Wearable Virtual White Cane: Assistive Technology for Navigating the Visually Impaired

摘要

Thirty-eight million people are visually impaired in the world. They encounter many disadvantages in mobility due to vision loss, which poses significant challenges when navigating unstructured environments. Conventional travel aids conveying simple tactile feedback to the visually impaired, such as fixed-length canes, provide limited ability to detect obstacles in a relatively limited distance. As a result, it can be difficult for the visually impaired to navigate smoothly using a cane. Much research effort has been focused on developing electronic travel aids (ETAs). Computer vision-based ETAs [1-5] aim to help guide the user using specialized landmarks or predetermined features. The robustness of such devices is still questionable; for instance, the devices fail to provide navigation in scenarios lacking visual cues or repetitive features [1]. ETAs based on different sensing principles have been presented in literature to overcome these drawbacks. Palleja et al. recently developed a hand-held laser sensor based ETA device. The object detection signal is converted to pressure feedback generated by a belt on the user's wrist [6]. The limited scanning angle reduces region of interest for navigation. For other ETA devices like Miniguide [7] and the Nurion Laser Cane [8], the user needs intense focus and must intentionally sweep the device over the environment. To ease this inconvenience, Sonic Pathfinder [9,10] mounts an ultrasonic sonar ETA on a headband. The Pathfinder gives audio feedback in the form of notes on a musical scale, based on the proximity to objects ahead the user. Similar to other audio feedback designs [11,12], the major drawback is that audio signals can mask important environmental sounds. Although more complex to implement, devices relying on tactile sensation may thus present advantages.