Utility analysis and evaluation method study of side channel information

In order to improve the efficiency and success rate of the side channel attack, the utility of side channel information of the attack object must be analyzed and evaluated before the attack implementation. Based on the study of side-channel attack techniques, a method is proposed in this paper to analyze and evaluate the utility of side channel information and the evaluation indexes of comentropy Signal-to-Noise Ratio （SNR） are introduced. On this basis, the side channel information （power and electromagnetic） of a side channel attack experiment board is analyzed and evaluated, and the Data Encryption Standard （DES） cipher algorithm is attacked with the differential power attack method and differential electromagnetic attack method. The attack results show the effectiveness of the analysis and evaluation method proposed in this paper.     

Study of frame-rate up conversion based on H.264

In this study, a low complexity frame-rate up conversion method using compressed domain information for H.264 decoder is proposed. In the proposed scheme, the motion vectors (MVs) are estimated using constant acceleration motion model, and the MVs regarded as no credibility are corrected, and the interpolation method is applied on the basis of the macroblock (MB) coded types. Applied to the H.264 decoder, the proposed method provides high quality interpolation frames and an obvious decrease of the block artifacts.     

SPATIAL ERROR CONCEALMENT BASED ON MOJETTE TRANSFORM

This letter presents a novel spatial error concealment algorithm for the H.264 video coding. The error concealment algorithm is based on directional interpolation. Mojette transform is used to estimate the orientation features of the damaged blocks,and the image is interpolated in the appro-priate directions. The proposed method is compared with bilinear interpolation algorithm in the ref-erence implementation of H.264 and all directional interpolation. Experimental results prove that the proposed algorithm has better subjective and objective image reconstruction quality.     

Reconstruction of Multifunction Radar Search Plan Based on Multiple Sequence Alignment

Multifunction radar （MFR） is a sophisti- cated sensor which could perform several different func- tions simultaneously. The problems of deciphering the signals of MFR and inferring the information of its ca- pabilities have posed a great challenge to the Electronic intelligence （ELINT） society. In this paper, we propose a method to reconstruct MFR＇s search plan from its sig- nals by drawing lessons from the bioinformatics approach “Multiple sequence alignment （MSA）” which is used ex- tensively for gene analysis. In the method, the signal of MFR is represented as a structured task sequence, and is segmented into several blocks according to the inherent pe- riodicity of the search plan. Then, these blocks are aligned optimally to distinguish the tasks relevant to the search function from the others. Simulation results show that the proposed method is applicable and effective.     

A fast quarter-pixel motion estimation algorithm for H.264/AVC

A fast quarter-pixel motion estimation algorithm is proposed in this paper. The proposed algorithm based on mathematical models of the motion compensated prediction errors. Unlike conventional quarter-pixel accurate motion estimation algorithm, proposed algorithm can avoid fractional-pixel interpolation and subsequent fracfional-pixel search after integer-precision motion estimation. Experiments show that the proposed algorithm greatly reduces the computational complexity of quarterpixel motion estimation, while keeping the nearly equal quality of the image     

A NEW UNSUPERVISED CLASSIFICATION ALGORITHM FOR POLARIMETRIC SAR IMAGES BASED ON FUZZY SET THEORY

In this letter, a new method is proposed for unsupervised classification of terrain types and man-made objects using POLarimetric Synthetic Aperture Radar （POLSAR） data. This technique is a combination of the usage of polarimetric information of SAR images and the unsupervised classification method based on fuzzy set theory. Image quantization and image enhancement are used to preprocess the POLSAR data. Then the polarimetric information and Fuzzy C-Means （FCM） clustering algorithm are used to classify the preprocessed images. The advantages of this algorithm are the automated classification, its high classification accuracy, fast convergence and high stability. The effectiveness of this algorithm is demonstrated by experiments using SIR-C/X-SAR （Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar） data.     

Distributed Compressive Video Sensing with Adaptive Measurements Based on Structural Similarity

This paper presents a Distributed compressive video sensing scheme with Adaptive measurements （DCVS-AM）. In this approach, the key frame in each Group of pictures （GOP） is coded by Compressive sensing （CS） with a fixed measurement rate; whereas other frames in the same GOP are compressed by an adaptive random projection in two stages, yielding the Adaptive compressive sensing （ACS） frames. The first stage uses a small and fixed measurement rate and recovers a coarse version. In the second stage, each coarse-version ACS-frame together with its proceeding and following key frames will go through a joint analysis at the decoder side and the analysis result - Structural similarity （SSIM） that is based on a motion-guided interpolation and calculated in a multilevel discrete wavelet transform domain - is sent back to the encoder side to facilitate a re-sampling of the ACS-frame with an adaptive measurement rate. Experimental results show that our proposed DCVS-AM consistently outperforms the state-of-the-art DCVS with a fixed measurement.     

