Sheng-He Sun

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In our scheme, we choose AC coefficients in the integer DCT domain for the bit-shift operation, and therefore the capacity and the quality of the watermarked image can be adjusted by selecting different numbers of coefficients of different frequencies. To prevent overflows and underflows in the spatial domain caused by modification of the DCT coefficients,(More)
In this paper, a new and fast encoding algorithm for vector quantization is presented. This algorithm makes full use of two characteristics of a vector: the sum and the variance. A vector is separated into two subvectors: one is composed of the first half of vector components and the other consists of the remaining vector components. Three inequalities(More)
Genetic algorithm (GA) has been successfully applied to codebook design for vector quantization (VQ). However, most conventional GA-based codebook design methods need long runtime because candidate solutions must be "ne tuned by LBG. In this paper, a partition-based GA is applied to codebook design, which is referred to as genetic vector quantization (GVQ).(More)
A h s h c t : lligital watcrinui+kitig has bccii prescntctl i t i recent litci'iilurcs ils i i tcchiiiqtic to protccl h e copyright ol iiiultimedia (lain. Rut tiiusl of tliese litcriiturcs focus (111 the algorittiins of cmbcdrliiig aiic-ditiicnsiunnl watermarks 01' Iwo-dimciisioaal biiiaty digital wntcriiinrks. I n this piipci., a method or ciiibedrliiig a(More)
We present a renrsible watermarking scheme which achie\'es perfect restoration of both the embedded watermark and the original image during extraction. The proposed scheme embeds data by modifying those integer DCT coefficients with peak amplitudes in each coefficient histogram. The integer DCT performed over the original image is a loss less 8 X 8 block(More)
With multimedia developing rapidly, copyright protection and authentication is more and more important. Digital watermark is one of the most efficient methods to protect multimedia products. Print and scan attack is a challenging problem for most of digital watermarks. In this paper, the geometric distortion and halftone in print-and-scan process is(More)
We investigate in this paper several recently proposed reversible watermarking algorithms based on value expansion schemes: bit-shifting, histogram modification, spread spectrum, companding and prediction-error expansion, and present a general model - histogram expansion - for all value expansion based reversible watermarking algorithms, which demonstrates(More)
This paper presents a new image data fusion scheme by combining median "ltering with self-organizing feature map (SOFM) neural networks. The scheme consists of three steps: (1) pre-processing of the images, where weighted median "ltering removes part of the noise components corrupting the image, (2) pixel clustering for each image using self-organizing(More)