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.

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

In this work, a new method to deal with the unconnected pixels in motion compensated temporal filtering (MCTF) is presented, which is designed to improve the performance of 3D lifted wavelet coding. Furthermore, multiple description scalable coding (MDSC) is investigated, and novel MDSC schemes based on 3D wavelet coding are proposed, using the lifting imple- mentation of temporal filtering. The proposed MDSC schemes can avoid the mismatch problem in multiple description video coding, and have high scalability and robustness of video transmission. Experimental results showed that the proposed schemes are feasible and adequately effective.

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.

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.

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.

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.

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.

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.

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.

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.

MULTI-RESOLUTION MOTION ESTIMATION AND COMPENSATION BASED ON ADJACENT PREDICTION OF FRAME DIFFERENCE IN WAVELET DOMAIN

Aiming at the higher bit-rate occupation of motion vector encoding and more time load of full-searching strategies, a multi-resolution motion estimation and compensation algorithm based on adjacent prediction of frame difference was proposed.Differential motion detection was employed to image sequences and proper threshold was adopted to identify the connected region.Then the motion region was extracted to carry out motion estimation and motion compensation on it.The experiment results show that the encoding efficiency of motion vector is promoted, the complexity of motion estimation is reduced and the quality of the reconstruction image at the same bit-rate as Multi-Resolution Motion Estimation(MRME) is improved.

码率可分级小波视频编码算法的研究

对于多种视频传输业务,传统的分层可分级性已不能很好地满足要求,编码器需要提供码率可分级性.采用改进的零树小波编码算法生成了高性能的嵌入式码流,实现了一个码率可分级视频编解码器.而在码率可分级编解码算法中,同一码流需要在较大的码率范围内保持编码效率.目前的解决方案在目标码率提高时,重建图像的质量得不到有效的改善.指出了码率可分级编码算法不仅要考虑误差扩散问题,还要考虑帧间依赖关系,并提出了一种新的算法.实验结果表明,该算法使同一码流能在多种码率下提供更好的重建图像的质量,而且所提算法可用于其他采用运动补偿算法降低时间冗余的码率可分级编解码器中.

基于小波变换的点量化图像编码算法

首先扼要介绍小波理论 ,分析小波变换的统计特性和重要系数的分布特点 ,着重对几种最具代表性和生命力的点量化图像编码算法进行详细的论述 ,并对它们进行比较 ;然后 ,重点讨论基于时间轴小波变换的视频分割算法在视频图像编码上的应用 ,提出今后研究的方向 .

基于三维子波变换和分级零树扫描的视频编码算法研究

本文研究了三维子波变换和分级三维零树混合视频编码算法，对图像序列体作３层２２子带时空分解后，再对最低频子带进行４子带空间分解．对这个特殊分解的三维子波结构，推广了零树的概念．用ＨＶＳ量化模型对子波系数施加量化，用分级三维零树表示量化后的２５带子波系数，这一方案比单级零树方法节省约６％的码率，并且实现了空间和时间可尺度化码流结构．

分布式视频编码虚拟依赖信道模型研究

视频信息固有的非平稳特性,如冲突区域等,使时域预测技术变得非常复杂.在分布式视频编码(DVC)中,由于解码端不能获取当前编码帧的信息,精确地对时域相关噪声进行建模变得更为困难.文中以虚拟依赖信道模型为切入点对如何降低时域相关噪声进行了研究.首先对DVC虚拟依赖信道进行了建模,并对影响边信息的主要因素进行了分析,分析结果表明在变换域中不同的频率子带对时域相关噪声的敏感度不同.在此基础上提出了一种新的基于小波变换域的虚拟依赖信道模型VCMDWT,基于分类编码的思想对较为平稳的LL子带进行Wyner-Ziv编码,对非平稳的高频子带进行SPIHT帧内编码.实验结果表明,与基于像素域的方法相比,所提出的VCMDWT模型能够得到更稳定的虚拟信道,提高DVC系统的率失真性能达到2.6dBs以上.

基于多线性子空间KL变换的可伸缩视频压缩方法

该文提出一种基于多线性子空间KL(Karhunen-Loeve)变换的可伸缩视频压缩算法。该算法将纹理不同的图像子块投影到多个线性子空间中去,然后分别进行KL变换编码,使得每个子空间内变换系数更接近高斯分布,从而最大限度地在变换编码阶段提高压缩效率。同时,该算法结合多尺度小波分解,实现了质量可伸缩的视频编码,提高了视频压缩率。通过与DCT、小波变换以及多向DCT算法进行比较,证明该算法可获得更好的率失真性能。

基于db2提升小波的可伸缩视频编码方法

给出了一种基于db2提升小波的可伸缩视频编码系统的总体方案,提出了采用db2提升小波实现MCTF的方法,并针对运动估计过程中像素点类型给出了高通帧和低通帧的计算方法。实验结果表明,本方案与基于Haar小波的可伸缩性视频编解码方案相比,完全重建的视频图像质量和抽取部分帧后重建的视频图像质量都有了明显提高。

一种新的小波域视频可分级运动估计方案

首先提出了一种运动估计方法MLBS（Modified Low Band Shift），并在此基础上提出了基于MLBS的小波域视频可分级运动估计方案MLBSSME．利用MLBS方法，提高了运动估计的准确度．借助重叠块运动补偿方法，有效降低了最高分辨率下解码图像的块效应．根据小波变换的多分辨率特性，利用缩小了的搜索窗口提高了搜索速度．这种方法可有效应用于空间可分级和数率可分级的视频编码器中．实验结果证明，对于多种类型的标准测试视频流，MLBSSME算法始终能保持很高的估计精度．利用该算法补偿得到的预测帧，其PSNR较之基于下层LL子带的分层运动估计方法和子带直接运动估计方法平均要高出1～3dB，而对于空间细节较简单的视频，其PSNR比LBS方法提高了0．5～1dB，并且算法的时空复杂度是LBS方法复杂度的30％～40％．