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Search Results: 1 - 10 of 62025 matches for " Zhe-Ming Lu "
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Vector Quantization Based on Self-Organizing Feature Map Neural Network
基于自组织特征映射神经网络的矢量量化

LU Zhe-ming,
陆哲明

中国图象图形学报 , 2000,
Abstract: In recent years, many scholars have successfully applied the Kohonen s self-organizing feature map (SOFM) neural networks to vector quantization image compression encoding. The two main shortcomings of the basic SOFM method are its high computation complexity and its poor codebook quality compared to the conventional LBG algorithm. In order to improve the codebook performance, some modification is made in the weight factor adjustment of the basic SOFM algorithm in this paper. In order to reduce the computation complexity of the basic SOFM algorithm, some fast search methods are used in SOFM iterations during the search for the winning neuron. The proposed algorithm is used to generate vector quantization codebook and the generated codebooks are used for image compression encoding in this paper. Simulation shows that the reduction of computation is substantial and the codebook performance is improved. Compared to the basic SOFM algorithm, the reduction of computation is about 75%. For not only image in the training set but also the image outside the training set, the encoding quality can be improved by 0.80dB~0.90dB compared to the basic SOFM algorithm.
Multipurpose Perceptual Image Hashing Based on Block Truncation Coding
Mei-Lei Lv,Zhe-Ming Lu
Information Technology Journal , 2011,
Abstract: This study presents a new multipurpose image hashing scheme based on Block Truncation Coding (BTC). Vector Quantization (VQ) and BTC are both block-based lossy image compression techniques for gray-level images, but BTC can maintain the mean and standard deviation after compression. In our scheme, the original gray-level image is first partitioned into non-overlapping small blocks. BTC is then performed on each block to yield two mean values, i.e., a lower mean and a higher mean, as well as a bit plane. The relationship between two mean values are utilized to generate the intermediate binary image for copyright protection, while the number of ‘1’s in the bit plane is compared with a threshold to generate the intermediate binary image for content authentication. Finally, the authentication mark and permuted copyright logo are respectively XOR-ed with the two intermediate binary images to obtain final authentication and protection fingerprints. Because BTC is a fast encoding scheme, our proposed method is therefore with lower complexity compared to VQ-based multipurpose image hashing schemes. Experimental results demonstrate the effectiveness and efficiency of the proposed scheme.
An Image Hashing Scheme based on Mean-removed Vector Quantization for Multiple Purposes
Mei-Lei Lv,Zhe-Ming Lu
Information Technology Journal , 2011,
Abstract: Perceptual hashing has been proved to be an effective solution for multimedia indexing, authentication or watermarking. Traditional perceptual hashing schemes are typical designed only for one purpose. This study presents a multipurpose image-hashing scheme based on Mean-Removed Vector Quantization (MRVQ) for both copyright protection and content authentication. The main idea is to perform MRVQ on the original image to yield two index tables, one for copyright protection and the other for content authentication. The original gray-level image is first divided into non-overlapping small blocks. The mean value for each block is calculated and quantized by the scalar quantizer to get a mean index and the quantized mean is removed from the image block to obtain the residual vector that is further quantized by the vector quantizer to obtain the residual index. All obtained mean indices constructed the mean index table and all obtained residual indices construct the residual index table. The obtained two index tables are then transformed into two intermediate binary images based on two different mapping functions, respectively. One mapping function is based on the variance of indices in a 3x3 neighborhood and the other mapping function is based on the number of indices larger than the mean of indices in a 3x3 neighborhood. Finally, the authentication mark and permuted copyright logo are respectively XOR-ed with the two intermediate binary images to obtain final authentication and protection fingerprints. Experimental results demonstrate the effectiveness of the proposed scheme.
Low Power Compact GaAs PHEMT Level Converter for Digital Control Logics of GaAs Switches
Wei Chen,Hao Luo,Min Zhou,Zhe-Ming Lu
Information Technology Journal , 2013,
Abstract: In this study a level converter based on GaAs pHEMT technology for a MFC (Multifunctional Chip) is designed, simulated and tested for the application of T/R (Transmit/Receive) module for an X band phase array radar system. It has the advantages of smaller chip size, lower power consumption, higher efficiency, lower cost and high stability. The circuit design is based on a feedback and feed-forward network which compensates the chip process variations during the wafer fabrication and operation temperature changing. It results the designed chip has a high stability. Its supply voltage is -5 v with a shared bias generator, this allows reducing the power consumption compared with the other design at -7.5 v in the literature. The testing results have shown that the proposed novel design has met all the specifications given in this project.
