共查询到19条相似文献,搜索用时 156 毫秒
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基于残差图像的ROI编码研究 总被引:7,自引:7,他引:0
与JPEG2000中的MAXSHIFT算法不同,本文将ROI编码与零树编码结合,给出一种基于残差图像的ROI编码算法RZ(residue zerotree)。RZ算法基于整数小波变换,对高压缩比下零树编码后ROI区域的残差图像作基于整数平方量化阈值的零树编码,并将所得残差数据熵编码后跟随原编码数据传输,可以实现ROI区域的有损或无损编码。实验结果表明,RZ算法实现了基于嵌入式零对小波变换(EZW)框架较低复杂度的ROI编码,可应用于基于网络的图像传输。 相似文献
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改进的图像多分辨率零树小波编码算法 总被引:8,自引:1,他引:8
本文在研究Shapiro零树方法进行小波图像编码基础上,提出一种改进型多分辨率零树编码算法。本算法从客观信噪比的角度出发,以码流中增加单位码字平均所能减少的系数量化误差为依据,确定各部分小波系数参加编码的顺序,同等码率下可提高PSNR0.1~0.5dB,同时改进后的算法可以使编码产生的码流在原来支持多码率解码的基础上,支持多分辨率图像解码 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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该文针对遥感图像的数据特点,提出了一种新的遥感图像编码方法。它基于一种改进的小波变换嵌入零块编码算法。新算法中改进了零块编码中四叉树分裂算法(quadtree),并设计亍新的链表生成和不重要集合排序策略。通过这些方法的改进,不仅提高了图像编码性能,同时还大大提高了运算效率。实验表明该文阐述的算法具有很低的复杂度和高的压缩率,PSNR和计算速度均超过SPIHT和SPECK。在1bpp下,该文方法的PSNR比SPIHT提高了0.3dB以上,计算速度比SPIHT提高了35%。 相似文献
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零树小波编码实现图像的高效压缩,能够有效的节省存储空间,提高Internet传输效率。其中的提升小波变换实现图像整数到整数的变化,给图像的无损压缩提供理论基础。零树小波编码非常好地适应高压缩比应用领域的要求。程序实现了对一幅静态图像进行零树小波编码压缩,将压缩后的文件保存在指定路径下。编码结束后,程序会显示压缩文件的存储容量,便于与压缩前的图像进行对照。在解码中,打开压缩文件,进行解码操作后,程序重新显示出图像。 相似文献
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Ganesh Bhokare Ujjwal Kumar Bhushan Patil Vikram Gadre 《Signal, Image and Video Processing》2012,6(1):99-108
In the Embedded Zerotree Wavelet (EZW) algorithm, a large number of bits are consumed in the encoding of Isolated Zero (IZ)
symbols. This is the main bottleneck of the EZW algorithm, which limits its performance in terms of compression gain. To circumvent
this limitation of the EZW algorithm, we propose in this paper, the Enhanced-EZW (E-EZW) algorithm based on the novel concept
of a sparse tree (ST) encoding scheme. The ST encoding scheme provides an efficient encoding of ‘IZ’ symbols and eventually
gives significant improvement in compression gain. Image features are clustered at various locations in an image, which gives
rise to spatial correlation between Significant Coefficients (SCs) at these locations. Based on the above observation, we
further propose differential coding of relative position of SCs in ST (DCORPS) in the E-EZW (DCORPS E-EZW) algorithm. We analyze
cases where the ST coding gives higher coding gain compared to the EZW algorithm. Further, we see that DCORPS in sparse tree
coding improves the overall coding efficiency of the E-EZW algorithm. By simulation results, we also demonstrate that the
E-EZW and DCORPS E-EZW algorithms outperform two other important wavelet-based compression algorithms: namely set partitioning
in hierarchical trees (SPIHT) and JPEG-2000 for a representative set of real-life images. 相似文献
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一般基于感兴趣区域(ROI)的图像编码算法都没有充分考虑人眼视觉特性,在分析了JPEG2000中感兴趣区域编码的优缺点后,利用小波变换的特点并结合人眼视觉的掩蔽效应,提出了一种改进的ROI图像编码算法。首先将图像小波域中的所有低频系数进行移位处理,而对于小波域中的高频系数,仅对其属于ROI区域的系数进行移位处理,再利用等级树集合分割(SPIHT)算法进行编码传输。仿真实验证明了该算法比原有算法的图像主观质量更好。 相似文献
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Region-of-interest image coding based on EBCOT 总被引:4,自引:0,他引:4
Yang H. Long M. Tai H.-M. 《Vision, Image and Signal Processing, IEE Proceedings -》2005,152(5):590-596
In this paper, an efficient, region-of-interest (ROI) coding scheme achieved by modifying the implicit ROI encoding method is proposed. This new method reduces the priority of background coefficients in the ROI code-block without compromising algorithm complexity. It is suitable for applications in which it may be desirable to encode the ROI to a higher quality level than the background. In addition, several EBCOT-based ROI coding schemes for image compression are discussed. Experimental results demonstrate that the proposed ROI coding scheme improves the compression efficiency and combines the advantages of the implicit ROI encoding method (low complexity) and the maxshift method (good ROI rate distortion performance). 相似文献
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基于最大可容忍深度失真模型的低复杂度深度视频编码 总被引:4,自引:4,他引:0
