基于小波变换的低比特率图像编码研究

运用小波变换理论,结合人类视觉系统特性,提出一种基于SPIHT算法的低比特率图像压缩的改进算法.实验证明,该算法在平滑图像的压缩中有较好效果,在低比特率压缩下减少了Gibbs现象,边缘模糊现象得到改善.     

基于三维小波变换的视频水印嵌入与盲提取算法

为了寻求有效的数字媒体保护方法,该文提出了一种在三维小波变换域内基于二值运算的数字视频水印嵌入算法.为了实现水印的获取,提出了一种相应的水印盲提取算法.水印的嵌入与提取算法不仅充分利用了小波变换良好的空时多分辨特性,而且占用内存空间少、时延低,适合视频流的在线水印嵌入和提取,并易于硬件的实时实现.     

小波变换用于色谱信号处理

利用快速离散小波变换(DWT)和小波逆变换(IDWT)对色谱信号进行小波分解、滤波和信号重构,同时,也与其他数字滤波方法进行了比较,结果表明,小波变换可以成功去除色谱信号中的噪声,使色谱信号平滑和提高信噪比.     

小波变换在图像压缩编码中的应用

对图像压缩编码技术进行综述性介绍,着重阐述了基于小波变换的图像压缩编码的基本思想与特点.     

小波变换在图像压缩编码中的应用

对图像压缩编码技术进行综述性介绍,着重阐述了基于小波变换的图像压缩编码的基本思想与特点。     

心电信号小波变换自适应编码压缩方法

动态心电监护具有监测时间长、数据量大的特点,所以心电数据压缩十分必要．对于心电信号压缩的方法有很多,文章提出了心电信号小波变换自适应编码压缩方法,与其它压缩方法相比,此方法减少了信号重建时的失真,压缩比5到12．     

用HTML5打造自己的网页视频播放器

介绍如何使用HTML 5中的video元素来播放视频文件,如何利用video元素的各种属性、事件与方法来定制属于自己的网页视频播放器。虽然目前很多主流浏览器都针对video元素提供了一个视频播放控件(在代码中可以通过使用video元素的controls属性来显示该控件),但是很多时候这个默认的播放控件并不能满足开发者或用户的某些特定需求,这就需要通过自己定义视频播放器来满足这种需求。     

基于小波变换和神经网络的视频文字检测

图像中文字的检测有广泛的应用范围。无论是出现在场景中的文字，还是以图形的形式附加在视频图像中的文字，都能提供重要的索引信息资源。在这篇文章中，我们实现了一种基于小波变换和人工神经网络的视频文字检测系统。它能检测出现在数字图像中的文字区域。我们的系统实现了一个层次间隔的特征提取器，其输出结果将达到一个用于提了文本区域的人工神经网络处理器，即智能分类器，分析出来的文字区域可以送往适当的光学字符识别系统。在对各种各样文本检测的试验中显示了我们的系统的性能。     

基于小波变换的低照度图像增强新算法

针对低照度图像暗、对比度低,同时存在大量黑暗连通区的特点,提出了一种基于小波系数融合的低照度图像增强算法,该算法对图像的低频和高频信息分别用空域法和频域法进行处理。实验表明,该方法在处理低照度图像的过程中,在调节图像动态范围和增强图像细节的同时,也达到了对高频信息降噪的目的。通过该算法处理,能有效减少拍摄图像所需的曝光时间。     

基于小波变换的低对比度图像增强改进算法

提出一种基于小坡变换的图像增强算法.利用小波变换的时频局域性和方向性特点,对分解后的高频系数进行子树划分,以子树为单位实现图像的对比度增强.在VC++环境下实现了该方法,实验结果表明该算法能得到整体视觉好的图像,是一种有效的图像增强算法.     

