Intrackability: Characterizing Video Statistics and Pursuing Video Representations
Intrackability: Characterizing Video Statistics and Pursuing Video Representations
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Intrackability：表征视频统计并追求视频表示
DOI：
10.1007/s11263-011-0486-3
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发表时间：
2011-09
影响因子：
19.5
通讯作者：
Song Chun Zhu
中科院分区：
文献类型：
--
作者：
Haifeng Gong;Song Chun Zhu
自然环境的视频包含各种各样的运动模式，其复杂性不同，在视觉文献中由许多不同的模型表示。在许多情况下，跟踪算法被公式化为最大化后验概率。在本文中，我们提出了衡量视频复杂性的熵后验概率，称为可插入性，表征视频统计和追求最佳的视频表示。基于可插入性的定义，我们的研究旨在三个目标。首先，我们通过可插入性来表征自然场景的视频片段。我们计算图像点的可插入性来度量局部推理的不确定性，并收集视频在空间和时间上的可插入性直方图作为全局视频统计。我们发现，基于可插入性直方图的前两个主成分的PCA散点图可以反映主要变化，即，图像缩放和对象密度，在自然的视频剪辑。其次，我们表明，不同的视频表示，包括可变形轮廓，跟踪内核与各种外观特征，密集的运动场，和动态纹理模型，连接的变化intrackability，从而开发一个简单的标准模型过渡和追求最佳的视频表示。第三，推导了可插入性测度与Shi-Tomasi纹理测度、条件数、Harris-StephensRscore之间的关系，并在跟踪实验中与Shi-Tomasi测度进行了比较。
Videos of natural environments contain a wide variety of motion patterns of varying complexities which are represented by many different models in the vision literature. In many situations, a tracking algorithm is formulated as maximizing a posterior probability. In this paper, we propose to measure the video complexity by the entropy of the posterior probability, called the intrackability, to characterize the video statistics and pursue optimal video representations. Based on the definition of intrackability, our study is aimed at three objectives. Firstly, we characterize video clips of natural scenes by intrackability. We calculate the intrackabilities of image points to measure the local inferential uncertainty, and collect the histogram of the intrackabilities over the video in space and time as the global video statistics. We find that a PCA scatter-plot based on the first two principle components of intrackability histograms can reflect the major variations, i.e., image scaling and object density, in natural video clips. Secondly, we show that different video representations, including deformable contours, tracking kernels with various appearance features, dense motion fields, and dynamic texture models, are connected by the change of intrackability and thus develop a simple criterion for model transition and for pursuing the optimal video representation. Thirdly, we derive the connections between the intrackability measure and other criteria in the literature such as the Shi-Tomasi texturedness measure, conditional number, and Harris-StephensRscore, and compare with the Shi-Tomasi measure in tracking experiments.