CN111428534B - Decryption identification method based on dot matrix hidden writing information coding - Google Patents
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- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/14—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation using light without selection of wavelength, e.g. sensing reflected white light
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Abstract
The invention provides a decryption identification method based on dot matrix hidden writing information coding, which comprises the following steps: obtaining a dot matrix image, wherein the dot matrix image comprises a positioning dot matrix and a hidden writing information dot matrix, and one positioning dot matrix corresponds to one hidden writing information dot matrix; respectively extracting a positioning lattice and a steganographic information lattice from the obtained lattice image; analyzing the type of the positioning lattice according to the positioning lattice; analyzing effective information according to the type of the positioning lattice and the extracted hidden information lattice; and decoding the effective information according to a preset decoding rule. The hidden information lattice in the image can be accurately extracted, the encrypted important information in the image can be accurately identified, the calculation process is simple, and the identification efficiency is high.
Description
Technical Field
The invention relates to the field of image processing, in particular to a decryption identification method based on dot matrix hidden writing information coding.
Background
In the prior art, a method for identifying based on specific hidden information mainly comprises the steps of identifying the surface of the specific hidden information by designing the specific hidden information into an irregular shape and by means of specific equipment for matching detection of the specific shape, so as to judge whether the specific hidden information is forged or is designed into a bar code shape, and adopting specific infrared scanning equipment for identification. Although the above-mentioned method has achieved the effect of anti-counterfeiting recognition to a certain extent, it needs to resort to specific hardware equipment in the implementation process, so that it has certain difficulties in terms of user popularization and anti-counterfeiting recognition overhead.
Therefore, in the prior art, a method that does not need to specify identification equipment is also designed, namely, the most widely used equipment, namely, a mobile phone is used for photographing and identification, but the method generally adopts a more complex processing process, is more complex in calculation, and is more complicated in hidden information image identification process, and the hidden information image identification process also changes greatly when the shape characteristics of the hidden information are changed, so that the whole conversion process is low in efficiency and more in time consumption, and cannot be applied to actual requirements and mass production. Meanwhile, the method has more unstable factors, the accuracy of identifying the steganographic information on the surface of the printed matter is low, and the texture characteristics of the steganographic information can not be extracted sometimes.
Disclosure of Invention
The invention aims to overcome at least one defect (deficiency) of the prior art, and provides a decryption identification method based on the dot matrix hidden information coding, which can accurately extract the hidden information dot matrix in the image and accurately identify the encrypted important information in the image, and has simple calculation process and higher identification efficiency.
The technical scheme adopted by the invention is as follows:
a decryption identification method based on dot matrix hidden writing information coding comprises the following steps:
obtaining a dot matrix image, wherein the dot matrix image comprises a positioning dot matrix and a hidden writing information dot matrix, and one positioning dot matrix corresponds to one hidden writing information dot matrix;
respectively extracting a positioning lattice and a steganographic information lattice from the obtained lattice image;
analyzing the type of the positioning lattice according to the positioning lattice;
analyzing effective information according to the type of the positioning lattice and the extracted hidden information lattice;
and decoding the effective information according to a preset decoding rule.
The method comprises the steps of extracting a positioning lattice and a steganographic information lattice from an obtained lattice image, analyzing the type of the positioning lattice according to the positioning lattice, analyzing effective information according to the type of the positioning lattice and the steganographic information lattice, and decoding the effective information according to a preset decoding rule so as to obtain steganographic information in the image.
Further, each positioning lattice comprises a first lattice and a second lattice, wherein the first lattice is used for positioning the second lattice and the hidden information lattice, and the second lattice is used for indicating the type of the positioning lattice;
the step of extracting the locating lattice and the hidden information lattice from the obtained lattice image comprises the following steps: extracting a first lattice from the obtained lattice image;
positioning and extracting a second lattice and a hidden information lattice according to the extracted first lattice;
the step of analyzing the type of the positioning lattice according to the extracted positioning lattice specifically comprises the following steps:
and analyzing the type of the positioning lattice according to the extracted second lattice.
The first dot matrix is extracted from the obtained dot matrix image, so that the hidden information dot matrix is rapidly positioned, the type of the positioning dot matrix is analyzed by extracting the second dot matrix from the obtained dot matrix image, and the accurate hidden information dot matrix can be extracted, so that the identification accuracy is improved.
