Spatial frequency domain imaging using an analytical model for separation of surface and volume scattering

Area of Science:

• Biomedical Optics
• Optical Imaging
• Photonics

Background:

• Surface scattering complicates accurate optical property retrieval in biomedical imaging.
• Existing methods in spatial frequency domain imaging (SFDI) are sensitive to surface roughness, leading to significant errors.
• Accurate characterization of bulk optical properties requires correction for surface effects.

Purpose of the Study:

• To develop and validate a novel method for correcting surface scattering in SFDI.
• To enable precise retrieval of bulk optical properties and surface scattering parameters.
• To reduce systematic errors caused by varying surface roughness in optical measurements.

Main Methods:

• A modified analytical solution of the radiative transfer equation was employed.
• The method calculates reflectance and phase for rough semi-infinite geometries.
• Phantoms with varying surface roughness were fabricated for validation.

Main Results:

• The modified theory significantly reduced systematic errors caused by surface scattering.
• Compared to state-of-the-art methods, the new approach minimized errors up to approximately 100% depending on surface roughness.
• Validation with SFDI measurements on a structured rough surface confirmed the method's effectiveness.

Conclusions:

• The developed method effectively corrects for surface scattering in SFDI.
• Precise retrieval of optical properties is achievable even with rough sample surfaces.
• This advancement improves the reliability of SFDI for quantitative optical property measurements.