Estimating time to contact with curves, avoiding calibration and aperture problem
A set of simple time to contact estimators are derived, using isolated points or curve segments. For this purpose the use of both optic flow and optic acceleration is suggested. For curves it is pointed out, that there is no aperture problem present, since normal flow and acceleration of the curve segment is sufficient for estimating time to contact. Time to contact with a curve segment may be calculated without calibrating camera focal length and camera coordinate system, without computing spatial velocity and depth maps and without computing the complete optic flow field for the curve segment. Computational illustrations with actual camera data are reported.
Unable to display preview. Download preview PDF.
- Arnspang, J.: Optic Acceleration. Proceedings of 2nd International Conference on Computer Vision, Tampa (1988), 364–373.Google Scholar
- Ballard, D. H. and Brown, C. M.: Computer Vision. Prentice Hall, (1982).Google Scholar
- Cipolla, R. and Blake, A.: Surface Orientation and Time to Contact from Image Divergence and Deformation. Proceedings of 2nd European Conference on Computer Vision, Genoa, Italy (1992), 187–202.Google Scholar
- Horn, B. K. P.: Robot Vision, MIT Press (1986).Google Scholar
- Hummel, R.: Estimating Time to Contact. Research symposium on Utrecht Biophysics Research Institute, June (1991), (Oral presentation).Google Scholar
- Koenderink, J. J. and van Doom, A. J.: Invariant Properties of the Motion Parallax Field due to the Movement of Rigid Bodies Relative to an Observer. Optica Acta 22, (1975), 773–791.Google Scholar
- Koenderink, J. J.: Local Structure of Movement Parallax of the Plane. Journal of the Optical Society of America (66). July (1976), 717–723.Google Scholar
- Waxman, A. M. and Wohn, K.: Image Flow Theory. In Advances of Computer Vision, ed. C. Brown. Erlbaum Publishers, (1986).Google Scholar