在保证虚拟视点绘制质量的前提下,如何降低深 度视频的编码复杂度是一个亟需解决的问题。本文提出了一 种基于最大可容忍深度失真(MTDD,maximum tolerable d epth distortion)模型的低复杂度深度编码算法,将MTDD模型引 入 到率失真(RD)代价函数,通过对编码单元(CU)进行失真度量判决 ,如果对当前CU进 行编码不会导致可察觉的绘制失真,则失真度量只考虑深度编码失真,否则失真度量同时考 虑深度编码失真和视点 合成失真(VSD),从而降低编码复杂度。实验结果表明,所 提出的算法在不 降低虚拟视点绘制质量和不增加编码码率的情况下,能显著降低深度视频的编码复杂度。 相似文献
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Embedded image coding using zerotrees of wavelet coefficients 总被引:20,自引:0,他引:20
The embedded zerotree wavelet algorithm (EZW) is a simple, yet remarkably effective, image compression algorithm, having the property that the bits in the bit stream are generated in order of importance, yielding a fully embedded code. The embedded code represents a sequence of binary decisions that distinguish an image from the “null” image. Using an embedded coding algorithm, an encoder can terminate the encoding at any point thereby allowing a target rate or target distortion metric to be met exactly. Also, given a bit stream, the decoder can cease decoding at any point in the bit stream and still produce exactly the same image that would have been encoded at the bit rate corresponding to the truncated bit stream. In addition to producing a fully embedded bit stream, the EZW consistently produces compression results that are competitive with virtually all known compression algorithms on standard test images. Yet this performance is achieved with a technique that requires absolutely no training, no pre-stored tables or codebooks, and requires no prior knowledge of the image source. The EZW algorithm is based on four key concepts: (1) a discrete wavelet transform or hierarchical subband decomposition, (2) prediction of the absence of significant information across scales by exploiting the self-similarity inherent in images, (3) entropy-coded successive-approximation quantization, and (4) universal lossless data compression which is achieved via adaptive arithmetic coding 相似文献
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《Signal Processing: Image Communication》2002,17(4):347-360
In this paper, a hybrid fractal zerotree wavelet (FZW) image coding algorithm is proposed. The algorithm couples a zerotree-based encoder, such as the embedded zerotree wavelet (EZW) coder or set partitioning in hierarchical trees, and a fractal image coder; this coupling is done in the wavelet domain. Based on perceptually-weighted distortion-rate calculations, a fractal method is adaptively applied to the parts of an image that can be encoded more efficiently relative to an EZW coder at a given rate. In addition to improving compression performance, the proposed algorithm also allows one to impose desirable properties from each type of image coder, such as progressive transmission, the zerotree structure, and range-domain block decoding. 相似文献
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兴趣区域优先的多尺度压缩感知渐进编码算法 总被引:1,自引:1,他引:0
针对面向目标探测识别的无线图像传输应用,为 了解决探测识别任务对图像质量的高要求和无线信道带宽约 束之间的冲突,提出一种感兴趣区域(ROI)优先的多尺度压缩 感知(CS)渐进编码算法。首先,选取多 尺度CS测量技术进行图像压缩,在相同压缩比情况下,可以保持更多的图像的细节 信息;其次,针对目标探测识别对 重构图像纹理、边缘信息完整保持的需求,选取基于小波的轮廓变换(WBCT) 作为CS的稀疏表示方法,可更多 地提取方向信息,从而可以较完整地保持边缘轮廓信息;最后,针对重构图像 ROI与背景区过度划分、ROI周边相关信息损失 过多的问题,给出ROI边界平滑处理的方法,可有效改善重构图像的主观视觉质量。 实验结果表明:在ROI压缩率高达 0.4的情况下,总的压缩率降至0.18,既保护 了ROI信息又显著提高了压缩比,基本满足目标探测识别任务的需求。 相似文献
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Salim Kahveci 《Telecommunication Systems》2014,57(3):223-228
In practice, channels in wireless communication systems are time-variable. Because of the variability of the channels in wireless systems and networks, the performance of error-control coding can be improved by adapting the rate of the code to the channel conditions. Thus, the bit-error performance of error-control coding system can be improved. In this study, an adaptive rate error control coding with concatenated Zigzag coding is investigated. The bit-error-rate performance of the adaptive rate Zigzag coding system is evaluated for channels with interference and noise. 相似文献