Scaling and discriminability of perceived gloss

While much attention has been given to understanding biases in gloss perception (e.g., changes perceived reflectance as a function of lighting, shape, viewpoint, and other factors), here we investigated sensitivity surface reflectance. We tested how visual differences specular varies the magnitude Stimuli consisted renderings glossy objects under natural illumination. Using maximum likelihood difference scaling (MLDS), created perceptual parameter Ward model. Then, using method constant stimuli standard 2AFC procedure, obtained psychometric functions for discrimination across range values derived from scale. Both methods demonstrate that discriminability is significantly diminished at high levels reflectance, thus indicating depends on change image produced by different values. Taken together, these experiments also suggest internal sensory noise remains suprathreshold near-threshold intervals which supports use MLDS highly efficient evaluating sensitivity.