TY - JOUR T1 - A New Method for Measuring Contact Angle of Impacting Drop TT - روشی جدید جهت محاسبه زاویه تماس قطره با سطوح JF - joc-isice JO - joc-isice VL - 11 IS - 4 UR - http://joc.kntu.ac.ir/article-1-416-en.html Y1 - 2018 SP - 47 EP - 55 KW - Measurement KW - Contact Angle KW - drop impact KW - Image Processing. N2 - In this paper, a new image processing technique has been proposed to measure the contact angle of symmetric and asymmetric drops. In our proposed method, the contact angle is calculated by analyzing the side view image of the drop without needing any liquid parameters. The procedure of the technique is according to the secant technique coupled with a Gaussian weighted function, as follows: at the beginning the exact location of the contact points is obtained by Harris corner detector function, then a series of points are selected on the drop boundary near the contact points. In the third step, a set of contact angles are estimated by passing secant lines through the contact point and each of the boundary points. In the final step, a gaussian weighted average function is applied to the calculated angles to estimate the main contact angle. The contact angle measurement algorithm is verified by comparing its results with the obtained measurements of a recent standard study. High accuracy, usability for all ranges of contact angles, applicability to both symmetric and asymmetric drops and being fully automatic are other advantages of the presented method. M3 ER -