Showing papers by "Wen-Hsiang Tsai published in 2002"

Determination of Head Pose and Facial Expression from a Single Perspective View by Successive Scaled Orthographic Approximations

Abstract: Human faces are the main organs for expressing human emotion. In this study, a new iterative approach to analyzing the head pose and the facial expression of a human face from a single image is proposed. The proposed approach extends the concept of successive scaled orthographic approximations, which was used to estimate the pose of a rigid object, to develop a method to estimate the parameters for a non-rigid object, namely, a human face. The implementation of the proposed method is simple; furthermore, no initial guess is required. The convergency property of the proposed method is also analyzed theoretically and experimentally. Experimental results show that the proposed method is robust and has a high percentage of convergency, and thus prove the feasibility of the proposed approach.

Embedded signature-based authentication by channel statistics using watermarking techniques

Abstract: This study examines the feasibility of using statistics to perform embedded signature-based authentication. Doing so is an attempt to view a reference watermark embedded with signature as side information. The reference watermark is extracted to determine channel statistics, based on the Bayes theorem, and used to extract the embedded signature. The reliability of the extracted signature and the uncertainty of the channel status are also measured. Experimental results demonstrate that the reliability and uncertainty measures based on channel statistics are meaningful, and that the embedded signature can survive high-quality JPEG compression and manipulation such as negation.