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This article presents a model-based approach for nonrigid object motion and deformation analysis from 3D data. The modeling primitives used in this research are the superquadrics, which have already been proven useful in describing a variety of natural and man-made objects. This model-based approach is not only in accordance with the human visual perception process but also able to decouple the large and unstructured nonrigid motion estimation system into simple and well structured subsystems. We develop a recursive algorithm for estimating global motion and object shape, which effectively incorporates a priori knowledge of the object into the estimation procedure and obtains a good estimate of the global motion and object shape even if the given 3D points are distributed bias. After compensating for the global motion of the object, a tensor model of local deformation is introduced and a spherical harmonic surface-fitting algorithm is described such that the localized deformations of the object surface can be characterized. The local deformations of the object are then estimated using tensor-description-based analysis and parametrized by the directions and magnitudes of the extreme deformations in a localized surface element. To illustrate the potential of this model-based approach for nonrigid motion analysis, a real data example is presented using the proposed approach. This example involves estimating the left ventricle motion and deformations from a time sequence of 3D coordinates of coronary artery bifurcation points. The estimation results show the success of the model-based approach even when the given bifurcation points are distributed only on half of the left ventricle surface. [ABSTRACT FROM AUTHOR]

We explain that the task of multiple rigid motion segmentation and estimation from image feature point correspondences demands an estimator of high robustness. We show that a heuristics-based partial modeling approach can be used to develop a highly robust estimator called the MF estimator for general regression, where ‘MF’ represents an abbreviation of Model Fitting. Finally, we provide experimental results in estimating single rigid motion from a mixture of 2D-2D (or image-image), 3D-2D (or range-image), and 3D-3D (or range-range) corresponding point data by using the proposed MF estimator. As will be seen. only four well matched corresponding point pairs are needed to get a good estimate of motion parameters no matter how m(my mismatched corresponding point pairs (or outliers) occur. The article represents an initial effort towards robust image-motion analysis. [ABSTRACT FROM AUTHOR]