I had in my plans for two cameras in a stereo scopic setup for down vision so I could figure out depth and distance to things on the table .

However. doh! , I was playing with my fancy PointGrey camera last night and realised I don’t need two cameras, I just need to take a image, and move the camera and take another image ! and I can move the camera with sub pixel accuracy in the FOV.

And then, another obvious penny dropped.  Image de blurring and refocussing  (enhancing depth of field) can be done with a series of images takes when a camera moves in a plane tangential to the object. I read that many  years ago .

And of course I can move my down (and up) camera and take multiple shots.

So a bit of searching and googling later reveals google have done it for Android

http://googleresearch.blogspot.com.au/2014/04/lens-blur-in-new-google-camera-app.html