Oblique-Viewing Endoscope Calibration via Rotational Offset Correction
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Solution Overview
Problem
Oblique-viewing rigid endoscopes face calibration challenges due to rotational offsets between the telescope and camera, leading to inaccuracies in initial calibration parameters, which are critical for augmented reality applications in minimally-invasive surgery.
Innovation Solution
A system and method utilizing spatial-tracking sensors, such as electromagnetic sensors, to correct for rotational offsets by obtaining and comparing calibrations at different poses, allowing for the selection of the most accurate calibration based on error values, and updating the camera matrix to account for rotations, thereby enhancing calibration accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the telescope is rotated relative to the camera head to achieve oblique viewing, then the field of view is improved, but rotational offset between the actual object and projected object occurs
Solution Approach 1:
The system performs multiple calibrations at different telescope poses (first pose and second pose after rotation) and dynamically selects the most accurate calibration based on error value comparison. This dynamic adaptation allows the system to maintain calibration accuracy despite telescope rotation for oblique viewing.
Solution Approach 2:
The system changes the calibration parameters by obtaining different calibrations at different poses and selecting based on error values. This parameter change approach allows the system to optimize calibration accuracy for the current viewing angle while maintaining the benefits of oblique viewing.
2Ease of manufacture
If calibration is performed before rotation, then the calibration process is simplified, but calibration parameter inaccuracies occur after rotation
Solution Approach 1:
The system performs preliminary calibration at the first pose before rotation, then obtains a second calibration after rotation. By comparing error values from both calibrations, the system selects the most accurate one, thus maintaining reliability while keeping the process relatively simple.
Solution Approach 2:
The system uses error value feedback from both calibrations to determine which calibration to select. This feedback mechanism ensures that the most accurate calibration is used after rotation, maintaining reliability without requiring complete recalibration.
3Measurement precision
If multiple calibrations are obtained and compared, then calibration accuracy is improved, but the calibration time increases
Solution Approach 1:
The system obtains a second calibration after rotation only when needed, rather than performing multiple calibrations continuously. This partial action approach maintains calibration accuracy while minimizing the time penalty by performing additional calibration only when the telescope is rotated.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes calibration parameter inaccuracies, allowing for precise intraoperative visualization and improved surgical precision by correcting rotational offsets in oblique-viewing rigid endoscopes, reducing procedure times and complications.
Implementation Method 1
A system and method utilizing spatial-tracking sensors, such as electromagnetic sensors
Data Source
AI summary
The present disclosure relates to an apparatus and method for correcting rotational error during use of an oblique-viewing endoscope. Specifically, the present disclosure relates to a fast calibration process wherein a new approach is employed in estimating a center of rotation of a plane of an image. Moreover, the approach, allows for updating of a camera matrix during use.