Cheirality Richard

Cheirality Invariants

It is known that a set of points in 3 dimensions is determined up to projectivity from two views with uncalibrated cameras. It is shown in this paper that this result may be improved by distinguishing between points in front of and behind the camera. Any point that lies in an image must lie in front of the camera producing that image. Using this idea, it is shown that the scene is determined fr...

Cheirality in Epipolar Geometry

The image points in two images satisfy epipolar constraint. However, not all sets of points satisfying epipolar constraint correspond to any real geometry because there can exist no cameras and scene points projecting to given image points such that all image points have positive depth. Using the cheirality theory due to Hartley and previous work on oriented projective geometry, we give necessa...

Calibration with Robust Use of Cheirality by Quasi-Affine Reconstruction of the Set of Camera Projection Centres

A method for upgrading a projective reconstruction to metric is presented. The reconstruction is first transformed by considering cheirality so that the convex hull of the set of camera projection centres is the same as in the metric counterpart. The method then proceeds iteratively and starting from such a reconstruction is a necessary condition for many iterative calibration algorithms to con...

Refinement in 3D Reconstruction using Cheirality Constraints

The problem of 3D reconstruction has become more and more important with the increase in demands from virtual reality, visualization, security and biomedical industries. Uncalibrated reconstruction, from a set of images taken from any ordinary CCD camera, is complicated and difficult due to the presence of non-linear constraints on the scene. Any linear solution suffers from numerical instabili...

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