标题：Local blackness preserving visual cryptography for grayscale secret images
作者：Yan, Bin ;Chen, Na ;Yang, Hong-Mei ;Hao, Jian-Jun
作者机构：[Yan, Bin ;Chen, Na ;Hao, Jian-Jun ] College of Electronics, Communication and Physics, Shandong University of Science and Technology, 579, Qian-Wan-G 更多
来源：Journal of Information Hiding and Multimedia Signal Processing
摘要：Size-invariant visual cryptography (VC) for grayscale image has lower computational load during encoding, and lower memory and bandwidth requirements during storage and transmission. However, its visual quality is lower than the size-expanded VC, and sometimes unacceptable, especially for grayscale secret images. In order to improve the visual quality, we propose a local blackness preserving (LBP) VC algorithm. A block-based VC is designed with a mechanism to recover the local ratio between the black pixels and white pixels that is destroyed by the raw VC encoder. Comparison with recently proposed size-invariant VC algorithms confirms the effectiveness of the proposed method.
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