3-D Wavelet Transform for Very Low Bit-Rate Video Coding

A new improved Goh's 3 D wavelet transform(WT) coding scheme is presented in this paper. The new scheme has great advantages including a simple code structure, low computation cost and good performance in PSNR, compression ratios and visual quality of reconstructions, when compared to the other existing 3 D WT coding methods and the 2 D WT based coding methods. The new 3 D WT coding scheme is suitable for very low bit rate video coding.

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.

Very Low Bit-Rate Video Coding by Combining H.264/AVC Standard and 2-D Discrete Wavelet Transform

In this paper, we propose a new method for very low bit-rate video coding that combines H.264/AVC standard and two-dimensional discrete wavelet transform. In this method, first a two dimensional wavelet transform is applied on each video frame independently to extract the low frequency components for each frame and then the low frequency parts of all frames are coded using H.264/AVC codec. On the other hand, the high frequency parts of the video frames are coded by Run Length Coding algorithm, after applying a threshold to neglect the low value coefficients. Experiments show that our proposed method can achieve better rate-distortion performance at very low bit-rate applications below 16 kbits/s compared to applying H.264/AVC standard directly to all frames. Applications of our proposed video coding technique include video telephony, video-conferencing, transmitting or receiving video over half-rate traffic channels of GSM networks.

Enhanced Adaptive Approach of Video Coding at Very Low Bit Rate Using MSPIHT Algorithm

Nowadays video coding approach is a major key in many applications for easy transmission and storage consumption. The process of transformation is based on the empirical wavelet transform (EWT). The encoding process of video data provides secure and less consumption of storage and the reconstruction process consists of the reverse process with the extraction. In this paper, the coding of video is carried out at a very low bit rate with the enhancement of performance by proposing an approach of modified Set Partitioning in Hierarchical Tree (MSPIHT). This method encodes the high frequency frames with the scheduling of wavelet transform for efficient performances of encoding and improves the ability of both the frequency and time. By applying empirical wavelet transform on each video frame, the component of video frequency is extracted and the low frequency frame is encoded by the H.264/AVC standard. The low coefficient values are ignored in applying the threshold and in the reconstruction process, HBLPCE method is used for imaging enhancement. The simulation of the proposed approach analysis shows better performance in reliable process and efficiency when compared to existing.

VBR WAVELET VIDEO CODING AND ITS RATE CONTROL IN ATM NETWORKS

This paper presents a new video coding system based on wavelet transform and its rate control scheme over ATM networks. First, three dimensional wavelet transform is performed for the original image sequence, and an extension of set partitioning in hierarchical trees algorithm is employed to quantize the wavelet coefficients. Then, the output rate of the coder is controlled at group of frame scale, ensuring that it conforms to the parameters of a leaky bucket controller. Several leaky buckets with different sizes are discussed too. Simulation shows the efficiency of this codec and the effectiveness of the proposed rate control scheme.

AN EFFICIENT 3-DIMENSIONAL DISCRETE WAVELET TRANSFORM ARCHITECTURE FOR VIDEO PROCESSING APPLICATION

This paper presents an optimized 3-D Discrete Wavelet Transform (3-DDWT) architecture. 1-DDWT employed for the design of 3-DDWT architecture uses reduced lifting scheme approach. Further the architecture is optimized by applying block enabling technique, scaling, and rounding of the filter coefficients. The proposed architecture uses biorthogonal (9/7) wavelet filter. The architecture is modeled using Verilog HDL, simulated using ModelSim, synthesized using Xilinx ISE and finally implemented on Virtex-5 FPGA. The proposed 3-DDWT architecture has slice register utilization of 5%, operating frequency of 396 MHz and a power consumption of 0.45 W.

Very Low Bit-Rate Video Coding Based on Wavelet Transform

Two video coding schemes based on wavelet transform achieving very low bit rate are presented in this paper. The first is a hybrid motion compensated wavelet transform(MC WT)system which behaves better at very low bit rates than the block DCT residual coder. The second is a new efficient coding system based on a simple frame differencing wavelet transform(FD WT)which performs well in both PSNR and visual quality with substantially reduced complexity.

