Shih-Hsu Chang

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Based on 2-D cluster approach, a fast algorithm for point pattern matching is proposed to effectively solve the problems of optimal matches between two point pattern under geometrical transformation and correctly identify the missing or spurious points of patterns. Theorems and algorithms are developed to determine the matching pairs support of each point(More)
In this paper, a lossless data-hiding scheme is presented based on quantized coefficients of discrete wavelet transform (DWT) in the frequency domain to embed secret message. Using the quantized DWT-based method, we embed secret data into the successive zero coefficients of the medium-high frequency components in each reconstructed block for 3-level 2-D DWT(More)
In this paper, a lossless data-hiding approach is presented based on quantized coefficients of discrete wavelet transform (DWT) in the frequency domain to embed secret message. Using the quantized coefficients for 9/7 wavelet filter in DWT, we embed secret data into the successive zero coefficients of the medium-high frequency components in each(More)
Texture gradient is a popular operation for extracting features used for content-based image retrieval (CBIR) of texture images. It is useful for depicting gradient magnitude and direction of adjacent pixels in an image. In this thesis, we proposed two methods for retrieving texture images. In the first method, discrete wavelet transform (DWT) and gradient(More)
In this paper, a fast motion estimation algorithm combined hybrid predictor and search pattern (called HPS) is proposed to find the best motion vector (MV). Block-based motion estimation (ME) and pattern searching strategy are used to detect the fast vector motion. The advantages of the approach can improve the performance of existing fast ME algorithm and(More)
Image retrieval has become an important aspect in today's world as there is rapid growth of digital data day by day. It is required to have efficient search system with fast and accurate retrieval to cater to the need of end user with less computational cost and time. A new content based search system is required to address the problem. In this paper,(More)
This paper describes the block cipher SEA2. SEA2 is an evolutionary improvement of SEA. Modifications were made to increase the diffusion achieved per round, thus allowing for greater security and fewer rounds. Like SEA, SEA2 makes essential use of key-dependent permutations and substitutions to provide protection against differential cryptnalysis(DC) and(More)
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