Binocular Disparity Energy, Gabor Filter,
This binocular disparity energy (BDE) model has linear spatial filters that are
3-D Gabor functions (Gaussian times sinusoid) and a Gaussian temporal filter.
This model combines the spatial filter model described by Ohzawa et al (1990)
with a temporal filter to generate direction selective responses.
- Ohzawa I, DeAngelis GA, Freeman RD (1990) Stereoscopic Depth Discrimination
in the Visual Cortex: Neurons Ideally Suited as Disparity Detectors. Science 239:1047-1051.
- Adelson EH, Bergen JR (1985) Spatiotemporal energy models for the
perception of motion. J Opt Soc Am A 2:284-299.
The visual stimulus is processed (convolved) by four linear Gabor
filters. The icons on the top row show x-t slices of the 3D filters, while the
bottom row shows x-y slices for each subunit. The signals from the left and right
(even filters) and fl2
filters) are also inverted, and these positive and negative filter outputs are
combined and half-squared. The four resulting signals are added to form
, the binocular disparity energy with direction selectivity.
The raw signal (bde) is then offset, scaled and half-wave rectified
(although the signal is typically already non-zero unless the scaling
or offset has introduced negative values), and it is used to drive a
Poisson spiking mechanism. The spikes are time shifted to simulate a
neurobiological latency. See the model (.moo) files for the
parameters that govern these computations.