Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2020-09-28 Cooperative journals: 《计算机应用研究》
Abstract： Previous papers generally used Correct Decode Rate (CDR) or Bit Error Rate (BER) to evaluate the performance of Halftone Visual Cryptography (HVC) methods, but the distortion caused during data hiding process is not considered. This paper proposes an integrated evaluation algorithm for halftone visual cryptography methods which considers both the distortion caused by data hiding and BER of the extracted secret image. Choosing Average Distortion Per Pixels (ADPP) to measure the distortion caused during data hiding process, and to ensure the consistency of ADPP and BER data ranges, the max average distortion (MAD) can be generated by using the secret image and the threshold T, and then Integrated Distortion of Halftone Visual Cryptography (IDHVC) can be obtained by compressive calculation of BER, ADPP, MAD and coefficient λ. Compared with the existing algorithm, the proposed method has obvious advantage in the amount of computation. Experimental results show the proposed algorithm can evaluate halftone visual cryptographies in grayscale and color halftone images.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-11-29 Cooperative journals: 《计算机应用研究》
Abstract： This paper proposed halftone self-hiding algorithms, and a secret image can be hidden in dot diffused or error diffused halftone images. Based on the data hiding algorithm by dual conjugate dot diffusion, a dot diffused gray-scale halftone self-hiding algorithm can be realized, and this algorithm can be extended to an error diffused halftone image, and then an error diffused gray-scale halftone self-hiding algorithm can be proposed. Based on the data hiding algorithm by new color conjugate error diffusion and the data hiding algorithm by new color conjugate dot diffusion which are the latest color halftone visual cryptography, color halftone self-hiding algorithms in dot diffused and error diffused halftone images can be proposed. Experiments of four algorithms have been implemented and the performance of different algorithms can be compared. The results show that the color halftone self-hiding algorithm based on dot diffused and error diffusion has the best performance under the same parameters.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-24 Cooperative journals: 《计算机应用研究》
Abstract： (K, n) visual cryptography is an important data hiding algorithm. Using Shamir's secret sharing, a binary secret image can be shared into n meaningless shares, in order to make the generated shares more like noise images, adding the randomness within the process of sharing. Picking any k shares from n meaningless shares, the secret image can be revealed by using Lagrange interpolation. This paper applied Shamir's secret sharing to realize a (k, n) visual cryptography, and this method neither required code book nor suffers from pixel expansion. Experimental results show the proposed method can realize a (k, n) visual cryptography, and correct decoding rate (CDR) of revealed secret image can be guaranteed.
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-04-17 Cooperative journals: 《计算机应用研究》
Abstract： In the parameter identification of inverse problems, it was well-known that the information quantity contained in measurement information influences the reconstruction precision of parameter directly. How to describe the information quantity in measurement information plays an important role in the selection of the number of measurement points. According to the Bayesian method, the probability of the parameter sample to be identified is calculated by combining the priori probability reflecting prior information and the likelihood probability reflecting measurement information. The evaluation factors are calculated by the maximum entropy and information entropy of the parameter. This paper introduced the information entropy to describe the information quantity of measurement information with error before parameter identification. Numerical tests showed that this computing method proposed could describe the measured information with error effectively and determine the measured information in practice.
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