An Efficient MDC Framework Based on DCT and SPIHT
Lin-Lin Tang,Zhe-Ming Lu
Information Technology Journal , 2009,
Abstract: Multiple Description Coding (MDC) is one of the promising methods for robust transmission over non-prioritized and unpredictable networks. Based on the Discrete Cosine Transform (DCT) and the Set Partition in Hierarchical Trees (SPIHT) compression method, this study proposes a new MDC framework. We make full use of the energy concentration of DCT and the similarity among the blocks composed of reordered DCT coefficients to apply the SPIHT algorithm to the transform-domain images composed of reordered DCT blocks. The purpose of using the reordered coefficients is to realize the energy redistribution. Redundancy is introduced by the full and partial encoding method which means the three descriptions, each using different bit rates to encode the information from three different orientations, i.e., vertical, horizontal and diagonal directions. For transmission we adopt three channels, each containing the hybrid information from three different directions. Experimental results demonstrate that present technique is effective and practical.
A Blind Image Watermarking Scheme Using Fast Hadamard Transform
Yong Zhang,Zhe-Ming Lu,Dong-Ning Zhao
Information Technology Journal , 2010,
Abstract: This study presents a Hadamard transform based blind digital watermarking scheme whose extraction process doesn’t require the original image. In this scheme, we use a binary image as the original watermark. During the embedding process, the original cover image is first partitioned into non-overlapped 8x8 blocks and the Arnold transform is performed on the original watermark to make the scheme more robust. Secondly, the Hadamard transform is applied to the blocks. Thirdly, one bit information is embedded in each block by modifying the relationship of two coefficients in the transformed matrix. Finally, the inverse Hadamard transform is performed on the modified coefficient matrix to obtain the watermarked image. The experimental results show that the proposed watermarking method performs well in both security and robustness against general image processing operations and various kinds of attacks, while keeping the invisibility very well.
Quantization based Semi-fragile Watermarking Scheme for H.264 Video
Yong Zhang,Zhe-Ming Lu,Dong-Ning Zhao
Information Technology Journal , 2010,
Abstract: Although, many fragile video watermarking techniques have been proposed as an effective solution to content authentication problems, they cannot effectively distinguish between legal attacks and illegal attacks. In order to solve this problem, this paper proposes a novel semi-fragile video watermarking algorithm for H.264 video. Traditional fragile video watermarking methods often select the motion vectors as the embedding positions, while our scheme adopt the intra-prediction residuals after Integer DCT (Discrete Cosine Transform) and quantization to be embedding locations. During the watermark embedding process, we modify the standard H.264 quantizer and we embed the watermark based on the dither modulation technique in order to extract the watermark blindly. In the watermark extraction process, this paper adopts a threshold to distinguish between illegal attacks and legal attacks performed on the video clip. Experimental results demonstrate the effectiveness and feasibility of the proposed algorithm and the proposed scheme can survive legal recompression operations and recognize illegal filtering operations.
Joint Secret Sharing and Data Hiding for Block Truncation Coding Compressed Image Transmission
Hao Luo,Zhenfei Zhao,Zhe-Ming Lu
Information Technology Journal , 2011,
Abstract: This study proposed a scheme that incorporates secret sharing and data hiding techniques for block truncation coding compressed image transmission. The bitmap of each compressed block is encrypted and meanwhile two quantization levels are hidden in two share images. The secure transmission system still preserves the properties such as low complexity and acceptable reconstruction image quality of the standard block truncation coding compression. In addition, each share image is half size of the compressed version such that no extra burden is laid on available transmission resources. Experimental results demonstrate the effectiveness of our scheme.
Shadow Size Reduction and Multiple Image Secret Sharing Based on Discrete Fractional Random Transform
Zhenfei Zhao,Hao Luo,Zhe-Ming Lu
Information Technology Journal , 2010,
Abstract: This study proposes an improved image secret sharing scheme based on the discrete fractional random transform. In this (r, n)-threshold prototype, the shadow size is reduced to 1/r of the secret image. In contrast, all shadows are of the same size as that of the secret image in the original scheme. Consequently, much storage space and transmission time is saved. Besides, our scheme can be naturally extended to multi-image secret sharing, i.e., r secret images can be encrypted in n shadows at a time. Meanwhile, the security is perfectly preserved due to the randomness of the discrete fractional random transform. Experimental results demonstrate the effectiveness of our scheme.
Synchronizability Optimization for the Edge Iteration Based Deterministic Small-world Network with the Modified Simulated Annealing Algorithm
Xin-Feng Li,Shi-Ze Guo,Yu-Xin Su,Zhe-Ming Lu
Information Technology Journal , 2013,
Abstract: Recently, researchers have presented several deterministic small-world networks (DSWNs) which can be generated in a special iteration process without randomness. However, to the best of our knowledge, no one has studied the synchronizability of DSWNs up to now. In this study, we focus on the synchronizability of the edge iteration based deterministic small world network (EIB-DSWN) that was presented in 2006. Our testing results show that the EIB-DSWN has very poor synchronizability. To improve the synchronizability, we propose using the Modified Simulated Annealing (MSA) algorithm to optimize the EIB-DSWN. After MSA-based optimization, to check if the optimized network is still a kind of small-world network, we calculate its three main characteristics. It turns out that the MSA algorithm can significantly optimize the synchronizability of the EIB-DSWN under the premise of ensuring small world characteristics.
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