Determining geometric error model parameters of a terrestrial laser scanner through Two-face, Length-consistency, and...

Area of Science:

• Metrology
• Geomatics Engineering
• Industrial Manufacturing

Background:

• Terrestrial laser scanners (TLS) are critical for high-precision measurements in large-scale manufacturing and assembly.
• Meeting stringent uncertainty requirements (sub-millimeter) necessitates in-situ compensation of systematic errors through self-calibration.
• The established Network method uses multiple target measurements from various locations to determine TLS error model parameters.

Purpose of the Study:

• To propose and evaluate two novel self-calibration methods for TLS: the Two-face method and the Length-consistency method.
• To enhance the efficiency and reduce the cost of TLS calibration processes.
• To demonstrate the validity and compare the performance of the new methods against the existing Network method.

Main Methods:

• The Length-consistency method compares inter-target distances measured from multiple TLS positions to determine model parameters, improving upon the Network method's efficiency.
• The Two-face method is a two-step process: initial parameter determination from front-face/back-face measurements, followed by refinement using the Length-consistency method.
• Comparative analysis of model parameter uncertainties for the Network, Length-consistency, and Two-face methods.

Main Results:

• The proposed Length-consistency and Two-face methods were validated using a calibrated scale bar and target measurements.
• Both new methods demonstrated effectiveness in determining TLS model parameters.
• The study quantified and compared the uncertainties associated with each self-calibration technique.

Conclusions:

• The Length-consistency and Two-face methods provide efficient and valid alternatives for TLS self-calibration.
• These novel techniques eliminate the need for external reference instruments or calibrated artifacts, significantly reducing calibration costs.
• The proposed methods contribute to more accessible and cost-effective high-precision metrology in industrial applications.