A new image encryption/decryption algorithm has been designed using discrete chaotic systems as aSP (Substitution and Permutation) network architecture often used in cryptosystems. It is composed of two mainmodules: s...A new image encryption/decryption algorithm has been designed using discrete chaotic systems as aSP (Substitution and Permutation) network architecture often used in cryptosystems. It is composed of two mainmodules: substitution module and permutation module. Both analyses and numerical results imply that the algo-rithm has the desirable security and efficiency.展开更多
On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of bru...On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of brush method in detail, the result and efficiency were evaluated through experiments.展开更多
In this paper, two algorithms are presented for generating two code scan lists of an N dimensional Hilbert cell, and a formal proof of the backward encoding algorithm is given. On the basis of the self similarity prop...In this paper, two algorithms are presented for generating two code scan lists of an N dimensional Hilbert cell, and a formal proof of the backward encoding algorithm is given. On the basis of the self similarity properties of a Hilbert curve, this paper gives a novel algorithm for generating a static evolvement rule table through analyzing a Hilbert cell. By looking up the static evolvement rule table, the N dimensional Hilbert mappings are efficiently implemented.展开更多
Image subbands can be obtained by using filterbank. Traditional compression method uses direct entropy coding for each subband. After studying the energy distribution in image subbands, we proposed a vector quantizati...Image subbands can be obtained by using filterbank. Traditional compression method uses direct entropy coding for each subband. After studying the energy distribution in image subbands, we proposed a vector quantization (VQ) coding algorithm to image subband. In the algorithm, vector quantizers were adaptively designed for high-frequency bands in an image. In particular, the edges of the image were examined and fewer bits were assigned to high-energy regions. The experimental result showed that the algorithm had higher SNR and higher compression ratio than possible by traditional subband coding, JPEG and JPEG 2000.展开更多
An information hiding scheme for vector maps is presented to identify the source after the vector map is leaked in some key application areas. In this scheme, the fingerprint image of the map owner can be converted in...An information hiding scheme for vector maps is presented to identify the source after the vector map is leaked in some key application areas. In this scheme, the fingerprint image of the map owner can be converted into a character string as the watermark, and then the watermark will be embedded into the coordinate descriptions of the attribute file by the "0-bit value" programming method. This programming algorithm ensures that the accuracy is lossless and the graphics is unchanged for any vector map. Experiments show that the presented hiding scheme has stable robustness, the average similarity rate is 97.2% for fingerprints matching and the false non-match rate is 1.38% in the blocking test. In the opening test, the former reaches 84.46% and the latter reaches 5.56%.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No. 69874025)
文摘A new image encryption/decryption algorithm has been designed using discrete chaotic systems as aSP (Substitution and Permutation) network architecture often used in cryptosystems. It is composed of two mainmodules: substitution module and permutation module. Both analyses and numerical results imply that the algo-rithm has the desirable security and efficiency.
基金Supported by Internal Fund of Institute of Surveying and Mapping (No.Y0506) .
文摘On the basis of analysis of various algorithms, an anti-aliasing algorithm called brush method was presented, which is suitable to map publishing symbol. After introducing the basic principle and implementation of brush method in detail, the result and efficiency were evaluated through experiments.
文摘In this paper, two algorithms are presented for generating two code scan lists of an N dimensional Hilbert cell, and a formal proof of the backward encoding algorithm is given. On the basis of the self similarity properties of a Hilbert curve, this paper gives a novel algorithm for generating a static evolvement rule table through analyzing a Hilbert cell. By looking up the static evolvement rule table, the N dimensional Hilbert mappings are efficiently implemented.
文摘Image subbands can be obtained by using filterbank. Traditional compression method uses direct entropy coding for each subband. After studying the energy distribution in image subbands, we proposed a vector quantization (VQ) coding algorithm to image subband. In the algorithm, vector quantizers were adaptively designed for high-frequency bands in an image. In particular, the edges of the image were examined and fewer bits were assigned to high-energy regions. The experimental result showed that the algorithm had higher SNR and higher compression ratio than possible by traditional subband coding, JPEG and JPEG 2000.
文摘An information hiding scheme for vector maps is presented to identify the source after the vector map is leaked in some key application areas. In this scheme, the fingerprint image of the map owner can be converted into a character string as the watermark, and then the watermark will be embedded into the coordinate descriptions of the attribute file by the "0-bit value" programming method. This programming algorithm ensures that the accuracy is lossless and the graphics is unchanged for any vector map. Experiments show that the presented hiding scheme has stable robustness, the average similarity rate is 97.2% for fingerprints matching and the false non-match rate is 1.38% in the blocking test. In the opening test, the former reaches 84.46% and the latter reaches 5.56%.
