Spectral-Domain Endoscopy Imaging Speed and SNR

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Solution Overview

Problem

Current spectrally-encoded endoscopy techniques face challenges in achieving high-speed, high-resolution three-dimensional imaging with sufficient signal-to-noise ratio (SNR) due to limitations in hardware complexity, imaging speed, and light collection efficiency, especially when using flexible probes with small diameters.

Innovation Solution

The implementation of a spectral-domain spectrally-encoded endoscopy (SD-SEE) system that uses a high-speed line camera and interferometer with a rapidly scanning optical delay line, allowing for continuous scanning of the reference arm and over-sampling of spectrally-encoded lines to enhance SNR and imaging speed, achieving 3D imaging at 30 frames per second with an SNR of greater than 30 dB.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If time-domain heterodyne interferometry with rapid scanning optical delay line is used, then imaging speed is improved to about five volumes per second, but signal-to-noise ratio decreases to approximately 10 dB

Engineering Contradiction:
Improveimaging speedVSAvoidsignal-to-noise ratio
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent replaces time-domain heterodyne interferometry with spectral-domain interferometry, substituting mechanical scanning with spectral analysis. This allows simultaneous acquisition of multiple depth planes through Fourier transformation of spectral data, achieving both high imaging speed and high signal-to-noise ratio without the trade-off present in time-domain methods

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

Solution Approach 2:

The patent transitions from time-domain to spectral-domain analysis, adding a spectral dimension to the imaging process. By analyzing the spectral content of reflected light and applying Fourier transforms, the system extracts depth information across multiple planes simultaneously, enabling high-speed volumetric imaging with maintained signal quality

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Length of moving object

If low NA collection system is used to achieve large working distance, then working distance is improved, but light collection efficiency decreases to only 0.01% of scattered light

Engineering Contradiction:
Improveworking distanceVSAvoidlight collection efficiency
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent changes the optical parameters by using spectral-domain interferometry with broadband light sources and diffraction gratings. This allows the system to achieve high resolution and large working distance simultaneously by encoding spectral information that compensates for the low numerical aperture, extracting depth information through spectral analysis rather than relying solely on light collection efficiency

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If confocal imaging through fiber-bundle with high NA lens is used, then resolution is improved, but field of view is limited to less than a few millimeters

Engineering Contradiction:
ImproveresolutionVSAvoidfield of view
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent introduces spectral encoding as an additional dimension to the imaging process. By using diffraction gratings to encode spatial information spectrally and then decoding it through spectral-domain interferometry, the system achieves both high resolution and large field of view. The spectral dimension allows multiplexing of multiple spatial frequencies, effectively expanding the field of view while maintaining resolution

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 improves imaging speed and SNR, providing two to three orders of magnitude better performance than conventional techniques, enabling high-speed, high-resolution 3D imaging with a large working distance and reduced hardware complexity.

Implementation Method 1

Spectrally-encoded endoscopy ('SEE') is a techniques which uses a broadband light source and a diffraction grating to spectrally encode reflectance across a transverse line within a sample

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

Depth-resolved imaging can be achieved by incorporating an SEE probe into the sample arm of a Michelson interferometer. Using this arrangement, two-dimensional ('2D') speckle patterns can be recorded by a charge-coupled device ('CCD') camera at multiple longitudinal locations of a reference mirror

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 3

an interference signal can be recorded with a standard photodetector at every group delay scan of a rapid scanning optical delay line ('RSOD')

Methodology Applied
Scientific EffectOptical delay:

Data Source

PatentEP1971848B1Systems and methods for generating data based on one or more spectrally-encoded endoscopy techniques
Publication Date: 2019.12.04 THE GENERAL HOSPITAL CORP
  • EP1971848B1 patent drawingFigure 1
  • EP1971848B1 patent drawingFigure 2
  • EP1971848B1 patent drawingFigure 3A~3K

AI summary

Exemplary systems and methods for generating data associated with at least one portion of a sample can be provided. For example, according to one exemplary embodiment of such systems and methods, it is possible to provide a particular radiation using at least one first arrangement. The particular radiation can include at least one first electro-magnetic radiation directed to at least one sample and at least one second electro-magnetic radiation directed to a reference arrangement. The first radiation and/or the second radiation can comprise a plurality of wavelengths. The first electro-magnetic radiation can be spectrally dispersed along at least one portion of the sample. The second electro-magnetic radiation measured at two or more different lengths of the reference arrangement with respect to the first arrangement. Data can be generated which is associated with the first and second electro-magnetic radiations obtained at the two different lengths using at least one second arrangement which comprises a spectrometer arrangement.