Ulra-high sensitivity range finders?

johnwasser:

Morphinity:
I'm looking for a sensor that can detect changes ranging from 10 millimeters to 1 millimeter on a smooth surface, so I'll need something that can detect up to 3 decimal places. The system is meant to detect small cracks or dents with an accuracy/error rate of about 10%.

I'm not sure what you mean by "3 decimal places". Do you mean 1.00 to 10.0 mm or do you mean 1.000 to 10.000 mm?

1.00 to 10.000 mm or thereabouts. I'm sorry for confusing you.