Scrutinizing pseudo haptic feedback of surface roughness in virtual environments

Operators in virtual environments have to mostly rely on visual feedback when exploring virtual scenes and objects. If no additional haptic actuators are available then information about surface roughness will not be communicable and thus the degree of immersion will suffer. To compensate for this shortcome the usage of pseudo haptic feedback (Control/ Display ratio = visual cues encoding haptic object properties) is discussed and two psychophysical experiments are conducted. The first experiment deals with the perceptual scaling of different Control/ Display ratios while the second experiment examines the way, how human subjects assign suitable Control/ Display ratios to different real surfaces. It turns out that human operators can reliably perceive differences in Control/ Display ratios and a psychophysic function is established. The allocation of specific Control/ Display values to real materials does not give any generalizable results; only a global trend is observable.