[moftz]

This is an interesting idea but how does the cost compare both on computer resources and setup effort to scan the entire warehouse floor? Simply having robots with accurate motor encoders (and maybe IR sensors like in mice) and enough floor tags should allow the bots to move around the factory in safely defined paths. You can accomplish this with a basic microcontroller and can have robots quickly moving across the floor while scanning tags to update their positions. This image based system would allow more dynamic paths to be taken but now you need a much more expensive computer running image comparison and storing what I can imagine to be a massive image dataset.

[regularfry]

Motor encoders drift. If the wheels ever slip, your encoders are now telling you the wrong position. In fact, that's how this system works: they read encoders to get a dead reckoning position, then correct it with the visual system to give full accuracy.

The advantage of a photo survey is that you can do it with the bot hardware (as in fact they do here; they dragged it around but I don't see why you couldn't do random-walk to cover an area), so setup cost should be relatively constrained. Computationally you're not exactly breaking the bank either - it's running at 4fps on an Nvidia Jetson TX1, which I suspect is overkill.