Discriminability of Real and Virtual Surfaces with Triangular Gratings

Human sensitivity to height differences in textured surfaces is on the order of microns. Research on human texture perception requires texture samples with precisely controlled micro-geometry. This can be achieved with an electrical discharge machining (EDM) procedure, but the process is time consuming and labor intensive. An alternative approach is to simulate textured surfaces with a haptic interface with high position resolution. The present study measured the amplitude discrimination thresholds for surfaces with triangular gratings using real EDM textured samples and virtual textures rendered with a high-precision force-feedback device called the ministick. The results indicated that the just noticeable differences for real and virtual textures, respectively 3.69plusmn0.65 and 4.94plusmn0.96 mum, were of similar magnitude. Therefore, we propose that this device is suitable for the study human perception of surface micro-geometry with features on the scale of human perceptual resolution