Showing papers by "David J. Heeger published in 1988"

Optical flow using spatiotemporal filters

Abstract: A model is presented, consonant with current views regarding the neurophysiology and psychophysics of motion perception, that combines the outputs of a set of spatiotemporal motion-energy filters to estimate image velocity. A parallel implementation computes a distributed representation of image velocity. A measure of image-flow uncertainty is formulated; preliminary results indicate that this uncertainty measure may be used to recognize ambiguity due to the aperture problem. The model appears to deal with the aperture problem as well as the human visual system since it extracts the correct velocity for some patterns that have large differences in contrast at different spatial orientations.

Egomotion And The Stabilized World

Abstract: This paper formulates the tasks of moving-object detection and motion-based depth recovery as a problem of sensor fusion in the presence of uncertainty. We utilize two sensor systems, one providing information about the local image velocity (spsecifying a point in image-velocity space), and the othter providing information about the camera motion (specifying a line segment in image-velocity space). 1Ne utilize Mahalanobis distance as a threshold rule for determining consistency between the measurements from the two sensor systems. We also suggest a framework for using the resulting segmented flow field to update estimates of the egomotion parameters.