Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Research Article On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme | Hindawi Publishing Corporation EURASIP Journal on Advances in Signal Processing Volume 2010 Article ID 782438 11 pages doi 2010 782438 Research Article On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme Daoshun Wang and Feng Yi Department of Computer Science and Technology Tsinghua University Beijing 100084 China Correspondence should be addressed to Daoshun Wang wangdaoshun@ Received 25 November 2009 Revised 28 April 2010 Accepted 4 July 2010 Academic Editor Yingzi Du Copyright 2010 D. Wang and F. Yi. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Traditional Secret Sharing SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing VSS schemes decode the secret without computation but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing schemes for a binary image use only one subpixel to share the secret image however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes VSS schemes and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert transform a k k -SS scheme to a k k -VSS scheme for greyscale images. The generation of the shadow images shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images measured by average contrast is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale k k -SS scheme to a more general .
