From: "Mel Bartels" 
To: "ATM shore" 
Reply-To: "Mel Bartels" 


>>>
 Briefly: Cover the mirror with a mask containing an grid of small holes.
 Take two images at a known spacing.  Analyze the spots and viola - a
 complete surface profile.
<<<

I've done some thinking along these lines and discussed it with Jim
Burrows. He pointed out that the diffracion effects between the holes are
significant and suggested ignoring the focusing light from the holes and
instead concentrating on the diffraction pattern.  Perhaps Jim can discuss
this further.

Mel Bartels

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