Spatially resolved reflectance from turbid media having a rough surface. Part II: experiments

Area of Science:

• Biomedical Optics
• Optical Engineering
• Materials Science

Background:

• Spatially resolved reflectance (SRR) is vital for characterizing optical properties of turbid media.
• Surface roughness between the medium and surroundings can introduce significant errors in SRR measurements.
• Accurate optical property determination requires accounting for surface topography.

Purpose of the Study:

• To quantify errors in SRR measurements caused by unaddressed surface roughness.
• To compare different surface scattering models for their effectiveness in simulating rough surfaces.
• To establish a method for accurate optical property extraction in the presence of surface roughness.

Main Methods:

• Performed SRR measurements on rough epoxy-based phantoms.
• Utilized Monte Carlo simulations with Lambertian, Cook-Torrance, and generalized Harvey-Shack surface scattering models.
• Conducted goniometric measurements to parameterize surface scattering models.
• Determined optical properties using Monte Carlo simulations assuming a smooth surface after accounting for roughness.

Main Results:

• Surface roughness significantly impacts SRR measurements, leading to inaccuracies.
• The generalized Harvey-Shack model provided the best fit for experimental angularly resolved reflectance, indicating its suitability for modeling rough surfaces.
• The study successfully quantified the errors introduced by surface roughness.

Conclusions:

• Ignoring surface roughness in SRR measurements can lead to erroneous optical property values for turbid media.
• Accurate characterization of surface scattering is essential for reliable optical property determination.
• The findings highlight the importance of incorporating advanced surface scattering models in optical simulations for biological tissues and similar materials.