The Hubble Space Telescope has provided the world with incredible imagery of the surrounding universe. The aesthetic quality of this imagery is limited by production resources; by creating a method to harness the highly refined detail and quality of CG elements in live-action films, we can inspire and educate at a much greater level. In this thesis, I create a rendering approach that allows camera movement around and through elements such as nebulae and galaxies, creating a more cinematic experience. The solution will also allow for reasonable scientific accuracy, visual appeal, efficiency, and extendability to other astronomical visualizations. 3D meshes are constructed and textured using telescopic images as reference. Splats are volumetrically generated using a voxelized bounding box around the mesh. Valid splats within a user specified maximum distance receive initial color and alpha values from the texture map. Probability density functions are used to create a density falloff along the edges of the object, and modifications to the RGBA values are made to achieve the desired cloud-like appearance. The data sets are rendered using a C program developed at the Space Telescope Science Institute by Dr. Frank Summers. The methodology is applied to the test cases of a nebula, star-forming region Sharpless 2-106, and a galaxy, Messier 51, or the Whirlpool Galaxy. The results of this thesis demonstrate the visual, scientific, and technical success of this solution. The code developed during this project generates the desired imagery with reasonable efficiency. A short animation moving from outside the galaxy to a close up of the nebula exhibits the flexibility in scale and camera movement. A careful balance between scientific accuracy and visual appeal were maintained through consultation with astronomers at the Space Telescope Science Institute. The favorable efficient, flexible, visual, and scientific results presented by this work make this process extendable to most other cases of nebula and galaxy visualizations.

No description available.

No description available.

No description available.

No description available.

Image compression using neural networks in the past has focused on just reducing the number of bytes that had to be stored even thought the bytes had no meaning. This study looks at a new process that reduces the number of bytes stored but also maintains meaning behind the bytes. The bytes of the compressed image will correspond to parameters of an existing graphic algorithm. After a brief review of common neural networks and graphic algorithms, the back propagation neural network was chosen to be tested for this new process. Both three layer and four layer networks were tested. The four layer network was used in further tests because of its improved response compared to the three layer network. Two different training sets were used, a normal training set which was small and an extended version which included extreme value sets. These two training sets were shown to the neural network in two forms. The first was the raw format with no preprocessing. The second form used a Fast Fourier Transform to preprocess the data in an effort to distribute the image data throughout the image plane. The neural network’s response was good on images that it was trained on but responded poorly to new images that were not used in the training sets. / Department of Computer Science

Graph theory is a relatively new way of thinking in mathematics. Graphs can model a number of different problems. Graph theory introduces solutions to many problems which human beings have faced since ancient times.A study of graphs will not be complete without an introduction to both theory and algorithms. Invention of the tools for studying graphs is necessary in order to help people learn the theory and execute the algorithms. The study of graphs itself, by nature, needs graphical representation which can give clearer images for a better understanding. A windowing environment is selected as an instrument for developing a device to study graphs because of its friendly Graphical User Interface. / Department of Computer Science

Segment endpoint visibility graph is a representation scheme for art gallery problems, guard problems, and other shortest path or shortest circuit problems. In the research of visibility graphs, drawing graphs is a time-consuming task. VGE (Visibility Graphs Editor) is developed for visibility graphs reseacheres to create and modify graphs interactively in X-window environment. Appropriate graphics user interface allows the researcher to edit a graph, save and open a file, and make a hard copy of a graph. VGE is developed in C under X-window environment and using EZD[3] graphics tool. The thesis also discusses the uses of EZD. Although it is still only a prototype, VGE is a successful tool for analyzing visibility graphs. / Department of Computer Science

Fluid simulations for computer graphics applications have attracted the attention of many researchers and practitioners due to the enhanced realism that natural phenomena simulation adds to graphical applications. Vortex methods are receiving increasing attention from the computer graphics community for simple and direct modeling of complex flow phenomena such as turbulence. However, vortex methods have not been developed yet to the level of other techniques for fluid simulation in computer graphics. In this work we present a novel simulation framework to model inviscid flows using Lagrangian vortex particle methods. We introduce novel stable methods to solve the vorticity flow equations that produce highly detailed visual fluid simulations. We incorporate the full interplay of solids and fluids in our framework. The coupling between free-form solids, represented by arbitrary surface meshes and fluids simulated with vortex methods, leads to visually rich simulations. Previous vortex simulators only focus on modeling the solid as a boundary for the flow. We model solid boundaries using an extended potential flow at the solid surface coupled with a boundary layer simulation. This allows the accurate simulation of two processes of visual interest. The first is the introduction of surface vorticity in the main flow as turbulence (vortex shedding). The second is the motion of the solid induced by fluid forces, which is calculated from the dynamics of vorticity in the flow and the rate of vorticity creation at solid surfaces. We demonstrate high quality results of our methods simulating flows around solid objects and solid object propulsion due to flows. This work ameliorates one of the important omissions in the development of vortex methods for computer graphics, which is the simulation of two-way coupling of solids and fluids.

In this dissertation I examine how research in non-photorealistic rendering, human perception, and game-based learning can be combined to produce illustrative simulations of different visual systems that effectively convey information about vision to unprimed observers. The Visual Differences Simulation (VDS) methodology and framework that I propose is capable of producing simulations of animal visual systems based on how they relate to human vision, and can represent differences in color vision, hyperspectral sensitivity, visual acuity, light sensitivity, field of view, motion sensitivity, and eye construction. The simulations produced by the VDS framework run in real time, allowing users to explore computer-generated environments from `behind the eyes' of an animal in an interactive and immersive manner. I also examine how cognitive principles and game-based learning can be leveraged to demonstrate and enhance the educational impact of the simulations produced by the VDS framework. Two case studies are presented, where simulations of the cat and the bee visual systems are used as the basis to design educational games, and are evaluated to show that embedding the simulations in educational games is an effective and engaging way to convey information about vision to unprimed observers. / Graduate