This article the first instance I've heard of placing the mask directly on the sensor. I'd always had the impression that the coded aperture would be substituted for the original lens aperture. And the images I've found online seem to indicate that the aperture is macro-scale. This is something which could be imaged on lith film or hard-dot film.

I'd really like to play around with these techniques, but I don't know where to start. The only deconvolver I could find used Mathematica, so I'm not sure how useful making a coded aperture would be if I couldn't see the results.