Stereo-Optical 3D Surface Mapping Calibration
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Solution Overview
Problem
Current stereo-optical surface-mapping systems require calibration with fixed lens configurations and magnification, limiting their adaptability to varying optical settings, especially in surgical applications where continuous magnification and focal length adjustments are necessary, such as in brain surgery where tissue deformation occurs during procedures.
Innovation Solution
A method and system that determine surface profile reconstruction parameters at a reference setting and use warping parameters to adjust images from arbitrary settings to the reference setting, allowing for continuous magnification and focal length adjustments while maintaining accurate 3D surface mapping, using a stereo optical system with adjustable zoom lenses and image processing to correct for deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If fixed lens configuration and magnification are used for calibration, then measurement precision is improved, but adaptability deteriorates
Solution Approach 1:
The system changes the parameter being measured from optical settings to mechanical stage positions. By tracking the position of the optical stage rather than relying on fixed optical parameters, the system adapts to varying magnification and focal length settings while maintaining accurate surface mapping through coordinate transformation based on stage position data
Solution Approach 2:
The calibration system is designed to work universally across multiple magnification levels and lens configurations. Instead of requiring separate calibration for each optical setting, the mechanical stage position tracking provides a universal reference frame that works with any optical configuration, making the system multi-functional across different surgical viewing conditions
2Measurement precision
If calibration is performed at each magnification level, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary calibration by establishing a mapping between mechanical stage positions and image coordinates at a reference magnification level. This preliminary calibration creates a transformation framework that can be applied to other magnification levels through interpolation, eliminating the need for time-consuming recalibration at each setting while maintaining adequate precision
Solution Approach 2:
The system creates a computational model (copy) of the optical geometry at reference magnification and uses this model to predict and correct measurements at other magnification levels. By copying the geometric relationships and applying them through interpolation, the system avoids repeated physical calibration while preserving measurement accuracy across variable optical settings
Data Source
AI summary
A system for, and method of, extracting a surface profile from a stereo pair of images obtained at an arbitrary setting S of an optical system, includes determining surface profile reconstruction parameters for images obtained with the optical system at a reference setting So of the optical system; determining warping parameters for a digital image processor for warping images obtained with the optical system at the arbitrary setting S into images corresponding to the reference setting So; obtaining the stereo pair of images from at least one camera of the optical system; warping the stereo pair of images into images corresponding to the reference setting So, and using the surface profile reconstruction parameters to determine the surface profile. In a particular embodiment, the surface profile is passed to a computer model of tissue deformation and used to determine an intra-surgery location of a tumor or other anatomic feature of tissue.