Movement Detectors of the Correlation Type Provide Sufficient Information for Local Computation of the 2-D Velocity Field
The projection of the velocity vectors of objects moving in three-dimensional space on the image plane of an eye or a camera can be described in terms of a vector field. This so-called 2-D velocity field is time-dependent and assigns the direction and magnitude of a velocity vector to each point in the image plane. The 2-D velocity field, however, is a purely geometrical concept and does not directly represent the input site of a visual information processing system. The only information available to a visual system is given by the time-dependent brightness values as sensed in the image plane by photoreceptors or their technical equivalents. From spatio-temporal coherences in these changing brightness patterns motion information is computed. This poses the question about whether the spatio-temporal brightness distributions contain sufficient information to calculate the correct 2-D velocity field. Here we show that the 2-D velocity field generated by motion parallel to the image plane can be computed by purely local mechanisms.
Unable to display preview. Download preview PDF.
- 1.Horn, B.K.P.: Robot Vision. MIT Press, Cambridge, Mass., 1987 )Google Scholar
- 5.Koch, C.: In Neural Computers, ed. R. Eckmiller, Ch. von der Malsburg (Springer, Berlin, Heidelberg 1988 ) p. 101Google Scholar
- 7.Movshon, J.A., D.H. Adelson, M.S. Gizzi, W.S. Newesome: In Pattern Recognition Mechanisms, ed.C. Chagas, R. Gattass, C. Gross (Springer, Berlin, Heidelberg, New York, Tokyo 1985 ) p. 117Google Scholar
- 8.Hassenstein, B., W. Reichardt: Naturforsch. 11b, 513 (1956)Google Scholar
- 9.Reichardt, W.:In Principles of Sensory Communication, ed W.A. Rosenblith ( John Wiley, New York 1961 ) p. 303Google Scholar
- 10.van Doorn, A.J., J.J. Koenderink: Exp.Brain.Res. 45, 179 (1982)Google Scholar
- 11.van Doorn, A.J., J.J. Koenderink: ibid. 45, 189 (1982)Google Scholar
- 14.Reichardt, W., A. Guo: ibid. 53, 285 (1986)Google Scholar
- 17.Reichardt, W., R.W. Schlögl: in preparation (1988)Google Scholar
- 18.Courant, R., D. Hilbert: Methods of Mathematical Physics, Vol.II (Interscience Publishers, New York, London 1962)Google Scholar
- 19.Ballard, D.H., C.M. Brown: Computer Vision. (Prentice-Hall, Inc., Englewood Cliffs, New Jersey 1982 )Google Scholar