Dual Spectrometer OCT Noise Suppression

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Solution Overview

Problem

Existing optical coherence tomography (OCT) systems face challenges such as slow imaging speeds, cost-prohibitive light sources, and difficulty in calibration, particularly in achieving perfect spectral matching between spectrometers, which hinders effective RIN suppression and image quality.

Innovation Solution

The implementation of a dual spectrometer configuration with adaptive balancing, which involves precise temporal and spectral matching of RIN noise components between spectrometers, and an optimization routine to iteratively adjust the interpolation vector, allowing for subpixel matching and improved RIN suppression without the need for prior calibration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional single spectrometer configuration is used, then device complexity is reduced, but RIN suppression capability deteriorates

Engineering Contradiction:
Improvespectrometer configurationVSAvoidRIN suppression
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system divides the single spectrometer into two separate spectrometers (first and second spectrometers), each independently detecting light from the sample. This segmentation allows independent optimization of each spectrometer and enables differential detection to suppress RIN noise that affects both detectors similarly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements a feedback mechanism where the detected light signals from both spectrometers are processed to calculate RIN levels, and this information is used to adjust the imaging parameters or processing algorithms to compensate for and suppress the identified noise, creating a closed-loop noise suppression system.

Inventive Principle:
Principle #23Feedback

2Productivity

If high-power light sources are used to improve imaging speed, then productivity increases, but cost increases

Engineering Contradiction:
Improveimaging speedVSAvoidlight source cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The system uses feedback processing where the detected signals are analyzed to distinguish between actual tissue reflectance variations and RIN noise. This allows the use of lower-power, less expensive light sources while maintaining image quality through computational noise suppression rather than relying solely on high signal intensity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system replaces the mechanical/approach of using high-power light sources to overcome noise with a computational approach. Instead of increasing light power mechanically, the system uses signal processing algorithms to subtract RIN components from the detected signals, achieving the same effective signal-to-noise ratio improvement at lower cost.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If manual calibration procedures are implemented to achieve spectral matching, then measurement precision improves, but ease of operation deteriorates

Engineering Contradiction:
Improvespectral matching accuracyVSAvoidcalibration complexity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system implements self-calibration where the spectrometers automatically perform spectral matching using their own detected signals. The system autonomously identifies spectral characteristics, calculates matching parameters, and adjusts the spectral alignment without requiring external calibration equipment or manual intervention, making the system self-sufficient and easy to operate.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The calibration process uses feedback from the detected light signals to automatically adjust spectral matching parameters. The system continuously monitors the spectral output and makes real-time adjustments to maintain optimal alignment, eliminating the need for manual calibration while preserving measurement precision.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If subpixel matching is implemented to improve RIN suppression, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvespectral alignment accuracyVSAvoidinterpolation vector processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex hardware mechanisms for achieving subpixel alignment with computational methods. Instead of using精密 mechanical adjustment mechanisms or optical components to achieve subpixel spectral matching, the system uses digital signal processing and interpolation algorithms to achieve the same precision in the data domain, reducing mechanical complexity while maintaining or improving alignment accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach significantly reduces relative intensity noise (RIN), leading to improved image quality, faster imaging speeds, and reduced costs associated with light sources, making OCT systems more practical for research and clinical use.

Implementation Method 1

The interference of light occurs when the optical paths of the light reflected from a sample matches with an optical path of reference light within micrometer-scale precision (e.g., low-coherence)

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentUS20250031969A1Devices, methods, and systems of functional optical coherence tomography
Publication Date: 2025.01.30 NORTHWESTERN UNIV
  • US20250031969A1 patent drawing
  • US20250031969A1 patent drawing
  • US20250031969A1 patent drawing

AI summary

An optical coherence tomography imaging system is disclosed, including: a light source to generate a radiation beam; a pair of photodetectors to acquire data of the radiation beam; a coupler to direct portions of the beam to a sample arm and a reference arm, the coupler to combine light from the sample arm and the reference arm, the combined light to be split into portions to be detected by the pair of photodetectors; and a processor to measure and compare noise profiles of the data and to generate an image using the data, and the noise profile comparison.