Orientation Uncertainty Characteristics of Some Pose Measuring Systems

Area of Science:

• Robotics and Computer Vision
• Metrology and Measurement Science

Background:

• Pose measuring systems rely on fiducial markers for object orientation.
• Point-based, rigid body registration is commonly used to determine orientation matrices.
• Measurement uncertainty in fiducials directly impacts orientation matrix accuracy.

Purpose of the Study:

• To analyze the anisotropic propagation of measurement uncertainty in pose estimation systems.
• To identify the factors influencing uncertainty direction in orientation matrices.
• To investigate the practical implications of pose uncertainty for object surface points.

Main Methods:

• Investigated uncertainty propagation from fiducial marker measurements to orientation matrices.
• Analyzed the covariance matrix of orientation data to determine eigenvectors and eigenvalues.
• Examined the anisotropic nature of uncertainty propagation to object surface points.

Main Results:

• Orientation uncertainty propagation is anisotropic.
• The direction of minimum uncertainty is consistently linked to a specific eigenvector of the orientation data's covariance matrix.
• The direction of maximum uncertainty is pose-dependent and difficult to predict.

Conclusions:

• The stability of minimum uncertainty direction offers potential for system calibration.
• The unpredictable nature of maximum uncertainty direction poses challenges for applications requiring high precision in all directions.
• Understanding these anisotropic effects is crucial for designing robust pose measurement systems.