Hyperspectral Imaging Common-Path Interferometer
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Solution Overview
Problem
Existing hyperspectral imaging systems based on Fourier-transform spectroscopy face limitations due to chromatic dispersion and spatial separation of light replicas, which reduce interferometric modulation and signal-to-background ratio.
Innovation Solution
A Fourier-transform hyperspectral imaging system utilizing an adjustable birefringent common-path interferometer module with a movable birefringent wedge pair and a birefringent plate, minimizing chromatic dispersion and spatial separation, and allowing for simultaneous measurement of all wavelengths, thereby increasing signal-to-noise ratio and spectral resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Wollaston prisms are used to form an imaging Fourier transform spectropolarimeter, then polarimetric data can be acquired through channeled spectropolarimetry, but chromatic dispersion and spatial separation of light replicas occur, reducing interferometric modulation
Solution Approach 1:
The patent extracts and eliminates the harmful chromatic dispersion and spatial separation effects by using a common-path interferometer configuration where the reference and sample beams traverse identical optical paths. This removes the source of the harmful factors while preserving the useful interferometric modulation for polarimetric measurements.
Solution Approach 2:
The common-path interferometer design serves multiple functions simultaneously: it provides interferometric modulation for spectral analysis, maintains spatial coherence for imaging, and eliminates chromatic dispersion effects. The single optical path configuration achieves both spectral and spatial requirements without the trade-offs present in traditional dispersive systems.
2Measurement precision
If traditional Fourier-transform spectroscopy is used, then spectral information can be measured, but measurement time increases and signal-to-noise ratio decreases
Solution Approach 1:
The patent implements continuous spectral measurement through the common-path interferometer, where the interferogram is generated continuously as the sample beam passes through the interferometer. This eliminates the need for discrete scanning steps and mechanical movement, enabling continuous data acquisition that improves signal-to-noise ratio and reduces measurement time simultaneously.
Solution Approach 2:
The system performs preliminary optical path equalization and interference generation before detection, allowing the interferogram to be formed in advance of the actual measurement. This preliminary action enables efficient Fourier processing and spectral extraction without requiring time-consuming sequential scanning, thereby improving both signal quality and measurement speed.
3Reliability
If conventional interferometers are used, then spectral measurement is possible, but sensitivity to mechanical vibrations increases
Solution Approach 1:
The patent merges the reference and sample optical paths into a single common path, where both beams traverse identical optical elements. This merging eliminates differential path length changes that cause vibration sensitivity, as both beams experience the same mechanical disturbances. The unified optical path reduces system complexity while improving robustness against environmental vibrations.
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
The system achieves higher signal-to-noise ratio, increased spectral resolution, and reduced measurement time, with improved robustness against environmental conditions and mechanical vibrations, enabling more accurate and reproducible hyperspectral imaging across a wide spectral bandwidth.
Implementation Method 1
an adjustable birefringent common-path interferometer module (103) configured to produce replicas of the input radiation (INR) which are delayed from each other by adjustable phase delays
Implementation Method 2
configured to produce collinear replicas for entering optical rays parallel to the optical axis (z1) of the optical imaging system (106) and adapted to interfere with each other
Data Source
AI summary
A Fourier-transform hyperspectral imaging system may include an optical imaging system configured to produce an image of an object, and an adjustable birefringent common-path interferometer module comprising a movable birefringent element and configured to produce interfering replicas of an input radiation which are delayed from each other by a phase delay adjustable by the moving birefringent element. The interferometer module may be configured to produce collinear replicas for entering optical rays parallel to said optical axis. The hyperspectral imaging system further comprises a two-dimensional light detector configured to receive the replicas and provide digital images of the object depending on said adjustable phase delay. The system also includes an analysis device configured to perform a Fourier Transform of the digital images to obtain a hyperspectral representation of the object.