Repeatability and steadiness of fingertip force using depth feedback

An inexpensive Kinect color/depth camera can be used to give feedback to physical therapy patients. We compare the steadiness and repeatability of finger force on a deformable object for physical therapists given no feedback, as well as for untrained subjects who are provided with feedback from force sensors, or with feedback from Kinect depth, or with no feedback. For force repeatability, it is found that untrained subjects and physical therapists perform comparably, and that both force feedback and depth feedback allow the untrained subjects to achieve a given force more repeatably than the physical therapists with no feedback. In contrast, for steadiness, physical therapists outperform untrained subjects when neither group has feedback. Force feedback, but not depth feedback, makes the untrained subjects steadier than the therapists. Objects of different deformability are also compared.