Flexible Instrument Shape Estimation with Distributed Sensors
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Solution Overview
Problem
Existing medical procedures using elongate flexible instruments lack accurate shape estimation within the body, affecting instrument interaction with anatomy and navigation precision.
Innovation Solution
Implementing a system with distributed position sensors, such as electromagnetic sensors, along the elongate instrument to determine its shape by matching sensor positions and orientations, using control circuitry to estimate and render the instrument's shape relative to a virtual anatomical model.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distributed position sensors are implemented along the elongate instrument, then shape estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The instrument shaft is divided into multiple segments with sensors distributed at different positions along its length. Each sensor segment independently measures local position and orientation, and the control circuitry integrates these segmented measurements to reconstruct the overall instrument shape, resolving the contradiction between measurement accuracy and device complexity
Solution Approach 2:
The distributed sensor system serves multiple functions simultaneously: it tracks instrument position, determines orientation, estimates shape, and enables navigation guidance. This multi-functionality justifies the added device complexity by providing comprehensive shape estimation capabilities across multiple operational parameters
2Measurement precision
If multiple position sensors are distributed along the instrument length, then navigation precision is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is segmented into modular steps: first manufacturing the instrument shaft, then integrating sensors at predetermined positions, and finally calibrating the system. This segmentation of manufacturing operations reduces overall complexity compared to attempting to integrate all sensors simultaneously
Solution Approach 2:
Sensor positions and orientations are predetermined and pre-calibrated during manufacturing. The control circuitry is pre-programmed with expected sensor configurations, allowing for simplified assembly and reducing manufacturing complexity while maintaining high navigation precision
3Measurement precision
If sensor positions and orientations are determined to estimate shape, then shape estimation accuracy is improved, but computational requirements increase
Solution Approach 1:
The system determines position and orientation for all distributed sensors, which may be more data points than strictly necessary for basic shape estimation. This excessive action provides redundant information that improves accuracy through error averaging and outlier rejection, while the control circuitry efficiently processes only the essential parameters needed for shape reconstruction
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
Enhances navigation precision and interaction with anatomy by providing accurate shape estimation of the instrument, improving driving and articulation strategies during medical procedures.
Implementation Method 1
implementation of a plurality of sensors, such as electromagnetic (EM) sensors, along a length of an elongate member
Data Source
AI summary
A system includes an elongate instrument, such as an endoscope, having a plurality of position sensors associated therewith, the plurality of position sensors being distributed along a length of the instrument. The system further includes control circuitry configured to determine positions and orientations of each of the plurality of position sensors, determine a curve that passes through each of the respective positions of the plurality of position sensors and the respective orientations, and estimate a shape of the elongate instrument based on the curve.