Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 116-117). Also available via the Internet.

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The field of computer vision studies the computational tools and methods required for computers to be able to process visual information, for example images and video. Shape descriptors are one of the tools commonly used in image processing applications. Shape descriptors are mathematical functions which are applied to an image and produce numerical values which are representative of a particular characteristic of the image. These numerical values can then be processed in order to provide some information about the image. For example, these values can be fed to a classifier in order to assign a class label to the image. There are a number of shape descriptors already existing in the literature for 2D and 3D images. The aim of this thesis is to develop additional shape descriptors which provide an improvement over (or an alternative to) those already existing in the literature. A large majority of the existing 2D shape descriptors use surface information to produce a measure. However, in some applications surface information is not present and only partially extracted contours are available. In such cases, boundary based shape descriptors must be used. A new boundary based shape descriptor called Linearity is introduced. This measure can be applied to open or closed curve segments. In general the availability of 3D images is comparatively smaller than that of 2D images. As a consequence, the number of existing 3D shape descriptors is also relatively smaller. However, there is an increasing interest in the development of 3D descriptors. In this thesis we present two basic 3D measures which afterwards are modified to produce a range of new shape descriptors. All of these descriptors are similar in their behaviour, however they can be combined and applied in different image processing applications such as image retrieval and classification. This simple fact is demonstrated through several examples.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Student Number : 0400522J - MSc research report - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / The Government of Botswana has, since 1972, implemented several programmes of labour intensive work as a complementary effort to alleviate high levels of unemployment, poverty and rural under-development. This research project describes and evaluates six of the programmes: the Botswana Labour Intensive District Roads Programme (LG 34), the Rural Roads Programme (RRP), the Labour Intensive Public Works Schemes (LG 38), the Labour Intensive Drought Relief Programme (LG 117), the current National Public Works Programme (LG 1107) and the current Labour Intensive Routine Road Maintenance Programme. The programmes have been described and evaluated in relation to their internal objectives as well as against international literature on labour intensive work in order to determine whether or not they were successful. The study reveals that the LG 34 was a highly successful programme as it achieved most of its key objectives and was in conformity with international literature. The programme created jobs for a significant number of poor Batswana through the construction of good quality low cost roads. It developed and established road construction and maintenance units within the District Councils. The success of the LG 34 was, however, later undermined by a depreciated wage rate contributing to the eventual demise of the programme. The Labour Intensive Road Maintenance Programme, although currently in its early stages of expansion, has been impressive. It has successfully developed and demonstrated through a Pilot Project a model for the use of labour based small contractors, managed by a private sector consultant, for routine road maintenance. This had not been done before in Botswana. The rest of the programmes were plagued by inefficiencies resulting from poor initial planning, lack of training and technical supervisory personnel, lack of proper organisational systems for the programmes and incorporation into drought relief activities. Most of these programmes were wound up, and the on-going National Public Works Programme is struggling to survive. In sum, the Botswana experience has shown that labour intensive methods could be successful if attention were paid to initial design and planning, training of technical supervisory staff and the establishment of proper organisational systems. In addition, to differentiate proper labour intensive work from drought relief, wages must be paid at or close to the Industrial Class minimum wage. DPDoFcuments Complete Click Here & Upgrade Expanded Features Unlimited Pages

Multiple description coding (MDC) has received a lot of attention recently, and has been studied widely and extended to many demanding applications such as speech and video. MDC is a coding technique that generates correlated descriptions of the source stream for transmitting over a diversity system with several channels. The objective of this diversity system is to overcome channel impairments and provide more reliability. In the context of lossy source coding and quantization, a multiple description quantization system usually consists of multiple channels, side encoders to quantize the source samples and send over different channels, and side and central decoders to reconstruct the source. We propose two multiple description quantization schemes in order to design the codebooks and partitions of side and central quantizers of a multiple description system with two channels. The applied framework originated in the multiple description quantization via Gram-Schmidt orthogonalization approach. The basic idea of our proposed schemes is to minimize a Lagrangian cost function by an iterative technique which jointly designs side codebooks and partitions. Our proposed methods perform very closely to the optimum MD quantizer with considerably less complexity. We also propose a multiple description video coding technique motivated by human visual perception. We employ two simple parameters as a measure of the perceptual tolerance of discrete cosine transform (DCT) blocks against visual distortion. We duplicate the essential information such as motion vectors and some low-frequency DCT coefficients of prediction errors into each description, and split the remaining high-frequency DCT coefficients according to the calculated perceptual tolerance parameter. Our proposed technique has very low complexity and achieves superior performance compared to other similar techniques which do not consider perceptual distortion in the design problem. / Thesis (Master, Electrical & Computer Engineering) -- Queen's University, 2007-08-19 03:33:10.451

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 91-94). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaf 107). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 56-57). Also available via the Internet.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1993. / Vita. Abstract. Includes bibliographical references (leaves 147-149). Also available via the Internet.