This dissertation deals with optical vision probes being increasingly used for non-contact coordinate metrology. In the first place, a new definition of the measurement uncertainty of vision probes more relevantly than the conventional Rayleigh two-point resolution criterion. Then a theoretical approach has been made to derive the resolution in terms of the f-numbers of the imaging lens, magnification, and the spatial resolution of the CCD camera under various illumination conditions. Finally, the derived resolution has been verified through experiments.
The important findings of this investigation are summarized as follows:
(1) The measurement resolution becomes better when the illumination is coherent rather than incoherent. This result is evaluated in terms of worst values of resolution.
(2) In actual cases, the illumination turns out to be partially coherent. When the magnification is less than 5, however, the illumination may be approximated as being coherent. On the other hand, when the magnification becomes as much large as 20, the illumination is more close to the case of being incoherent.
(3) In general, the measurement resolution reaches one hundredth of the pixel size, much finer than one eighth generally known.