It is out by a factor of two because there is a mistake in single_sided_correction - guess it passes the tests because the tests only cover half the possible cases (odd or even) ...

A simple script for Quantitative Phase Imaging This contains a simple script to extract the local phase values from the image with interference pattern.

We agree it is simple, but actually, it isn’t so much Python per se, it is some pretty cool libraries (SciPy, in particular) that do all the hard work.