Solar Reflection Hyperspectral Imaging With Three-Band Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional solar reflection full-band hyperspectral imagers suffer from spectral aliasing, non-uniform quantum efficiency across the band, and the Etalon effect, leading to reduced detection accuracy and signal-to-noise ratio.
Innovation Solution
A three-band spectrometer system with a trisection field-of-view separator and grating-based spectrometers, utilizing positive first-order diffraction efficiency to optimize light distribution across CMOS, InGaAs, and HgCdTe detectors, eliminating spectral aliasing and Etalon effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If grating beam splitting is used to improve linear characteristics and expand detection range, then spectral coverage is improved, but overlapping diffracted beams of different orders cause spectral aliasing
Solution Approach 1:
The patent divides the full solar reflection band (0.4-2.5 μm) into three separate wavelength bands using a trisection field-of-view separator. Each band is then directed to dedicated spectrometers with appropriate detectors, preventing spectral aliasing while maintaining full-band coverage. This segmentation approach resolves the contradiction by achieving both broad spectral coverage and high measurement precision within each segment.
Solution Approach 2:
The patent introduces a trisection field-of-view separator as an intermediary device that separates incoming light into three distinct wavelength bands before they reach the spectrometers. This intermediary component prevents different order diffracted beams from overlapping at the detector, thereby eliminating spectral aliasing while preserving the advantages of grating beam splitting for broad spectral coverage.
2Adaptability or versatility
If two-band spectrometer system is used to cover full solar reflection band, then detection range is improved, but spectral aliasing and non-uniform quantum efficiency reduce detection accuracy
Solution Approach 1:
The patent transitions from a two-band to a three-band spectrometer system, further segmenting the solar reflection spectrum. This additional segmentation allows for more uniform distribution of spectral energy across detectors and eliminates the spectral aliasing problems inherent in the two-band approach, thereby improving both detection range and detection accuracy simultaneously.
Solution Approach 2:
The patent assigns different detector types (CMOS, InGaAs, HgCdTe) to different wavelength bands based on their optimal performance characteristics. This local quality approach ensures that each detector operates in its peak efficiency range, achieving non-uniform quantum efficiency optimization that improves overall detection accuracy across the full spectral range.
3Measurement precision
If detector substrate is thinned to improve quantum efficiency at band ends, then photoelectric conversion efficiency is improved, but severe Etalon effect is introduced
Solution Approach 1:
The patent extracts and eliminates the root cause of the Etalon effect by maintaining intact detector substrates and instead addressing the spectral distribution problem through optical system design. The three-band separation with appropriate cut-off filters removes the need for substrate thinning, thereby preserving quantum efficiency at band ends without introducing the harmful Etalon effect.
Solution Approach 2:
The patent converts the potential harm of reduced light transmission (due to not thinning substrates) into a benefit by optimizing the optical path and using three-band separation with cut-off filters. This approach maintains substrate integrity to avoid Etalon effects while still achieving high quantum efficiency through improved optical flux distribution and detector matching.
4Measurement precision
If optical filter is added to block non-measured sub-spectrum, then spectral aliasing is reduced, but overall transmittance decreases and filter installation deviation causes response inconsistency
Solution Approach 1:
The patent uses a trisection field-of-view separator to segment the incoming light into three distinct wavelength bands, inherently blocking non-measured sub-spectra before they reach the detectors. This segmentation approach achieves spectral purity without requiring additional optical filters, thereby reducing system complexity while maintaining spectral aliasing rejection.
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
Achieves high-efficiency, high-precision detection with uniform optical flux and improved signal-to-noise ratio across the full solar reflection band, enhancing detection accuracy and reducing system complexity.
Implementation Method 1
the linear characteristics of the grating beam splitting can effectively improve the above deficiencies
Implementation Method 2
due to the basic principle of grating dispersion, the grating beam splitting method causes the problem of overlapping diffracted beams of different orders
Implementation Method 3
the quantum conversion efficiency of the detector approaches 90% at around 550 nm
Data Source
AI summary
A solar reflection full-band hyperspectral imaging detection system comprises a telescope light collection system, a field-of-view separation assembly, a spectrometer assembly, and a detector assembly. The field-of-view separation assembly comprises an integrated trisection field-of-view separator, a first field-of-view assembly, a second field-of-view assembly, and a third field-of-view assembly; the spectrometer assembly comprises a first spectrometer, a second spectrometer and a third spectrometer; and the detector assembly comprises a CMOS (Complementary Metal Oxide Semiconductor) detector, an InGaAs detector, and an HgCdTe detector. The present invention adopts the three-band spectrometer, and the spectrum aliasing, high photoelectric efficiency in the middle and low photoelectric efficiency at two ends, limited detection dynamic range, severe Etalon interference effect and the like of a two-band spectrometer with a traditional solar reflection full-band hyperspectral detection system are solved.