Diffuse reflectance spectroscopy of particulate systems: a comparative study of discrete models

Area of Science:

• Optics and Photonics
• Materials Science
• Color Science

Background:

• Diffuse reflectance is crucial for characterizing particulate materials.
• Statistical particle models are used to predict optical properties.
• Accurate theoretical models are needed for reliable material assessment.

Purpose of the Study:

• To comparatively evaluate statistical particle model theories for diffuse reflectance.
• To assess model performance using CIELAB color difference calculations.
• To identify and correct errors in existing theoretical models.

Main Methods:

• Applied six theoretical models to six particulate samples (42-106 µm).
• Measured diffuse reflectance spectra experimentally.
• Calculated CIELAB color difference between experimental and theoretical predictions.
• Identified and corrected typographical errors in Fresnel reflection coefficient expressions.

Main Results:

• Model performance varied based on sample optical characteristics and particle size.
• CIELAB color difference provided a quantitative assessment of model accuracy.
• Numerous typographical errors were found in published Fresnel reflection coefficient expressions.
• Corrected expressions were provided for improved theoretical predictions.

Conclusions:

• The comparative study highlights the strengths and weaknesses of different diffuse reflectance models.
• Accurate Fresnel reflection coefficients are essential for reliable theoretical predictions.
• This work provides corrected expressions to enhance the predictive power of statistical particle models.