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Chinese Optics Letters 2008年第5期6卷 331-333页

作者：王柯俨吴成柯孔繁锵张磊 State Key Laboratory of Integrated Service Networks Xidian University

Based on the property analysis of interferential multispectral images, a novel compression algorithm of partial set partitioning in hierarchical trees （SPIHT） with classified weighted rate-distortion optimization is presented. After wavelet decomposition, partial SPIHT is applied to each zero tree independently by adaptively selecting one of three coding modes according to the probability of the significant coefficients in each bitplane. Meanwhile the interferential multispectral image is partitioned into two kinds of regions in terms of luminous intensity, and the rate-distortion slopes of zero trees are then lifted with classified weights according to their distortion contribution to the constructed spectrum. Finally a global rate- distortion optimization truncation is performed. Compared with the conventional methods, the proposed algorithm not only improves the performance in spatial domain but also reduces the distortion in spectral domain.

关键词： Boolean functions Data compression Electric distortion image coding image compression Motion estimation Optimization Programming theory Risk assessment Signal distortion Video signal processing Wavelet decomposition Wavelet transforms

SFCVQ and EZW coding method based on Karhunen-Loeve transformation and integer wavelet transformation

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Chinese Optics Letters 2007年第3期5卷 153-155页

作者：闫敬文陈嘉臻 Department of Electronic Engineering Shantou University Department of Electronic Engineering Xiamen University

A new hyperspectral image compression method of spectral feature classification vector quantization （SFCVQ） and embedded zero-tree of wavelet （EZW） based on Karhunen-Loeve transformation （KLT） and integer wavelet transformation is represented. In comparison with the other methods, this method not only keeps the characteristics of high compression ratio and easy real-time transmission, but also has the advantage of high computation speed. After lifting based integer wavelet and SFCVQ coding are intro- duced, a system of nearly lossless compression of hyperspectral images is designed. KLT is used to remove the correlation of spectral redundancy as one-dimensional （1D） linear transform, and SFCVQ coding is applied to enhance compression ratio. The two-dimensional （2D） integer wavelet transformation is adopted for the decorrelation of 2D spatial redundancy. EZW coding method is applied to compress data in wavelet domain. Experimental results show that in comparison with the method of wavelet SFCVQ （WSFCVQ）, the method of improved BiBlock zero tree coding （IBBZTC） and the method of feature spectral vector quantization （FSVQ）, the peak signal-to-noise ratio （PSNR） of this method can enhance over 9 dB, and the total compression performance is improved greatly.

关键词： Classification (of information) image coding Signal to noise ratio Vector quantization Wavelet transforms

Greylevel Difference Classification Algorithm in Fractal image Compression

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Journal of Computer Science & Technology 2002年第2期17卷 236-240页

作者：陈毅松卢坚孙正兴张福炎 State Key Laboratory for Novel Software Technology Department of Computer Science and Technology Nanjing University Nanjing 210093 P.R. China

This paper proposes the notion of a greylevel difference classification algorithm in fractal image compression. Then an example of the greylevel difference classification algo rithm is given as an improvement of the quadrant greylevel and variance classification in the quadtree-based encoding algorithm. The algorithm incorporates the frequency feature in spatial analysis using the notion of average quadrant greylevel difference, leading to an enhancement in terms of encoding time, PSNR value and compression ratio.

关键词： image coding fractal classification algorithm greylevel differenceclassifica- tion

An Adaptive Method of image CompressionBased on Wavelet Analysis

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Journal of Systems Engineering and Electronics 2001年第1期12卷 53-58页

作者： Xu Hao Dept. of Biomedical Engineering, Shanghai Jiaotong University, 200030, P. R. China Yu Jun Dept. of Computer and Engineering, Hangzhou University of Commerce, 310035, P. R. China Yao Min Dept. of Computer, Zhejiang University, Hangzhou 310028, P. R. Dept. of Biomedical Engineering Shanghai Jiaotong University 200030 P. R. China Dept. of Computer and Engineering Hangzhou University of Commerce 310035 P. R. China Dept. of Computer Zhejiang University Hangzhou 310028 P. R. China

Through research for image compression based on wavelet analysis in recent years, we put forward an adaptive wavelet decomposition strategy. Whether sub-images are to be decomposed or not are decided by their energy defined by certain criterion. Then we derive the adaptive wavelet decomposition tree (AWDT) and the way of adjustable compression ratio. According to the feature of AWDT, this paper also deals with the strategies which are used to handle different sub-images in the procedure of quantification and coding of the wavelet coefficients. Through experiments, not only the algorithm in the paper can adapt to various images, but also the quality of recovered image is improved though compression ratio is higher and adjustable. When their compression ratios are near, the quality of subjective vision and PSNR of the algorithm are better than those of JPEG algorithm.

