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立体图像客观质量评价与压缩技术研究

Research on Objective Quality Evaluation and Coding Algorithm of Stereo Image

【作者】 杨嘉琛

【导师】 侯春萍;

【作者基本信息】 天津大学 , 通信与信息系统, 2009, 博士

【摘要】 立体图像可以记录真实的三维世界信息,使观众产生身临其境的视觉感受,具有广阔的应用前景。目前,立体图像技术已经成功用于科研、军事、教育、工业、医疗等诸多领域,取得了丰硕的成果。它已经成为当今科学工作者研究的热点问题之一。本文主要从以下几个方面对立体成像技术进行了理论分析与实验研究。首先,为了更好的研究立体技术,本文基于现代医学对立体视觉研究、实验的结果,分析了人眼视觉特性,首次提出了一种基于人眼视觉特性的双眼立体视觉模型。通过对模型的研究提取出了一些影响人类立体感的参数,这些参数是研究立体图像客观质量评价与压缩编码的基础与依据。第二,为了给立体图像压缩研究提供有效快捷评价手段,本文先用实验证明绝对视差图对立体感的影响,并结合人类生理心理立体视觉、平面图像客观评价与绝对视差图,率先给出一种立体图像客观质量评价方法。该方法从图像质量与立体感两个方面对立体图像进行评价。经实验证明用本文提出客观评价方法对立体图像进行评估,其评价结果与通用主观评价方法得到的评价结果一致性较好。第三,本文还提出一种双视点立体图像压缩编码算法。该算法以特征点视差估计与三角网格映射为基础。为了保持压缩后视点对的视差不发生变化,本算法创造性地利用绝对视差图进行特征点选取,实验结果表明解码后的立体图像对立体感较好。进行残差图像编码时,该算法结合了心理立体视觉影响、人眼亮度色度特性、立体图像对色度特点与三角网格映射特点等因素,提出了立体残差编码只需对Y分量进行的方法。实验证明该算法具有一定的优越性,如压缩比大,图像质量与立体感均较好。同时,本文还提出了将双视点立体图像压缩编码扩展为多视点压缩编码算法,并给出了编码方案,并提出了一种立体图像中间视点的生成方法。实验证明,用本文提出的方法可以借助双视点立体图像对得到四视点立体图像组,且立体感几乎没有损失。最后,本文开发了基于DM6446处理器的立体电视硬件实验平台用于支持本文所提出方法及算法的验证。该平台除了能为各种立体图像算法的实验验证提供了支持之外,还能解决了立体电视小型化的问题。该平台包含了立体电视所需要的各类硬件接口,最高可以支持每秒60幅分辨率为1600×1200(或1920×1080)的图像输出,输出采用全数字DVI接口,输出速率达1.65Gbps。硬件平台集成了Linux操作系统,实现了所有硬件驱动程序,并移植了X窗口图形桌面。

【Abstract】 Stereo image can record the real information of the world and provide more natural visual sensation than the traditional plane image, so it has more bright applicable future. At present, the stereo image technology has been applied to many fields successfully, such as scientific research, military, education, industry, medication and so on. It has become one of the hottest issues that the scientists are studying on. This paper on stereo technology has done the theoretical analysis and experimental research from the following aspects:Firstly, to do better research on strereo technology, after analysis of the human visual feature, this paper originally proposes stereo visual model based human visual feature, which is based on the results of the research and experimemnts of stereo visual from the perspective of modern medical science. Then select several parameters that influence the human stereo perceive from the study of the model, which provide as the basis and evidence of the research on the stereo image objective quality assessment and coding.Secondly, to persent an effective and convenient assessment approach, this paper demonstrates the significance of the absolute disparity image to the stereo perceive. Combined with human physical and psychological stereo vision, plane image objective evaluation and absolute disparity image, this paper originally proposes a stereo image objective assessment method. This method evaluates stereo image from both the quality of the image and the stereo perceive. Experiments demonstrate that this method performs satisfactorily on the assessment of the stereo image, and the results of the objective assessment show strong correlation with the results of the subjective one.Thirdly, this paper also proposes a double-perspective stereo image coding algorithm, based on disparity estimate of feature points and triangle mesh mapping. To maintain the disparity of two view-points after coding, this algorithm originally extracts feather points with the absolute disparity image, and experiments indicate the decoded stereo image make a good stereo perceive. When coding from the residual pictures, this algorithm proposes the method that only conducting stereo residual coding in Y vector based on the influence of the psychological stereo perceive, luminance and tint feature of human eyes, the tint feature of the stereo image pair and feature of the triangle mesh mapping etc. Experiments demonstrate the advantage of the algorithm: the compression ratio is large, and the quality and stereo perceive of the stereo image are good. This paper also extends double-view stereo image coding to multi-view coding algorithm and provides the coding strategy. At the same time, this paper proposes a novel method to generate new stereo image view and the experiments manifest that this method can generate quadri-view stereo image from double-view stereo image, which have strong stereo perceive.At last, this paper developes a stereo TV hardware developing experimental platform based DM6446 processor, which provides supported hardware to the stereo image experiment and gives a solution to the utility of stereo TV as well. The platform concludes all the hardware interfaces that stereo TV needed, and can support a maximum output of 60 images with a resolution of 1600×1200(or1920×1080)per second. The output adopts digital DVI interface, and can reach a velocity of 1.65Gbps. The hardware platform integrates Linux operation system, develops all the hardware drive programs, and transplants X windows graphical desktop at the same time.

  • 【网络出版投稿人】 天津大学
  • 【网络出版年期】2010年 12期
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