A seamless blending of the real and virtual worlds is key to increased immersion and improved user experiences for augmented reality (AR). Photorealistic and non-photorealistic rendering (NPR) are two ways to achieve this goal. Non-photorealistic rendering creates an abstract and stylized version of both the real and virtual world, making them indistinguishable. This could be particularly useful in some applications (e.g., AR/VR aided machine repair, or for virtual medical surgery) or for certain AR games with artistic stylization. Achieving temporal coherence is a key challenge for all NPR algorithms. Rendered results are temporally coherent when each frame smoothly and seamlessly transitions to the next one without visual flickering or artifacts that distract the eye from perceived smoothness. NPR algorithms with coherence are interesting in both general computer graphics and AR/VR areas. Rendering stylized AR without coherence processing causes the final results to be visually distracting. While various NPR algorithms with coherence support have been proposed in general graphics community for video processing, many of these algorithms require thorough analysis of all frames of the input video and cannot be directly applied to real-time AR applications. We have investigated existing NPR algorithms with coherence in both general graphics and AR/VR areas. These algorithms are divided into two categories: Model Space and Image Space. We present several NPR algorithms with coherence for AR: a watercolor inspired NPR algorithm, a painterly rendering algorithm, and NPR algorithms in the model space that can support several styling effects.

A user controlled interactive computer graphics postprocessor for two-dimensional static and dynamic finite element analysis is developed. This post processor is a menu driven interactive program. This post processor supports more than 50 graphics devices. This program can manipulate the original finite element mesh data, displacement, stress, strain and up to four other values such as temperature. The user can choose any one of the following methods to display the values: Deformed mesh, Vector flow, Color Contours or Curved Contours. With this postprocessor, an improved contouring algorithm is proposed specially for finite element method. This algorithm uses the same isoparametric element representation as used in the analysis stage. That means the contour curves are accurate assuming that the nodal values are accurate and the real values inside the element can be interpolated by the element shape functions. So, this algorithm provides a continuity as the same order as that of the shape functions used for the finite element.

published_or_final_version / Computer Science and Information Systems / Doctoral / Doctor of Philosophy

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The HP2623 graphics terminal emulator is implemented on the PC for use with the Starbase graphics package provided on the departmental HP9000 series 500 computer system. This paper discusses the development and implementation of this emulator. A demonstration of its compatibility with Starbase is also provided along with a users' manual and a programmers' reference.

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Current Graphic Processing Units (GPUs) (circa. 2003/2004) have programmable vertex and fragment units. Often these units are implemented as SIMD processors employing parallel pipelines. Data dependent conditional execution on SIMD architectures implemented using processor idling is inefficient. I propose a multi-pass approach based on conditional streams which allows dynamic load balancing of the fragment units of the GPU and better theoretical performance on programs using data dependent conditionals and loops. The proposed system can be used to turn the fragment unit of a SIMD GPU into a stream processor with data dependent control flow.

This thesis describes the process of writing a software application geared toward developing computer graphics in the Windows environment. The code is written using Visual C++ and the Microsoft Foundation Classes (MFC). As an illustration of this process we will walk through the development of a software application. This application will allow a user to create and edit an image composed of simple line graphics and geometric shapes. The user can select drawing colors, select drawing styles, and do area filling. This application also illustrates the use of menus and dialog boxes. / Department of Computer Science

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