim 7, wherein, The width of the blank image is positively correlated with the size of the pixel block and the number of bits of the digital code respectively, and the height of the blank image is determined according to the size of the pixel block.

9. The watermark processing method of claim 7, wherein, The number of bits of the digital code is positively correlated with the width and height of the positioning image respectively.

10. The watermark processing method of claim 1, wherein, Superimposing the composite image into the watermark carrier includes: The composite image is superimposed into the watermark carrier in a tiling manner.

11. The watermark processing method of claim 1, wherein, The positioning texture includes at least one of text content and graphic content.

12. A watermarking method for a watermark carrier, wherein The watermark carrier is superimposed with a composite image in which a watermark image is embedded in a positioning image, the watermark image is generated according to and reflects an identity of a user browsing the watermark carrier, the positioning image and the composite image both include a positioning texture for positioning a position of the watermark image in the watermark carrier in a watermark extraction process, wherein in the process of superimposing the composite image into the watermark carrier, a first pixel value of the positioning texture in the positioning image is obtained, a second pixel value of the positioning texture in the composite image is restored to the first pixel value, and the composite image in which the second pixel value of the positioning texture is restored to the first pixel value is superimposed into the watermark carrier, so as to increase the clarity of the positioning texture, and the watermark processing method includes: An image of at least a part of the watermark carrier is obtained as a to-be-processed image. The position of the composite image in the watermark carrier is positioned by using the positioning texture in the positioning image and the positioning texture in the to-be-processed image, so as to position the position of the watermark image in the watermark carrier. The watermark image is extracted from the to-be-processed image according to the position of the composite image in the watermark carrier.

13. The watermark processing method of claim 12, wherein, Positioning the position of the composite image in the watermark carrier includes: An image feature point matching operation is performed on the positioning image and the to-be-processed image, a plurality of groups of feature point pairs are obtained, each group of feature point pairs is a corresponding relationship between pixel position coordinates of a feature-matched pixel point in the positioning image and pixel position coordinates in the to-be-processed image; The position of the composite image in the watermark carrier is positioned according to the plurality of groups of feature point pairs.

14. The watermark processing method of claim 13, wherein, Extracting the watermark image from the to-be-processed image includes: An affine matrix is calculated according to the plurality of groups of feature point pairs; An alignment operation is performed on the to-be-processed image according to the affine matrix; A to-be-processed sub-image in which one of the composite images is superimposed is intercepted from the to-be-processed image after alignment according to the position of the composite image in the watermark carrier; The watermark image is extracted from the to-be-processed sub-image.

15. The watermarking method of claim 14, wherein, Extracting the watermark image from the to-be-processed sub-image includes: determining, for each image channel of the to-be-processed sub-image, a pixel value range representing a background of the to-be-processed sub-image according to pixel values of respective pixel points in the each image channel; performing enhancement processing on the composite image superimposed in the to-be-processed sub-image according to the pixel value range; extracting the watermark image from the to-be-processed sub-image after the enhancement processing.

16. The watermarking method of claim 15, wherein, The enhancement processing on the composite image superimposed in the to-be-processed sub-image comprises: determining a maximum pixel value and a minimum pixel value in the pixel value range; for each image channel of the to-be-processed sub-image, updating a pixel value of each pixel point according to a size relationship between the pixel value of the each pixel point and the maximum pixel value and the minimum pixel value, so as to increase a contrast between the background of the to-be-processed sub-image and the composite image.

17. The watermarking method of claim 16, wherein, The composite image and the to-be-processed sub-image are both grayscale images, and the updating of the pixel value of the each pixel point comprises: for each pixel point in each image channel of the to-be-processed sub-image, in a case where the pixel value of the each pixel point is less than the minimum pixel value, updating the pixel value of the each pixel point to 0; in a case where the pixel value of the each pixel point is greater than the maximum pixel value, updating the pixel value of the each pixel point to 255; in a case where the pixel value of the each pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, updating the pixel value of the each pixel point according to a difference between the maximum pixel value and the minimum pixel value and the pixel value of the each pixel point, so that the updated pixel value is greater than the pixel value before the updating.

