Browsing by Author "Su, Wei-Kai"

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Error Correction of Secret Images by Search Order Coding
(2009)
Su, Wei-Kai
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Chen, Lee Shu-Teng
;
Lin, Ja-Chen
;
資訊工程學系
;
Department of Computer Science
In this paper, an image recovery method based on search-order coding (SOC) is proposed. By using SOC, a SOC-image of the secret image can be generated. If the secret Image is damaged, people can still obtain a version of the secret image that looks not bad by referring to the SOC-image. Also, the information of the secret image cannot be retrieved from the SOC-image alone.
Fault-tolerant VQ-style Secret Image Sharing
(2009)
Su, Wei-Kai
;
Chen, Lee Shu-Teng
;
Lin, Ja-Chen
;
資訊工程學系
;
Department of Computer Science
In this paper, we propose a fault-tolerant secret image sharing scheme based on vector quantization (VQ). The proposed method uses some of the n host images to generate the codebooks for VQ, and compresses the secret image by VQ with the generated codebooks. The VQ indices are thus created and then shared among n shadows. After obtaining the n shadows, they are embedded together with the mixed information of the generated codebooks into the n host images to form the n stego-images. When collecting any r (r <= n) of the n stego-images, the VQ indices and codebooks can be retrieved to recover the secret image. However, no information about the secret image can be revealed if obtaining less than r stego-images. Because of using VQ, the secret image is compressed to the VQ indices, and thus easier to be hidden than the non-compressed one. The quality of the recovered image is the same as the one of the ordinary VQ.
Theoretical Deviation and Ray Tracing Analysis of Optical Rotary Encoder
(2016)
Chiang, Hou-Chi
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Su, Wei-Kai
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Huang, Ting-Wei
;
Mang Ou-Yang
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電機學院
Servomotor system is widely used in industry for precise positioning system. In this paper, a method of numerical integration solution based on radiometry theory was proposed. The non-sequential ray tracing simulations analyzed the optical distribution of Optical Rotary Encoder. The numerical integration solution and ray tracing simulations had been verified. The method of numerical integration solution apply in the pattern design of Code Mask and Code Disk on both Incremental Encoder and Absolute Encoder.