Further, the first lattice is an m1×n lattice, the second lattice is an m2×n lattice, the values of m1 and n are integers greater than or equal to 2, the value of m2 is an integer greater than or equal to 1, each point position of the first lattice has a point, and at least one point position of the second lattice has no point;
the step of extracting the first lattice from the obtained lattice image specifically includes:
calculating the dot distance in the obtained dot matrix image;
determining a positioning frame for framing all 2X 2 lattices in the positioning lattices according to the lattice distance;
judging whether points of the 2X 2 lattice selected by the positioning frame exist or not;
if all the point positions of the 2X 2 lattice selected by the positioning frame exist, determining that the 2X 2 lattice selected by the positioning frame is a four-positioning lattice;
when the value of m1 is 2, the four positioning lattices are first lattices;
when the value of m1 is an integer greater than 2, determining a first lattice according to the crossing condition of the four positioning lattices.
The dot distance in the dot matrix image is calculated, the positioning frame for positioning the dot matrix is determined according to the dot distance, and whether the dot matrix selected by the positioning frame has dots is judged, so that the positioning dot matrix can be accurately extracted, and the extraction calculation process is simple and convenient.
Further, the step of determining the first lattice according to the crossing condition of the four positioning lattices specifically includes: and selecting points of the same corresponding position of each four-positioning lattice, calculating the inclination angle and the coordinate difference between the points of the same corresponding position of each two four-positioning lattices, determining whether the two four-positioning lattices are crossed according to whether the inclination angle and the coordinate difference are within a preset range, and determining the first lattice according to whether the two four-positioning lattices are crossed in a preset direction.
The first lattice is determined by determining whether the four-positioning lattices are crossed according to the calculated inclination angle and the coordinate difference between the points at the same corresponding position of every two four-positioning lattices, the process is simple, and the accuracy of extracting the first positioning lattice can be improved.
Further, the step of calculating the dot distance in the obtained dot matrix image specifically includes:
calculating the distance from each point to other points in the obtained dot matrix image;
and selecting the minimum value of the distance from each point to other points, and determining the point distance according to each selected minimum value.
The point distance is determined according to the minimum value of the distance from each point to other points, so that the problem of inaccurate point distance caused by selecting different values is avoided, and the accuracy of determining the positioning frame can be improved according to the minimum value.
Further, after the step of determining that the m1×n lattice selected by the positioning frame is a four-positioning lattice, the method further includes:
calculating the theoretical distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the point distance;
calculating the actual distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the position of each point in the extracted four-positioning lattice;
and screening the extracted four-positioning lattice according to errors of the theoretical distance and the actual distance.
The four-positioning dot matrix is screened according to the errors of the theoretical distance and the actual distance by calculating the theoretical distance and the actual distance from the center point of the four-point dot matrix to each point of the four-positioning dot matrix, and the four-positioning dot matrix which does not meet the requirements is removed, so that the accuracy of subsequent analysis of steganographic information is improved or the accuracy of subsequent determination of the first dot matrix is improved.
Further, the step of resolving the type of the positioning lattice according to the extracted second lattice specifically includes:
and analyzing the type of the positioning lattice according to whether the points of the extracted second lattice exist.
By judging whether the points of the second lattice exist or not, the type of the positioning lattice is resolved, the process is simple, the accuracy is high, and the recognition efficiency is improved.
Further, before the step of analyzing the type of the positioning lattice according to whether the points of the positioning lattice exist, the method further includes:
and carrying out affine transformation on the extracted positioning lattice and the hidden information lattice according to the extracted positioning lattice.
By carrying out radiation transformation on the extracted positioning lattice and the hidden information lattice, the extracted positioning lattice and hidden information lattice are more accurate, and the decryption accuracy is improved.
Further, the step of analyzing the effective information according to the type of the positioning lattice and the extracted hidden information lattice specifically includes:
judging whether each point of the extracted hidden information lattice exists, if so, marking the point as a first number, and if not, marking the point as a second number so as to convert the extracted hidden information lattice into a digital matrix;
and according to the type of the positioning lattice, analyzing effective information from the converted digital matrix.
