Snapshot Multispectral Imaging With Multiplexed LED Illumination
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Solution Overview
Problem
Current spectral imaging systems face challenges with slow temporal resolution due to mechanically spinning filters, complexity in disparity correction, and limited spectral precision, especially in biomedical applications where biological tissue reflectance is complex.
Innovation Solution
A single-aperture, single-lens, single-camera system using multiplexed illumination with a multi-bandpass filter and LED illumination, allowing fast switching and spectral unmixing to achieve high precision and adjustable fields of view, while avoiding disparity correction and spectral cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mechanically spinning filter wheel is used to separate spectral bands, then spectral precision is improved, but temporal resolution deteriorates (slow speed)
Solution Approach 1:
The patent replaces the mechanical filter wheel system with an electronic multiplexed illumination system using multiple LEDs. Each LED emits a specific wavelength band, and by selectively activating different LEDs, the system achieves spectral separation without mechanical movement. This substitution of mechanical filtering with electronic wavelength selection resolves the contradiction by eliminating the slow mechanical spinning while maintaining spectral precision through controlled LED emission.
Solution Approach 2:
The system uses periodic activation of different LED groups to illuminate the scene at different wavelengths. By rapidly switching between LED combinations in a periodic manner and capturing images at each phase, the system achieves high temporal resolution while maintaining spectral precision through the structured periodic illumination sequence.
2Speed
If multiple color cameras with multi-band bandpass optical filters are used, then temporal resolution is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple camera functions into a single color camera by using a single multi-bandpass optical filter that transmits multiple discrete wavelength bands simultaneously. Instead of requiring multiple separate cameras each with their own filters, the system combines all spectral detection capabilities into one imaging device, reducing overall system complexity while maintaining fast temporal resolution.
Solution Approach 2:
The single multi-bandpass optical filter serves multiple functions by simultaneously transmitting multiple discrete wavelength bands to a single color camera. This universal filter design allows one camera to perform the work of multiple cameras, achieving spectral imaging across multiple bands without increasing the number of imaging devices, thus reducing system complexity.
3Device complexity
If a single-aperture system with multi-bandpass filter is used, then device complexity is reduced, but spectral cross-talk increases
Solution Approach 1:
The patent segments the illumination spectrum by using multiple LEDs, each emitting a specific wavelength band, rather than using a single broadband light source. This segmentation of the illumination source, combined with the multi-bandpass filter that segments the transmitted wavelengths, allows the single-aperture system to achieve precise spectral separation and minimize cross-talk by controlling which wavelengths are present in the illumination and detection paths.
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 provides high-speed multi-spectral imaging with improved spectral precision, reduced motion artifacts, and cost-effectiveness, suitable for real-time biomedical applications.
Implementation Method 1
a multi-bandpass filter positioned over the aperture, wherein the multi-bandpass filter is configured to allow passage of light in the four or more predetermined wavebands
Implementation Method 2
a light source configured to illuminate an object by selectively emitting light comprising one or more wavebands of a set of four or more predetermined wavebands
Implementation Method 3
an image sensor configured to receive a reflected portion of the emitted light that is reflected by the object
Data Source
AI summary
The present technology comprises a single-aperture snapshot multi-spectral imaging device generally consisting of at least a color camera, a customized Octa-Band optical filter, a motorized zoom lens, and an 8-wavelength multi-color LED illumination system. The present technology also comprises a method about designing time sequences and combinations of LED illuminations, along with an unmixing algorithm for 8 MSI images generation. According to the present device and method, it is capable of fast multi-spectral image acquisition speed (<100 milliseconds), fast post-processing speed based on adopting a single aperture system without disparity correction calculation, adjustable FOVs, smaller form factors and lower costs, and high precision of spectral information.