Hi all,

I'm a maters student who is working in the area of gait. I have
access to data from a multi-camera vision system. I am looking
into the problem of missing markers and the ability to track them and
predict their path while they are out of view of the vision systems. I
have come across some interesting techniques.

Unfortunately, I haven't been able to find out how big this missing
marker problem really is. I understand that as long as the markers
placed in the anatomical sites are viewed by any two cameras the 3D
positions of these markers can be calculated. However, in case of
pathalogical gait, the use of canes, walkers, walking pattern, etc., can
cause the marker to be obstructed from view of the cameras. I haven't
been able to find any information to show if this really is a problem
other than the words of a few people who work in gait laboratories.

In many of the vision systems, when the vision system loses sight of the
markers the tracks of the marker paths become disjointed. Generally the
user has had to connect the disjointed tracks manually. Is there software
that makes these connections automatically? If so how do they do it?

Finally, in the prediction of motion, I have narrowed my search to using
motion models of those limbs. Are there better techniques, esp. for
pathological gait?

I would greatly appreciate any help in this area. Also, I will summarize
all my replies and post them to this newsgroup.

Yours sincerely,
Joshua Swamidas

--
joshua@tera.engr.mun.ca

Box 30, Faculty of Engineering and Applied Science,
Memorial University of Newfoundland
St. John's, NF A1B-3X5
(709) 737-8809