The positions of the points are marked as the first numbers or the second numbers by judging whether the points of the extracted hidden information lattice exist or not, so that the hidden information lattice can be simply and quickly converted into a digital matrix; different types of positioning lattices correspond to different pieces of steganography information, and effective information can be accurately analyzed by analyzing the effective information from the digital matrix according to the types of positioning points.
Further, the step of analyzing the effective information from the converted digital matrix according to the type of the positioning lattice specifically includes:
when a plurality of positioning lattices of the same type are provided, an effective digital matrix is determined according to a plurality of digital matrices converted from hidden information lattices respectively corresponding to the plurality of positioning lattices of the same type;
when the single positioning lattice is used, the digital matrix converted from the hidden writing information lattice corresponding to the single positioning lattice is used as an effective digital matrix;
and analyzing the effective information from the effective digital matrix according to the type of the positioning lattice.
When a plurality of positioning lattices of the same type are provided, an effective digital matrix is determined from a plurality of digital matrices corresponding to the positioning lattices of the same type, so that the accuracy of subsequent effective information analysis is greatly improved.
Compared with the prior art, the invention has the beneficial effects that:
the invention realizes the rapid positioning of a single dot matrix image by utilizing positioning dot matrix matching, thereby being capable of rapidly extracting the hidden information and resolving the effective information, the processing process is simple, the related calculation process is also simpler, and the recognition efficiency and the accuracy of the image with the hidden information are improved; after the effective information is obtained, the effective information is decoded according to a decoding rule, and the decoding rule is simple and convenient to calculate.
Drawings
Fig. 1 is a flowchart showing the whole decryption identification method of the present embodiment;
FIG. 2 is a print image with a dot matrix according to the present embodiment;
fig. 3 is a schematic diagram of an effect of normalizing an image according to the present embodiment;
FIG. 4 is a schematic diagram of a six-position lattice according to the present embodiment;
FIG. 5 is a schematic diagram showing the effect of the block selection of the four-position lattice according to the present embodiment;
FIG. 6 is a schematic diagram of determining the effect of six-location lattice according to the present embodiment;
FIG. 7 is a schematic diagram of a repeating lattice unit in the present embodiment;
fig. 8 is a schematic diagram of a decoding rule in the present embodiment.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the invention. For better illustration of the following embodiments, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the actual product dimensions; it will be appreciated by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The embodiment provides a decryption identification method based on lattice steganographic information encoding, as shown in fig. 1, which is an overall flowchart of the decryption identification method of the embodiment, and the specific process is as follows:
s1, acquiring a dot matrix image, wherein the dot matrix image comprises a positioning dot matrix and a hidden writing information dot matrix, and one positioning dot matrix corresponds to one hidden writing information dot matrix;
s2, respectively extracting a positioning lattice and a steganographic information lattice from the obtained lattice image;
s3, analyzing the type of the positioning lattice according to the positioning lattice;
s4, analyzing effective information according to the type of the positioning lattice and the extracted hidden information lattice;
s5, decoding the effective information according to a preset decoding rule.
In this embodiment, the dot matrix image is obtained from a captured image with a dot matrix, then a positioning dot matrix and a steganographic information dot matrix are respectively extracted from the obtained dot matrix image, the type of the positioning dot matrix is analyzed according to the positioning dot matrix, the effective information in the steganographic information dot matrix is analyzed according to the type of the positioning dot matrix, and finally the effective information is decoded according to a preset decoding rule. The decryption process is simple, the identification accuracy is high, no specific identification equipment is needed for identifying the image, and the application range is wide.
In the specific implementation process, as shown in fig. 2, a printed matter image with a dot matrix is obtained by performing preprocessing operations such as normalization and binarization on the captured image with the dot matrix, and the influence of illumination and shadow on the obtained dot matrix image can be removed by performing normalization processing on an RGB color space of the image, as shown in fig. 3, the printed matter image with the dot matrix is normalized; then converting the image from RGB color space to HSV color space, extracting dot matrix image in the image by taking the color of dot matrix in the image as characteristic, compared with RGB color space, HSV color space can intuitively express brightness, tone and vividness of color, and is convenient for comparison between colors, so that the conversion of the image from RGB color space to HSV color space is helpful for obtaining dot matrix image in the image, furthermore, the color is taken as main identification characteristic, so that the embodiment can obtain dot matrix image with various colors, and the identification of dot matrix image with different colors is realized by the hierarchical height characteristic of different colors in the color space; the positioning lattices can be four positioning lattices, six positioning lattices and the like, and the types of different positioning lattices are different, as shown in a schematic diagram of the six positioning lattices in fig. 4, wherein the six positioning lattices are three types, namely a first type positioning lattice, a second type positioning lattice and a third type positioning lattice.
