Enhancing Navigation through Natural Sensory Mappings: A Cross-Modal Approach

Individuals with visual impairments frequently depend on assistive navigation tools to live independent lives. Sensory substitution devices (SSDs) can provide navigational assistance through advancements in human sensory processing, hardware, and algorithms. In this paper, we incorporate psychological mechanisms into SSD design to facilitate intuitive and measurable cross-modal translation for assisted navigation in unknown spaces. We developed LightWave, a device that translates visual distance into frequency (via touch or sound) using a cross-modal mapping function derived from psychophysical research, which demonstrates a natural correlation between visual distance and frequency across auditory and tactile modalities. Blindfolded participants navigated cluttered environments using either a traditional cane, auditory frequency cues, or tactile frequency cues. Key performance metrics including walking distance, time, and collisions, were measured to compare effectiveness across devices. The results show that both auditory and tactile frequency navigation outperformed the traditional cane, achieving near-100% success rates compared to the cane’s 85%. Participants using the audio and tactile devices covered an average of 13 meters between start and end points, compared to 18.05 meters with the cane, and completed navigation faster, taking 54.8 seconds with audio and 50.95 seconds with tactile, versus 74.09 seconds with the cane. These findings show the potential for improving SSDs by incorporating cross-modal psychological principles, demonstrating in LightWave a novel approach to enhance personal navigation through natural, intuitive feedback mechanisms.