Surgical Endoscope Calibration via Image Registration
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Solution Overview
Problem
Existing endoscope calibration techniques struggle with accurately modeling the nonlinear behavior of endoscopes due to friction and stiffness, leading to difficulties in real-time feedback and precise navigation during surgical procedures.
Innovation Solution
A surgical robotic system that automatically calibrates endoscopes by using image registration and calibration curves to determine parameters such as translational and rotational movements, hysteresis, and dead zones, accounting for the nonlinear behavior of endoscope components like sheaths and leaders, and mitigating unwanted bending through helix sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration techniques are used, then the calibration process is simpler to implement, but the measurement precision and accuracy of endoscope tip position deteriorates due to nonlinear behavior and hysteresis
Solution Approach 1:
The patent replaces manual mechanical calibration procedures with an automated image-based calibration system. The system uses images captured by the endoscope's image sensor and processing circuitry to automatically determine calibration parameters, eliminating the need for manual manipulation and reducing human error while maintaining high measurement precision.
Solution Approach 2:
The endoscope performs self-calibration by capturing images of calibration structures and using its own processing circuitry to determine calibration parameters. The system automatically models the endoscope's nonlinear behavior and hysteresis without requiring external manual intervention, enabling the device to calibrate itself.
2Reliability
If real-time feedback of endoscope motions is implemented, then navigation precision improves, but the device complexity increases due to the need to account for compressible and hysteresis effects
Solution Approach 1:
The system performs preliminary calibration by capturing images of calibration structures before actual surgical use. During this preliminary phase, the processing circuitry determines calibration parameters and models the endoscope's nonlinear behavior and hysteresis characteristics. This pre-established model enables accurate real-time feedback during surgery without adding complexity to the operational phase.
Solution Approach 2:
The patent implements a feedback mechanism where the calibrated model of endoscope motion is continuously applied during surgical procedures. The processing circuitry uses the determined calibration parameters to compensate for nonlinear behavior and hysteresis in real-time, providing accurate feedback on the actual tip position based on commanded motions.
3Loss of time
If limited amounts of endoscope tip deflection are used in manual calibration, then the calibration process is faster, but the measurement precision deteriorates because it does not accurately model motions of the tip
Solution Approach 1:
The patent replaces mechanical deflection-based calibration with an automated image processing system. The processing circuitry analyzes images captured during calibration to determine tip position and motion characteristics, enabling comprehensive modeling of the full range of endoscope motions without requiring time-consuming manual deflection procedures.
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
Enables accurate modeling and navigation of endoscopes, improving precision and reducing manual intervention during surgical procedures by accounting for nonlinear behavior and minimizing muscling and curve alignment.
Implementation Method 1
Calibration parameters can be determined using an image registration process. Changes between two of the captured images correspond to a shift in perspective of the image sensor due to a movement of the endoscope.
Data Source
AI summary
A surgical robotic system includes an endoscope, a robotic arm including a drive mechanism, the drive mechanism coupled to the endoscope. The surgical robotic system further includes a controller configured to receive a command to move the endoscope using the robotic arm, access a set of calibration parameters associated with the endoscope, generate an adjusted command based on the command and the set of calibration parameters, and provide the adjusted command to the robotic arm to move the endoscope.