Date on Master's Thesis/Doctoral Dissertation

5-2011

Document Type

Doctoral Dissertation

Degree Name

Ph. D.

Department

Physics and Astronomy

Committee Chair

Kielkopf, John F.

Author's Keywords

Edge detection; Turbulence; Structural health; Modulation; Biomedical; Remote sensing

Subject

Computer vision; Image processing--Digital techniques; Motion perception (Vision)--Data processing; Remote sensing--Data processing

Abstract

High dynamic range imaging involves imaging at a bit depth higher than the typical 8-12 bits offered by standard video equipment. We propose a method of imaging a scene at high dynamic range, 14+ bits, to detect motion correlated with changes in the measured optical signal. Features within a scene, namely edges, can be tracked through a time sequence and produce a modulation in light levels associated with the edge moving across a region being sampled by the detector. The modulation in the signal is analyzed and a model is proposed that allows for an absolute measurement of the displacement of an edge. In addition, turbulence present in the received optical path produces a modulation in the received signal that can be directly related to the various turbulent eddy sizes. These features, present in the low frequency portion of the spectrum, are correlated to specific values for a relative measurement of the turbulence intensity. In some cases a single element sensor is used for a measurement at a single point. Video technology is also utilized to produce simultaneous measurements across the entire scene. Several applications are explored and the results discussed. Key applications include: the use of this technique to analyze the motions of bridges for the assessment of structural health, noncontact methods of measuring the blood pulse waveform and respiration rate of an individual(s), and the imaging of turbulence, including clear air turbulence, for relative values of intensity. Resonant frequencies of bridges can be measured with this technique as well as eddies formed from turbulent flow.

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