Global illumination rendering algorithms are capable of producing images that are visually realistic. However, this typically comes at a large computational expense. The overarching goal of this research was to compare different rendering solutions in order to understand why some yield better results when applied to rendering synthetic objects into real photographs. As rendered images are ultimately viewed by human observers, it was logical to use psychophysics to investigate these differences. A psychophysical experiment was conducted judging the composite images for accuracy to the original photograph. In addition, iCAM, an image color appearance model, was used to calculate image differences for the same set of images. In general it was determined that any full global illumination is better than direct illumination solutions only. Also, it was discovered that the full rendering with all of its artifacts is not necessarily an indicator of judged accuracy for the final composite image. Finally, initial results show promise in using iCAM to predict a relationship similar to the psychophysics, which could eventually be used in-the-rendering-loop to achieve photo-realism.
Library of Congress Subject Headings
Computer graphics; Image processing--Digital techniques; Visual perception; Psychophysics
Department, Program, or Center
School of Photographic Arts and Sciences (CIAS)
Hattenberger, Timothy, "A psychophysical investigation of global illumination algorithms used in augmented reality" (2006). Thesis. Rochester Institute of Technology. Accessed from
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