Sensor Fusion Calibration for Real-Time Tissue Deformation Tracking
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Solution Overview
Problem
Existing computer-integrated surgery systems are limited in their ability to accurately track surgical tools and measure real-time shape deformation of flexible and deformable human organs, such as those found in surgeries involving the breast, face, or incised skin, due to their focus on hard tissues like bone.
Innovation Solution
A method and apparatus that fuses heterogeneous sensors, including depth sensors and a three-dimensional localizer, to integrate data into a single coordinate system, allowing simultaneous real-time measurement of surface shape deformation and tool positions/orientations, using one-time calibration and rigid body transformation matrices to ensure accurate tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing surgical navigation systems are used, then tool position tracking is provided, but real-time shape deformation measurement of flexible tissues cannot be performed
Solution Approach 1:
The patent combines depth sensors (for shape measurement) and optical localizers (for tool tracking) into a single integrated surgical navigation system. The depth sensors capture 3D surface geometry of flexible tissues while the optical localizers track tool positions, and both data streams are fused in a common coordinate system to enable simultaneous measurement of shape deformation and tool positioning during surgery on flexible organs.
Solution Approach 2:
The surgical navigation system is designed to perform multiple functions: it can measure the 3D shape and deformation of flexible tissues using depth sensors, track the positions and orientations of surgical tools using optical localizers, and provide real-time feedback to surgeons. This multi-functional system adapts to different surgical scenarios involving flexible organs such as the breast, face, and skin.
2Adaptability or versatility
If multiple heterogeneous sensors are integrated, then both shape measurement and tool tracking are enabled, but system complexity increases
Solution Approach 1:
The patent performs a one-time calibration process before surgery to establish the spatial relationship between the depth sensors and optical localizers. During this calibration, a calibration plate with known geometric features is used to compute transformation matrices that align all sensor coordinate systems to a common reference frame. This preliminary calibration eliminates the need for continuous complex coordinate transformation during surgery, simplifying real-time operation.
Solution Approach 2:
The patent introduces a rigid frame as an intermediary structure that holds both the depth sensors and optical localizers in fixed, known relative positions. This rigid frame serves as a mechanical bridge that enables accurate registration between different sensor types without requiring complex active coordination systems. The rigid frame's stable structure simplifies the integration of heterogeneous sensors while maintaining precise spatial relationships.
Data Source
AI summary
Provided is a method for fusing heterogeneous sensors having a plurality of depth sensors and a three-dimensional localizer and capable of simultaneous real-time human body deformation measurement and medical instrument tracking. The method may include setting a separation position and angle of the plurality of depth sensors and the three-dimensional localizer, performing a one-time calibration to estimate a relationship between coordinate systems of the plurality of depth sensors and the three-dimensional localizer, which are fixed to a frame according to the set separation position and angle, integrating data of the plurality of depth sensors and the three-dimensional localizer into a single coordinate system using the one-time calibration result, and simultaneously measuring real-time surface shape deformation of a target object and tracking positions and orientations of medical instruments using the integrated single coordinate system.