Surface Reconstruction and Evolution from Multiple Views

Applications like 3D Telepresence necessitate faithful 3D surface reconstruction of the object and 3D data compression in both spatial and temporal domains. This makes us feel immersed in virtual environments there by making 3D Telepresence a powerful tool in many applications. Hence 3D surface reconstruction and 3D compression are two challenging problems which are addressed in this thesis

Five dimensions in the communication of design intent

Industries which utilize Computer Aided Design, (CAD), are in a similar situation to the film industry, where the use of Computer Graphics, (CG), has reached such a level of reality that audiences often do not spot where CG has been used. This has resulted in a general attitude among critics of: “CG is what you expect in a film, but what we often lack is a decent plot”. Over a similar period, CAD software has become a powerful tool with proficient users, whilst the marketplace for such services now takes such facilities for granted. The ‘wow factor’ has faded. The special effects used in films has contributed to this dulling of presentation impact, which leads us to question where we stand in relation to a competitive edge, with the realization that: “CAD is what you expect from a firm, but what we often lack is clear intent.” The questioning of competitive edge draws us into some complex issues, concerning the reduction of compromise for design intent, where priorities fight for first place. There is no disputing the importance of time to market, yet the time compression technologies may no longer be providing a sufficient cutting edge. Even if new technologies facilitate even shorter lead-times we will always face the threat of a time management trap and potential loss of design quality. As a high-risk strategy for competitive advantage, contractual agreements for specified short lead-time deliveries, in some cases with penalty clauses written in, have established an expectation among the client base. Such a strategy leads us to effectively burn our bridges, in sacrificing margins for schedule 3 slippage and error compensation, leaving us nowhere to go but back. With such a lean approach to product development we have to improve our focus on the plot and its intent for design quality. The more investment we make at the front end, to enable the decision making process, the more likely we are to avoid pain at the back-end. Presently, decisions are made on a resource of available quality and quantity of data, using a perspective which is based on the experience, tacit knowledge and intuition of those involved. Whilst intuition is a good starting point or fall-back, as with tacit knowledge, it often proves difficult to substantiate. Background experience is the most valuable asset here but proves ineffectual when faced with low quality data, either through ambiguity, error or lack of substance. The improvement of quality standards require that we look closely at the production and presentation of data in the context of decision making and establish a process by which quality decisions can be made quickly and efficiently. This paper focuses on the process of communication between designers and their colleagues and clients, concerning the presentation of CAD models, from a cognitive perspective. It first establishes a context for individual differences in the management of auditory and visual information for decision making. This is followed by a discussion of five approaches to the communication of design intent and concludes with a checklist, to aid selection of an effective approach to communication

Face Detection And Lip Localization

Integration of audio and video signals for automatic speech recognition has become an important field of study. The Audio-Visual Speech Recognition (AVSR) system is known to have accuracy higher than audio-only or visual-only system. The research focused on the visual front end and has been centered around lip segmentation. Experiments performed for lip feature extraction were mainly done in constrained environment with controlled background noise. In this thesis we focus our attention to a database collected in the environment of a moving car which hampered the quality of the imagery. We first introduce the concept of illumination compensation, where we try to reduce the dependency of light from over- or under-exposed images. As a precursor to lip segmentation, we focus on a robust face detection technique which reaches an accuracy of 95%. We have detailed and compared three different face detection techniques and found a successful way of concatenating them in order to increase the overall accuracy. One of the detection techniques used was the object detection algorithm proposed by Viola-Jones. We have experimented with different color spaces using the Viola-Jones algorithm and have reached interesting conclusions. Following face detection we implement a lip localization algorithm based on the vertical gradients of hybrid equations of color. Despite the challenging background and image quality, success rate of 88% was achieved for lip segmentation