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Hedlin, Eric

University of British Columbia

In this thesis, we develop Computer Vision methods for Human body pose and stride length estimation. We first describe a framework for estimating the stride length of a walking subject from video using a multi-view camera setup. We specifically look into its utility in diagnosing Parkinson's disease. We do this using per frame 3D pose estimates and using an analysis of foot movement, we determine the length of the stride. Parkinson's diagnosis partly relies on stride length information; we claim that our method can be helpful in diagnosis. The current practice in the medical field is to estimate stride with complicated and fundamentally flawed sensors as they tend to affect the gait of the subjects using them. A benefit of our method is that cameras are relatively cheap, easily obtainable, and only need to be set up once. We also describe work done in improving the state of the art in human pose estimation. We first propose a pose refinement method that enhances state-of-the-art methods. Through analysis of our refiner, we show a flaw inherent in the human body model---the inaccuracy in the typical shape-to-pose regressor (joint regressor)---for a standard human pose dataset and show that the results on the top methods are actually being underreported. This flaw results in a situation where the ground truth joints are unsatisfiable with biologically plausible poses. We then address this flaw by modifying a part of the human body model. We reevaluate top state-of-the-art methods and show these models perform better with this modification without retraining.

Text

2021-08-28

Attribution-NoDerivatives 4.0 International

http://hdl.handle.net/2429/79506

Computer Science

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nd/4.0/