Library/strategy for rotate & scale image alignment/registration I have two raster images of maps, A and B.  I know that B contains A but I do not know the scale or rotation.  There should not be any other distortions between the image but there may be noise.  Please could anyone recommend an approach or software library which would provide me with the scale and rotation transformations to align A onto B, thus allowing me to transform arbitrary points between the coordinate spaces?



Left: A: source, B: destination.

Right: Location of A on B

Given the high contrast, plane sharing and 'edgyness' of the images I would hope it would be fairly trivial compared to most image analysis tasks.  There are similar questions on here but they seem to be doing something more complex.
One option is keep all the edge points, or to identify key points (junctions, corner) on both images, and then perform a (semi-)rigid matching, such as Coherent Point Drift, which is robust to missing points. 

Further, you could split the biggest images into smaller overlapping patches, and adapt the template to the different patches.