Measurement of absorption and scattering properties of milk using a hyperspectral spatial frequency domain imaging system

In response to the research demand in spatial frequency domain techniques at continuous wavelengths in the field of agricultural and food products, a line scan hyperspectral spatial frequency domain combined imaging (LSH-SFDI) system was developed for quantitative hyperspectral optical imaging in the spatial frequency domain for detecting absorption ( μ a ) and reduced scattering ( μ′ s ) parameters of tissues in the continuous spectral range. Systematic calibration of the LSH-SFDI system was performed using the configured liquid phantoms, and the average errors of μ a and μ′ s at 56 wavelength bands between 450 and 740 nm were obtained as 9.24% and 6.08%, respectively. The optical parameters of milk were measured using the LSH-SFDI system, and the μ a and μ′ s values of milk samples at continuous wavelengths were analyzed by linear regression with the fat and protein contents of the corresponding milk, and the final results verified the correlation between the fat content and μ′ s and the protein content and μ a of milk. The developed system can be further used for milk quality evaluation and classification subsequently, as well as for other agricultural products and foods.