Instrumentation and methods for optical metrology of heliostats

A system for providing a contour map of the surface of a heliostat from reflected sunlight using a fly's eye camera comprising:

• an entrance screen configured to receive sunlight reflected by the heliostat;
• an array of imaging apertures extending across the entrance screen, each aperture forming an image of said heliostat from a different viewpoint to provide a plurality of heliostat images;
• one or more digital cameras configured to view all of said plurality of heliostat images;
• an image processor configured to map out from said plurality of heliostat images a location of sunlight delivered to said entrance screen by each of a plurality of different resolved subsections of the heliostat reflecting surface to obtain a plurality of maps, and to provide, based on centroids of said maps a tip and tilt of each said subsection,
• wherein a reflecting surface profile of the heliostat is obtained by integration of said subsection tilts across all the subsections.