All zero macroblock decision method for H.26L

In order to reduce the computation in the part of motion search and transform in H.26L encoder, an all-zero macroblock decision method based on integer transform and motion search is proposed in this paper. According to the characteristics of integer transform and motion search in H.26L, all-zero macroblock decision is made in inter frame coding by comparing Sum of the Absolute Differences(SAD) with a value related with Quantization Parameter(QP) before integer transform. It avoids a large amount of computation in motion search, transform and quantization. This technology highly improves the efficiency of real time H.26L encoder by skipping all-zero macroblock before integer transform and shortening the code stream at the same time.     

Motion-based region growing segmentation of image sequences

This paper proposes a motion-based region growing segmentation scheme for the object-based video coding, which segments an image into homogeneous regions characterized by a coherent motion. It adopts a block matching algorithm to estimate motion vectors and uses morphological tools such as open-close by reconstruction and the region-growing version of the watershed algorithm for spatial segmentation to improve the temporal segmentation. In order to determine the reliable motion vectors, this paper also proposes a change detection algorithm and a multi-candidate pro- screening motion estimation method. Preliminary simulation results demonstrate that the proposed scheme is feasible. The main advantage of the scheme is its low computational load.     

Clustering compressed sensing based on image block similarities

Compressed sensing （CS） algorithm enables sampling rates significantly under classical Nyquist rate without sacrificing reconstructed image quality. It is known that, a great number of images have many similar areas which are composed by the same number of grayscale or color. A new CS scheme, namely clustering compressed sensing （CCS）, was proposed for image compression, and it introduces clustering algorithm onto framework of CS based on similarity of image blocks. Instead of processing the image as a whole, the image is firstly divided into small blocks, and then the clustering algorithm was proposed to cluster the similar image blocks. Afterwards, the optimal public image block in each category is selected as the representative for transmission. The discrete wavelet transform （DWT） and Gaussian random matrix are applied to each optimal public image block to obtain the random measurements. Different from equal measurements, the proposed scheme adaptively selects the number of measurements based on different sparsity of image blocks. In order to further improve the performance of the CCS algorithm, the unequal-CCS algorithm based on the characteristics of wavelet coefficients was proposed as well. The low frequency coefficients are retained to ensure the quality of reconstructed image, and the high frequency coefficients are compressed by the CCS algorithm. Experiments on images demonstrate good performances of the proposed approach.     

无反馈分布式视频编码中的速率控制算法

针对现有比特平面级编码端速率控制算法估计精度要求高的问题,提出了一种帧级编码端速率控制算法。该算法通过在编码端利用分层快速运动补偿内插产生高质量的边信息估计,并根据循环移位去除比特平面间的级别性,使每个比特平面的编码速率均匀化,从而实现帧级别的速率控制。实验结果表明,与现有算法相比,所提算法对中高速运动视频边信息估计质量有明显提升,且解码视频的平均PSNR(peak signal-to-noise ratio)均有提高。     

一种空间域Wyner-Ziv视频编码系统的性能改进算法

分布式视频编码是建立在Slepian-Wolf和Wyner-Ziv信息编码理论基础上的全新视频编码框架,具有编码复杂度低,编码效率较高,抗误码性能好的特点.本文首先简单介绍了一种典型的分布式视频编码实现方案——空间域Wyner-Ziv视频编码,随后提出一种空间域Wyner-Ziv视频编码系统的性能改进算法,该算法在不增加编码复杂度的基础上,在解码端利用双向运动估计预测获取更高质量的边信息,同时采用基于Huber-Markov随机场约束的联合迭代解码算法重建图像.实验结果表明,在相同的输出码流情况下,本文改进算法在解码端重建图像的峰值信噪比与空间域Wyner-Ziv视频编码算法相比平均提高2dB,并且主观效果有所改善.     

一种运动自适应去隔行技术及其VLSI结构

提出一种有效的运动自适应去隔行算法.该算法通过对同极性的相邻场进行运动检测,把插值点所处的区域分为快速运动区域、慢速运动区域和静止区域,对不同的区域采用不同的插值算法.在边缘检测方面,采用改进型ELA算法克服了传统的ELA算法处理水平边缘方面的不足,使边缘得到有效保护.与运动补偿算法相比,该算法计算复杂度较低,易于VL...     

