The researchers made a study where they compared different experimental techniques and demonstrated that using the Hue technique for image processing is the most robust way to map pH and carbon dissolution in porous media.
Unlike other methods, the Hue is resistant to changes in LED luminance, camera settings, and fluid thickness, providing a stable "map" of how CO2 behaves in space and time.
While their study focused on CO2 convection for CCUS, the implications go much further. This high-resolution mapping can be adapted to monitor (1) contaminant transport: tracking how pollutants migrate through groundwater; (2) reactive transport: observing chemical reactions in soil geochemistry in real-time.
The paper compares different image analysis approaches and shows that a hue-based method is surprisingly robust, even when experimental conditions (lighting, thickness of fluid, camera parameters etc.) vary.