Extension of Projection Area using Head Orientation in Projected Virtual Hand Interface for Wheelchair Users

A projected virtual hand interface, which visually extends arms of users using projection images, enables wheelchair users to reach unreachable objects; however, its projection area is narrower than the reaching area required for the users. To address this problem, we propose a wheelchair system enhanced with a projected virtual hand that allows controlling a projection area using user's head orientation. The proposed system estimates the current orientation of a user's head and controls the pan and tilt of a projector accordingly to move a projection area considering the positional relationship with a projection plane. As users can operate the projection area simply by turning their head, this operation can be executed simultaneously with operations of a virtual hand using their hands. We propose a control model for projector rotation according to the user's head direction. The conducted user experience study has revealed that the proposed method enables users to perform pointing tasks in a shorter time compared with the existing method, and moreover, it has acceptable interface usability.