We describe quality and performance enhancements, which work in real-time, to all well-known Non-photorealistic (NPR) rendering styles for use in an interactive context. These include Comic rendering, Sketch rendering, Hatching and Painterly rendering, but we also attempt and justify a widening of the established definition of what is considered NPR. In the individual Chapters, we identify typical stylistic elements of the different NPR styles. We list problems that need to be solved in order to implement the various renderers. Standard solutions available in the literature are introduced and in all cases extended and optimised. In particular, we extend the lighting model of the comic renderer to include a specular component and introduce multiple inter-related but independent geometric approximations which greatly improve rendering performance. We implement two completely different solutions to random perturbation sketching, solve temporal coherence issues for coal sketching and find an unexpected use for 3D textures to implement hatch-shading. Textured brushes of painterly rendering are extended by properties such as stroke-direction and texture, motion, paint capacity, opacity and emission, making them more flexible and versatile. Brushes are also provided with a minimal amount of intelligence, so that they can help in maximising screen coverage of brushes. We furthermore devise a completely new NPR style, which we call super-realistic and show how sample images can be tweened in real-time to produce an image-based six degree-of-freedom renderer performing at roughly 450 frames per second. Performance values for our other renderers all lie between 10 and over 400 frames per second on homePC hardware, justifying our real-time claim. A large number of sample screen-shots, illustrations and animations demonstrate the visual fidelity of our rendered images. In essence, we successfully achieve our attempted goals of increasing the creative, expressive and communicative potential of individual NPR styles, increasing performance of most of them, adding original and interesting visual qualities, and exploring new techniques or existing ones in novel ways. / KMBT_363 / Adobe Acrobat 9.54 Paper Capture Plug-in

Device-free locators allow the user to interact with a system without the burden of being physically in contact with some input device or without being connected to the system with cables. This thesis presents a device-free locator that uses computer vision techniques to recognize and track the user's hand. The system described herein uses a video camera to capture live video images of the user, which are segmented and processed to extract features that can be used to locate the user's hand within the image. Two types of features, namely moment based invariants and Fourier descriptors, are compared experimentally. An important property of both these techniques is that they allow the recognition of hand-shapes regardless of affine transformation, e.g. rotation within the plane or scale changes. A neural network is used to classify the extracted features as belonging to one of several hand signals, which can be used in the locator system as 'button clicks' or mode indicators. The Siltrack system described herein illustrates that the above techniques can be implemented in real-time on standard hardware. / Dissertation (MSc (Computer Science))--University of Pretoria, 2007. / Computer Science / unrestricted

The purpose of this research is to develop an optimal kernel which would be used in a real-time engineering and communications system. Since the application is a real-time system, relevant real-time issues are studied in conjunction with kernel related issues. The emphasis of the research is the development of a kernel which would not only adhere to the criteria of a real-time environment, namely determinism and performance, but also provide the flexibility and portability associated with non-real-time environments. The essence of the research is to study how the features found in non-real-time systems could be applied to the real-time system in order to generate an optimal kernel which would provide flexibility and architecture independence while maintaining the performance needed by most of the engineering applications. Traditionally, development of real-time kernels has been done using assembly language. By utilizing the powerful constructs of the C language, a real-time kernel was developed which addressed the goals of flexibility and portability while still meeting the real-time criteria. The implementation of the kernel is carried out using the powerful 68010/20/30/40 microprocessor based systems.

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This thesis examines a manufacturing process using a real time interface with a 6502 microprocessor that gives the appearance of parallel processing. Two separate processes are operated, apparently simultaneously with an asynchronous interface between the two processes. An Apple microcomputer, an ISAAC data transfer system and a constructed simulation model are used to demonstrate this process. The model is constructed of Fischertechnik manufactured parts for the support framework, as well as gearing devices, small DC electric motors, and sensing devices in the form of photo-electric switches and single pole double throw switches physically activated by the constructed model. The software, written in Applesoft BASIC and Cyborg's Labsoft, was designed to operate the modeled processes simultaneously and allow an asynchronous interaction between the two processes. The model has applications for use as a method to illustrate manufacturing techniques and to assist in the design and control of manufacturing processes.

This thesis describes the design and implementation of real-time image-processing tasks on a custom computing platform called Splash-2. The tasks that have been implemented are image histogram generation, median filtering using 3X3 neighborhoods, and morphological dilation and erosion. These problems are computationally intensive, involving large amounts of data. The problems are especially difficult when the images need to be processed at real-time rates, typically 30 frames per second. Splash-2 is a reconfigurable FFPGA-based attached processor featuring several programmable processing elements and programmable communication paths. Although not designed specifically for image-processing applications, it possesses architectural properties that make it well suited for high speed computations and data transfer rates that are characteristic of this class of problems. This thesis discusses the design process which has been used to map the tasks to Splash-2, and presents results which demonstrate the effectiveness of custom computing platforms for high performance image processing. / Master of Science