Projection superimposition for the generation of high-resolution digital grating

Area of Science:

• Optical Engineering
• Metrology
• Micro-electromechanical Systems (MEMS)

Background:

• Fringe projection profilometry using MEMS micro-vibration mirrors offers advantages like speed, depth of field, and cost-effectiveness.
• Accurate 3D reconstruction requires high-frequency fringes, which necessitates sufficient projector pixel resolution.
• Existing MEMS projectors may face limitations in achieving the high pixel resolution needed for advanced fringe projection applications.

Purpose of the Study:

• To introduce a novel high-resolution projection technique, the delay superposition method, for MEMS-based fringe projection profilometry.
• To demonstrate the capability of this method to overcome the pixel resolution limitations of conventional MEMS projectors.
• To validate the improvement in reconstruction accuracy achieved by the proposed technique.

Main Methods:

• The delay superposition method involves projecting a series of low-resolution fringe patterns with controlled delays during a single camera exposure.
• These delayed patterns are superimposed by the camera's exposure, effectively creating a higher-resolution fringe pattern.
• The technique achieves pixel interpolation by subdividing angular intervals through the precise timing of projected fringes and mirror movement.

Main Results:

• Experimental results confirm a significant enhancement in the effective pixel resolution of the MEMS projector.
• The proposed method leads to a marked improvement in the accuracy of 3D surface reconstruction.
• The achieved pixel resolution surpasses that of common Digital Light Processing (DLP) projectors in one direction.

Conclusions:

• The delay superposition method is a viable technique for achieving high-resolution projection in MEMS-based fringe projection systems.
• This advancement enables MEMS projectors to achieve superior pixel resolution and reconstruction accuracy compared to conventional systems.
• The method holds significant potential for applications requiring high-frequency fringe projection and precise 3D measurements.