Contact angle is important in the study of many industrial processes, such as wetting, adhesion and floatation. Numerous methodologies have been developed for the measurement of contact angles. But there still exist many problems; in particular, there is no good method available for measuring contact angles of irregular drop shapes. To overcome those difficulties, we developed a method based on image analysis, with edge detection in sub-pixel resolution. The method employs a user-oriented computer program in C++ language written on Windows 98 SE. Comparing with other methods, our method can better satisfy the need of simplicity, accuracy, and flexibility in measuring contact angles; it can be applied to situations of asymmetric drop shapes. We will further use this method to measure line tensions and study the adhesion of yeast cells to various surfaces.
