Three-dimensional phantoms for curvature correction in spatial frequency domain imaging

Area of Science:

• Biomedical Optics
• Optical Imaging
• Metrology

Background:

• Non-contact optical imaging is sensitive to surface topography, potentially causing measurement errors.
• Existing correction methods for surface profile effects are calibration-based, model-based, or computation-based.

Purpose of the Study:

• To develop and validate an experimental method for correcting surface profile effects on spectral images.
• To improve the accuracy of optical properties (absorption and reduced scattering coefficients) measured by spatial frequency domain imaging.

Main Methods:

• Utilized 3D printing to create acrylonitrile butadiene styrene (ABS) plastic phantoms with varying surface complexities.
• Applied a novel 3D phantom-based experimental method to correct spectral images acquired using spatial frequency domain imaging.
• Verified the correction method on objects with simple to complex surface profiles, including variations in height and slope.

Main Results:

• Successfully detected and corrected erroneous optical properties caused by surface variations (minimum 4 mm height, 80-degree slope).
• Demonstrated significant improvement in the accuracy of absorption coefficients (μ(a)) and reduced scattering coefficients (μ(s)') after correction.
• Validated the method's effectiveness across objects with diverse surface topographies.

Conclusions:

• The proposed 3D phantom-based method effectively corrects surface profile-induced errors in spatial frequency domain imaging.
• This technique enhances the reliability of optical property measurements for physiological parameter extrapolation.
• The method offers a versatile approach with discussed advantages and limitations for various applications.