In this embodiment, each of the positioning lattices includes a first lattice and a second lattice, where the first lattice is used to position the second lattice and the hidden information lattice, and the second lattice is used to indicate a type of the positioning lattice; the step of extracting the locating lattice and the hidden information lattice from the obtained lattice image comprises the following steps: extracting a first lattice from the obtained lattice image;
positioning and extracting a second lattice and a hidden information lattice according to the extracted first lattice;
the step of analyzing the type of the positioning lattice according to the extracted positioning lattice specifically comprises the following steps:
and analyzing the type of the positioning lattice according to the extracted second lattice.
In this embodiment, the first lattice is an m1×n lattice, the second lattice is an m2×n lattice, values of m1 and n are integers greater than or equal to 2, values of m2 are integers greater than or equal to 1, points exist at positions of all points of the first lattice, and at least one point of the second lattice is not a point; the step of extracting the first lattice from the obtained lattice image specifically includes:
calculating the dot distance in the obtained dot matrix image;
determining a positioning frame for framing all 2X 2 lattices in the positioning lattices according to the lattice distance;
judging whether points of the 2X 2 lattice selected by the positioning frame exist or not;
if all the point positions of the 2X 2 lattice selected by the positioning frame exist, determining that the 2X 2 lattice selected by the positioning frame is a four-positioning lattice;
when the value of m1 is 2, the four positioning lattices are first lattices;
when the value of m1 is an integer greater than 2, determining a first lattice according to the crossing condition of the four positioning lattices.
In this embodiment, after the step of determining that the m1×n lattice selected by the positioning frame is the four-positioning lattice, the method further includes:
calculating the theoretical distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the point distance;
calculating the actual distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the position of each point in the extracted four-positioning lattice;
and screening the extracted four-positioning lattice according to errors of the theoretical distance and the actual distance.
In the implementation process, as shown in fig. 4, a second lattice in the positioning lattices is represented by a box 1, which is used for representing the type of the positioning lattices, and a first lattice in the positioning lattices is represented by a box 2, which is used for positioning the second lattice and the hidden information lattice; after obtaining a dot matrix image from the image with the dot matrix, firstly extracting a first dot matrix from the dot matrix image, wherein the first dot matrix is an m1×n dot matrix, and each dot position of the first dot matrix is provided with a dot for positioning a second dot matrix and a hidden information dot matrix; and locating a second lattice and a hidden information lattice according to the extracted first lattice, wherein the second lattice is an m2 multiplied by n lattice, the values of m1 and n are integers which are more than or equal to 2, the value of m2 is an integer which is more than or equal to 1, and at least one point of the second lattice does not exist. Specifically, calculating the dot distance in the obtained dot matrix image, determining a positioning frame for framing all 2X 2 dot matrixes in the positioning dot matrixes according to the dot distance, judging whether the dot positions of the 2X 2 dot matrixes framed by the positioning frame exist, and if the dot positions exist in all the positions, framing the 2X 2 dot matrixes framed by the positioning frame into four positioning dot matrixes; when the value of m1 is 2, the four-positioning lattice is the first lattice, and when the value of m1 is an integer greater than 2, the first lattice is determined according to the crossing condition of the four-positioning lattice, as shown in fig. 5, which is an effect schematic diagram of the frame selection of the four-positioning lattice.
