共查询到19条相似文献,搜索用时 140 毫秒
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该文提出一种自适应小波包图像压缩感知方法。该方法选用小波包变换分解图像,基于数学期望和信息熵分析各个小波包系数块的属性,自适应地将其划分为低频信号、无价值信号、特殊处理信号和压缩感知处理信号等4种信号类型,再针对不同的信号类型设计对应的处理方法,适应不同特征的图像。通过此种方法,在图像压缩感知过程中,可以根据不同图像和小波包系数块自适应地选取采样值,来提高压缩感知质量。实验结果表明该文提出的自适应小波包图像压缩感知方法在相同采样值的前提下,不仅提高了图像的重构质量,同时也降低了算法的计算复杂度和所需存储空间。 相似文献
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多小波以其具有正交性、对称性、短支撑和较大的消失矩等多个良好特性弥补了单小波的不足.在介绍多小波理论的基础上,提出一种新的图像压缩方法.该方法以CL多小波为基础,结合SPIHT图像压缩算法,对多小波系数进行压缩处理.采用Matlab 6.5进行实验,实验结果表明,经该算法压缩后的图像,其质量优于一般小波变换的传统方法. 相似文献
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一种改进的零树结构编码算法研究 总被引:1,自引:1,他引:0
现在大部分图像压缩技术都利用了小波变换后图像不同分辨率反相同方向子带之间的相关性。采用双正交提升小波将图像变换到小波域,通过增加熵编码的符号集,提出了一种基于正交小波变换的增广零树压缩编码算法,在整个编译码过程中仅使用一个系数列表,况且不进行任何排序操作。通过相关实验,证实该方法能有效进行图像压缩,提高了压缩率。 相似文献
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分析了医学图像压缩的必要性,简要介绍了二维离散小波变换和Mallat算法,重点讨论小波变换的原理及其在医学图像压缩方面的具体应用,实验结果表明,小波变换算法具有较高的压缩比和较好的图像恢复质量,选用不同的小波基压缩图像得到的压缩比不同,在同一小波系列内,压缩比随小波序数的增大而减小。 相似文献
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整数小波域张量Tucker分解的多光谱图像压缩 总被引:1,自引:1,他引:0
针对常用多光谱图像压缩算法-把图像作为矩阵向量量化后再进行相应压缩处理-导致图像的本征结构被破坏、信息损失以及压缩效率低等问题,提出一种基于非负张量(NTD)Tucker分解的多光谱图像压缩算法。首先将多光谱图像的每个谱段进行二维提升整数5/3小波变换,消除多光谱图像的空间冗余。然后将所有谱段的每级小波变换的4个小波子带看作为4个NTD。对每个非负小波子带张量采用改进局部HALS-NTD算法进行Tucker分解,消除光谱冗余和空间残余冗余。最后,将分解的核心张量和模式矩阵进行熵编码。实验结果表明,本文提出的压缩算法具有良好压缩性能,在压缩比32∶1~4∶1范围内,平均信噪比(SNR)高于40dB,与传统多光谱图像压缩算法比较,提高了1.779dB,有效提高了多光谱图像压缩算法的压缩性能。 相似文献
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The aim of this paper is to examine a set of wavelet functions (wavelets) for implementation in a still image compression system and to highlight the benefit of this transform relating to today's methods. The paper discusses important features of wavelet transform in compression of still images, including the extent to which the quality of image is degraded by the process of wavelet compression and decompression. Image quality is measured objectively, using peak signal-to-noise ratio or picture quality scale, and subjectively, using perceived image quality. The effects of different wavelet functions, image contents and compression ratios are assessed. A comparison with a discrete-cosine-transform-based compression system is given. Our results provide a good reference for application developers to choose a good wavelet compression system for their application 相似文献
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提出了一种基于平滑双正交小波和自适应分割算法的小波域分形图像编码算法,在基于离散有限方差(DFV)最优准则下得到了适合图像编码的一种新的平滑双正交小波,从而改善了分块效应。在小波域的分形编码中,提出了一种基于图像信息分布特征的自适应分割算法,实验表明,该文算法在相同压缩比的情况下,解码图像的主观视觉质量和峰值信噪比都明显优于SQS方法、基本分形图像编码方法和SPIHT方法。 相似文献
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提出了一种可用于视频解码器中的参考帧压缩算法.该算法利用小波变换和标量量化以及比特分配等技术.实现了对参考帧固定压缩率的压缩;结构简单易于实现,并因其固定压缩率而可方便地随机访问压缩的数据.实验证明.该算法在减少存储参考帧的存储器成本的情况下仍能保持优良的图像质量. 相似文献
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一种改进的嵌入式零树小波编码算法 总被引:2,自引:2,他引:0
嵌入式零树小波编码算法是基于小波变换的一种图像压缩方法,它可以实现渐进编解码,进行有损或无损压缩,具有较高的压缩比和图像恢复质量.全文在研究嵌入式零树小波编码算法及原理的基础上,表述了算法的应用过程,阐述了具体的实现思路,指出了其不足之处,并在原来方法的基础上进行了有效改进,具有比较好的效果. 相似文献
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In this paper, a novel 2-D adaptive lifting wavelet transform is presented. The proposed algorithm is designed to further reduce the high-frequency energy of wavelet transform, improve the image compression efficiency and preserve the edge or texture of original images more effectively. In this paper, a new optional direction set, covering the surrounding integer pixels and sub-pixels, is designed. Hence, our algorithm adapts far better to the image orientation features in local image blocks. To obtain the computationally efficient and coding performance, the complete processes of 2-D adaptive lifting wavelet transform is introduced and implemented. Compared with the traditional lifting-based wavelet transform, the adaptive directional lifting and the direction-adaptive discrete wavelet transform, the new structure reduces the high-frequency wavelet coefficients more effectively, and the texture structures of the reconstructed images are more refined and clear than that of the other methods. The peak signal-to-noise ratio and the subjective quality of the reconstructed images are significantly improved. 相似文献
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A fast and low memory image coding algorithm based on lifting wavelet transform and modified SPIHT 总被引:1,自引:0,他引:1
Due to its excellent rate–distortion performance, set partitioning in hierarchical trees (SPIHT) has become the state-of-the-art algorithm for image compression. However, the algorithm does not fully provide the desired features of progressive transmission, spatial scalability and optimal visual quality, at very low bit rate coding. Furthermore, the use of three linked lists for recording the coordinates of wavelet coefficients and tree sets during the coding process becomes the bottleneck of a fast implementation of the SPIHT. In this paper, we propose a listless modified SPIHT (LMSPIHT) approach, which is a fast and low memory image coding algorithm based on the lifting wavelet transform. The LMSPIHT jointly considers the advantages of progressive transmission, spatial scalability, and incorporates human visual system (HVS) characteristics in the coding scheme; thus it outperforms the traditional SPIHT algorithm at low bit rate coding. Compared with the SPIHT algorithm, LMSPIHT provides a better compression performance and a superior perceptual performance with low coding complexity. The compression efficiency of LMSPIHT comes from three aspects. The lifting scheme lowers the number of arithmetic operations of the wavelet transform. Moreover, a significance reordering of the modified SPIHT ensures that it codes more significant information belonging to the lower frequency bands earlier in the bit stream than that of the SPIHT to better exploit the energy compaction of the wavelet coefficients. HVS characteristics are employed to improve the perceptual quality of the compressed image by placing more coding artifacts in the less visually significant regions of the image. Finally, a listless implementation structure further reduces the amount of memory and improves the speed of compression by more than 51% for a 512×512 image, as compared with that of the SPIHT algorithm. 相似文献