Effect of detector noise on the positioning accuracy of an autofocus system.
An autofocus system has been developed that automatically detects the presence of fringes in a white-light interference microscope and adjusts the vertical position of the microscope objective such that the focus error is minimal. The system consists of a motorized stage, a beam splitter, an optical detector, and associated electronics. In order for the interference microscope to provide accurate measurements of the optical wavefront, the error in the focus position must be small. The goal of this paper is to calculate the rms noise produced by the detector and electronics and use the results to predict the positioning error of the autofocus system.
Caber
P J
PJ
Cohen
D K
DK