共查询到20条相似文献，搜索用时 750 毫秒
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In this paper, a two-level Bregman method is presented with graph regularized sparse coding for highly undersampled magnetic resonance image reconstruction. The graph regularized sparse coding is incorporated with the two-level Bregman iterative procedure which enforces the sampled data constraints in the outer level and updates dictionary and sparse representation in the inner level. Graph regularized sparse coding and simple dictionary updating applied in the inner minimization make the proposed algorithm converge with a relatively small number of iterations. Experimental results demonstrate that the proposed algorithm can consistently reconstruct both simulated MR images and real MR data efficiently, and outperforms the current state-of-the-art approaches in terms of visual comparisons and quantitative measures. 相似文献
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李红 《咸阳师范专科学校学报》2013,(6):36-39
稀疏表示能够有效地表示图像的固有特征,利用KSVD学习算法对30幅自然图像训练得到了鲁棒的字典,利用“滑窗”策略对两幅源图像进行分块,使用OMP算法在字典上对各图像块进行稀疏分解,分解后的系数采用系数绝对值选大法进行融合,进而得到融合后和图像块.理论分析与实验结果表明,该方法能够有效地对已配准的待融合图像进行融合,融合后的结果无论是视觉效果还是客观评价参数均优于文中对比方法的效果. 相似文献
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一种基于零树的树形扫描图像压缩编码方法 总被引：1，自引：0，他引：1
金彩虹 《宁夏师范学院学报》2004,25(6):7-10
嵌入式零树编码被认为是目前国际上最先进的图像编码方法之一，但该算法在编“孤立零”码时会造成比特位冗余．因此本文提出了基于零树的树形扫描的图像压缩编码方法．实验结果表明该方法在保证恢复图像具有良好视觉效果的前提下，提高了压缩比，缩短了编码时间． 相似文献
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图像稀疏表示是指用很少的数据捕获感兴趣目标的重要信息的能力,通过基或字典中很少量元素的线性组合的形式来描述信号.图像稀疏表示研究已成为近年来图像表示研究的热点.本文系一文献综述,主要阐述了信号稀疏表示和图像稀疏表示的基本理论及其在压缩方面的应用,并且介绍了一种新的稀疏性正则化的泊松噪声图像去噪算法. 相似文献
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Image subbands can be obtained by using filterbank. Traditional compression method uses direct entropy coding for each subband. After studying the energy distribution in image subbands, we proposed a vector quantization (VQ) coding algorithm to image subband. In the algorithm, vector quantizers were adaptively designed for high-frequency bands in an image. In particular, the edges of the image were examined and fewer bits were assigned to high-energy regions. The experimental result showe… 相似文献
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提出了一种性能良好的图像水印算法，该算法在嵌入水印时先对水印信息进行奇偶编码再嵌入到图像中，在提取水印时对恢复出的水印信息进行奇偶解码，实验结果表明，该算法比未采用奇偶编码的同一水印算法具有更好的不可见性和稳健性。 相似文献
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In this paper, a CMOS image sensor(CIS) is proposed, which can accomplish both decorrelation and entropy coding of image compression directly on the focal plane. The design is based on predictive coding for image decorrelation. The predictions are performed in analog domain by 2×2 pixel units. Both the prediction residuals and original pixel values are quantized and encoded in parallel. Since the residuals have a peak distribution around zero,the output codewords can be replaced by the valid part of the residuals' binary mode. The compressed bit stream is accessible directly at the output of CIS without extra disposition. Simulation results show that the proposed approach achieves a compression rate of 2. 2 and PSNR of 51 on different test images. 相似文献
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合成孔径雷达(SAR:Synthetic Aperture Radar)具有海量的成像数据,极大的动态范围,不仅要用浮点来表示数据,而且令JPEGJ、PEG 2000和H.264等标准最初为光学图像而设计,并且主要针对8比特整数图像数据的标准压缩算法难以胜任.本文应某研究所的要求,针对32位的SAR浮点模图像数据, 相似文献
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为去除常出现在图像采集和日常摄影中的摩尔纹噪声,提出一种由样条小波生成的紧框架下的稀疏信号恢复算法。该算法利用摩尔纹噪声的频域特性确定受影响的傅里叶频谱区域;利用图像在给定紧框架下的稀疏性,根据压缩感知理论实现数据在傅里叶频谱上的非线性插值。实验结果表明,相比传统频域滤波算法,该算法恢复图像的峰值信噪比更高,更符合人的视觉审美,在去除摩尔纹噪声的同时,还可有效保留图像边缘信息。 相似文献
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XUChiang－man ZHANGZhao－yang 《上海大学学报(英文版)》2001,5(1):57-59
Fast algorithms for reducing encoding complexity of fractal image coding have recently been an important research topic.Serach of the bast matched domain block is the most computation intensive part of the fractal encoding process.In this paper,a fast fractal approximation coding scheme implemented on a personal computer based on matching in range block‘s neighbours is presented.Experimental results show that the proposed algorithm is very simple in implementation,fast in encoding time and high in compression ratio while PSNR is almost the same as compared with Barnsley‘s fractal block coding. 相似文献
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HU Yuping YU Shengsheng ZHOU JingLi SHI Lei College of Computer Science Technology Huazhong University of Science Technology Wuhan P.R. China 《重庆大学学报(英文版)》2004,3(1):34-38
1.IntroductionInrecentyears,digitalimagewatermarkingtechni-queshavegrowndramatically.Digitalimagewater-markingisconcernedwithhidinginformationintoadigitalimage.Thisinformationmaybeusedforvariousapplicationssuchasauthentication,copyright,andproofofownership.Insomeapplicationsitisrequirednotonlytoidentifytherightfuluserofanimage,butalsotoembedsomeadditionalinformation.Forexample,incopyrightprotectionapplication,thewatermarkmaycontainadate,atime,aserialnumber,oranidentificationoftherightfuluser.… 相似文献
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LI Ji-liang FANG Xiang-zhong HOU Jun 《浙江大学学报(A卷英文版)》2007,8(4):620-624
In this paper, we propose a sparse overcomplete image approximation method based on the ideas of overcomplete log-Gabor wavelet, mean shift and energy concentration. The proposed approximation method selects the necessary wavelet coefficients with a mean shift based algorithm, and concentrates energy on the selected coefficients. It can sparsely approximate the original image, and converges faster than the existing local competition based method. Then, we propose a new compression scheme based on the above approximation method. The scheme has compression performance similar to JPEG 2000. The images decoded with the proposed compression scheme appear more pleasant to the human eyes than those with JPEG 2000. 相似文献
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邓定胜 《实验室研究与探索》2021,(1):32-35,44
稀疏表示分类方法在图像遮蔽、弱光等情况下具有良好的应用及识别效果,但在测试样本少的环境下仍具有一定局限.将稀疏表示分类算法联合概率协同表示分类算法,以稀疏表示系数增强概率系统表示分类算法的表示系数,采用FERET、Multi-PIE与FRGC人脸数据库进行实验测试.结果显示,稀疏增强概率协同表示分类算法能够显著提升人脸... 相似文献