論文アブストラクト：Recognizing others is a major challenge for people with visual impairments (VIPs) and can hinder engagement in social activities. We present Accessibility Bot, a research prototype bot on Facebook Messenger, that leverages state-of-the-art computer vision and a user's friends' tagged photos on Facebook to help people with visual impairments recognize their friends. Accessibility Bot provides users information about identity and facial expressions and attributes of friends captured by their phone's camera. To guide our design, we interviewed eight VIPs to understand their challenges and needs in social activities. After designing and implementing the bot, we conducted a diary study with six VIPs to study its use in everyday life. While most participants found the Bot helpful, their experience was undermined by perceived low recognition accuracy, difficulty aiming a camera, and lack of knowledge about the phone's status. We discuss these real-world challenges, identify suitable use cases for Accessibility Bot, and distill design implications for future face recognition applications.