I’d like to leave it open to the people interested in actually building this to define the actual scope.
My take is that we really want to have a compiler IR here, designed with transformations/optimizations in mind. I am not confident enough to answer how orthogonal (or how similar) are the optimizations on the usual set of op in the Tensor domain (like in nGraph/HLO) compare to what you would want to achieve with image processing kind of primitives from OpenVX/OpenCV.
G-API has also PlaidML as a new backed. So I think some CV related operation could pass over MLIR with the PlaidML MLIR refactoring. /cc Is it correct @flaub?