A Novel coarse-to-fine Localization Algorithm for Automated Vickers Hardness Measurement

Abstract Vickers hardness testing is one of the most useful methods to determine the hardness of materials. To calculate the hardness of materials, the key is to measure the diagonal length of the Vickers indentation on the surface accurately. However, since this length is extremely minuscule, there are many challenges to achieve accurate measurement. Especially, when the indentation corner is cracked, the precise position of the corner cannot be obtained by conventional methods. In this paper, we proposed a method of coarse-to-fine localization to accurately locate the indentation corner. The coarse localization process can be used to determine the position and size of the indentation. During fine localization, the linear equations of the indentation edges are calculated by the line fitting method. The capabilities of the proposed method are compared to manual measurement and results are presented.