Figure 3
(a) Normalized intensity of reflected light curves for air, sample and background. The curves are normalized with respect to the maximum value of the intensity of the air. (b) Reflectance curve of sample and its first derivative curve. (c) Normalized reflected intensity of glycol, glycerol, cedar oil and background. (d) Distribution of reflectance curves for glycol, glycerol and cedar oil. (e) First derivative of reflectance curves for glycol, glycerol and cedar oil. It shows that information of reflected light with θi ∈ (θc − 1°,θc + 1°) is sufficient to confirm the peak of first derivative of reflectance-angle curve.
