This thesis regards the method of full field time-of-flight depth imaging by way of amplitude modulated continuous wave signals correlated with step-shifted reference waveforms using a specialized solid state CMOS sensor, referred to as photonic mixing device. The specific focus deals with the inherent issue of depth ambiguity due to a fundamental property of periodic signals: that they repeat, or wrap, after each period, and any signal shifted by a whole number of wavelengths is indistinguishable from the original. Recovering the full extent of the signal’s path is known as phase unwrapping. The common, accepted solution requires the imaging of a series of two or more signals with differing modulation frequencies to resolve the ambiguity, the time delay of which will result in erroneous or invalid measurements for non-static elements of the scene. This work details a physical model of the observable illumination of the scene which provides priors for a novel probabilistic framework to recover the scene geometry by imaging only a single modulated signal. It is demonstrated that this process is able to provide more than adequate results in a majority of representative scenes, and that it can be accomplished on typical computer hardware at a speed that allows for the range imaging to be utilized in real-time, interactive applications.
One such real-time application is presented: alpha-matting, or foreground segmentation, for background substitution of live video. This is a generalized version of the common technique of green-screening that is utilized, for example, by every local weather reporter. The presented method, however, requires no special background, and is able to perform on high resolution video from a lower resolution depth image.
|Commitee:||Davis, James E., Elkaim, Gabriel H., Manduchi, Roberto|
|School:||University of California, Santa Cruz|
|School Location:||United States -- California|
|Source:||DAI-B 77/06(E), Dissertation Abstracts International|
|Keywords:||Computer vision, Phase unwrapping, Range imaging, Time of flight|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be