The experiment results from practical multispectral images have shown that this algorithm is efficient . if the original image is reconstructed by five eigen subimages , the nearlossless compression ratio is above 11 for the data used in this paper and the psnr is more than 45db 实验结果表明，对机载64波段多光谱遥感图像进行k - l变换和整数小波变换后，选用五个本征子图像重建原图像，压缩比可以达到11以上，峰值信噪比则超过45db ，取得了其它方法无法获得的效果。
Through anatomizing ezw coding algorithm and taking the effects of human being ’ s vision characteristics on quality of reconstituting image . a improved zeretrees algorithm are put forward . at last a new image compression encoding algorithm based on wavelet transform and vector quantization is put forward . the experiment show , in very low bit rate , using the proposed algorithm , the reconstructed image is superior to that of ezw in both of perception and psnr 最后,在小波树的基础上,通过对矢量量化的研究,本文提出了一种基于四叉树结构新的小波树矢量量化压缩编码算法,实验证明,在较高压缩比的情况下,使用此方法得到的重构图象质量(视觉效果和峰值信噪比)比通常的小波压缩算法有了较大的提高。
Image coding experiments show that the lfrc performs better than the rbc , with higher psnr and less distortion , moreover , it is superior to the spiht on preserving the edges and details of the image . therefore , the lfrc is quite suitable for high speed and real time remote sensing image compression 实验结果表明,采用同样的编码方法,经lfrc压缩后重建图像的峰值信噪比( psnr )普遍高于rbc ,主观质量有明显改善,对边缘和细节的保持能力超过了运算量更多的spiht算法,因此十分适合高速、实时图像压缩。
In the third part , the essences of steganography and disadvanges of common visual perception evaluation , such as psnr and wpsnr are studied . based on analysis local error that is introduced by embedding information , combining hvs , three objective perception evaluation method for steganography performance are proposed , which are based on human visual systems and local statistic error distribution respectively . in the steganalysis part , a steganography security statistic attack model and methods for some steganography methods are presented 在信息隐藏的性能评价方面，研究了常用的峰值信噪比，加权峰值信噪比等前人提出的感知性能评价准则，指出针对信息隐藏的性能评价不能单纯从视觉特性出发，提出从信息隐藏的数据特性和感知特性出发，结合局部特性来考察失真误差的变化的思想，并据此提出基于局部区域误差统计分布和视觉掩模方法评价信息隐藏性能的方法。
The experimental results manifest that the psnr of both the full reconstructed video sequences and the ones of frame rates changed are improved compared to the system base on haar wavelet . moreover , the decoding time of db2 filters is shorter than the haar one , the shorter the decoding time , the better the real - time displaying in the client side 实验结果表明,本系统与基于haar小波的可伸缩性视频编解码系统相比,完全重建的视频图像质量和帧速率改变后的重建视频图像质量都有了明显的提高,并且解码时间也有所缩短,具备了更好的实时性。
After investigating the new character of the motion estimation and fast algorithms adopted by h . 264 , three high - efficiency motion estimation algorithms fitted to h . 264 are proposed . experimental results show that about half time of motion estimation is cut down while keeping the similar video quality and bit - rate 实验结果表明,本算法同标准快速搜索法相比,在搜索5个参考帧的情况下,能在psnr降低不超过0 . 05db 、码率增加不超过2 . 32 %的情况下节省至少56 . 5 %的时间。
In the fourth part , some key technologies about fine granular scalable video coding , decoding and rate shaping are surveyed , including how to shape the stream to get a better psnr , and how to allocate the rate of base and enhancement layer . a comparison study on the rate shaping analytic model of normal layered coding and fgs coding is presented 另外，本文在对现有的fgs编解码技术深入研究的基础上，改进了精细分层编码中的截取算法，并讨论了码率分配算法，通过实验得到了码率分配的重要结论，且提出和对比了一般分层编码和精细分层编码的码流截取算法解析模型。
The algorithm introduced in this paper provides prospective psnr performance that is close to the fsbma . the algorithm tries to achieve better performance in terms of all three parameters in the speed - quality - bitrate tradeoff , so satisfies high estimation performance and efficient implementation and can be used for real time low bit - rate video coding 这种运动估计方法性能上接近全搜索法和三步法，有较快的估计速度和较高的峰值信噪比，搜索效率高，在减少计算量的同时，保持较好的图像性能，因而是一种性能良好的运动估计方法。
The design scheme with a multi - state trellis states also shows a better snr performance than current reported schemes . the author , in the meanwhile , uses tcq to implement sar image compressions . the result proves that the compressed images are high psnr and low distortion characters , which is suitable to be used in space - borne and airborne sar systems 论文还采用tcq算法对sar图像进行了压缩试验，结果表明，经过tcq算法压缩后的图像具有较高的信噪比，而且图像失真小，可以作为今后星载、机载sar平台进行数据压缩的一种可选择的技术方案。
The third part proposes a new compression and coding scheme with dct ( discrete consine transform ) and wavelet transform through solving the problem that is dfd ( displaced frame difference ) after motion compensation has many high - frequency coefficients which handicap compression . the new dfd which is preprocessed with dct is adaptive to wavelet transform . the new algorithm has been tested with experiment and achieved the higher psnr than the original algorithm , which proves its availability 第三部分针对基于dfd (差值帧)的小波视频压缩算法中运动补偿后的dfd具有较多的高频信号、不利于小波变换的缺陷，提出了小波变换和dct (离散余弦变换)相结合的混合编码方案，使得经过dct处理后的新的dfd更加适合于小波变换，小波变换后的高频系数大大减少，有利于压缩。
