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Comment by frozenport | Hacker News Reader

Its always fun when somebody from another field (computer science) discovers something that is very well know in your field (E&M). One of the parts missing from this paper is that the PSF's of optical systems have a real and imaginary part but measuring the imaginary part is quite difficult and is mostly only done for biological samples.

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Heh! This is especially true for SIGGRAPH! Just take some ten year old physics / engineering paper, implement the algorithm on a GPU, done!

To be fair, SIGGRAPH has a strong focus on applied work, and the contributions are often extremely amazing, despite the fact that the underlying method has been developed by someone else and published before.

There are some really clever techniques out there for recovering the imaginary parts actually, at least in a similar domain (transmission electron microscopy), but they're still somewhat new.

Could you please elaborate on these techniques? I'd be most interested in any relevant papers. Thanks!

Can't find a good holistic reference off-hand, but you're looking at focal series reconstruction (or, if you're using specialised equipment, holography) to recover phase information of your wave. That can then be used to reconstruct transfer functions and the like. [This isn't something I do personally so I don't want to go into too much detail in case I explain something incorrectly!]

These guys have a method: rogers.matse.illinois.edu/files/2011/slimoptexpr.pdf‎

I just realized something.

The complex PSF isn't important for camera applications because the complex field carries the transparency information. I don't want to see transparent things with my camera.

The imaginary part can be grabbed in several ways.

The Lytro camera is the closest I'm aware of to bringing such things to market.

Can you point at some papers in your field on this topic?

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