# Optical Flow: Method to estimate a very small displacement

As I was searching for available resources( here, here, here and many more), I realize that many developed optical algorithm is to estimates LARGE displacement. However, there is very limited information or journals that put effort on estimate very small displacement. The small displacement I'm taking here is at sub-pixel level. The smaller the resolution the better.

So my question, you guys have any idea in mind that might inspire a new method, or suggest an existed method (that I might not be aware of/that can be improved)? Any method/suggestion/comment is very welcomed!