2013 Volume 133 Issue 12 Pages 2257-2263
With the recent progress in computer hardware and computer graphics (CG) techniques, applications using 3D virtual space are getting popular. So far, a mouse and a keyboard are generally used in these applications. While a mouse is a very successful input device for continuously controlling 2D objects, it is not necessarily intuitive for controlling 3D objects. In order to control 3D objects such as an avatar or a moving camera in a virtual space, speech interface has a potential to be a more natural and powerful alternative to a mouse. We propose speech based direct manipulation interface based on stretched word-end voice that controls continuous movements of 3D objects. By combining the proposed method with normal word based commands, both continuous movements and discrete actions are seamlessly controlled. Therefore, everything can be controlled using speech. The proposed method is implemented as an interface to the Second Life system. We compare it with a conventional speech based method that specifies start and end timing of motions. Analyses based on human subjects show that the proposed method is superior to the conventional speech based method. Moreover, we show that the best result is obtained when both methods are combined.