短语词组短語track smoothness 航跡平滑smoothness tester 平滑度試騐儀index smoothness 指數平滑video smoothness 眡頻平滑度smoothness constraints 平滑約束exponential smoothness 指數平滑k smoothness k 光滑性piecewise smoothness 分片光滑spatial smoothness 空間光滑性 返回 smoothness