Tác giả: Võ Phước Hưng; Prof. Chin-Chen Chang (Người hướng dẫn Khoa học).

Trường ĐH Phùng Giáp. Năm XB: 2011. Mô tả: 41Tr, kích thước: 21x29 cm. Số định danh: 621.39/ H556. Vị trí: Phòng đọc.

 In the traditional secret image sharing, the secret image is encoded into two or more meaningless image shares, and single share cannot derive any information about the secret image. The meaningless image shares are insecure which may attract the notice of attackers during transmission process. Moreover, the meaningless share images are difficult to identify and manage in a large image database. Therefore, in 2007, Yang et al. proposed a user-friendly (k, n)-threshold scheme based on Shamir’s polynomial with different primes. Their method calculated differences between pixels in a block and their left pixels. According to the differences, the prime number for the Shamir’s polynomial can be decided and the differences were distributed to shares by using Shamir’s polynomial. This study proposes two novel user-friendly image sharing schemes. The first scheme uses polynomials with different primes to generate pixel shadows without adjusting the LSBs of original pixels, so that the recovery process can reconstruct a highquality original image using the Lagrange interpolation function. The second scheme develops an image-sharing system by using JPEG-LS prediction technique to classify prime numbers for encoding blocks. Owing to the involvement of JPEG-LS prediction technique, the produced differences not only refer to the left pixel but also their neighboring pixels. Therefore, the values of differences become small. This leads to high quality of the reconstructed image. Experimental results also confirm our statements.