Thesis (Ph. D.)--University of Wisconsin--Madison, 1984. / Typescript. Vita. Includes bibliographical references (leaves 131-142).

Thesis (Ph. D.)--University of Washington, 2005. / Vita. Includes bibliographical references (p. 86-88).

Thesis (M.Phil.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 59-65). Also available in electronic version.

Thesis (M.Eng.)--University of Louisville, 2007. / Title and description from thesis home page (viewed May 9, 2007). Department of Computer Engineering and Computer Science. Vita. "May 2007." Includes bibliographical references (p. 54-55).

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 147-162).

Thesis (M.S. & I.T.) -- Lincoln University, 2008. / Degree named as Master of Applied Computing at head of abstract. Also available via the World Wide Web.

It was desired to design an image processing system that resembled the human retina, for the processing of two-dimensional images. In particular the system was required to carry out basic image processing tasks such as edge detection. A new filtering technique was deduced from the physiological findings on the distribution of the receptive fields of the ganglion cells on the retina. This filtering technique was then incorporated in designing an image processing system in which the spatial resolution was increased linearly towards the geometrical center of the image. The design was based on a discrete distribution of processing areas on an inhomogeneous hexagonal sampling grid. This resulted in a highly localized processing system which simplified the development of algorithms for higher image processing tasks such as boundary following. The retinal image processing system was simulated on the VAX-11/750. The computational cost of conducting operations such as edge detection, boundary detection and boundary following, using the designed system, was evaluated and compared with that of the conventional image processing system. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Contrast enhancement techniques are used widely to improve the visual quality of images. The difference in luminance reflected from two adjacent surfaces creates contrast between the surfaces in the image. The greater the contrast, the easier it is to recognize and differentiate objects in an image. Thus object contrast is an important factor in the perception of the visual quality of an image and in its usefulness for object recognition and image analysis applications. The focus of this thesis is on studying how well different contrast enhancement techniques developed for visible spectrum photographic images work on infrared images; to determine which techniques might be best suited for incorporation into commercial infrared imaging applications. The database for this thesis consists of night vision infrared images taken using a Photon 320 camera by FLIR Systems, Inc. Numerous contrast enhancement techniques found in literature were reviewed in this project, out of which four (4) representative techniques have been selected and presented in detail. Homomorphic filtering, fuzzy-logic enhancement, and single-scale retinex techniques have been implemented based on published papers. These were each compared to the classical technique of histogram equalization using metrics of computational time, histogram standard deviation, sharpness and user observations. These metrics provide both quantitative and qualitative analyses of the implemented techniques which are relevant to the end user applications of infrared imaging. Based on the metric calculations and results, homomorphic filtering and histogram equalization proved to have better results compared to the other techniques. All the implemented techniques are global contrast enhancement methods and for future work local contrast enhancement techniques may be applied to the results obtained in this investigation as a post-processing technique.

Includes bibliographies. / Sonar beamforming is usually accomplished using a multi-element transducer array. To obtain high resolution, such a system is costly and complex. In contrast, many mammals are capable of good angular resolution using only a single active element surrounded by an irregular reflector – the ear. A study of monaural localisation was therefore undertaken, with a view to the development of a novel beamforming system which uses only a single active element. Computer simulations have shown that the direction of a source can be determined by cross –correlating the output signal spectrum with the known spectral responses of the receiving system for all angles.

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