  Presenters commonly use slides as visual aids for informative talks. When
presenters fail to verbally describe the content on their slides, blind and
visually impaired audience members lose access to necessary content, making the
presentation difficult to follow. Our analysis of 90 presentation videos
revealed that 72% of 610 visual elements (e.g., images, text) were
insufficiently described. To help presenters create accessible presentations,
we introduce Presentation A11y, a system that provides real-time and
post-presentation accessibility feedback. Our system analyzes visual elements
on the slide and the transcript of the verbal presentation to provide
element-level feedback on what visual content needs to be further described or
even removed. Presenters using our system with their own slide-based
presentations described more of the content on their slides, and identified
3.26 times more accessibility problems to fix after the talk than when using a
traditional slide-based presentation interface. Integrating accessibility
feedback into content creation tools will improve the accessibility of
informational content for all.
