Wavefront sensing is an old yet fundamental problem in adaptive optics. Traditional wavefront sensors are limited to time-consuming measurements, complicated and
expensive setup, or low theoretically achievable resolution.
In this thesis, we introduce an optically encoded and computationally decodable
novel approach to the wavefront sensing problem: the Coded Shack-Hartmann. Our
proposed Coded Shack-Hartmann wavefront sensor is inexpensive, easy to fabricate
and calibrate, highly sensitive, accurate, and with high resolution. Most importantly,
using simple optical flow tracking combined with phase smoothness prior, with the
help of modern optimization technique, the computational part is split, efficient, and
parallelized, hence real time performance has been achieved on Graphics Processing
Unit (GPU), with high accuracy as well. This is validated by experimental results.
We also show how optical flow intensity consistency term can be derived, using
rigor scalar diffraction theory with proper approximation. This is the true physical law
behind our model. Based on this insight, Coded Shack-Hartmann can be interpreted
as an illumination post-modulated wavefront sensor. This offers a new theoretical
approach for wavefront sensor design.
|Date of Award||Dec 2016|
|Original language||English (US)|
- Computer, Electrical and Mathematical Science and Engineering
|Supervisor||Wolfgang Heidrich (Supervisor)|
- Computational imaging
- Wavefront sensing