TI A Real-time 3D Motion Tracking System 

LT TR-93-16 
AU Johnny Wai Yee Kam 
MN April 
YR 1993 
PA 95 
OR UBC 

AB Vision allows one to react to rapid changes in the surrounding
environment. The ability of animals to control their eye
movements and follow a moving target has always been a focus in
biological research. The biological control system that governs
the eye movements is known as the \fIoculomotor control\fP
system. Generally, the control of eye movements to follow a
moving visual target is known as \fIgaze control\fP. .br The
primary goal of motion tracking is to keep an object of interest,
generally known as the visual target, in the view of the observer
at all time. Tracking can be driven by changes perceived from the
real world. One obvious change introduced by a moving object is
the change in its location, which can be described in terms of
displacement. In this project, we will show that by using stereo
disparity and optical flow, two significant types of
displacements, as the major source of directing signals in a
robotic gaze control system, we can determine \fIwhere\fP the
moving object is located anperform the tracking duty, without
recognizing \fIwhat\fP the object is. .br The recent advances in
computer hardware, exemplified by our Datacube MaxVideo 200
system and a network of Transputers, make it possible to perform
image processing operations at video rates, and to implement
real-time systems with input images obtained from video cameras.
The main purposes of this project are to establish some simple
control theories to monitor changes perceived in the real world,
and to apply such theories in the implementation of a real-time
three-dimensional motion tracking system on a binocular camera
head system installed in the Laboratory for Computational
Intelligence (LCI) at the Department of Computer Science of the
University of British Columbia (UBC). .br The control scheme of
our motion tracking system is based on the
Perception-Reasoning-Action (PRA) regime. We will describe an
approach of using an active monitoring process together with a
process for accumulating temporal data to allow different hardwr
components running at different rates to communicate and
cooperate in a real-time system working on real world data. We
will also describe a cancellation method to reduce the unstable
effects of background optical flow generated from ego-motion, and
create a ``pop-out'' effect in the motion field to ease the
burden of target selection. The results of various experiments
conducted, and the difficulties of tracking without any knowledge
of the world and the objects will also be discussed. 

AV ftp ftp.cs.ubc.ca:ftplocaltechreports1993TR-93-16.ps