Generalized Fast Approximate Energy Minimization via Graph Cuts: Alpha-Expansion Beta-Shrink Moves

We present α-expansion β-shrink moves, a simple generalization of the widely-used αβ-swap and α-expansion algorithms for approximate energy minimization. We show that in a certain sense, these moves dominate both αβ-swap and α-expansion moves, but unlike previous generalizations the new moves require no additional assumptions and are still solvable in polynomial-time. We show promising experimental results with the new moves, which we believe could be used in any context where α-expansions are currently employed.