Watermarking method for high-definition map based on invisible characters

A watermarking device for a high-definition map based on invisible characters, comprising:

• an acquisition unit, configured to acquire a set of identifiers I from data of the high-definition map represented by I=(I1, I2, I3, . . . Ii), i∈[1, N], N representing a length of the set of identifiers, an identifier Ii in the set of identifiers I comprising a set of attribute values Ii represented by Ii=(A1, A2, A3, . . . An(i)), and n(i) representing a length of the set of attribute values corresponding to the identifier Ii in the set of identifiers I;
• a first scrambling unit, configured to scramble an embedding sequence of watermark information based on a logistic map to generate a chaotic sequence, wherein the logistic map is expressed as follows:
• Xn+1=f(Xn,μ)=μXn(1−X), and an initial condition of the logistic map is as follows:
• X
• 0
• =
• |
• sin
• ⁢
• N
• N
• |
• +
• |
• ∑
• i
• =
• 1
• N
• cos
• ⁢
• n
• ⁡
• (
• i
• )
• n
• ⁡
• (
• i
• )
• |
• ;
• a second scrambling unit, configured to scramble the set of identifiers I and the set of attribute values Ii according to the chaotic sequence generated based on the logistic map to obtain a scrambled set of identifiers I′ represented by I′=(I′1, I′2, I′3, . . . I′i) and a scrambled set of attribute values I′i represented by I′i=(A′1, A′2, A′3, . . . A′n(i));
• a first conversion unit, configured to convert the initial condition X0 of the logistic map into an invisible character according to a mapping relationship between decimal characters and invisible characters, and insert the invisible character into a header identifier of the data of the high-definition map;
• a sequence generation unit, configured to add index position information corresponding to watermark bits of a binary watermark information character sequence W of the watermark information and verification code information into the binary watermark information character sequence W of the watermark information to obtain a composite watermark character sequence represented by WM={wm[j], j∈[0, m−1]}, m representing a length of the composite watermark character sequence, wm[j] representing a watermark character, and j representing an index position corresponding to the watermark character;
• and
• a second conversion unit, configured to obtain attribute value fields in the scrambled set of attribute values I′i, convert the watermark character wm[j] and the index position corresponding to the watermark character wm[j] into invisible characters based on a mapping relationship between invisible characters and bit characters and a space character, and the mapping relationship between invisible characters and decimal characters, and insert the invisible characters into ends of the attribute value fields until scrambled sets of attribute values corresponding to identifiers in the scrambled set of identifiers I′ are traversed;
• wherein the sequence generation unit is further configured to:
• generate a plaintext character string according to identification information of the watermark information, and encode the plaintext character string to generate the binary watermark information character sequence W represented by W={w[i], 0≤i≤ N1}, a length of the binary watermark information character sequence W being N1, w[i] representing a watermark character with a value of 0, or 1, or a space, and i representing an index position corresponding to the watermark character with the value of 0 or 1 or the space;
• divide the binary watermark information character sequence W into K copies of binary string sequences by taking the space as a separator, and then store the K copies of binary string sequences in a binary string set represented by WL={WL[j], 0≤j≤K}, and WL[j] representing a single binary string sequence;
• transverse the binary string set WL, perform Hamming code encoding on each of the K copies of binary string sequences, convert the binary string set WL added with the verification code information into a binary character sequence WLStr represented by WLStr={WLStr[l], 0≤l≤L}, a length of the binary character sequence WLStr being L, l representing an index position of a corresponding binary character, and WLStr[l] representing a binary character with a value of 0, or 1, or a space;
• and
• obtain the composite watermark character sequence WM having characters of the index position information and the watermark information, wherein the character of the index position information is represented by the index position l of the corresponding binary character, and the character of the watermark information is represented by the WLStr [l].