Very low bit-rate video coding using motion compensated 3-d wavelet transform

A new motion-compensated 3-D wavelet transform (MC-3DWT) video coding scheme is presented in this paper. The new coding scheme has a good performance in average PSNR, compression ratio and visual quality of reconstructions compared with the existing 3-D wavelet transform (3DWT) coding methods and motion-compensated 2-D wavelet transform (MC-WT) coding method. The new MC-3DWT coding scheme is suitable for very low bit-rate video coding. Project supported by the National Natural Science Foundation of China(69875009)     

Very low bit-rate video coding based on wavelet transform

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Very Low Bit-Rate Video Coding Using Motion ompensated 3-D Wavelet Transform

A new motion-compensated 3-D wavelet transform (MC-3DWT) video coding scheme is presented in thispaper. The new coding scheme has a good performance in average PSNR, compression ratio and visual quality of re-constructions compared with the existing 3-D wavelet transform (3DWT) coding methods and motion-compensated2-D wavelet transform (MC-WT) coding method. The new MC-3DWT coding scheme is suitable for very low bit-rate video coding.     

Multiple description scalable video coding based on 3D lifted wavelet transform

INTRODUCTION With the expansion of multimedia applications, video transmission is becoming an important issue in the research area of communication. It is very im- portant to compress a large amount of video data effectively, which has already attracted considerable attention recently. To make source coders both er- ror-resilient and network-adaptive are two main challenges facing the video compression techniques. It is necessary to make the bitstreams temporal, spa- tial and SNR scalabl…     

Watermarking on 3D mesh based on spherical wavelet transform

INTRODUCTIONTherapidgrowthofdigitalmediaoverInternetprovideseverybodywiththefacilityofeasyaccess,copy,editanddistributionofdigitalcontentssuchaselectronicdocuments,images,soundsandvideos.Thereisurgentdemandfortechniquestoprotectthecopyrightoftheoriginaldigitaldataandtopreventunauthorizedduplicationortampering.Digitalwatermarkingordatahidingisonesolutionforthecopyrightprotectionofdigitaldata.Digitalwatermarkingisaprocessbywhichauser-specifiedsignal(watermark)ishiddenorembeddedintoanothersi…     

Watermarking on 3D mesh based on spherical wavelet transform

In this paper we propose a robust watermarking algorithm for 3D mesh. The algorithm is based on spherical wavelet transform. Our basic idea is to decompose the original mesh into a series of details at different scales by using spherical wavelet transform; the watermark is then embedded into the different levels of details. The embedding process includes: global sphere parameterization, spherical uniform sampling, spherical wavelet forward transform, embedding watermark, spherical wavelet inverse transform, and at last resampling the mesh watermarked to recover the topological connectivity of the original model. Experiments showed that our algorithm can improve the capacity of the watermark and the robustness of watermarking against attacks.     

3 D Wavelet Transform for Very Low Bit Rate Video Coding

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Entropy of images after wavelet transform

We studied the variation of image entropy before and after wavelet decomposition, the optimal number of wavelet decomposition layers, and the effect of wavelet bases and image frequency components on entropy. Numerous experiments were done on typical images to calculate （using Matlab） the entropy before and after wavelet transform. It was verified that, to obtain minimal entropy, a three-layer decomposition should be adopted rather than higher orders. The result achieved by using biorthogonal wavelet decomposition is better than that of the orthogonal wavelet decomposition. The results are not directly proportional to the vanishing moment, however.     

Multiple descriptions based wavelet image coding

INTRODUCTIONJPEG2 0 0 0 (LawsonandZhu ,2 0 0 2 )isanewlypublishedstillimage codinginternationalstandard .Itsintroductionmeantthatforthefirsttime,thediscretewavelettransform (DWT)wouldbeusedforthedecompositionandrecon structionofimagestogetherwithanefficientcod ingscheme.IntheJPEG2 0 0 0coder,beforeanywaveletdecompositionisperformed ,theimageispartitionedintonon overlappingtiles.Thesetilesareofequalsizeexceptpossiblyforthoseadjacenttotheimageboundary .Thenwavelettransformisappliedtotr…