Enhancing measurement accuracy of position sensitive detector (PSD) systems using the Kalman filter and distortion rectifying

Abstract

Factors affecting measurement accuracy of Position Sensitive Detector (PSD) systems consist of inaccuracies caused by interface circuits, system connection, outside environment change, and the semi-conductive properties of the sensor. The presence of these factors causes noises and distortions that are interpreted as a valid signal by the PSD system. As a result, these inaccuracies heavily degrade the PSD performance and hamper the measurement resolution and accuracy of the PSD system, which greatly limit its applications in micro/nano positioning systems. Our work is to (1) design a Kalman filter for the system that is used to recursively and optimally estimate the laser spot position value of the modeled second-order linear lateral effect PSD sensing system from a series of measurements mixed with these noises and (2) develop a distortion rectifying methodology to collect pincushion-type radial distortion associated with the lateral effect PSD systems, so as to enhance measurement accuracy in a larger active area of the PSD. After implementation, both the developed Kalman filter and distortion rectifying algorithm can greatly improve the measurement accuracy of the PSD systems. It will be very useful in a wide variety of applications that use a PSD embedded system.