Discrimination of Virtual Square Gratings by Dynamic Touch on Friction Based Tactile Displays

In this paper, we investigate the use of friction based tactile displays for the simulation of finely textured surfaces, as such displays offer a promising way for the development of devices with co-located vision and tactile feedback. The resolution of the textures rendered with such devices and their matching to real textures have never been investigated. The paper first contributes to the evaluation of the texture resolution of friction based tactile displays. In a controlled experiment, we investigate the differential thresholds for square gratings simulated with a friction based tactile device by dynamic touch. Then we compare them to the differential thresholds of real square wave gratings. We found that the Weber fraction remains constant across the different spatial period at 9%, which is close to the Weber fraction found for corresponding real square gratings. This study inclines us to conclude that friction based tactile displays offers a realistic alternative to pin based arrays and can be used for co-located vision and tactile rendering. From the results of the experiment, we also give the design guidelines to improve the perception of textures on friction based tactile displays.