Stereoscopic viewing, roughness and gloss perception
Abstract
This thesis presents a novel investigation into the effect stereoscopic vision has upon the
strength of perceived gloss on rough surfaces. We demonstrate that in certain cases
disparity is necessary for accurate judgements of gloss strength.
We first detail the process we used to create a two-level taxonomy of property terms,
which helped to inform the early direction of this work, before presenting the eleven
words which we found categorised the property space. This shaped careful examination
of the relevant literature, leading us to conclude that most studies into roughness, gloss,
and stereoscopic vision have been performed with unrealistic surfaces and physically
inaccurate lighting models.
To improve on the stimuli used in these earlier studies, advanced offline rendering
techniques were employed to create images of complex, naturalistic, and realistically
glossy 1/fβ noise surfaces. These images were rendered using multi-bounce path tracing
to account for interreflections and soft shadows, with a reflectance model which
observed all common light phenomena. Using these images in a series of
psychophysical experiments, we first show that random phase spectra can alter the
strength of perceived gloss. These results are presented alongside pairs of the surfaces
tested which have similar levels of perceptual gloss. These surface pairs are then used to
conclude that naïve observers consistently underestimate how glossy a surface is
without the correct surface and highlight disparity, but only on the rougher surfaces
presented.