Thesis (Ph. D.)--University of Louisville, 2004. / Department of Psychological & Brain Sciences. Vita. "May 2004." Includes bibliographical references (leaves 105-111).

The concept of depth from focus involves calculating distances to points in an observed scene, by modelling the effect that the camera's focal parameters have on images acquired with a small depth of field. This technique does not require special scene illumination, and needs only a single camera. This thesis provides a background understanding of the concept and theory of depth from focus, surveys the literature on current methods of obtaining depth from focus, analyzes the key problems, and presents a novel solution to the problem, complete with experimental results. Deconvolving and modelling the defocus operator, is the most difficult segment of calculating depth from focus. Isolating the defocus operator has conventionally been performed by taking local spatial regions, and inverse filtering in the spatial frequency domain. This thesis exposes some fundamental problems with this method: inaccuracies in finding the frequency domain representation and the presence of border effects. To solve the general depth from focus problem, a novel application of an iterative matrix based method is presented. This method uses two images of the same scene, obtained under different conditions of defocus. The defocus operator may be assumed using a parametric model, or experimentally measured. Trade-offs in implementation are resolved through regularization. The method is theoretically justified, and shown to eliminate the problems mentioned above. A constrained inverse filtering method and the author's iterative matrix based method are experimentally implemented on four scenes. The experiments show the iterative matrix solution consistently yielding more accurate results. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

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Of all the forms of radiation known, sound travels through the sea the best, therefore it is widely used in underwater detection and signal transmission. However, the ambient noise in the ocean will affect the quality of these applications, so that understanding of ambient noise is important for improving acoustic capability. Previous literatures show that ambient noise at deep water should decrease with depth, but would it be the same in the shallow? Most studies of ambient noise were made at deep water in the past, the reason is that great depth variation of ambient noise is easily observed. The ASIAEX 2001 South China Sea experiment is on the continental shelf-break, so the depth effect of ambient noise in shallow water can be explored. A typhoon shall affect experimental zone during May 10-14, 2001. From the results of this study, afternoon effect shall affect distribution of temperature and ambient noise under water depth. The other, a typhoon can not only affect seriously ambient noise, but also intercept the shine and variation of sea temperature, and reduce afternoon effect. Another, ambient noise has insignificant change with depth, however it¡¦s is much affected by the variation of temperature, frequency, and occurrence of internal wave.

Thesis (M.A.)--York University, 1999. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 97-104). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pMQ56179.

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