I imagine the only way to hide objects from this technology is to enclose them well enough to prevent most photons that bounce off the objects from leaving the enclosure.
And this is just an early-stage proof-of-concept. There's a good chance the technology can and will improve significantly over time.
Summary: by bouncing light off of a target barrier and having the light scatter around the barrier, you can compute an image of objects behind the barrier.
Edit: I'm also wondering if anyone has any idea as to the estimated cost of such a technology? Thousands, tens/hundred of thousands, millions? A quick search of lidar sensors seem to be in the range of $2500 - ~$10000 for ranges of sub 30 meters.
This technology seems similar(?) to lidar from what I can tell.
I imagine that idea could be improved more with this technology, but Tesla is very anti lidar so it’s have to be someone else.
On a more upbeat note though, imagine the possibility of producing a 3d image of your internals during keyhole surgery or inspecting remote structures like solar panels and dams via satellite.
Most of the cost will be in the telescopes.
If you don't count personnel time integrating/fiddling around, maybe $1000 at qty 1?
Or other non-line-of-sight things, like sensing through an aperture in a body?
For example, vehicles seeing around corners to avoid collisions or being able to see further into damaged industrial sites than robots can go today (i.e. Fukushima), or for cave explorations (especially if they improve significantly and start building images from multiple reflections - see around the corners that themselves are around corners).