In OP's setting, imho you can use the term you want: inpainting because it's a large missing area, SR because some people see SR as filling in new rows and columns (I don't, I prefer to see it as inverting the lens degradation) and interpolation because it just means "adding things between other things", at least in my native language. I'm not sure what usual methods you are referring to, but you could suggest them to OP!