For some reason I thought this article would explain how to ID a specific cat, that is basically facial recognition for cats.

Is this even something that's possible with current tech? Like, surely cats have some facial features that can be used to uniquely identify them? It would be cool to have a global database of all cats that users would be able to match their photos against. Imagine taking a picture of a cat you see on the street, and it immediately tells you the owner's details and whether it's missing.

I wrote the CatBench vector search playground toy app exactly for this reason! [1] ("cat-similarity search for recommendation engines and cat-fraud detection"). I built it both for learning & fun, but also it's useful for demoing vector search functionality, plugged in to regular RDBMS application schemas in business context. I used cats & dogs as it's something everyone understands, instead of diving deep into some narrow industry vertical specific use case.

[1]: https://tanelpoder.com/posts/catbench-vector-search-query-th...

I imagine when they run out of other sensors to add to our phones, they’ll add chip readers so you can just scan for the implanted microchip on a cat you encounter. (said semi-sarcastically since the tech requires close proximity between animal and reader which most cats you encounter on the street will not countenance)

Yes, I've worked in this space for dogs (for re-identifying animals that have been vaccinated for rabies). It's a very difficult problem, but mostly because getting/scraping good training data is difficult. You really want lots of paired images of the same animal and that's hard compared to searching for "cat". Plus the usual challenges: animals don't like to stay still so getting good pictures is hard and users must have good guidance for lighting/pose to get the best results. Human facial recognition benefits from strong commercial interest and the most robust methods rely on extras like 3D scanning.

Tricks include facial alignment + cropping and very strong constraints on orientation to make sure you have a good frontal image (apps will give users photo alignment markers). Otherwise it's a standard visual seatch. Run a face extraction model to get the crop, warp to standard key points, compute the crop embedding, store in a database and do a nearest neighbour lookup.

There are a few startups doing this. Also look at PetFace which was a benchmark released a year or so ago. Not a huge amount of work in this area compared to humans, but it's of interest to people like cattle farmers as well.

https://github.com/mapooon/PetFace