autocorr2 - Two-point autocorrelation

Determine the radially averaged autocorrelation of a binary image

This function calculates the radially averaged autocorrelation (also known as pair correlation or two-point correlation of the pixels of an image as a function of distance. The function is really fast because it uses the Fourier transform for the convolution of the original image. The code also corrects for the finite image size: images close to the edge have fewer neighbors than particles near the center.

The code is inspired by its imagej version, programmed by Michael Schmid. More information here: https://imagejdocu.tudor.lu/macro/radially_averaged_autocorrelation