Gary Meyer Department of Computer Science University of Minnesota "Visual Difference Metrics and Computer Graphics" Thursday April 28th, 12:20-1:10, Lind 409

Abstract
Visual difference metrics (VDMs) are used by image scientists to predict the perceptual significance of pictorial artifacts. Given an original image and one containing defects, a VDM produces a map that shows where the artifacts are visually detectable. In this talk the theory that underlies VDMs will be presented followed by three different applications of VDMs to computer graphics. In the first application, the high speed matrix and vector operations available on contemporary graphics cards are exploited to develop a hardware implementation of a VDM. This makes it possible to execute the VDM in near real time. In the next application a ray tracing algorithm is modified so that it uses a VDM to determine where rays should be cast into a scene. This improves the efficiency of the algorithm and provides a perceptually based halting condition. In the final application a VDM is employed as part of a re-meshing algorithm. This allows a decrease in the number of polygons where surface texture and environmental lighting produce strong masking or contrast sensitivity effects.