Polarization Control Apparatus for OCT Imaging Calibration
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Solution Overview
Problem
Conventional polarization-sensitive OCT and SLO systems cannot perform calibration when the polarization state changes during usage, leading to instability in imaging.
Innovation Solution
A control apparatus and method that includes an irradiation unit, a restriction unit, and a polarization control unit to calibrate the polarization state by controlling the measuring beam based on reflections and scatterings, using a polarization controller and a shutter to adjust the polarization of the beam and ensure stable imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polarization-sensitive OCT or SLO imaging is performed using modulated light beams, then polarization parameters (retardation and orientation) can be measured to generate detailed fundus tissue images, but the polarization state changes during usage due to factors like heat, making calibration impossible with conventional apparatus
Solution Approach 1:
The patent performs calibration in advance by capturing images of a calibration chart with known polarization characteristics before actual measurement. This preliminary action stores reference data that compensates for polarization state changes occurring during subsequent usage, enabling reliable measurements even when the polarization state drifts over time
Solution Approach 2:
The system continuously monitors the polarization state by comparing captured images against stored calibration data. When deviations are detected, the system can adjust or recalculate measurements based on the observed polarization changes, creating a feedback loop that maintains measurement accuracy throughout the imaging session
2Productivity
If the measuring beam is continuously directed at the measurement object for imaging, then continuous fundus tissue visualization is achieved, but the polarization state changes along with usage time, leading to imaging instability
Solution Approach 1:
The system performs initial calibration by capturing images of a calibration chart before actual imaging begins. This preliminary calibration establishes a reference polarization state that accounts for system characteristics, enabling stable and accurate measurements throughout continuous imaging operations
Solution Approach 2:
The patent introduces a calibration chart with specific polarization characteristics as an intermediate reference object. By capturing images of this chart and analyzing its known polarization properties, the system can determine and compensate for polarization state changes, thereby maintaining imaging stability over time
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 effective calibration of the polarization state, resulting in stable and accurate imaging even when the polarization state changes due to factors like heat, thereby improving the quality of images obtained in ophthalmologic and other applications.
Implementation Method 1
a restriction unit configured to restrict the measuring beam from being incident on the measurement object and to reflect or scatter the measuring beam
Implementation Method 2
a polarization control unit configured to control, based on the measuring beam reflected or scattered by the restriction unit, polarization of the measuring beam
Data Source
AI summary
A control apparatus includes an irradiation unit configured to irradiate a measurement object with a measuring beam, a restriction unit configured to restrict the measuring beam from being incident on the measurement object and to reflect or scatter the measuring beam, and a polarization control unit configured to control, based on the measuring beam reflected or scattered by the restriction unit, polarization of the measuring beam.