GOAL OF THE PROJECT
Following the work of Yicheng Wu and Ashok Veeraraghavan presented in Nature LSA, this project is a continuation of the WISH algorithm for high resolution wavefront sensing. This would in term allow full field measurement in a hot atomic vapor experiment. We very sincerely thank Yicheng for sharing his Matlab code with us !
The approach presented in the 2 references is to use the SLM to modulate the face, and then use phase retrieval algos (Gerchberg-Saxton). The main advantage is that instead of doing one single calculation through a phase retrieval algo that is not perfect, one can average over the modulation thus greatly improving the precision of the reconstruction.
COMPUTE CGH
A small holographic pattern generator is available here. A detailed readme file explains the usage of the code.
WISH
In the WISH folder you will find our python implementation of Yicheng Wu's Matlab code allowing replication of the results of their LSA paper. In the dev folder you will find the development version of our tailored version of this code. The code has a main class WISH_lkb.py that handles the computations. Its workflow is described in the following figure.
The simulations can be carried out using WISH_simulation.py and the actual measurements using WISH_measurement.py. Note that the latter is designed to run with a Point Grey camera, and an SLM or DMD that are handled as secondary screens.
CONTRIBUTION
If you want to contribute, you are more than welcome to do so. Simply create a new branch with you name on it. If you do not know how to do it, simply use the GitHub webpage and click on "branches" and type the name of the branch you want to create:
Then do not forget to checkout as this new branch ! :)
Also feel free to declare issues if you see some, the code is still far from ideal.
PYTHON LIBS AND DEPENDENCIES :
The computation are mainly carried out on GPU using CUDA. For the Python front-end, Cupy is used as a drop-in replacement to run a Numpy-like API. Data acquisition is handled by an OpenCV like interface for Point Grey cameras : EasyPySpin that relies on the official Python API from FLIR, PySpin. Control of the SLM (or DMD) is handled using PySLM.
REFERENCES :
https://hal.archives-ouvertes.fr/hal-00533180/document