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基于GPU的视频编码和分割的研究
Alternative TitleResearch on Video Coding and Segmentation Based on GPU
朱立华
Subtype工学硕士
Thesis Advisor常红星
2003-06-01
Degree Grantor中国科学院研究生院
Place of Conferral中国科学院自动化研究所
Degree Discipline模式识别与智能系统
Keyword图形处理芯片 整数离散余弦变换 运动估计 视频分割 Graphical Processing Unit Inter-dct Motion Estimation Video Segmentation
Abstract视频编码和分割的主要任务是怎样改善编码和分割的效率。但是由于CPU(Central Processing Unit)性能及其它因素的限制,现在很多的视频分割和编码难以 达到多媒体服务的实时要求。根据图形处理芯片GPU(Graphic Processing Unit)的技 术发展和性能特点(支持整型运算、内部图形处理运算精度只有四分之一个精度), 论文提出了使用GPU和CPU相结合来改善视频编码和分割效率的方案,并分析了传 统的视频分割和视频编码的方法,探讨了如何找到适合GPU运算的算法,来完成视 频压缩编码和分割需要的视频对象。 本论文从GPU特点出发,提出了算法改进的指导思想:(1)用整型运算方法来替 代浮点运算方法,或者把部分CPU的整型运算转移到GPU上来:(2)以图像面而不是 以像素点来考虑问题。本文对基于GPU的视频编码和视频分割深入系统的研究,具 体的创新和研究成果如下: 一、本文在可变大小块四分树分割的基础上提出了一个基于对象的运动估计算 法。该算法根据图像边缘的特性,对图像的内容做适当的分析,将图像画面分割为静 止及运动物体的块,然后根据运动物体块的边缘特性分割出不同的区域,针对不同的 区域分别进行运动估计。实验表明,利用边缘特性做分割块的准则符合人类视觉系统 的特性,其重建的图像更接近人眼实际观看的品质。本论文的算法的速度和所预测出 来的图像的效果要优于目前的全局搜索法和可变四分树分割算法。 _二、根据GPU的运算精度低的特点,提出了一个提升方案修改变换系数,采用 舍入操作,把传统的离散余弦变换算法从线性变换转变为的整数变换,推导出一维整 数离散余弦变换算法和二维整数离散余弦变换算法,并采用整数离散余弦变换完成视 频编码工作。 三、在GPU与CPU相结合的视频分割算法研究方面,介绍了如何选择合适的色彩 空间,并结合基于对象的运动估汁,提出了一个时域上的分割算法,建立了一个有效 牢的统计模型来估计在运动状态下之可预测点;并详细描述了一个改进传统马尔可夫 随机场的空域分割模型,并且使用了图之间边与边的关系得到适合寻找最佳路径的权 值,提出了适合GPU运算的随机游动邻接矩阵算法。实验表明,相对传统的视频分割 算法与本文的算法错误概率较小,分割速度要快。
Other AbstractThe major task of the video coding and video segmentation technologies for multimedia applications is how to improve the coding and segmentation efficiency. However, because of the limitation of CPU (Central Processing Unit) and other reasons, most of video coding and segmentation technologies can not satisfy the real-time demanding of multimedia applications. This thesis is to solve these problems by using GPU (Graphical Processing Unit). But GPU only supports integer computation and the precision of pixel shader is very low, this thesis tries to solve this difficulty, and several new algorithms are proposed by combining GPU and CPU. According to the properties of GPU, our algorithms are directed by two bases: 1) Floating operations are replaced by integer operations, or integer operations on CPU are transferred to GPU; 2) CPU is processed pixel values in image processing, while GPU is processed the whole image surface. The main contributions of the thesis are as following.: The first part proposes a motion estimation algorithm based on the Variable Block-Size Quad-tree segmentation algorithm. The algorithm first obtains different regions by analyzing the object character and image edge character, and then gets motion vectors of different regions. Experimental results show the proposed algorithm not only agrees on the human visual system, but also the whole running speed and quality of the predicted image are better than those of full search algorithm and Variable Block-Size Quad-tree segmentation algorithm. The second part will discuss how to complete Discrete Cosine Transform (DCT) by GPU. Because the operation precision of GPU is very low, we improve traditional DCT algorithm and propose an Inter Discrete Cosine Transform algorithm by lifting scheming and rounding operation. First we introduce the theory fundament of integer DCT, and then propose one dimension DCT and two dimensions DCT algorithms. The third part is to propose a video segmentation algorithm combining GPU and CPU. Firstly, we introduce how to select appropriate color space, and then discuss the time-domain segmentation algorithm based on object motion estimation. In the end, we propose a spatial-domain algorithm based on Markov Random Field and Graph model. Experimental results show the proposed technology not only has the small error probability but also has high coding efficiency.
shelfnumXWLW707
Other Identifier707
Language中文
Document Type学位论文
Identifierhttp://ir.ia.ac.cn/handle/173211/6790
Collection毕业生_硕士学位论文
Recommended Citation
GB/T 7714
朱立华. 基于GPU的视频编码和分割的研究[D]. 中国科学院自动化研究所. 中国科学院研究生院,2003.
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