Enhanced Fourier-Hilbert-transform suppression for saturation-induced phase error in phase-shifting profilometry

Area of Science:

• Optics and Photonics
• Metrology
• Computer Vision

Background:

• Structured-light techniques are crucial for 3D measurements.
• Intensity saturation in high dynamic range (HDR) measurements introduces significant phase errors.
• Existing methods struggle to fully compensate for saturation-induced errors and other residual errors.

Purpose of the Study:

• To present an enhanced Fourier-Hilbert-transform (EFHT) method for suppressing saturation-induced phase errors.
• To address residual errors including nonuniform reflectivity, phase-shift, and fringe-edge errors.
• To improve the accuracy of 3D measurements in phase-shifting profilometry.

Main Methods:

• Applied background normalization to saturated fringe patterns to mitigate nonuniform reflectivity.
• Developed a self-correction method to address large phase-shift errors in compensated phase data.
• Utilized self-corrected phase error detection to locate fringe-edge areas for accurate phase computation using a sub-period phase error model.

Main Results:

• Demonstrated significant suppression of saturation-induced phase errors.
• Effectively corrected other residual errors: nonuniform reflectivity, phase-shift, and fringe-edge errors.
• Achieved accurate 3D measurements using fewer images compared to conventional methods.

Conclusions:

• The proposed EFHT method is highly effective in reducing phase errors caused by intensity saturation.
• The method robustly handles multiple types of residual errors, enhancing measurement reliability.
• EFHT offers an efficient solution for accurate HDR 3D measurements using structured-light profilometry.