Multi-dimensional, non-contact metrology using trilateration and high resolution FMCW ladar.

Area of Science:

• Metrology and Measurement Science
• Optical Engineering
• Laser Technology

Background:

• Accurate non-contact 3D metrology is crucial for various industrial and scientific applications.
• Existing methods often face limitations in resolution, range independence, or setup flexibility.
• Frequency Modulated Continuous Wave (FMCW) ladar offers high-resolution ranging capabilities.

Purpose of the Study:

• To propose and demonstrate a multidimensional, non-contact length metrology system.
• To achieve high-resolution 3D measurements independent of standoff range.
• To enable flexible system setup and self-calibration.

Main Methods:

• Design of a system integrating high-resolution FMCW ladar with trilateration.
• Utilizing multiple optical fiber-connected transmitters for length measurements.
• Experimental proof-of-concept using a 2 THz bandwidth chirped laser source, two emitters, and a scanning emitter/receiver.

Main Results:

• Demonstrated 1D surface profiling (2D metrology) of diffuse targets.
• Achieved measured coordinate precision of less than 200 microns.
• Identified laser speckle from diffuse scattering as the primary limitation.

Conclusions:

• The proposed FMCW ladar and trilateration system offers a viable approach for high-resolution, range-independent 3D metrology.
• The system's self-calibration capability enhances setup flexibility.
• Further research is needed to mitigate laser speckle for improved precision with diffuse targets.