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by mbarronj 2489 days ago
Not only wave length, but also beam width. The laser is spatially very compact. Radio waves need larger antenna apertures to be that focused. It's hard to get tight spatial resolution with a beam that looks like a balloon animal.

Also, multipath and time-of-flight is difficult with radio waves, and the EM reflectance is weirder. Light is just much more convenient for this purpose. But - it's not outside of the realm of possible.
2 comments
jjoonathan 2489 days ago
> Light is just much more convenient for this purpose

With RADAR you get phase information, which helps a lot, and now that 60GHz wifi is a thing the balloon animal has a manageable size :)

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orbital-decay 2489 days ago
>It's hard to get tight spatial resolution with a beam that looks like a balloon animal.

Would compressed sensing help? It doesn't need the focus to be precise to reconstruct the scene from a single pixel detector.

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woeirua 2488 days ago
No, compressed sensing only allows you to attempt to reconstruct the original signal from a limited subset of the data sampled in a specific way, as long as you can assume some kind of sparsity on the data in another domain.

Fundamentally, you cannot get something from compressed sensing that you wouldn't be able to otherwise normally.

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