Specifically, the positioning frames for selecting all 2×2 lattices in the positioning lattices are determined according to the point distances, and the positioning frames for selecting the 2×2 lattices are determined mainly by calculating the offsets of four directions of each point according to the point distances and determining the positioning frames for selecting the 2×2 lattices according to the offsets of four directions of each point and the mass center of the point; then judging whether the points at each position in the 2X 2 lattice selected by the positioning frame exist or not, if so, determining that the 2X 2 lattice selected by the positioning frame is a four-positioning lattice; after the four-positioning lattice is obtained, the method further comprises the steps of verifying and screening the four-point lattice, and the specific steps are as follows: calculating theoretical distance under ideal condition according to the point distance, calculating the range of ideal actual distance according to the preset error parameter, wherein the error parameter is 0.17 in the embodiment, calculating the range of ideal actual distance according to the theoretical distance and the error parameter, calculating the center point position of the 2X 2 lattice according to the positions of four points in the framed 2X 2 lattice, respectively calculating the actual distances from the center point to the four points, judging the calculated actual distance and the range of ideal actual distance, and taking the point at the left upper corner in the four positioning lattices as the initial point when the actual distance from the four points to the center point is in the ideal actual distance range; when the value of m1 is 2, the four-positioning lattice is the first lattice, and when the value of m1 is an integer greater than 2, the first lattice is determined according to the crossing condition of the four-positioning lattice.
Specifically, before determining the positioning frames for looking at all 2×2 lattices in the frame selection positioning lattices according to the lattice distance, removing noise points with too small area and influence areas with too large area in the lattice image, so that the accuracy of extracting the positioning lattices can be improved.
In this embodiment, the step of calculating the dot distance in the obtained dot matrix image specifically includes:
calculating the distance from each point to other points in the obtained dot matrix image;
and selecting the minimum value of the distance from each point to other points, and determining the point distance according to each selected minimum value.
In the implementation process of the embodiment, firstly, the distance from the center of each point to the centers of other points is calculated, then the minimum value of the distance from the center of each point to the centers of other points is taken, and finally the average value of the selected minimum values is taken as the finally determined point distance.
In this embodiment, the step of determining the first lattice according to the crossing condition of the four positioning lattices specifically includes:
and selecting points of the same corresponding position of each four-positioning lattice, calculating the inclination angle and the coordinate difference between the points of the same corresponding position of each two four-positioning lattices, determining whether the two four-positioning lattices are crossed according to whether the inclination angle and the coordinate difference are within a preset range, and determining the first lattice according to whether the two four-positioning lattices are crossed in a preset direction.
Specifically, selecting points of the same corresponding position of each four-positioning dot matrix, selecting head points in the four-positioning dot matrix, namely upper left corner points, calculating coordinate differences between the head points of every two four-positioning dot matrixes, specifically subtracting the coordinates of the head points of every two four-positioning dot matrixes, and marking as dxy, wherein dxy [0] is an error value on an x-axis of two points, dxy [1] is an error value on a y-axis of two points, and then calculating an inclination angle: angle=arctan (|dxy [0]/dxy [1] |), wherein angle is the inclination angle of the first point of the two four positioning points, if the inclination angle of the first point of the two four positioning points is within a preset inclination angle range and the coordinate difference of the two points is within a preset coordinate difference range, the two four positioning points are determined to have an intersection, specifically, the inclination angle range is [0,15 pi/180 ], finally, the first point array is determined according to whether the two four positioning points have an intersection in a preset direction or not, specifically, in a specific implementation process, the first point array is determined according to whether the two four positioning points have an intersection in a y-axis direction or not. Taking the value of m1 as 3 as an example, as shown in fig. 5, after selecting four-point lattices in a frame, judging whether the two crossed four-positioning lattices have a cross according to the inclination angle and the coordinate difference between the first points of every two four-positioning lattices, if the two four-positioning lattices have a cross, judging whether the two crossed four-positioning lattices have a cross in the y-axis direction, if the two crossed four-positioning lattices have a cross, the two four-positioning lattices are the first lattice, namely the six-positioning lattice, and as shown in fig. 6, a result diagram for determining the six-positioning lattice is shown.
In this embodiment, before the step of analyzing the type of the positioning lattice according to whether the points of the positioning lattice exist, the method further includes:
and carrying out affine transformation on the extracted positioning lattice and the hidden information lattice according to the extracted positioning lattice.
