Browsing by Author "Ou, Zhan-He"

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A robust watermarking method for stereo-pair images based on unmatched block bitmap
(2016-03)
Ou, Zhan-He
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Chen, Ling-Hwei
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資訊工程學系
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Department of Computer Science
A stereo-pair image contains two views of a scene called the left image and right image. This paper proposes a novel watermarking method for stereo-pair images. The proposed method is divided into three parts: watermark creation, watermark embedding, and watermark verification. Because the left and right images of a stereo pair appear to be highly similar, a robust watermark is first created based on a feature map that records the positions of the unmatched blocks between these two images. The created watermark is then embedded into the left image by swapping the AC coefficients. A feature map is first extracted from the watermarked stereo-pair image during the verification process. Subsequently, the embedded watermark is extracted from the watermarked left image and converted into an estimated feature map. Ownership is proved when the feature map and the estimated feature map are similar. Experimental results indicate that the proposed method exhibits greater robustness against malicious attacks and produces less distortion than existing methods do.
A steganographic method based on tetris games
(2014-08-20)
Ou, Zhan-He
;
Chen, Ling-Hwei
;
資訊工程學系
;
Department of Computer Science
Although various steganographic methods have been proposed that use distinct cover media, using games to hide data remains a recent development. The study presents a steganographic method based on online Tetris games, in which secret messages are embedded using a generated tetrimino sequence. Each time a person plays an online Tetris game, a new tetrimino sequence should be generated. The proposed method meets this requirement, generating a distinct stegoed tetrimino sequence for each game played. In addition, the study presents a scenario and a simulator for the proposed method. Theoretical proof and experimental results are provided to demonstrate that the proposed method is undetectable. (C) 2013 Elsevier Inc. All rights reserved.