Static Coded Aperture Spectrometer for Hyperspectral Imaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hyperspectral imaging systems face challenges in achieving high optical efficiency with low component and design cost, and are constrained by the 'missing cone' problem, which affects spectral resolution and requires complex and expensive components.
Innovation Solution
The use of static coded aperture spectrometers that combine translation, rotation, and defocus to estimate spectral images using a 2D coded aperture and a spectrally dispersive element, allowing for high throughput and well-conditioned estimation of spatial and spectral features without the need for interferometric stability or dynamic spatial light modulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If traditional isomorphic systems with tunable filters or pushbroom spectrometers are used, then spectral imaging capability is achieved, but optical efficiency is poor and acquisition time is long
Solution Approach 1:
The patent employs a dynamic scanning mechanism where the spectrometer translates along the optical axis to vary the coded image over time. This dynamic approach allows a single static coded aperture to capture multiple spectral measurements, improving optical efficiency without requiring multiple physical apertures or complex filter systems.
Solution Approach 2:
The system uses periodic translation of the spectrometer to systematically vary the coded image projections. This periodic scanning enables complete spectral data collection through a sequence of measurements, achieving high optical efficiency while maintaining manageable acquisition time through structured sampling.
2Loss of energy
If Fourier transform interferometry or Hadamard transform dispersion is used, then throughput is high (50-100%), but component cost and design complexity are high
Solution Approach 1:
The patent replaces expensive, stability-critical components (interferometers, dynamic spatial light modulators) with a simple static coded aperture mask. This static mask is inexpensive to manufacture and does not require active control or stabilization systems, dramatically reducing component cost while maintaining high throughput through efficient light collection.
Solution Approach 2:
The invention extracts the essential spectral encoding function from complex dynamic systems and implements it through a simple static coded aperture. By removing the need for interferometric components or programmable modulators, the system achieves high throughput with minimal complexity.
3Adaptability or versatility
If spectral tomography is used, then multiplexing capability is achieved, but the missing cone problem degrades spectral resolution
Solution Approach 1:
The patent resolves the missing cone problem by dynamically translating the spectrometer along the optical axis during data collection. This temporal variation in the coded image projections provides additional sampling angles in the spatial-frequency domain, completing the spectral information that would otherwise be missing in static tomography approaches.
Solution Approach 2:
The system adds the temporal dimension to the spectral tomography problem. By collecting measurements over time as the spectrometer translates, the system captures spectral information from multiple effective angles, filling in the missing cone regions in the spatial-frequency spectrum and enabling accurate spectral reconstruction.
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 enables hyperspectral imaging with high optical efficiency, low component and design costs, and avoids the 'missing cone' problem, allowing for accurate estimation of spectral images with fewer measurements and improved signal-to-noise ratio.
Implementation Method 1
a coded image from the coded aperture is detected on a two-dimensional detector array of the spectrometer through a spectrally dispersive element of the spectrometer
Data Source
AI summary
Embodiments of the present invention relate to systems and methods for spectral imaging. In one embodiment, an image of the scene is formed on a coded aperture of a spectrometer. A coded image from the coded aperture is detected on a two-dimensional detector array of the spectrometer through a spectrally dispersive element of the spectrometer. Data from the two-dimensional detector array is collected as the coded image is varied over time. The spectral image is estimated from the data collected and the variation of the coded image over time. The data collected is varied over time through translation, rotation, and defocus.