opencv. How to determine the blur kernel given the original and the blurred image?

Question

C++ / C#

There are 2 downloaded pictures in Matyu format. The
same size, depth, etc. The second of them is a convolution of the first one with a certain core whose size, let's say we know. How can we calculate this kernel in opencv?
Thanks in advance

Answer 1

It seems that solving a system of equations with 9 elements, in the case of a 3x3 matrix, will help.
There is an Eigen library for this