I like the idea of photographing the books on the shelves, I wonder if you could possibly OCR the title of the book from the spine. Although I guess fonts used on books are pretty varied.
(Unrelatedly I also had a gig OCRing books for someone with a visual disability, which is where I got the idea.)
Today I work in the AI division of a major tech company and I can say with some confidence that you could absolutely OCR spines if your OCR platform is new enough :3