Freehand Target Acquisition With a Force-Assisted Device

This study investigated a “force cursor” technique combining the pressure-based input of the non-preferred hand, the velocity, and the distance of the preferred hand movement to control a cursor for target acquisition. A pointer acceleration (PA) technique based on an improved sigmoid transfer function and two kinds of pressure value mapping methods were applied to the force cursor. A prototype of an interface using a force-sensitive resistor and Leap Motion (a hand motions sensor) was implemented and used for the user experiment. A usability experiment was conducted to compare the task performance and the user satisfaction of the two kinds of force cursor and a standard cursor based on an original PA technique. The experimental results indicated that the force cursor had higher performance and better user experience in target acquisition. That is, pressure-based input could be combined with other inputs in freehand interaction to help improve task performance without adding too much cognition burden. The force applied to the human-computer interaction could be an indicator of the precision of the task conducted by the user. Based on the results of the investigation, we found that the bimanual interaction was a natural way to interact with the computer, while overly complicated operations applied to both hands might affect the cognition of the users, leading to worse performance. Finally, some suggestions for bimanual and pressure-based interaction designs were discussed.