Improved wavefront reconstruction algorithm for Shack–Hartmann type wavefront sensors

In the present work, we propose an improved wavefront reconstruction algorithm for zonal wavefront estimation using Shack–Hartmann type wavefront sensors. We start with the well known W H Southwell reconstruction algorithm, where phase at a central point is described in terms of horizontal and vertical slope values. We develop the mathematical expressions to show that by incorporating the diagonal slope values in addition to the horizontal and vertical slope values, accuracy in phase estimation can be increased. We present here experimental results that demonstrate significant improvement in the wavefronts, estimated using the proposed algorithm, in comparison to the Southwell algorithm.