An automated methodology for grain segmentation and grain size measurement from optical micrographs

Grain size of a material and its distribution has tremendous impact on strength and toughness of a material. An image processing based automated methodology has been developed in this work and applied on the optical micrographs of different types of interstitial-free steels. Polished and etched surfaces of the specimens were observed in an optical microscope and number of images was captured by digital camera. The methodology developed in this work has been applied over these images to find the grain size of the steel and their distributions. In this methodology, a sequence of steps has been applied on the images to obtain closed contours of the grains which enable measurement of grain size. The outcome of the proposed methodology has been found comparable with other commonly used methods. (C) 2019 Elsevier Ltd. All rights reserved.