Image extraction

The program is still in a development phase, but it seems to do what it should. One main problem is the use of both global variables and function arguments. (Images shown here may slightly differ from the current program version.)

In the first part, the user has to specify different imaging and setup parameters:

Currently, these have to be set manually and checked before use. The defaults assume that phase stepping is done over one G2 period with 10 steps. The final images are cut to include only the area of the grating. Usually these defaults are fine, and one only has to change the image and folder names.

Next, the images from "imfolder" are read with the read_images function:

Currently the program is set to read the raw .smv files created by the Python programs.

All images are normalized by the mean image of the reference images:

Image extraction is done with the extract_images_FFT function, which uses the Fast Fourier transform. The final images are constructed by subtracting or dividing the images. With the differential phase image, unwrapping may be needed.  Matlab's own unwrap function might not work for every situation.

Finally the images are plotted: