Multi-Plane X-Ray Calibration Using Coordinate Matrices
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Solution Overview
Problem
Multi-plane X-ray units face challenges in precise calibration, especially with independently movable radiographic planes, where only one plane can be stably calibrated, leading to frequent recalibration needs and potential maladjustment during operation.
Innovation Solution
A method and device for calibrating multi-plane X-ray units by defining internal and external spatial coordinate systems, using reference projection geometries, and calculating projection matrices to determine the position of radiographic planes relative to each other, allowing for precise and automated calibration with minimal unit movement and flexible calibration point selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independently moveable radiographic planes are used in multi-plane X-ray units, then operational flexibility and instrument navigation capability are improved, but calibration stability deteriorates requiring frequent recalibration
Solution Approach 1:
The patent introduces a calibration device as an intermediary object that establishes a common reference coordinate system for multiple radiographic planes. This calibration device with known spatial coordinates serves as a mediator that enables consistent coordinate transformation between different planes, resolving the calibration instability issue while maintaining operational flexibility of independently moveable planes
2Measurement precision
If frequent recalibration is performed to maintain positioning accuracy, then measurement precision is improved, but loss of time and operational efficiency deteriorate
Solution Approach 1:
The patent performs calibration operations in advance by establishing a common reference coordinate system using a calibration device before actual imaging operations begin. The calibration parameters and transformation matrices are predetermined and stored, allowing the system to skip frequent recalibration during operation while maintaining positioning accuracy, thus reducing time loss
3Measurement precision
If complex calibration procedures are used to achieve precise positioning, then measurement precision is improved, but device complexity and ease of operation worsen
Solution Approach 1:
The calibration system performs self-calibration by automatically capturing images of the calibration device from multiple radiographic planes and computing transformation matrices through coordinate correspondence. The system autonomously completes the calibration process without requiring complex manual adjustments or expert intervention, simplifying operations while maintaining precision
4Adaptability or versatility
If manual calibration adjustment is performed, then adaptability to different configurations is improved, but ease of operation and automation deteriorate
Solution Approach 1:
The system implements automated feedback-based calibration by capturing images of the calibration device, comparing detected coordinates with pre-stored reference coordinates, and automatically computing correction matrices. The system iteratively refines calibration parameters based on feedback from image analysis, adapting to different configurations automatically without manual intervention
Data Source
AI summary
For calibrating a multi-plane X-ray unit, an internal matrix mapping coordinate system internal to the unit onto coordinate system of a first radiographic plane is predefined in a reference projection geometry. An external matrix mapping coordinate system external to the unit onto coordinate system of the first plane is determined from image data captured by the first plane at calibration points and coordinates of the calibration points. An external matrix mapping coordinate system external to the unit onto coordinate system of a second radiographic plane is determined from image data captured by the second plane at the calibration points and the coordinates of the calibration points. A measure of position of the second plane with respect to coordinate system internal to the unit or with respect to the first plane is determined from the internal and external matrix of the first plane and the external matrix of the second plane.