My feeling is that: - lots of people in the DNN for machine vision community do not have a background in classical techniques. - a lot of classical techniques

My feeling is that: - lots of people in the DNN for machine vision community do not have a background in classical techniques. - a lot of classical techniques and preprocessing pass make no real difference when applied to the input of a DNN and are thus worth eliminating from the pipeline to simplify it (this has been my experience). However, I do think that there are gain to be gotten by combining classical image processing ideas with neural networks. It just hasn't really happened yet.