title: Given Three Points Compute Affine Transformation
body: <p>I have two images and found three similar 2D points using a sift. I need to compute the affine transformation between the images. Unfortunately, I missed lecture and the information out there is a little dense for me. What would the general method be for computing this 2x3 matrix?</p>
  
  <p>I have the matrix of points in a 2x3 matrix [x1 y1;x2 y2;x3 y3] but I am lost from there.
  Thanks for any help.</p>