Motion‐Compensated Frame Interpolation Using a Parabolic Motion Model and Adaptive Motion Vector Selection

We propose a motion‐compensated frame interpolation method in which an accurate backward/forward motion vector pair (MVP) is estimated based on a parabolic motion model. A reliability measure for an MVP is also proposed to select the most reliable MVP for each interpolated block. The possibility of deformation of bidirectional corresponding blocks is estimated from the selected MVP. Then, each interpolated block is produced by combining corresponding blocks with the weights based on the possibility of deformation. Experimental results show that the proposed method improves PSNR performance by up to 2.8 dB as compared to conventional methods and achieves higher visual quality without annoying blockiness artifacts.     

Motion compensated frame interpolation based on H.264 decoder

A low complexity motion compensated frame interpolation method using compressed-domain information based on an H.264 decoder is presented. In the proposed method, the motion vectors are estimated using the constant acceleration motion model, and the interpolation algorithm is applied based on the macroblock coded types. Results show that the proposed method provides high quality interpolation frames     

Local motion-adaptive interpolation technique based on block matching algorithms

Interpolation techniques based on block-by-block motion compensation algorithms are studied for the video conference/video telephone signals. In this paper, we propose the local motion-adaptive interpolation technique, which can be used in the codec using a motion compensated coding-block matching algorithm (MCC-BMA). Computer simulation results at 2:1 subsampling rate of the proposed local motion-adaptive interpolation techniques combined with the conventional three-step search algorithm and the fast BMA using integral projections are given.     

Advanced side information creation techniques and framework for Wyner–Ziv video coding

Recently, several distributed video coding (DVC) solutions based on the distributed source coding (DSC) paradigm have appeared in the literature. Wyner–Ziv (WZ) video coding, a particular case of DVC where side information is made available at the decoder, enable to achieve a flexible distribution of the computational complexity between the encoder and decoder, promising to fulfill novel requirements from applications such as video surveillance, sensor networks and mobile camera phones. The quality of the side information at the decoder has a critical role in determining the WZ video coding rate-distortion (RD) performance, notably to raise it to a level as close as possible to the RD performance of standard predictive video coding schemes. Towards this target, efficient motion search algorithms for powerful frame interpolation are much needed at the decoder. In this paper, the RD performance of a Wyner–Ziv video codec is improved by using novel, advanced motion compensated frame interpolation techniques to generate the side information. The development of these type of side information estimators is a difficult problem in WZ video coding, especially because the decoder only has available some reference, decoded frames. Based on the regularization of the motion field, novel side information creation techniques are proposed in this paper along with a new frame interpolation framework able to generate higher quality side information at the decoder. To illustrate the RD performance improvements, this novel side information creation framework has been integrated in a transform domain turbo coding based Wyner–Ziv video codec. Experimental results show that the novel side information creation solution leads to better RD performance than available state-of-the-art side information estimators, with improvements up to 2 dB; moreover, it allows outperforming H.264/AVC Intra by up to 3 dB with a lower encoding complexity.     

H.264/AVC中快速1/4像素运动估计算法

提出了一种快速1/4像素的运动估计算法.该算法基于运动补偿预测误差模型,与传统的1/4像素的分层运动估计算法不同,仅通过一步计算就能直接得到1/4像素精度的运动矢量,而且完全避免了运算量很大的分数像素内插运算和整像素搜索完成后的分数像素搜索.实验结果表明,该算法在保持图像质量的前提下极大地减少了1/4像素运动估计的运算量.     

分布式视频编码中边信息的产生

阐述了分布式视频编码中边信息的产生原理,介绍了几种主要的边信息产生方法,提出了一种新的算法,即基于对称运动矢量和hash码字的运动补偿内插法.最后,对不同的边信息产生方法进行了计算机仿真,仿真结果表明,提出的方法可明显提高边信息的精度.     

Edge-based motion compensated classified DCT with quadtree for image sequence coding

The motion compensated discrete cosine transform coding (MCDCT) is an efficient image sequence coding technique. In order to further reduce the bit-rate for the quantizied DCT coefficients and keep the visual quality, we propose an adaptive edge-based quadtree motion compensated discrete cosine transform coding (EQDCT). In our proposed algorithm, the overhead moving information is encoded by a quadtree structure and the nonedge blocks will be encoded at lower bit-rate but the edge blocks will be encoded at higher bit-rate. The edge blocks will be further classified into four different classes according to the orientations and locations of the edges. Each class of edge blocks selects the different set of the DCT coefficients to be encoded. By this method, we can just preserve and encode a few DCT coefficients, but still maintain the visual quality of the images. In the proposed EQDCT image sequence coding scheme, the average bit-rate of each frame is reduced to 0.072 bit/pixel and the average PSNR value is 32.11 dB.