18. The watermarking method of claim 17, wherein, In the case where the pixel value of the each pixel point is greater than or equal to the minimum pixel value and less than or equal to the maximum pixel value, the updated pixel value is negatively correlated with the difference and positively correlated with the pixel value before the updating.

19. The watermarking method of claim 12, wherein, The positioning of the position of the composite image in the watermark carrier comprises: performing preprocessing on the to-be-processed image, the preprocessing comprising at least one of histogram equalization and local binarization; positioning the position of the composite image in the watermark carrier by using a positioning texture in the positioning image and a positioning texture in the to-be-processed image after the preprocessing.

20. The watermark processing method of claim 12, further comprising: after the extraction of the watermark image, calculating an average value of pixel values of respective pixel points in each pixel block in the extracted watermark image as a pixel block average value; determining, according to the pixel block average value, positions of pixel blocks in which respective digits of a digital code corresponding to the identity of the user are located; determining the digital code according to the determined positions of the pixel blocks in which the respective digits are located; determining the identity of the user according to the digital code.

21. The watermarking method of claim 20, wherein, The digital code is N digits, N being a positive integer, and the determination of the positions of the pixel blocks in which the respective digits of the digital code corresponding to the identity of the user are located comprises: calculating an average value of the respective pixel block average values as a reference average value; From the average values ​​of each pixel block corresponding to each pixel block, determine the positions of the N pixel blocks with the largest differences from the reference average value as the positions of the pixel blocks containing each digit of the digital code.

22. A watermark processing apparatus for a watermark carrier, comprising: The generation module is configured to generate a watermark image reflecting the identifier of the user browsing the watermark carrier; The acquisition module is configured to acquire a positioning image, the positioning image including a positioning texture for locating the position of the watermark image in the watermark carrier during the watermark extraction process; An embedding module is configured to embed the watermark image into the positioning image to obtain a composite image, the composite image including the positioning texture; An overlay module is configured to overlay the composite image onto the watermark carrier to add the watermark image to the watermark carrier. The module acquires a first pixel value of the positioning texture in the positioning image, restores a second pixel value of the positioning texture in the composite image to the first pixel value, and overlays the composite image, in which the second pixel value of the positioning texture is restored to the first pixel value, onto the watermark carrier to increase the clarity of the positioning texture.

23. A watermarking apparatus for a watermark carrier, wherein, The watermark carrier is overlaid with a composite image in which a watermark image is embedded in a positioning image. The watermark image is generated based on and reflects the identifier of the user browsing the watermark carrier. Both the positioning image and the composite image include a positioning texture for locating the position of the watermark image in the watermark carrier during watermark extraction. During the overlaying of the composite image onto the watermark carrier, a first pixel value of the positioning texture in the positioning image is obtained, a second pixel value of the positioning texture in the composite image is restored to the first pixel value, and the composite image with the second pixel value restored to the first pixel value is overlaid onto the watermark carrier to increase the clarity of the positioning texture. The watermark processing device includes: The acquisition module is configured to acquire at least a portion of the image of the watermark carrier as the image to be processed; The positioning module is configured to locate the position of the composite image in the watermark carrier by using the positioning texture in the positioning image and the positioning texture in the image to be processed, so as to locate the position of the watermark image in the watermark carrier. The extraction module is configured to extract the watermark image from the image to be processed based on the position of the composite image in the watermark carrier.

24. A watermark processing apparatus for a watermark carrier, comprising: Memory; as well as A processor coupled to the memory, the processor being configured to execute at least one of the watermarking methods as described in any one of claims 1 to 11 and as described in any one of claims 12 to 21, based on instructions stored in the memory.

25. A computer-storeable medium having stored thereon computer program instructions that, when executed by a processor, implement at least one of the watermarking methods as claimed in any one of claims 1 to 11 and as claimed in any one of claims 12 to 21.

Images