Neural-network-based method for improving measurement accuracy of four-quadrant detectors.

Due to the high accuracy and fast response, measurement systems based on four-quadrant detectors (4QDs) are widely used. There is a non-linear relationship between the output signal offset (OSO) of the 4QD and the actual spot position, resulting in limited measurement accuracy. Existing methods improve detection accuracy by collecting large amounts of data and approximating the OSO curve.