Investigation of average optical density and degree of liquids saturation in sand by image analysis method

Abstract

This research aims to apply an image analysis technique to investigate relationships between liquid saturations and Average Optical Densities (AODs) of four different porous media (i.e., Ottawa#3820, Ottawa#3821, Toyoura, and Chonburi sands).  Water and diesel are used as liquids. Twenty tested samples, including 10 samples of air-water two-phase system and 10 samples of air-diesel two-phase system with variations of diesel and water saturations, are prepared for each porous medium.  All samples are compacted into cylindrical containers then photos of each sample are taken by two digital cameras fitted with different band-pass filters.  The photos are analyzed by an in-house program to obtain average optical densities for each spectral band.  Relationships between AODs and liquid saturations are analyzed for each porous media.  The results indicate that AODs are linearly proportion to degree of water and diesel saturations for all porous media in both spectral bands except Chonburi sand.  The reason is due to the fact that Chonburi sand has a very rough surface which can absorb water and other liquids more than other media.