Specifically, firstly, obtaining the size of a dot matrix image corresponding to a single positioning dot matrix according to the side length of a single dot of the dot matrix in original coding and the dot distance preset during generation; then selecting x nonlinear points from the positioning point array, wherein the value of x is an integer point which is more than or equal to 3, the x nonlinear points are not positioned on the same straight line, and carrying out affine transformation on the point array image according to the x linear points to obtain a new point array image; in the specific implementation process, three nonlinear points are extracted from a positioning dot matrix as transformation standards to obtain a mapping relation of affine transformation, and affine transformation is carried out on a dot matrix image according to the mapping relation to obtain a new dot matrix image.
In this embodiment, the step of analyzing the effective information according to the type of the positioning lattice and the extracted hidden information lattice specifically includes:
judging whether each point of the extracted hidden information lattice exists, if so, marking the point as a first number, and if not, marking the point as a second number so as to convert the extracted hidden information lattice into a digital matrix;
and according to the type of the positioning lattice, analyzing effective information from the converted digital matrix.
Specifically, traversing a hidden information lattice extracted from a new lattice image obtained after lattice image or affine transformation, judging whether the position of each point of the hidden information lattice exists, if so, marking the position of the point as 1, and if not, marking the position of the point as 0, thereby obtaining a 01 matrix corresponding to the hidden information lattice; finally, according to the type of the positioning lattice, analyzing the effective information from the 01 matrix obtained by conversion
In this embodiment, the step of analyzing the effective information from the digital matrix obtained by conversion according to the type of the positioning lattice specifically includes:
when a plurality of positioning lattices of the same type are provided, an effective digital matrix is determined according to a plurality of digital matrices converted from hidden information lattices respectively corresponding to the plurality of positioning lattices of the same type;
when the single positioning lattice is used, the digital matrix converted from the hidden writing information lattice corresponding to the single positioning lattice is used as an effective digital matrix;
and analyzing the effective information from the effective digital matrix according to the type of the positioning lattice.
Specifically, the printed matter image includes a plurality of repeated dot matrix images including hidden information, the dot matrix image including complete hidden information is called a dot matrix unit, the locating dot matrix type in each dot matrix unit is not repeated, but when the printed matter image is shot and identified, the repeated dot matrix units may be shot, as shown in fig. 7, the dot matrix images included in the boxes 1, 2 and 3 are the same, or when a first dot matrix determined according to the crossing condition of every two four locating dot matrixes crosses another first dot matrix in the horizontal direction, the locating dot matrix type is also caused to be repeated, therefore, when a plurality of locating dot matrixes of the same type extracted from the obtained dot matrix image are provided, the numbers of the corresponding positions of all hidden information corresponding to the locating dot matrix of the same type are accumulated, and under the same condition, the numbers of the corresponding positions are obtained after the opposite positions are accumulated, and finally, if the voting value of the opposite positions of the first dot matrix and the first dot matrix are obtained after the opposite weights are not obtained, the voting value is obtained after the opposite positions are obtained is equal to the total voting value is less than 0; finally, decoding the effective digital matrix according to the type of the positioning dot matrix and the decoding rule shown in fig. 8 to obtain the effective information of the dot matrix image; therefore, when the printed matter image is identified, all the hidden information contained in the printed matter image can be obtained only by shooting and identifying the local part of the printed matter image, so that shooting and identifying of the complete printed matter image are not needed.
It should be understood that the foregoing examples of the present invention are merely illustrative of the present invention and are not intended to limit the present invention to the specific embodiments thereof. Any modification, equivalent replacement, improvement, etc. that comes within the spirit and principle of the claims of the present invention should be included in the protection scope of the claims of the present invention.