关键词： Adaptive algorithms image coding image quality Signal to noise ratio Wavelet transforms

Polarization state and image rotation via spontaneously generated coherence in a spinning fast light medium

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Communications in Theoretical Physics 2020年第11期72卷 99-103页

作者： Habibur Rahman Mansoor Khan Shabir Ahmad Muhammad Tayyab Haseena Bibi Hazrat Ali Department of Physics Govt Post Graduate College Dargai MalakandPakistan Department of Physics University of Malakand ChakdaraDir(L)Pakistan Department of Physics Gomal University Dera Ismail KhanPakistan Department of Physics Abbottabad University of Science and TechnologyHavellainPakistan

In this article we propose a four-level rubidium(Rb87)atomic system for observing interesting features of polarization state rotation in a fast light *** investigate spontaneously generated coherence(SGC)for a spinning *** show how SGC can affect different spectral profiles of the polarization state and images in this suggested *** observe a 0.5 radian rotation and 2.5 microsecond time advancement in our proposed *** precise results will provide a new platform for researchers in quantum optics due to its applications in image coding,telecommunications and cloaking technology.

关键词： spinning medium SGC effect image coding

Improvement of Camera Calibration Accuracy Based on Periodic Arrangement Characteristics of Calibration Target Pattern

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Transactions of Tianjin University 2017年第6期23卷 582-590页

作者： Qingguo Tian Yunpeng Li Jinjiang Wang Tianyu Chang School of Precision Instruments and Opto-Electronics Engineering Tianjin UniversityTianjin 300072China Key Laboratory of Opto-Electronics Information Technology of Ministry of Education Tianjin 300072China

Conventional camera calibration that employs calibration targets is a commonly used method to acquire a camera’s intrinsic and/or extrinsic parameters. The calibration targets are usually designed as periodic arrays of simple high-contrast patterns that provide highly accurate world coordinate system points and the corresponding image pixel coordinate system points. The existing pixel coordinate extraction algorithms can reach a sub-pixel level; however, they treat each single pattern in one image as an independent individual, which makes it difficult to further improve extraction accuracy. In this paper, a novel method is proposed by utilizing the periodic arrangement characteristics of the calibration target pattern as a global constraint to improve the calibration accuracy. Based on a camera’s pinhole model, the intersection point of two fitted curves is used as an optimized pixel point to replace the initial one. Following the pixel coordinate optimization procedures, experiments were performed using real data from a 3D laser line scanner and a dynamic precision calibration target. Our results show that the relative errors of camera homography matrix elements obtained by the proposed optimization method were reduced compared with the commonly used method. The average coordinate measurement accuracy can be improved by nearly 0.05 mm. It is shown that the proposed optimization method can enhance the camera calibration accuracy, especially when the extracted pixels are of poorer precision. © 2017 Tianjin University and Springer-Verlag Berlin Heidelberg

关键词： Cameras Curve fitting Extraction image coding image processing Pinhole cameras Pixels

Detecting Double Mixed Compressed images Based on Quaternion Convolutional Neural Network

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Chinese Journal of Electronics 2024年第3期33卷 657-671页

作者： Hao WANG Jinwei WANG Xuelong HU Bingtao HU Qilin YIN Xiangyang LUO Bin MA Jinsheng SUN Department of Automation Nanjing University of Science and Technology Engineering Research Center of Digital Forensics Ministry of Education Department of Computer and Software Nanjing University of Information Science and Technology School of Management Nanjing University of Posts and Telecommunications Department of Computer Science and Engineering Guangdong Province Key Laboratory of Information Security Technology Sun Yat-sen University State Key Laboratory of Mathematical Engineering and Advanced Computing Qilu University of Technology

