A sample wire is vertically dropped and photographed from a direction perpendicular to a dropping direction and a meandering degree of a curve found out from a photographed image is sectioned into 2 to 25 times the length of a loop and evaluated. 試供ワイヤを垂下し、垂下方向に垂直方向から撮影し、撮影像から求めた曲線の蛇行度をループ長さの2〜25倍の長さに区切って評価する。 - 特許庁