paper: structure from motion

[Ning Qian]

Dear colleagues,

The following paper (1.3MB) is available at:

http://brahms.cpmc.columbia.edu/publications/sfm.pdf

(It was published a couple of months ago but I never announced it
before.) 


Computing relief structure from motion with a distributed velocity and
disparity representation

Julian Martin Fernandez, Brendon Watson, and Ning Qian, Vision
Research, 2002, 42:883-898.

Recent psychophysical experiments suggest that humans can only recover
relief structure from motion (SFM); i.e., an object's 3D shape can
only be determined up to a stretching transformation along the line of
sight. Here we propose a physiologically plausible model for the
computation of relief SFM, which is also applicable to the related
problem of motion parallax. We assume that the perception of depth
from motion is related to the firing of a subset of MT neurons tuned
to both velocity and disparity. The model MT neurons are connected to
each other laterally to form modulatory interactions. The overall
connectivity is such that when a zero-disparity velocity pattern is
fed into the system, the most responsive neurons are not those tuned
to zero disparity, but instead are those having preferred disparities
consistent with the relief structure of the velocity pattern. The
model computes the correct relief structure under a wide range of
parameters and can also reproduce the SFM illusions involving coaxial
cylinders. It is consistent with the psychophysical observation that
subjects with stereo impairment are also deficient in perceiving
motion parallax, and with the physiological data that the responses of
direction- and disparity-tuned MT cells covary with the perceived
surface order of bistable SFM stimuli.


Many earlier papers at http://brahms.cpmc.columbia.edu/ are now also
available in PDF format.


Best regards,

Ning

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http://brahms.cpmc.columbia.edu  Ning Qian, Ph. D.
qian at brahms.cpmc.columbia.edu    Associate Professor
nq6 at columbia.edu                 Ctr. Neurobiology & Behavior
                                 Columbia University / NYSPI
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