Detection of color images that have undergone double compression is a critical aspect of digital image *** the existence of various methods capable of detecting double Joint Photographic Experts Group(JPEG) compression,they are unable to address the issue of mixed double compression resulting from the use of different compression *** particular,the implementation of Joint Photographic Experts Group 2000(JPEG2000)as the secondary compression standard can result in a decline or complete loss of performance in existing *** tackle this challenge of JPEG+JPEG2000 compression,a detection method based on quaternion convolutional neural networks(QCNN) is *** QCNN processes the data as a quaternion,transforming the components of a traditional convolutional neural network(CNN) into a quaternion *** relationships between the color channels of the image are preserved,and the utilization of color information is ***,the method includes a feature conversion module that converts the extracted features into quaternion statistical features,thereby amplifying the evidence of double *** results indicate that the proposed QCNN-based method improves,on average,by 27% compared to existing methods in the detection of JPEG+JPEG2000 compression.

关键词： image coding image color analysis Quaternions Forensics Transform coding Color Feature extraction

Fast prediction unit selection method for HEVC intra prediction based on salient regions

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Optoelectronics Letters 2016年第4期12卷 316-320页

作者：冯磊戴明赵春蕾熊晶莹 Key Laboratory of Airborne Optical Imaging and Measurement Changchun Institute of Optics Fine Mechanicsand Physics Chinese Academy of Sciences Changchun 130033 China University of Chinese Academy of Sciences Beijing 100039 China

In order to reduce the computational complexity of the high efficiency video coding(HEVC) standard, a new algorithm for HEVC intra prediction, namely, fast prediction unit(PU) size selection method for HEVC based on salient regions is proposed in this paper. We first build a saliency map for each largest coding unit(LCU) to reduce its texture complexity. Secondly, the optimal PU size is determined via a scheme that implements an information entropy comparison among sub-blocks of saliency maps. Finally, we apply the partitioning result of saliency map on the original LCUs, obtaining the optimal partitioning result. Our algorithm can determine the PU size in advance to the angular prediction in intra coding, reducing computational complexity of HEVC. The experimental results show that our algorithm achieves a 37.9% reduction in encoding time, while producing a negligible loss in Bjontegaard delta bit rate(BDBR) of 0.62%.

关键词： Codes (symbols) Computational complexity Computational efficiency image coding image segmentation Ion beams

A Fast Algorithm of the DCT and IDCT for VLSI Implementation

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A Fast Algorithm of the DCT and IDCT for VLSI Implementation

Wavelet Transform coding of Color images

1996 3rd International Conference on Signal Processing(ICSP’96)

作者： Hong Ying Hou Zhaohuan Institute of Acoustics Chinese Academy of Sciences

ISBN: (纸本)0780329120

＜正＞Since DCT performs very close to the statistically optimal Karhunen-Loeve Transform（KLT）,it is widely used in digital signal processing,especially for speech and image data *** DCT algorithms and VLSI architectures for real-time computation capabilities are required *** is known that VLSI implementation of distributed arithmetic is very efficient for computing ***,an algorithm is presented to convert the DCT and inverse DCT（IDCT） to *** implementation of the algorithm has same advantage as any implementation using distributed arithmetic.

关键词： VLSI discrete cosine transforms inverse problems transform coding digital signal processing chips data compression speech coding image coding digital arithmetic convolution number theory IDCT DCT VLSI implementation fast algorithm digital signal processing statistically optimal Karhunen-Loeve transform image data compression speech compression VLSI architectures real-time computation distributed arithmetic inverse DCT skew-convolution number theoretic transforms

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Progress in Natural Science:Materials International 1993年第6期 535-545页

作者：胡国生鲍虎军 Department of Applied Mathematics and State Key Laboratory of Computer Aided Design & Computer Graphics Hangzhou 310027 PRC Zheijiang University

An efficient coding method based on wavelet transform is presented for color *** tristimulus signals R,G,B of the original images are first converted into the Y,I,Q signals,whichare then decomposed into the luminance and edge subimages with the wavelet ***,the edgesubimages are encoded with edge pattern vector quantization while the cosine transform coding method isused to encode the luminance *** results are obtained for coding of color images in thebitrate range from 0.24 to 0.50 bits/***,because of the simplicity of the structure in ourmethod,it is suitable for hardware implementation,and can be used in real time encoding system.

关键词： wavelet transform image decomposition edge pattern vector quantization image coding