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- Kahl, Fredrik, et al.
(författare)
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Motion Estimation in Image Sequences Using the Deformation of Apparent Contours
- 1998
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Ingår i: Proceedings of IEEE 6th International Conference on Computer Vision. - 81 7319 221 9 ; , s. 939-942
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Konferensbidrag (refereegranskat)abstract
- The problem of determining the camera motion from apparent contours or silhouettes of curved three-dimensional surfaces is considered. In a sequence of images is shown how to use the generalized epipolar constraint on apparent contours. One such constraint is obtained for each epipolar tangency point in each image pair. Thus in theory the motion can be calculated from the deformation of a single contour. A robust algorithm for computing the motion is presented based on the maximum likelihood estimate. It is shown how to generate initial estimates on the camera motion using only the tracked contours. It is also shown how to improve this estimate by maximizing the likelihood function. The algorithm has been tested on real image sequences. The result is compared to that of using only point features. The statistical evaluation shows that the technique gives accurate and stable results
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- Kahl, Fredrik, et al.
(författare)
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Structure and Motion from Points, Lines and Conics with Affine Cameras
- 1998
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Ingår i: [Host publication title missing]. - 3 540 64569 1 ; 1, s. 327-341
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We present an integrated approach that solves the structure and motion problem for affine cameras. Given images of corresponding points, lines and conics in any number of views, a reconstruction of the scene structure and the camera motion is calculated, up to an affine transformation. Starting with three views, two novel concepts are introduced. The first one is a quasi-tensor consisting of 20 components and the second one is another quasi-tensor consisting of 12 components. These tensors describe the viewing geometry for three views taken by an affine camera. It is shown how correspondences of points, lines and conics can be used to constrain the tensor components. A set of affine camera matrices compatible with the quasi-tensors can easily be calculated from the tensor components. The resulting camera matrices serve as an initial guess in a factorisation method, using points, lines and conics concurrently, generalizing the well-known factorisation method by Tomasi-Kanade (1992). Finally, examples are given that illustrate the developed methods on both simulated and real data
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- Kahl, Fredrik, et al.
(författare)
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Using Conic Correspondences in Two Images to Estimate the Epipolar Geometry
- 1998
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Ingår i: Sixth International Conference on Computer Vision (IEEE Cat. No.98CH36271). - 81 7319 221 9 ; , s. 761-766
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this paper it is shown hour corresponding conics in two images can be used to estimate the epipolar geometry in terms of the fundamental/essential matrix. The corresponding conics can, be images of either planar celtics or silhouettes of quadrics. It is shown that one conic correspondence gives two independent constraints on the fundamental matrix and a method to estimate the fundamental matrix from at least four corresponding conics is presented. Furthermore, a new type of fundamental matrix for describing conic correspondences is introduced. Finally, it is shown that the problem of estimating the fundamental matrix from 5 point correspondences and 1 conic correspondence in general has 10 different solutions. A method to calculate these solutions is also given together with an experimental validation
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