Research Assistant PRISM Computer Science and Engineering Arizona State University |
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Compressed Facade Displacements Maps A solution for ray-tracing a special class of displacement maps, façade models, in the fragment shader. We contribute two main ideas: an efficient ray tracer for the special case of box like displacements maps and an encoding strategy to render a displacement map from compressed representations directly. |
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Reconstruction of SVD Compressed Images on the GPU Modern GPUs have of the order of 1 gigabyte of memory. To accomodate larger textures we invistigate on-the-fly reconstruction of texture images compressed with Singular Value Decomposition technique. The results are numerically comparable to those produced by MATLAB. |
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Hierarchical Data Structures for GPU Ray Tracing of Heightfields We investigate data structures for ray tracing height fields on the GPU. Height fields can be rendered via traditional zbuffering and hardware rasterization of triangles stressing mainly the vertex shader. Alternatively, the height field can be ray traced on the GPU in the pixel shader. We analyze hybrid algorithms and data structures to distribute the load between vertex shader and pixel shader. We show how to cover the height field with primitives so that a correct version of the height field can be ray traced in the pixel shader with fewer triangles. |
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Dual Marching Tetrahedra An improved and simplified method to compute iso-surfaces from volume data sets. The discrete 3D grid used in the classical Marching Cubes algorithm is "tetrahedralized". Interpolation is then performed over the tetrahedral cells to compute a polygonal approximation to a given iso-surface. Computation over tetrahedral domain is much simpler and faster because the number of possible configurations is reduced from 23 to 4. A dual operator is then applied to the mesh to reduce the number of "long-and-thin" triangles. The dual mesh is smoother, more regular and reduces shading artifacts. |
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Ray Casting An implementation of Levoy's method for display of surfaces from volume data using ray casting technique. Experimented with different sampling strategies and transfer functions. Developed a technique to find a suitable transfer function based on user feedback. |
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Quantitative Rock Abrasion In collaboration with the Jet Propulsion Laboratory, Pasadena. An exploratory grant to study morphological features resulting from abrasion of rocks due to natural elements. Rocks are abraded in a natural environment (Mojave Desert) as well as at the NASA Ames and ASU wind tunnels at both Earth and Mars pressures. Tasks include laser scanning of abraded rocks and analysis of range data with Raindrop Geomagic Studio and in-house software. Project Webpage Poster |
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Texture Synthesis An implementation of fast texture synthesis method using tree structured vector quantization proposed by Wei and Levoy. Developed an interactive application to perform both single resolution and multi-resolution TSVQ texture synthesis. Screenshot |
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Wavelet Compression of Heightfields A project to implement and study wavelet compression of grayscale heightfield images representing terrain. Experimented with Haar wavelets and Daubechies D4, D6 wavelets. Compared the relative error in reconstruction using two methods of coefficient thresholding. |
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Whitted Ray Tracing Simple Whitted ray tracer. |
