High-flexibility and high-accuracy phase delay calibration method for MEMS-based fringe projection systems

Area of Science:

• Optics and Photonics
• Mechanical Engineering
• Computer Vision

Background:

• Microelectromechanical system (MEMS) mirror based laser beam scanning (LBS) projectors are popular for fringe projection profilometry (FPP) due to their compact size and affordability.
• Variations in the initial phase of scanning MEMS mirrors cause unstable fringe patterns, degrading the accuracy of 3D topographic reconstruction.

Purpose of the Study:

• To propose an efficient phase delay calibration method for MEMS mirror-based LBS projectors.
• To enhance the accuracy of 3D topographic reconstruction by addressing fringe pattern distortions.

Main Methods:

• Development of a unique fringe projection sequence and a corresponding image processing algorithm for phase delay calibration.
• Implementation of the calibration method without requiring additional hardware components.
• Construction of an LBS projector utilizing a uniaxial electrostatic MEMS mirror (2.5 mm × 2.5 mm) with a 60° field of view at 1523 Hz resonance.

Main Results:

• The proposed method effectively compensates for phase uncertainty and variations in MEMS mirror-based LBS projectors.
• 3D reconstruction experiments demonstrated a significant improvement in accuracy.
• The standard deviation of sphere reconstruction was reduced from 2.05 mm to 0.20 mm after compensating for a 5 μs positive phase delay deviation.

Conclusions:

• The developed phase delay calibration method offers an efficient solution for unstable fringe patterns in LBS projectors.
• This technique enhances the precision of 3D topographic reconstruction without extra hardware.
• The results highlight the method's effectiveness in improving the reliability of MEMS-based FPP systems.