AN ALGORITHM FOR CODING VIDEO SIGNAL BASED ON 3-D WAVELET TRANSFORMATION

This paper presents an algorithm for coding video signal based on 3-D wavelet transformation. When the frame order t of a video signal is replaced by order 2, the video signal can be looked as a block in 3-D space. After splitting the block into smaller sub-blocks, imitate the method of 2-D wavelet transformation for images, we can transform the sub-blocks with 3-D wavelet. Most of video signal energy is in the decomposed low-frequency sub-bands. These sub-bands affect the visual quality of the video signal most. Quantizing different sub-bands with different precision and then entropy encoding each sub-band, we can eliminate inter- and intra-frame redundancy of the video signal and compress data. Our simulation experiments show that this algorithm can achieve very good result.

Flexible three-band motion-compensated temporal filtering for scalable video coding

A novel scheme for scalable video coding using three-band lifting-based motion-compensated transform is presented in this article. A series of flexible three-band motion-compensated lifting steps are used to implement the temporal wavelet transform, which provide improved compression performance by selecting specific motion model according to real video sequences, and offer higher temporal scalability flexibility by using three-band lifting steps. The experimental results compared with motion picture expert group （MPEG）-4 codec concerning standard video sequences demonstrate the effectiveness of the method.

A Video Coding Algorithm Based on Intraframe and Interframe Joint Prediction of Wavelet Coefficients

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Three-dimensional quantum wavelet transforms

Wavelet transform is being widely used in the field of information processing.One-dimension and two-dimension quantum wavelet transforms have been investigated as important tool algorithms.However,three-dimensional quantum wavelet transforms have not been reported.This paper proposes a multi-level three-dimensional quantum wavelet transform theory to implement the wavelet transform for quantum videos.Then,we construct the iterative formulas for the multi-level three-dimensional Haar and Daubechies D4 quantum wavelet transforms,respectively.Next,we design quantum circuits of the two wavelet transforms using iterative methods.Complexity analysis shows that the proposed wavelet transforms offer exponential speed-up over their classical counterparts.Finally,the proposed quantum wavelet transforms are selected to realize quantum video compression as a primary application.Simulation results reveal that the proposed wavelet transforms have better compression performance for quantum videos than two-dimension quantum wavelet transforms.

整数(5,3)小波变换结合SPIHT的无损图像压缩

讨论了整数(5,3)小波变换的构造方法,在此基础上提出了一种整数(5,3)小波与SPIH T以及自适应编码相结合的无损图像压缩编码方法,该方法运算速度快,硬件实现简单,实验结果表明,与其他的无损压缩方法相比,压缩比均有提高,是一种有效的无损图像压缩方法。

SPIHT图像编码算法研究及改进

提出一种改进的SPIHT算法，通过避免对部分重要系数的冗余扫描、采用更小的初始根节点子集以及对原始图像进行偏移处理，明显提高编码效率。实验结果表明，与标准SPIHT算法相比，本改进算法在不同码率下重构图像的PSNR提高了约0．3—6db。

基于3D-SPIHT的立体视频图像压缩编码

该文提出一种新的立体视频编码方案:在辅助序列中进行视差补偿预测和三维等级数集合分区(3D-SPIHT)编码,3D-SPIHT算法建立在真三维小波分解基础上,通过定义一种新的时空方向树结构,实现了静止图像SPIHT算法的三维扩展,实验结果表明该方案的编码性能略高于传统方案,具有较低的计算复杂度,所产生的嵌入式辅助序列码流,可根据通道带宽自适应调整输出码率,最大限度地提高辅助序列的质量。

无链表SPIHT图像提升小波编码的硬件算法

为了解决小波零树编码算法中,SPIHT(分级树的集合分裂)算法占用大量存储空间的问题,给出了一种无链表SPIHT图像压缩算法.在这种算法中,小波系数按照SPIHT的顺序输入到编码器中,编码器按照NLS算法编码,小波变换采用9/7提升分解算法,量化算法为均匀标量量化,图像边界延拓采用了补零延拓方法.实验结果表明,该算法图像压缩比与JPEG2000的EBCOT(基于优化截断的嵌入式块编码)算法几乎相同,编码速度大约是后者的2倍,一幅512×512的图像仅需要17.875KB额外内存.

