Co-phasing segmented surfaces using the geometric sensor

This paper presents a method to co-phase segmented mirror. For this purpose, we use the geometric sensor, thus only two defocused images are acquired. The van Dam and Lane algorithm [1] is applied to obtain the tip-tilt in every segment, and a new method is used to restore the original local piston. Furthermore, by using specialized hardware the computations can be performed in real time, within the stability time of the atmosphere.