A novel technique for improving interferometric determination of emulsion film thickness by digital filtration.
Determination of the thickness of emulsion films by using the film interferometric images is usually less accurate than that of foam films, due to the close values of the refractive indices of the liquid film and adjacent liquid phases (hence, low contrast and high level of noise at high magnification). A new technique was developed to improve the thickness determination by obtaining the interferometric images without directly filtering the illuminating light, as is usually done in the classical Scheludko interferometric technique. The new method then uses digital filtration during the off-line image post-processing to obtain monochromatic interferometric images required for the thickness determination. The technique was tested with foam films stabilised by sodium dodecyl sulfate and successfully applied to determine thickness of toluene-water-toluene emulsion films using the green and red digital filters. Results for emulsion film thickness determined by either the green or red digital filtration are comparable, thus validating the new technique developed here for emulsion films.
Karakashev
Stoyan I
SI
Discipline of Chemical Engineering, School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
Nguyen
Anh V
AV
Manev
Emil D
ED