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How would these cameras identify spills? I would imagine it would be hard to detect a clear liquid spill from a ceiling camera, but maybe I'm wrong. I would imagine if ceiling cameras could do this job, they would, as it seems way less expensive and intrusive.

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Polarization imaging [1] could probably do it. Granted, the sensors are expensive and lower resolution than one might like.

Another way is to measure surface specularity. Use one or more IR spotlights at different angles to the surface and strobe them on and off. A wet surface will have a different angular variation in reflectivity vs a dry surface, unless the floor is very shiny.

1. https://thinklucid.com/tech-briefs/polarization-explained-so...

Can the bot reliably identify clear liquid spills?

Even if it can't, it has wheels and, I assume, distance measuring sensors/encoders, etc. Slip is "easily" detected by monitoring wheel response to motion commands.

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