Applying the Techniques of Microstructural Image Processing Toward Measuring Interface Angles in Unsaturated Geomaterials

Previously, researchers have examined phase interactions in multi-phase systems such as geomaterials at different degrees of saturation. Some studies have measured the angle made by the solid-liquid and liquid-air interfaces using physical laboratory tests. The lack of technological advancements that enabled microstructural inter-phase examination has largely impeded results from such efforts. In addition, the measurement of contact angle has largely been dominated by user interference. Recent developments in image acquisition and associated advanced image processing platforms have enabled automated quantification of microstructural features. This study proposes two image-based contact angle-measurement approaches: the "liquid-pixel" and "regression" approaches. The study also investigates "center" identification for contact angle measurement. Statistical evaluation of the measurements is performed for both methods and the observed results are discussed. It is concluded that the "non-zero-intercept" approach, one variation within the regression-based techniques, gave the most reliable angle measurement.