INSPECTION METHOD, INSPECTION APPARATUS AND CONTROL METHOD OF ROLLING APPARATUS

To provide an inspection method which can highly accurately detect a minute concave-convex defect generated on the surface of a metal rolled plate.SOLUTION: An inspection method comprises: a step A of preparing a metal plate WP that is rolled along the first direction; a step B of projecting the striped illumination in which a plurality of bright and dark streaks extending in the second direction alternately appear along the third direction intersecting the second direction on the surface of the metal plate so as to have an angle equal to or greater than about 80° and equal to or less than about 100° between the first direction and the second direction; a step C of acquiring a two-dimensional image of a striped pattern formed on the surface of the metal plate; and a step D of extracting a defective section image in a predetermined size or smaller from the two-dimensional image.SELECTED DRAWING: Figure 1 【課題】金属圧延板の表面に発生した微小な凹凸欠陥を高い精度で検出することができる検査方法を提供する。【解決手段】検査方法は、第１の方向に沿って圧延加工された金属板ＷＰを用意する工程Ａと、金属板の表面に、第２の方向に延びる複数の明暗の筋が第２の方向に交差する第３の方向に沿って交互に現れる縞照明を、第２の方向を第１の方向に対して約８０°以上約１００°以下の角度を成すように投射する工程Ｂと、金属板の表面に形成された縞状パターンの２次元画像を取得する工程Ｃと、２次元画像から予め決められたサイズ以下の欠陥部画像を抽出する工程Ｄとを包含する。【選択図】図１