Cristhian Altamirano

Our research primarily focuses on the achromatic, or black to white, dimension. We study in particular, lightness constancy, which is how the observer’s perceived lightness (black to white spectrum) stays roughly constant under varying illumination levels. We have done work in the past with lightness constancy in a two-dimensional scene and three dimensional scene, seen through a veiling luminance (e.g. such as sun glare or fog), or layer of light. We have found several correlations that explain why a 3-D scene produces better constancy than a 2-D scene: (1) when shadows were present in the 3-D scene, lightness constancy went up (objects were perceived more accurately for the shade of gray they actually are). (2) When colored objects were added to the 3-D scene, lightness constancy improved, while lightness constancy did not improve for a 2-D scene. (3) Achromatic curved objects also improved lightness constancy. Regarding work done in the chromatic (color) dimension, we are doing work with chromatic induction. Chromatic induction is a phenomenon that occurs when a color induces or produces, a tint of its opposite color, on a neighboring, neutral area. What we are working on is trying to figure out how much color/saturation does a background have to have for you to start experiencing chromatic induction. In other words, we want to know the threshold. Finally, work has been done on perceived illumination of a field. Using a vision tunnel, we found that perceived illumination (brightness) is anchored to the highest luminance (the most amount of light that is being reflected by a surface), rather than the average luminance, as previously believed by theorists.