PSF extraction (Tool under development not public available)
A new tool is under development that allows simulation of the star-test images taken at the eyepiece. The software works like this:
a) load the star-test image
b) accurately pin-point at the middle of the diffraction image
c) calculate the average pixel value for different radii around the diffraction-center. These average pixel values are the observed PSF-values (see image below)
d) simulate a diffraction image with initial aberration-parameters (focus/obstruction)
e) calculate the average pixel value for different radii around the simulated diffraction-center. These average pixel values are the simulated PSF-function.
f) calculate per pixel the squared difference in PSF between observed and simulated and sum these over the range of the diffraction image.
g) change the aberration settings and go back to d) until the squared differences are minimized till a certain tolerance level
The iterative routine uses a multidimensional simplex search to find a best solution.