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Comment by serjester | Hacker News Reader

I wrote a similar article a couple of months ago, but focusing instead on PDF bounding boxes—specifically, drawing boxes around content excerpts.

Gemini is really impressive at these kinds of object detection tasks.

https://www.sergey.fyi/articles/using-gemini-for-precise-cit...

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That's really interesting, thanks for sharing!

Are you using that approach in production for grounding when PDFs don't include embedded text, like in the case of scanned documents? I did some experiments for that use case, and it wasn't really reaching the bar I was hoping for.

Yes, this was completely image-based. Not quite of a point of using it in production since I agree it can be flakey at times. Although I do think there's viable workarounds, like sending the same prompt multiple times, and seeing if the returned results overlap.

It really feels like we're maybe half a model generation away from this being a solved problem.

Thanks for this post — I'm doing something similar for a personal/hobby project (just trying to work with very old scanned PDFs in Sanskrit etc), and the bounding box next to "Sub-TOI" in your screenshot (https://www.sergey.fyi/images/bboxes/annotated-filing.webp) is like something I'm encountering too: it clearly “knows” that there is a box of a certain width and height, but somehow the box is offset from its actual location. Do you have any insights into that kind of thing, and did anything you try fix that?

I suspect this is a remnant of how images get tokenized - simplest solution is probably to increase the buffer.

What buffer are you referring to / how do you increase it? And did that solution work for you (if you happened to try)?

For what it's worth, I worked around this by first calling Google's older OCR api (Cloud Vision), which gives the coordinates and bounding boxes for each word in the document. Then I pass this whole response to Gemini, and it's finally able to give me much more reasonable bounding boxes. Clearly overkill, and would be ridiculously expensive to do at scale, but works for me.

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