A Calibration Algorithm for Solar Tracking System

Solar tracking systems that use cameras, lenses and mechanical motion stages usually calibrate each device independently. While this scheme allows modular systems characterization it has the disadvantage of using additional expensive calibration patterns. In this work, we present a low cost solar tracking platform integrating on the shelf components. To avoid the use of additional components for system calibration we propose an algorithm to perform motion stage-camera calibration using minimal data from the earth sun geometry, decoder motor values and solar image locations. Thus, from a known set of measurements: angular values from motor decoder and sun image locations a linear system of equations allow to find the parameters that represent the transformation from pixel displacement to angular values. In addition we present a real time module based on modern graphics cards for image processing. Results are presented to show the feasibility of our approach to circumvent camera lens distortion and mechanical instabilities of the low cost tracking system.