Use of Reference Frame in Haptic Virtual Environments: Implications for Users with Visual Impairments

摘要

Reference frame is key in explaining the relationship between two objects. This paper focused on the orientation parameter of a reference frame in use of projective spatial terms, and its use by visually impaired participants using a haptic device to explore a haptic virtual environment. A total of nine visually impaired participants between 12 and 17 years of age participated in this study. After exploring the 3D virtual environment with a haptic device, participants answered questions about the frame they had utilized. Overall results indicated that the participants used relative frame of reference slightly more than the intrinsic frame of reference. This inclination was especially clear when both the target object and the reference object were on the horizontal plane. Only when objects were on horizontal plane but intrinsically vertical to the reference object, the intrinsic frame of reference was preferred. We also found evidence that participants used a reflective subtype of the relative frame, and vertically aligned objects were easy to be perceived with the relative reference frame. We concluded that the virtual environment and haptic input had influence on the result by separating the user from the computer, only allowing one point of contact. Thus it would be possible to apply the result of this study to the development and assessment of assistive technology for people with visual impairment, especially in regard to how spatial information between the systems and the user is communicated.