Real-time implementation of the spiral algorithm for Shack-Hartmann wavefront sensor pattern sorting on an FPGA

A real-time implementation of the spiral algorithm is proposed for sorting the spot patterns of a Shack-Hartmann Wavefront Sensor with an FPGA. The standard spiral algorithm is adapted to the end of rendering the algorithm real-time capable, deterministic, and efficient such that it finally be highly suited for implementation on an FPGA. Preserving the primary characteristics of the original spiral algorithm, i.e. high-range and accuracy, the modified algorithm additionally shows low-latency and high-throughput concerning the ordering and calculation of the centroids. Simulation and experimental results underscore that the algorithm yields excellent performance in view of run-time and robustness requirements while remaining relatively simple in its implementation. (C) 2016 Elsevier Ltd. All rights reserved.