Hadamard Transform Fluorescence Imaging Multiplexing
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Solution Overview
Problem
Conventional excitation-emission matrix (EEM) spectroscopy is slow and limited by low signal-to-noise ratios, making it ineffective for characterizing spatially extended or heterogeneous samples, and it cannot be coupled with imaging systems.
Innovation Solution
Hyperspectral imaging systems using multiplexing techniques based on the Hadamard transform allow for the simultaneous sampling of multiple excitation wavelengths, enabling the capture of four-dimensional images that include spatial and spectral information, allowing for the characterization of chemical compounds through programmable light sources and hyperspectral cameras.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional EEM spectroscopy is used with sequential wavelength scanning, then spectral data can be obtained, but acquisition time is very long and signal-to-noise ratio is low
Solution Approach 1:
The patent applies periodic modulation of excitation wavelengths using Hadamard transform coding, where multiple wavelengths are modulated in a periodic sequence and detected simultaneously. This allows the system to acquire spectral information through coded periodic excitation rather than sequential scanning, dramatically reducing acquisition time while improving signal-to-noise ratio through the mathematical properties of Hadamard transforms.
Solution Approach 2:
The patent merges multiple excitation wavelength measurements into a single simultaneous detection event. By combining multiple wavelengths into coded excitation beams and using the Hadamard transform to decode the composite signal, the system obtains information from multiple wavelengths at once rather than sequentially, resolving the time versus signal quality contradiction.
2Adaptability or versatility
If conventional EEM spectroscopy is used, then spectral fingerprint data can be obtained, but it cannot be coupled with imaging systems for spatially extended samples
Solution Approach 1:
The patent creates a universal system that can perform both spectroscopic analysis and spatial imaging simultaneously. The Hadamard transform fluorescence excitation-emission-matrix imaging system is designed to handle both spectral dimension (through coded excitation) and spatial dimension (through imaging detectors), making it adaptable to various sample types from single points to extended spatially heterogeneous samples without requiring separate instrumentation.
Solution Approach 2:
The patent adds the spatial dimension to traditional EEM spectroscopy by coupling the coded excitation system with imaging detectors. This transforms the system from one that only measures spectral data at a single point to one that simultaneously captures spatial distribution and spectral characteristics, enabling characterization of extended samples through four-dimensional imaging data (x, y, excitation wavelength, emission wavelength).
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 acquisition time for EEM spectra, enabling the monitoring of time-dependent processes and allowing for the separation of components in space and their spectral analysis, applicable in fluorescence microscopy and process control, among other fields.
Implementation Method 1
Fluorescence spectroscopy is commonly used to detect and identify molecules in a mixture by exciting a chemical or biological sample with a laser and measuring the emission spectra produced in response
Data Source
AI summary
Multi-spectral imaging systems include an excitation light source that produces an excitation beam having an excitation light spectrum. A programmable light source sequentially selects three or more excitation wavelength ranges from a plurality of excitation wavelength ranges based on code words defined by a selected code. Based on the code words, a sequence of encoded excitation beams is produced which are sequentially directed to a sample location. An imaging system such as a hyperspectral camera is situated to produce spectral images of a sample associated with a plurality of emission wavelength ranges in response to each of the encoded excitation beams. The spectral images are decoded to produce a spectral emission image corresponding to emitted intensity at the plurality of emission wavelengths as a function of excitation wavelength.