# FreeFlow: A Bias-free Hierarchical Transformer for Optical Flow Estimation > Source: > Published: 2026-09-11 09:30:34+00:00 Optical flow methods typically rely on task-specific inductive biases, such as correlation volumes, feature warping, and iterative refinement, among others, to reach high accuracy. While effective, such biases constrain the model to predefined heuristics, which can limit its expressivity and lead to