Claims (8)
1. A decryption identification method based on dot matrix hidden writing information coding is characterized by comprising the following steps:
obtaining a dot matrix image, wherein the dot matrix image comprises a positioning dot matrix and a hidden writing information dot matrix, and one positioning dot matrix corresponds to one hidden writing information dot matrix;
respectively extracting a positioning lattice and a steganographic information lattice from the obtained lattice image;
analyzing the type of the positioning lattice according to the positioning lattice;
analyzing effective information according to the type of the positioning lattice and the extracted hidden information lattice;
each positioning lattice comprises a first lattice and a second lattice, wherein the first lattice is used for positioning the second lattice and the hidden information lattice, and the second lattice is used for indicating the type of the positioning lattice;
decoding the effective information according to a preset decoding rule;
the step of extracting the locating lattice and the hidden information lattice from the obtained lattice image comprises the following steps:
extracting a first lattice from the obtained lattice image;
positioning and extracting a second lattice and a hidden information lattice according to the extracted first lattice;
the step of analyzing the type of the positioning lattice according to the extracted positioning lattice specifically comprises the following steps:
analyzing the type of the positioning lattice according to the extracted second lattice;
the first lattice is an m1 Xn lattice, the second lattice is an m2 Xn lattice, the values of m1 and n are integers larger than or equal to 2, the value of m2 is an integer larger than or equal to 1, each point position of the first lattice is provided with a point, and at least one point position of the second lattice is not provided with a point;
the step of extracting the first lattice from the obtained lattice image specifically includes:
calculating the dot distance in the obtained dot matrix image;
determining a positioning frame for framing all 2X 2 lattices in the positioning lattices according to the lattice distance;
judging whether points of the 2X 2 lattice selected by the positioning frame exist or not;
if all the point positions of the 2X 2 lattice selected by the positioning frame exist, determining that the 2X 2 lattice selected by the positioning frame is a four-positioning lattice;
when the value of m1 is 2, the four positioning lattices are first lattices;
when the value of m1 is an integer greater than 2, determining a first lattice according to the crossing condition of the four positioning lattices.
2. The decryption and identification method based on lattice steganographic information coding according to claim 1, wherein the step of determining the first lattice according to the crossing condition of the four positioning lattices specifically comprises:
and selecting points of the same corresponding position of each four-positioning lattice, calculating the inclination angle and the coordinate difference between the points of the same corresponding position of each two four-positioning lattices, determining whether the two four-positioning lattices are crossed according to whether the inclination angle and the coordinate difference are within a preset range, and determining the first lattice according to whether the two four-positioning lattices are crossed in a preset direction.
3. The decryption and identification method based on the encoding of the hidden information of the dot matrix according to claim 1, wherein the step of calculating the dot pitch in the obtained dot matrix image specifically comprises:
calculating the distance from each point to other points in the obtained dot matrix image;
and selecting the minimum value of the distance from each point to other points, and determining the point distance according to each selected minimum value.
4. The decryption and identification method based on hidden information coding according to claim 1, further comprising, after the step of determining that the m1×n lattice selected by the positioning frame is a four-positioning lattice:
calculating the theoretical distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the point distance;
calculating the actual distance from the center point of the four-positioning lattice to each point of the four-positioning lattice according to the position of each point in the extracted four-positioning lattice;
and screening the extracted four-positioning lattice according to errors of the theoretical distance and the actual distance.
5. The decryption and identification method based on the hidden information coding of the lattice according to claim 1, wherein the step of resolving the type of the positioning lattice according to the extracted second lattice specifically comprises:
and analyzing the type of the positioning lattice according to whether the points of the extracted second lattice exist.
6. The decryption and identification method based on hidden information coding of lattice according to claim 1, wherein before the step of resolving the type of the positioning lattice according to whether there is a point in each point of the positioning lattice, further comprising:
and carrying out affine transformation on the extracted positioning lattice and the hidden information lattice according to the extracted positioning lattice.
7. The decryption and identification method based on lattice hidden information coding according to any one of claims 1 to 6, wherein the step of parsing effective information according to the type of the positioning lattice and the extracted hidden information lattice specifically comprises:
judging whether each point of the extracted hidden information lattice exists, if so, marking the point as a first number, and if not, marking the point as a second number so as to convert the extracted hidden information lattice into a digital matrix;
and according to the type of the positioning lattice, analyzing effective information from the converted digital matrix.
8. The decryption and identification method based on lattice steganographic information coding according to claim 7, wherein the step of resolving effective information from the converted digital matrix according to the type of the positioning lattice specifically comprises:
when a plurality of positioning lattices of the same type are provided, an effective digital matrix is determined according to a plurality of digital matrices converted from hidden information lattices respectively corresponding to the plurality of positioning lattices of the same type;
when the single positioning lattice is used, the digital matrix converted from the hidden writing information lattice corresponding to the single positioning lattice is used as an effective digital matrix;
and analyzing the effective information from the effective digital matrix according to the type of the positioning lattice.
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