Extension of and Performance Study With a Haptic Mouse for Fingertip Tactile Display of 2.5D Data

We present the development and evaluation of the TMouse, a new iteration of a haptic device designed to enhance the tactile presentation of 2.5D images, for instance for visually impaired users. The TMouse builds on an earlier design, targeting a reduced, compact size, as well as more stable tactile rendering. The system employs a set of 3 × 3 linear actuators moving a triangular surface to deliver tactile feedback directly to a user's fingertips. A comprehensive user study was conducted to assess the device's performance for rendering 2.5D shapes. In contrast to pilot studies comprising the earlier design, in this work different interaction modes were investigated, as well as more complex tactile shapes, also including distractors in a forced-choice task. Regarding the former, participants were asked to identify the tactile profiles, when exploring either freely, or guided, or passively with the haptic mouse. Results showed no significant difference in recognition rates, with regard to exploration condition; however, participants clearly preferred the option of free exploration. The accuracy of shape detection was mostly influenced by the shape complexity, as well as the similarity to the distractor shapes. Finally, a slight learning effect in recognition rates for some shapes was observed over the course of the study. Overall, the new device design and the study insights can provide guidance for future development of similar haptic mouse-type systems, aiming at fingertip tactile display of data.