Computations Underlying the Measurement of Visual Motion
Name
AIM-761.pdf
Size
7.07 MB
Format
Adobe PDF
Checksum (MD5)
6c9a5b53f870aabcef99548b05b48778
Name
AIM-761.ps
Size
9 MB
Format
PostScript
Checksum (MD5)
7c8e31d283d7dbfd852e166a8da7dd58
Author(s)
Hildreth, Ellen C.
Date Issued
March 1, 1984
Series/Report no.
AIM-761
Abstract
The organization of movement in a changing image provides a valuable source of information for analyzing the environment in terms of objects, their motion in space, and their three-dimensional structure. This movement may be represented by a two-dimensional velocity field that assigns a direction and magnitude of velocity to elements in the image. This paper presents a method for computing the velocity field, with three main components. First, initial measurements of motion in the image take place at the location of significant changes, which give rise to zero-crossings in the output of the convolution of the image with a *** operator. The initial motion measurements provide the component of velocity in the direction perpendicular to the local orientation of the zero-crossing contours. Second, these initial measurements are integrated along contours to compute the two-dimensional velocity field. Third, an additional constraint of smoothness of the velocity field, based on the physical constraint that surfaces are generally smooth, allows the computation of a unique velocity field. The details of an algorithm are presented, with results of the algorithm applied to artificial and natural image sequences.
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