It seems that other computer vision tasks such as classification, segmentation and synthesis have seen huge advances in accuracy thanks to CNNs, but there seems to be no equivalent advance in image registration. I tried searching for advances in image registration, but it seems that researchers still use ‘classical’ image registration techniques like mutual information, cross-correlation, etc. Even though there are DL image registration research papers, they are not well adopted in the community.

Fundamentally, is there a reason why this task is more complex that the aforementioned ones?