An Evaluation of the Presentation of Acoustic Cues for Shorelining Techniques

The study explores various scenarios for providing shorelining information via spatial-audio auditory sensory augmentation with a view to assisting people who are blind or have low-vision. Shorelining is a strategy often associated with the use of the "white cane" and generally refers to path-following approaches that rely on contours of structures within a built environment. The aim is to support clear, logical paths of travel. In one approach, auditory shorelining cues are provided via a sequence of two auditory earcons rendered spatially along the shoreline and at the participant’s left or right side. In another approach, the auditory cues are rendered spatially as "gate posts" in between which the participant should walk. The rendering of the auditory earcons follows the participant’s path of travel so that at any given time, there is only ever a sequence of two auditory earcons that provides local shorelining information. The auditory earcons are rendered via two methods: (i) using loudspeakers appropriately placed along the path of travel and (ii) using binaural rendering of virtual speakers via smart glasses. We compared the performance of spatial-audio sensory augmentation with non-spatialized spoken language instruction. Participants’ performance was measured in terms of task accuracy, time, and walking behavior. The cognitive workload was measured using a self-reporting questionnaire. Results indicate that sensory augmentation provided via spatial-audio earcons can provide faster and smoother navigational assistance and guidance compared with spoken verbal instructions. The results also suggest that current binaural rendering using simple augmented-reality tool sets is not as robust as real sound in providing navigational guidance. Lastly, the "gate post" shorelining approach seems more effective than the left and right shorelining technique.