Near-Infrared Camera Calibration for Optical Surgical Navigation

Area of Science:

• Medical imaging
• Optical engineering
• Surgical navigation systems

Background:

• Near-infrared cameras (NICs) are vital for surgical navigation, but their tracking accuracy depends heavily on precise calibration.
• Existing calibration methods may lack the systematic approach needed for optimal performance in complex surgical environments.

Purpose of the Study:

• To develop and validate a systematic calibration method for NICs used in surgical navigation.
• To improve the accuracy and reliability of optical tracking devices through enhanced camera calibration.

Main Methods:

• A systematic calibration method using movable plates and reference objects was established.
• Analysis of NIC distortion models, direct linear transformation for initial parameter estimation, and nonlinear optimization for accurate parameter determination were employed.
• Calibration images captured from diverse positions and orientations were utilized.

Main Results:

• The proposed method achieved low relative errors for focal lengths (0.244-0.282%) and principal points (0.735-1.111%) for both left and right NICs.
• Image residuals were below 0.01 pixels, with a standard calibration error under 1 and measurement error below 0.3 mm.
• Experimental validation confirmed the effectiveness and favorable results of the NIC calibration technique.

Conclusions:

• The developed movable plate calibration method provides accurate internal and external parameters for NICs.
• This systematic approach significantly enhances the tracking accuracy of surgical navigation systems.
• The method is effective and yields high-quality calibration results, crucial for precise surgical interventions.