A Visual Computing Environment Based On A Scalable Stereo Display Wall

Modern large-scale scientific computing features multi-parameters, high resolutions and multi-scale, and standard display methods are not able to display the panoramic scene of these computational results. Visual Computing Environment (VCE) based on new styled display devices can help scientists steer, analyze and understand the scientific computing, and thus is a topic receiving many recent attentions.Display wall is preferred among various display devices for its super high display resolution and large display size. The traditional display wall is built on tight-coupled graphic pipeline and high-end projectors. The hardware and supported software are all produced by professional companies, and thus very costly. Also its updating, alteration, maintenance and extending is very difficult. Therefore, the traditional display wall is only accessible to high-end government laboratories.With the dramatic advances of computing technology, it is becoming feasible to build display walls completely using commodity hardware. This thesis studies the construction of a scalable stereo display wall using only standard commodity hardware and its integration into a multi-disciplinary VCE. The stereo display wall is tiled by a PC cluster-driven projector array. Each pair of projectors projects to the same area of the screen to implement passive stereo. The projectors can be aligned casually, and the precise alignment and color match is achieved by software method assisted with a digital camera. Both the hardware construction method and enabling software has good scalability, and users can build a display wall of many sizes and resolution readily under certain limits.The main contributions of this thesis include:1. The construction of a stereo display wall has been systematically studied, including system architecture, selection of hardware, geometry calibration, color calibration, stereo implementation, software platform, etc. Two improved methods are proposed. A two-pass projection geometry calibration method with on-line nonlinear elements elimination. This method simplifies the calibration process and improves the precision. A transparent integrating method for geometry and color calibration of applications. This method runs a calibration daemon on graphic card without interrupting the front ground application at all.2. Three technologies are studied to improve the speed of parallel rendering which drives the stereo display wall: Stream cache and dynamic display list construction. Because of the similarity between continuous frames, caching the data stream in the servers can reduce the amount of the data that have to be transferred, and constructing display lists on these cached streams can speedup instructions execution. Static load balance method based on Hilbert curve. Hilbert curve can decluster space evenly. Utilizing this characteristic to distribute the load of rendering can improve the load balance in most situations. Mesh-based fast clustering dynamic load balance method. This method adds object group boundary recognition to the GRID method to reduce the geometry overlay. It can improve the rendering speed when the number of geometry objects is not too large.3. A problem solving environment EEMAS running with the display wall is designed and implemented to compose a complete visual scientific computing environment. EEMAS is designed for large-scale, multi-disciplinary scientific computation. The framework of EEMAS uses the blackboard architecture. All kinds of function modules can plug in/out dynamically and collaborate with each other to solve a certain problem. A lots of modules are integrated, especially the enabling tools for problems based on Partial Differential Equations (PDE). A new geometry handling pre-processing module and a modified version of visualization software Paraview are developed.With these methods and software, two visual computing environment prototypes have been developed in Zhejiang University and a national aerospace research institute. Practice shows that such an environment can improve efficiency of scientists and engineers by helping them visually steer the computing process in a semi-immersive way.