Fast Calibration of Haptic Texture Synthesis Algorithms

Calibrating displays can be a time-consuming process. We describe a fast technique for adjusting the subjective experience of roughness produced by different haptic texture synthesis algorithms. Its efficiency is due to the exponential convergence of the ldquomodified binary search methodrdquo (mobs) applied to find points of subjective equivalence between virtual haptic textures synthesized by different algorithms. The method was applied to find the values of the coefficient of friction in a friction-based texture algorithm that yield the same perception of roughness as the normal-force variations of conventional texture synthesis algorithms. Our main result is a table giving the perceptual equivalence between parameters having different physical dimensions. A similar method could be applied to other perceptual dimensions provided that the controlling parameter be monotonically related to a subjective estimate.