I have a project where I would like to image an object and be able to derive the heights of features in this image to sub-millimetre precision (exactly how precise is still yet to be determined, but let's say 100ths of a millimetre for now).
I have been previously advised that direct laser ranging techniques will not be appropriate
- the travel time will be too small and thus will require too much precision to make precise calculations
- minor vibrations (such as a person walking near the apparatus) will perturb the results
I have observed a laser device that sells for approximately $1000 that can achieve the precision but suffers from the vibration problem (which is fine, mechanically isolating the apparatus is another discussion).
I would prefer to achieve a result that is more cost effective, and considered stereo vision as an alternative. Being a novice to this field I am uncertain if the desired precision can be achieved.
Is the desired precision (at least) theoretically attainable?
Is there a recommended paper or resource that would help explain this topic further?
The objects in question will range from approximately 1/2" square up to about 2 1/2" square with some times very low thickness (1/16"?). A large percentage of the surface should be flat, though one test will be to confirm that assertion. Features will be fairly rough (generally sharp transitions). Aug 17 at 11:00
One of the "harder" interesting objects would be about 20mm square, 1.25mm high. The surface features in question would be on the order of .1 - .3mm I'm estimating. The camera position would likely be on the order of 6" above. Does this give you better insight? Aug 17 at 15:15
I am not looking to perform a single profile/relief measurement, but rather attempting to generate a surface height map of the object. The surface features of the object, as well as the overall profile, are of significant interest.