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NavCog3: An Evaluation of a Smartphone-Based Blind Indoor Navigation Assistant with Semantic Features in a Large-Scale Environment

Navigating in unfamiliar environments is challenging for most people, especially for individuals with visual impairments. While many personal navigation tools have been proposed to enable in- dependent indoor navigation, they have insufficient accuracy (e.g., 5-10 m), do not provide semantic features about surroundings (e.g., doorways, shops, etc.), and may require specialized devices to function. Moreover, the deployment of many systems is often only evaluated in constrained scenarios, which may not precisely reflect the performance in the real world. Therefore, we have de- signed and implemented NavCog3, a smartphone-based indoor navigation assistant that has been evaluated in a 21,000 m2 shop- ping mall. In addition to turn-by-turn instructions, it provides in- formation on landmarks (e.g., tactile paving) and points of interests nearby. We first conducted a controlled study with 10 visually im- paired users to assess localization accuracy and the perceived use- fulness of semantic features. To understand the usability of the app in a real-world setting, we then conducted another study with 43 participants with visual impairments where they could freely nav- igate in the shopping mall using NavCog3. Our findings suggest that NavCog3 can open a new opportunity for users with visual im- pairments to independently find and visit large and complex places with confidence.