A much better way of doing this...
Why not just encode a z-channel into normal photos?
I bet most decent modern DSLRs with multi-focus sensors could do this, I am sure it could be rigged up with an IR laser too.
The film & special effects industry has been doing this for 20 years or so by encoding the z-channel (image depth) into images. The pictures are rendered with an aperture of infinity (hey, because you can!) which makes everything crystal clear, then you choose what you want your depth of field to be, and where, Gaussian-blur filter by z-channel mask and presto!
Same effect, easier, quicker, all the advantages of DSLR or even PAS cameras, standard image format (TIF) and images only 25% larger (4 channels instead of 3).
Hmmm, maybe I should patent that.