Virtual active touch: Perception of virtual gratings wavelength through pointing-stick interface

Tactile feedback enhances the usability and enjoyment of human-computer interfaces. Many feedback techniques have been devised to present tactile stimuli corresponding to a user's hand movements taking account of the concept of active touch. However, hand movements may not necessarily be required for achieving natural tactile feedback. Here, we propose a virtual-active-touch method that achieves haptic perception without actual/direct hand movements. In this method, a cursor manipulated by a force-input device is regarded as a virtual finger of the operator on the screen. Tactile feedback is provided to the operator in accordance with cursor movements. To validate the translation of virtual roughness gratings, we compare the virtual-active-touch interface with an interface that involves actual hand movements. By using the appropriate force-to-velocity gain for the pointing-stick interface, we show that the virtual-active-touch method presents the surface wavelengths of the gratings, which is a fundamental property for texture roughness, and that the gain significantly influences the textures experienced by the operators. Furthermore, we find that the perceived wavelengths of objects scaled and viewed on a small screen are skewed. We conclude that although some unique problems remain to be solved, we may be able to perceive the surface wavelengths solely with the intentions of active touch through virtual-active-touch interfaces.