Roughness and spatial density judgments on visual and haptic textures using virtual reality

The purpose of this study is to investigate multimodal visual-haptic texture perception for which we used virtual reality techniques. Participants judged a broad range of textures according to their roughness and their spatial density under visual, haptic and visual-haptic exploration conditions. Partici- pants were well able to differentiate between the different textures both by us- ing the roughness and the spatial density judgment. When provided with visual- haptic textures, subjects performance increased (for both judgments) indicating sensory combination of visual and haptic texture information. Most interest- ingly, performance for density and roughness judgments did not differ signifi- cantly, indicating that these estimates are highly correlated. This may be due to the fact that our textures were generated in virtual reality using a haptic point- force display (PHANToM). In conclusion, it seems that the roughness and spa- tial density estimate were based on the same physical parameters given the dis- play technology used.