@conference {14168, title = {Global rigidity constraints in image displacement fields}, booktitle = {, Fifth International Conference on Computer Vision, 1995. Proceedings}, year = {1995}, month = {1995/06/20/23}, pages = {245 - 250}, publisher = {IEEE}, organization = {IEEE}, abstract = {Image displacement fields-optical flow fields, stereo disparity fields, normal flow fields-due to rigid motion possess a global geometric structure which is independent of the scene in view. Motion vectors of certain lengths and directions are constrained to lie on the imaging surface at particular loci whose location and form depends solely on the 3D motion parameters. If optical flow fields or stereo disparity fields are considered, then equal vectors are shown to lie on conic sections. Similarly, for normal motion fields, equal vectors lie within regions whose boundaries also constitute conics. By studying various properties of these curves and regions and their relationships, a characterization of the structure of rigid motion fields is given. The goal of this paper is to introduce a concept underlying the global structure of image displacement fields. This concept gives rise to various constraints that could form the basis of algorithms for the recovery of visual information from multiple views}, keywords = {3D motion parameters, algorithms, Automation, Computer science, Computer vision, conic sections, curves, equal vectors, Fluid flow measurement, global geometric structure, global rigidity constraints, image displacement fields, Image motion analysis, Image segmentation, Image sequences, imaging surface, Laboratories, Layout, Motion estimation, Motion measurement, motion vectors, multiple views, normal flow fields, optical flow fields, regions, rigid motion, stereo disparity fields, Stereo vision, vectors, visual information recovery}, isbn = {0-8186-7042-8}, doi = {10.1109/ICCV.1995.466779}, author = {Ferm{\"u}ller, Cornelia and Aloimonos, J.} }