Detection of radial frequency motion trajectories

Increment thresholds for radial frequency trajectories produce a dipper function

Radial frequency (RF) trajectories are a new class of stimuli that have been developed to study the visual perception of periodic motion (Or et al., 2011). These stimuli are described by a moving dot that traces a distorted path through space with periodic radial deformations whose frequency, amplitude, and phase can be independently specified. Here, we extend Or et al.'s findings by investigat...

Global shape coding for motion-defined radial-frequency contours

The visual system is highly skilled at recovering the shape of complex objects defined exclusively by motion cues. But while low-level and high-level mechanisms involved in shape-from-motion have been studied extensively, intermediate computational stages remain poorly understood. In the present study, we used motion-defined radial-frequency contours--or motion RFs--to probe intermediate stages...

Local motion effects on form in radial frequency patterns.

Sinusoidal modulation of radial speed around a circular path of tangentially oriented Gabor patches results in the percept of modulation of the radius. These patterns have been called motion radial frequency (RF) patterns. Sensitivity to these patterns has been attributed to global summation of local speed by mechanisms, analogous to those proposed to explain sensitivity to spatial RF patterns,...

Detection and Generalization of Spatio-temporal Trajectories for Motion Imagery

Motion trajectories

In this paper, we present a simple algorithm for selecting and linking interesting ow vectors across a sequence of frames for computing motion trajectories. We track tokens which have both interesting pixel gray values in the spatial domain and in the optical ow eld in the temporal domain. This and operation eeectively remove some redundant trajectories. Due to errors introduced during the comp...