1. static scene 2. forward-facing view 3. with small view-port changes. Smaller viewport change / forward facing views, No moving / deforming objects. (e.g. a car driving across the street, a bird flying across the sky, people waving hands), No significant illumination/exposure changes. (e.g. camera moving from pointing towards the sun to back to the sun), No focal length changes. Currently assume all input share the same camera intrinsics.