基于二进制小波变换和改进SPIHT算法的图像编码方法

提出了一种基于二进制小波变换和改进SPIHT算法的图像编码方法.二进制小波变换将图像从实数域变换到实数域,消除像素之间的空间冗余性,得到了具有整数准确度的紧致描述.针对传统SPIHT算法解码图像视觉效果差的缺点,提出了改进方法.根据图像分析结果,将二进制小波变换变换系数按视觉重要性重新排序,通过对视觉重要系数优先编码,把量化误差集中在视觉不敏感区域,从而在不影响编码率失真性能的同时,有效地提高了解码图像的视觉效果.实验结果表明,和其它流行的编码算法相比,本文算法对不同性质的图像具有最优的编码性能和视觉效果.

整数CDF(2,2)双正交小波变换结合SPIHT的无失真图像压缩

讨论了整数CDF(2,2)可逆双正交小波变换,该方法可以由加法和移位完成,所以运算速度快,便于硬件实现该方法与SPIHT以及熵编码相结合可以实现无失真图像压缩,与ARJ、JPEG、整数Haar变换结合DPCM中使用的无失真编码方法相比,压缩比分别平均提高了40%、30%、15%左右。

基于混合域的改进SPIHT图像编码算法

为使图像压缩编码算法同时具有较高的压缩比和较好的图像复原质量,提出了一种基于Contourlet与小波变换的混合域图像编码方案,并在分析SPIHT算法的基础上进一步改进,取消了SPIHT算法中对LIS表的分类,统一按照先子代后孙代的小波空间树顺序进行编码。仿真实验结果表明,提出的混合域图像压缩编码方案是一种高效的数字图像压缩算法,与SPIHT算法相比,该算法的重建图像具有更好的视觉效果,而且提高了编码速度。

一种SPIHT编码和运动补偿相结合的可扩展视频压缩算法

提出了一种 SPIHT(set partition in hierarchical trees)编码和分块运动补偿相结合的视频压缩算法 ,适用于视频监控、视频会议、可视电话等许多视频图像的运动范围较小的场合。该算法具有如下 3个特点 :一是采用基于最低码率的自适应算法 ,实现了波动带宽下编码端和解码端参考帧的一致性 ;二是采用对预测残差帧的小波压缩编码 ,进一步增加了残差图的零像素数量 ,从而获得了更高的压缩比 ;三是采用了 SPIHT多级树集合分裂算法 ,实现了码率的可扩展性 ,能适应波动带宽和不同性能接受端的需要。运用本文提出的算法 ,能进一步提高视频编码的压缩比和解码复原质量。实验结果表明 ,本算法对于运动范围较小的视频序列 Akiyo,具有很高的压缩比和较好的复原质量 ,在 2 7kbps带宽下 ,压缩比可达 35 5∶ 1,相应的 PSNR(Y) =36 .33d B,PSNR(U) =4 0 .2 2 d B,PSNR(V) =4 2 .5 2 d B;对于运动范围较大的 Singer序列 ,本算法与 MPEG- 4校验模型相比 ,性能相差不大。此外 ,在最大码率下 ,本算法的 PSNR(Y)比 MPEG- 4校验模型平均提高约 4 .0 d

改进的多级树集合分裂(SPIHT)算法

基于中频和高频子带小波系数中的不重要数的相关性,对SPIHT算法提出一些改进.在改进SPIHT算法中,利用一个组合函数来减少相应位置中频子带的不重要小波系数的冗余.构造集合d来减少高频子带带间的冗余.实验结果表明,改进SPIHT算法相对于改进前SPIHT算法有理想的压缩效果,峰值信噪比和人眼视觉效果都有所提高.