Recovering slant and angular velocity from a linear velocity field: modeling and psychophysics.
The data from two experiments, both using stimuli simulating orthographically rotating surfaces, are presented, with the primary variable of interest being whether the magnitude of the simulated gradient was from expanding vs. contracting motion. One experiment asked observers to report the apparent slant of the rotating surface, using a gauge figure. The other experiment asked observers to report the angular velocity, using a comparison rotating sphere. The results from both experiments clearly show that observers are less sensitive to expanding than to contracting optic-flow fields. These results are well predicted by a probabilistic model which derives the orientation and angular velocity of the projected surface from the properties of the optic flow computed within an extended time window.
Domini
Fulvio
F
Department of Cognitive and Linguistic Sciences, Brown University, P.O. Box 1978, Providence, RI 02912, USA. fulvio_domini@brown.edu
Caudek
Corrado
C
D003867:Depth Perception / Q000502:physiology*; D006801:Humans; D009039:Motion Perception / Q000502:physiology; D009949:Orientation; D011601:Psychophysics / Q000379:methods; D014792:Visual Acuity / Q000502:physiology