People typically rely heavily on visual information when finding their way to unfamiliar locations. For individuals with reduced vision, there are a variety of navigational tools available to assist with this task if needed. However, for wayfinding in unfamiliar indoor environments the applicability of existing tools is limited. One potential approach to assist with this task is to enhance visual information about the location and content of existing signage in the environment. With this aim, we developed a prototype software application, which runs on a consumer head-mounted augmented reality (AR) device, to assist visually impaired users with sign-reading. The sign-reading assistant identifies real-world text (e.g., signs and room numbers) on command, highlights the text location, converts it to high contrast AR lettering, and optionally reads the content aloud via text-to-speech. We assessed the usability of this application in a behavioral experiment. Participants with simulated visual impairment were asked to locate a particular office within a hallway, either with or without AR assistance (referred to as the AR group and control group, respectively). Subjective assessments indicated that participants in the AR group found the application helpful for this task, and an analysis of walking paths indicated that these participants took more direct routes compared to the control group. However, participants in the AR group also walked more slowly and took more time to complete the task than the control group. The results point to several specific future goals for usability and system performance in AR-based assistive tools.

Developmental abnormalities in otoliths can impact growth and survival in teleost fishes. Here, we quantified the frequency and severity of developmental anomalies in otoliths of delta smelt (Hypomesus transpacificus), a critically endangered estuarine fish that is endemic to the San Francisco Estuary. Left–right asymmetry and anomalous crystalline polymorphs (i.e., vaterite) were quantified and compared between wild and cultured populations using digital image analysis. Visual estimates of vaterite were validated using X-ray diffraction, Raman spectroscopy, laser ablation ICPMS, and electron probe microanalysis. Results indicated that cultured delta smelt were 80 times more likely to contain a vateritic otolith and 18 times more likely to contain relatively large (≥ 15%) amounts of vaterite. Similarly, cultured fish exhibited 30% greater asymmetry than wild fish. These results indicate that cultured delta smelt exhibit a significantly higher frequency of vestibular abnormalities which are known to reduce fitness and survival. Such hatchery effects on otolith development could have important implications for captive culture practices and the supplementation of wild fish populations with cultured individuals.