Noninvasive particle sizing using camera-based diffuse reflectance spectroscopy

Otto Højager Attermann Abildgaard1, Jeppe Revall Frisvad1,*, Viggo Falster1, Alan Parker2, Niels Jørgen Christensen1, Anders Bjorholm Dahl1, and Rasmus Larsen1

1Technical University of Denmark, Department of Applied Mathematics and Computer Science, Richard Petersens Plads, 2800 Kongens Lyngby, Denmark
2Firmenich SA, Research Division, Department of Materials Science, 1 Route des Jeunes, CH-1211 Genèva 8, Switzerland
*Corresponding author

Diffuse reflectance measurements are useful for noninvasive inspection of optical properties such as reduced scattering and absorption coefficients. Spectroscopic analysis of these optical properties can be used for particle sizing. Systems based on optical fiber probes are commonly employed, but their low spatial resolution limits their validity ranges for the coefficients. To cover a wider range of coefficients, we use camera-based spectroscopic oblique incidence reflectometry. We develop a noninvasive technique for acquisition of apparent particle size distributions based on this approach. Our technique is validated using stable oil-in-water emulsions with a wide range of known particle size distributions. We also measure the apparent particle size distributions of complex dairy products. These results show that our tool, in contrast to those based on fiber probes, can deal with a range of optical properties wide enough to track apparent particle size distributions in a typical industrial process.

Reference

Abildgaard, O. H. A., Frisvad, J. R., Falster, V., Parker, A., Christensen, N. J., Dahl, A. B., and Larsen, R. Noninvasive particle sizing using camera-based diffuse reflectance spectroscopy. Applied Optics 55(14), pp. 3840-3846, May 2016. [abstract]