At work I had to make a custom image registration pipeline, that uses only 2 degrees of freedom, so just x,y translation. OpenCV did not have anything that did this, but a python library called Kornia does this well.

https://kornia-tutorials.readthedocs.io/en/latest/image_regi...

Actually base-OpenCV has a great function for this: `cv2.findTransformECC()`: https://learnopencv.com/image-alignment-ecc-in-opencv-c-pyth...

It can do dense translation, translation + rotation, Affine, and Homography alignment; I've used it in the past to do sub-pixel Aruco/AprilTag alignment (and I'd probably also use it for astrophotography).

The opencv_contrib repo does have a module, called "reg", for direct alignment.