Match two edges extracted from different but partly overlapped images

I have two image blocks largely overlapped with each other, i.e. with small displacement or transformations. I want to actually register them but the image block is too small to use feature points. I considered to use edges but do not get good result in matching edges of them. Is there a way to match two edges or a good solution for registering small size images. The attachment is showing edges of two image blocks of 100*100.