Pattern vector based reduction of large multimodal data sets for fixed rate interactivity during visualization of multiresolution models

The main focus of the research presented in this dissertation is real-time visualization of large photo-realistic models created from multimodal data sets. These models are derived from range and intensity data acquired from a laser range camera along with color, thermal, or radiation data from the scene. The capability to maintain a constant display rate when dealing with these large models is desired in addition to the ability for multiple users to interact with the data. A 3D virtual reality environment is perfect for interaction with and visualization of the models created from the data sets that have been acquired. To achieve our goal, a tool for visualization consisting of both hardware and software is designed and implemented. The hardware is based around the concept of a CAVE system comprised of a large screen and several projectors. The hardware setup employed is known as the MERLIN (Multi-usER Low-cost INtegrated) visualization system. This includes a desktop SGI computer driving three VGA projectors which display onto a custom-built screen along with several VR interface devices. To maintain a constant display rate, since the number of triangles that a specific machine can draw each second is fixed, a means by which the number of triangles can be adjusted is needed. This requires both a reduction method and a multiresolution representation. The multiresolution modeling technique that is presented is a pattern vector based technique known as POLYMUR (POLYgon MUltimodal Reduction) which is capable of handling the multimodal data sets. This method outputs a multiresolution file which can be used to automatically select the proper resolution needed to maintain the user's desired frame rate when interacting with the model and fill in the details when the model is stationary.