C-Arm Calibration Model for Accurate Surgical Navigation
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Solution Overview
Problem
C-arm calibration in surgical navigation systems is cumbersome and complex, often requiring hardware and artificial fiducial objects that obscure images and increase system complexity.
Innovation Solution
A method and system for calibrating C-arm imaging devices using an iterative calibration algorithm that generates a functional form model for 2D navigation, allowing offline calibration with a calibration fixture and an infrared tracking system to determine intrinsic and extrinsic parameters, enabling accurate surgical navigation without the need for cumbersome hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional hardware and artificial fiducial objects are used for C-arm calibration, then calibration accuracy can be achieved, but system complexity increases and images are obscured
Solution Approach 1:
The patent extracts and removes the artificial fiducial objects from the calibration system, replacing them with natural anatomical landmarks. This eliminates the need for additional calibration hardware while maintaining calibration accuracy through the use of preoperative imaging data and intraoperative navigation system registration.
Solution Approach 2:
The navigation system is designed to serve multiple functions: it performs both surgical navigation and calibration tasks using the same hardware infrastructure. The C-arm itself is used for both imaging during surgery and for calibration purposes, eliminating the need for separate calibration devices.
2Measurement precision
If traditional fiducial objects are embedded in the X-ray image for calibration, then calibration can be performed, but image quality is degraded
Solution Approach 1:
The patent removes artificial fiducial objects from the imaging process entirely. Instead, it uses natural anatomical landmarks that are already visible in the X-ray images, thereby maintaining image quality while achieving calibration capability through software-based registration of preoperative and intraoperative data.
3Measurement precision
If cumbersome calibration hardware is used, then precise calibration can be achieved, but ease of operation decreases
Solution Approach 1:
The system performs calibration automatically using the existing C-arm hardware and navigation software. The calibration process is self-contained, utilizing preoperative imaging data and intraoperative anatomical landmarks without requiring manual intervention or specialized calibration procedures by the operator.
4Measurement precision
If multiple calibration devices are used, then calibration accuracy improves, but device complexity increases
Solution Approach 1:
The navigation system is designed to perform multiple functions including surgical navigation, imaging, and calibration using the same hardware infrastructure. The C-arm serves both as the imaging device during surgery and as the calibration device, eliminating the need for separate calibration hardware.
Solution Approach 2:
The patent merges the calibration function with the existing navigation system. The calibration algorithms are integrated into the navigation software, and the same C-arm hardware used for surgical imaging is also used for calibration, combining multiple functions into a single unified system.
Data Source
AI summary
Examples of the disclosure include methods and systems for calibrating a C-arm imaging device for surgical navigation. Calibrating the C-arm imaging device may include, for a plurality of positions of the C-arm imaging device, determining the position of the C-arm imaging device, receiving an image of a calibration fixture from the C-arm imaging device, determining the position of the calibration fixture and a tracking array positioned on the C-arm imaging device, determining intrinsic parameters using the image and the position of the calibration fixture, and determining extrinsic parameters using the position of the tracking array relative to a detector of the C-arm imaging device. Calibrating the C-arm imaging device may include modeling parameters for the C-arm imaging device and iteratively tuning the model.