GVU Technical Report Number:
GIT-GVU-93-08
Title:
Translational Decomposition of Flow Fields
Authors:
Daryl T. Lawton
Warren F. Gardner
Abstract:
We introduce a low-level description of image motion
called the local translational decomposition (LTD). This
description associates with image features or small image areas, a
three-dimensional unit vector describing the direction of motion of
the corresponding environmental feature or small surface area. The
local translational decomposition is derived by applying a
procedure for processing purely translational motion to small
overlapping image areas. This intermediate representation of motion
considerably simplifies the inference of motion parameters for
ego-motion and can support qualitative inferences for non-rigid
motions. We first show how to compute the LTD from optic flow
fields and then show how the LTD is used to recover the parameters
of rigid body motions. We present three cases for which the
recovery of motion parameters is particularly robust: motion
constrained to a determined plane (the normal to the plane is
known); motion constrained to an undetermined plane (the normal to
the plane is not known); arbitrary motion relative to locally
planar surfaces. We then discuss techniques for computing the local
translational decomposition directly from real image sequences
without the initial extraction of optic flow and other areas for
future work.
Keywords:
Image motion, local translational decomposition (LTD), optic flow fields,
rigid body motion
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