Design of Quadrant Photoelectric Detection System and Method of Displacement Calculation

A quadrant photoelectric detection system was built to accurately measure the displacement of laser spot. The designation of the quadrant photoelectric detection system was separated into a theoretical part and an experimental part. In the process of deducing the theoretical formula, the addition-subtraction algorithm was utilized to derive the azimuth offsets of the Gaussian beam, and polynomial fitting functions were used to calculate the position of laser spot center. In the process of building experimental platform, a two-stage amplification circuit for the quadrant photoelectric detection system was specifically designed to enlarge the weak signals, and wavelet threshold denoising was utilized to reduce the noise of the output voltage signals. Moreover, an experimental platform was built as well to measure the position of laser spot center compared with theoretical ones. Both of simulations and experimental results show that the designed quadrant photoelectric detection system can preciously calculate the displacement of laser spot center, and the absolute position errors of measured spot center are less than 0.02 mm.