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Single image matting refers to the problem of accurately estimating the foreground object given only one input image. It is a fundamental technique in many image editing applications and has been extensively studied in the literature. Various matting techniques and systems have been proposed and impressive advances have been achieved in efficiently extracting high quality mattes. However, existing matting methods usually perform well for relatively uniform and smooth images only but generate noisy alpha mattes for complex images. The main motivation of this thesis is to develop a new matting approach that can handle complex images. We examine the color sampling and alpha propagation techniques in detail, which are two popular techniques employed by many state-of-the-art matting methods, to understand the reasons why the performance of these methods degrade significantly for complex images. The main contribution of this thesis is the development of two novel matting algorithms that can handle images with complex texture patterns. The first proposed matting method is aimed at complex images with homogeneous texture pattern background. A novel texture synthesis scheme is developed to utilize the known texture information to infer the texture information in the unknown region and thus alleviate the problems introduced by textured background. The second proposed matting algorithm is for complex images with heterogeneous texture patterns. A new foreground and background pixels identification algorithm is used to identify the pure foreground and background pixels in the unknown region and thus effectively handle the challenges of large color variation introduced by complex images. Our experimental results, both qualitative and quantitative, show that the proposed matting methods can effectively handle images with complex background and generate cleaner alpha mattes than existing matting methods.

The wavefront construction (WFC) method is an effective tool to compute seismic ray fields and has wide applications. This paper applies the WFC method to a heterogeneous earth model represented as a 3-D grid instead of a sequence of smooth layers, as the layered model is insufficient for the regions with complex geological structures. In order to utilize gridded models, highly heterogeneous models must be smoothed for reliable numerical results. A new velocity gradient smoothing method is proposed that is able to control quantitatively the smoothness of the velocity model while preserving the main structural characteristics of the original model. A modified inverse distance weighting method is applied to obtain velocities or densities at an arbitrary point in the model for successive wavefront propagation. A very complex 3-D grid model based on the standard Marmousi reference model is tested to compare the new approach to alternative smoothing schemes, and the first arrival travel times from the WFC method are compared with results from an eikonal solver. These results are obtained more quickly, but the algorithm is restricted to computing only first arrivals. However, comparison helps to establish the accuracy of the WFC solutions and assess the influence of the smoothing schemes. The modeling comparisons verify the effectiveness of the proposed smoothing methods and the enhanced performance of the WFC algorithm with the 3-D grid model.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1996. / Includes bibliographical references (leaves 139-161). / Microfiche. / xiv, 161 leaves, bound photos 29 cm

Thesis (M App Sc) -- University of South Australia, 1992

Typewritten copy / Includes bibliography. / 74 leaves : diag. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, 1957?

Experiments were conducted to evaluate the reproductive biology, cytology and phenology of the Australian everlasting daisy Rhodanthe anthemoides and related species. The principal objective was the development of new cultivars with novel bract colours and an assessment of intra-specific variation, mutation breeding and inter-specific hybridisation with R. diffusa, R. manglesii and R. chlorocephala subsp. rosea was carried out.R. anthemoides is a variable eastern state species and plants collected from the New England region of N.S.W have a chromosome number of 2n=22 as does R. diffusa. Other distinct morphological types of R.anthemoides, mostly from the Alpine regions of N.S.W, returned counts of 2n-22 indicating that this species is cytologically divergent and in need of botanical revision with the recognition of at least one new species.R. anthemoides is outbreeding and features a conspicuous involcure, protandry and long stigmatic papillae which aid in pollen presentation and favours insect pollination. The stigma in this species becomes receptive before it is fully exposed and remains receptive for at least 8 days. All of the above species are strongly self-compatible and in R. anthemoides the SI system functions by inhibiting pollen tube penetration of the stigma. (For complete abstract open document)

Thesis (Ph.D.)--University of Adelaide, 1957? / Typewritten copy. Includes bibliography.

Thesis (Ph. D.)--Catholic University of America, 1922. / Vita. Includes bibliographical references. Bibliography: p. 176-182.

Thesis (M.S.)--University of Wisconsin--Madison, 1970. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.