Figure 3
From: Contact geometry and mechanics predict friction forces during tactile surface exploration
Normalized proportion of time of contact between the finger and surface locations (both subjects, all trials). At the highest level on the scale (1, white), the finger was in contact with the surface for the highest proportion of time, while at the lowest level on the scale (0, black), the surface was never contacted by the finger. In each trial, finite width regions of every surface satisfied this last condition (two regions in the case of bumps); we refer to them as “tactile blind spots”. Their widths ranged from 0.47 mm (Step Up surface, 2 mm scale) to 1.71 mm (Right Bump surface, 4 mm scale).
