| Description |
Predictive computer graphics can be used to visualize the appearance of an object or scene from a virtual design. A seminal experiment in that field was performed in 1984 to evaluate the perceptual quality of computer graphics images with a physical model of the scene. The original study was limited to ideally diffuse surfaces and simple geometry, with the greatest flaw being the artificially diffuse surface materials of a type rarely found in real scenes. Although subsequent work extended graphics algorithms to handle more complex environments and materials, comparisons of later results to a physical standard were scarce. This study attempts to recreate the original experiment in a more general setting using materials commonly found in real scenes. A physical scene was constructed using standard interior architectural materials, including carpet, a ceiling tile, and an incandescent light bulb, and photographed for use as a standard of comparison. A synthetic image of the same scene was rendered using Kajiya-style path tracing, a physically-based variant of the traditional ray casting algorithm, to simulate the effects of global illumination on micro-faceted geometry and directionally reflective materials lit by a hemispherical area light source. The resulting real and artificial images of the scene are presented together and subjectively analyzed to determine promising directions for further research on rendering common materials, and to comment on the legitimacy of ray tracing as a method for photorealistic image synthesis. |
