DROP INTERFACE SHAPE RECONSTRUCTION USING STEREOSCOPICSPECKLE MEASUREMENTS
Abstract
A stereoscopic speckle imaging technique is developed for measuring three-dimensionalinstantaneous profiles of asymmetric liquid drops on rough surfaces. The surface rough-ness creates a speckle pattern that allows for the cross-correlation of images with andwithout the drop present. The difference in the images captured using two stereoscopiccameras are encoded as shift vectors caused by light refraction across the drop inter-face. The drop profile is reconstructed using a simplex optimization procedure to findthe shape for which the calculated shift vectors best match the measured shift vectors.An error analysis was performed and found contact angle error to be within -3.4° and2° for one standard deviation. The stereoscopic approach is shown to better reconstructcontact angles as compared to the single camera method while simultaneously increasingthe maximum measurable drop contact angle from 50° to 70°. This is due to the an-gled stereoscopic cameras delaying the internal reflection of light refracting through thewater-air interface. Drop volume, height, and pinning force estimates generated using theapproach are analyzed and discussed.
Citation
Giordano, Hugo (2021). DROP INTERFACE SHAPE RECONSTRUCTION USING STEREOSCOPICSPECKLE MEASUREMENTS. Master's thesis, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /193136.