The projection diagram.

Area of Science:

• Optics and optical engineering
• Photogrammetry and remote sensing

Background:

• Fringe projection techniques are widely used for 3D surface measurement.
• Interpreting fringe patterns and understanding system geometry can be complex.
• Existing methods may lack a unified graphical approach for analysis.

Purpose of the Study:

• To introduce a new graphical tool, the projection diagram (PD), for analyzing fringe projection operations.
• To demonstrate the PD's utility in understanding system geometry and measurement sensitivity.
• To extend the application of graphical analysis to include effects like defocusing.

Main Methods:

• The projection diagram (PD) is generated as a Moiré pattern between two spoke targets.
• These targets mimic central projections found in projection and observation systems.
• The PD is adapted from principles previously applied to stereoscopic observation systems.

Main Results:

• The PD provides a straightforward graphical method for interpreting fringe projection.
• Key information regarding the sensitivity vector is readily obtainable from the PD.
• The geometry of contouring surfaces can be visualized and analyzed using the PD.
• The diagram accommodates the inclusion of defocusing effects in the analysis.

Conclusions:

• The projection diagram (PD) offers a valuable and intuitive tool for fringe projection analysis.
• It enhances the understanding of geometric and sensitivity aspects in optical measurement systems.
• The PD's adaptability makes it a versatile tool for various fringe projection applications.