Articulation-Invariant Representation of Non-planar Shapes
Articulation-Invariant Representation of Non-planar Shapes
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DOI：
10.1007/978-3-642-15558-1_21
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发表时间：
2010-09
期刊：
影响因子：
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通讯作者：
Raghuraman Gopalan;P. Turaga;R. Chellappa
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文献类型：
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作者：
Raghuraman Gopalan;P. Turaga;R. Chellappa
给定与非平面形状的2D投影相对应的一组点，我们希望获得不随关节而变化的表示(在无自遮挡的情况下)。这是一个具有挑战性的问题，因为我们需要考虑由于3D关节、视点变化而导致的2D形状的变化，以及由于其非平面性导致的成像过程对形状不同区域的不同影响。通过将关节形状建模为由非凸连接连接的近似凸部分的组合，我们提出通过(I)通过近似凸分解来估计形状部分，通过引入稳健的凸度量来估计形状部分，以及(Ii)通过假设弱透视摄像机模型来执行部分仿射归一化，然后使用对平面关节不敏感的内部距离来关联点之间的距离。我们在具有非平面结构的数据集和标准形状检索数据集(如MPEG7)上演示了该表示的有效性。
Given a set of points corresponding to a 2D projection of a non-planar shape, we would like to obtain a representation invariant to articulations (under no self-occlusions). It is a challenging problem since we need to account for the changes in 2D shape due to 3D articulations, viewpoint variations, as well as the varying effects of imaging process on different regions of the shape due to its non-planarity. By modeling an articulating shape as a combination of approximate convex parts connected by non-convex junctions, we propose to preserve distances between a pair of points by (i) estimating the parts of the shape through approximate convex decomposition, by introducing a robust measure of convexity and (ii) performing part-wise affine normalization by assuming a weak perspective camera model, and then relating the points using the inner distance which is insensitive to planar articulations. We demonstrate the effectiveness of our representation on a dataset with non-planar articulations, and on standard shape retrieval datasets like MPEG-7.