Motion Tracking pixel coordinates

I am testing for strain in a really thin smart material, but I would like to solve for strain by finding the change in position or size from 2 or more images imported into MATLAB. So, I am trying to create a program that will take in at least 2 pictures. In these two pictures there will be several white dots on a black surface. I am trying to calculate the euclidean distances the white dots travel between the two pictures. From there I can calculate strain, but I do not know how to calculate the distances traveled.

I am looking to see if anyone has any pointers on how to start this. I have attached what I have so far (not very much) but I am unsure of what the next step is.