Multimode Filter Array with Band-Limiting for Hyperspectral Imaging
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Solution Overview
Problem
Existing hyperspectral imaging systems face challenges in acquiring accurate hyperspectral information across a broader wavelength range with reduced errors, particularly due to the interference of low-order modes in longer-wavelength ranges and high-order modes in shorter-wavelength ranges within the same filter structure.
Innovation Solution
The proposed solution involves a filter array configuration that includes a combination of multimode filters and band-limiting filters. Each multimode filter has peak wavelengths within a target wavelength range, while the band-limiting filters restrict transmission in specific sub-wavelength ranges, thereby enhancing the randomness of the transmittance across the broader wavelength range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single filter structure is used to cover a broad wavelength range, then the device complexity is reduced, but the measurement precision deteriorates due to interference between low-order modes in longer wavelengths and high-order modes in shorter wavelengths
Solution Approach 1:
The patent divides the filter array into multiple filters, where each filter is responsible for a specific wavelength band. This segmentation prevents the interference between low-order modes in longer wavelengths and high-order modes in shorter wavelengths that occurs in single-filter structures, thereby maintaining measurement precision across the broad wavelength range.
Solution Approach 2:
Each filter in the array is designed with specific local characteristics optimized for its designated wavelength band. The filters have different peak wavelengths and transmittance characteristics tailored to their specific bands, ensuring high measurement precision for each band while collectively covering the broader wavelength range.
2Adaptability or versatility
If the wavelength range is expanded, then the adaptability is improved, but the measurement precision deteriorates due to increased interference between different order modes
Solution Approach 1:
The patent segments the broad wavelength range into multiple bands, with each filter handling a specific band. This allows the system to achieve broad adaptability across the entire wavelength range while maintaining high measurement precision in each individual band by avoiding mode interference through segmentation.
Solution Approach 2:
The patent changes the parameters of different filters (peak wavelengths, transmittance characteristics) to match their respective wavelength bands. This parameter optimization ensures that each filter operates at peak efficiency for its band, maintaining measurement precision while expanding overall adaptability.
3Measurement precision
If multimode filters are used to increase transmittance randomness, then the measurement precision is improved, but the device complexity increases due to the need for multiple filter types
Solution Approach 1:
The patent segments the filter array into multiple filters with different multimode characteristics, where each filter type is optimized for specific wavelength bands. This segmentation approach increases measurement precision through enhanced transmittance randomness while managing device complexity by organizing filters in a structured, band-specific manner.
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 configuration effectively reduces estimation errors in hyperspectral images by maintaining high randomness of transmittance throughout the broader wavelength range, thereby improving the accuracy of hyperspectral data generation.
Implementation Method 1
a first multimode filter that has, within a target wavelength range, first peak wavelengths at each of which an optical transmittance is at a local maximum
Implementation Method 2
a first band-limiting filter that restricts transmission of light in a first sub-wavelength range that is a part of the target wavelength range
Data Source
AI summary
A filter array includes optical filters arranged in two dimensions. The optical filters include a first filter and a second filter. The first filter includes a first multimode filter having, within a target wavelength range, first peak wavelengths at each of which the optical transmittance is at a local maximum, and a first band-limiting filter having, as a limiting band, a first sub-wavelength range that is a part of the target wavelength range. The second filter includes a second multimode filter having, within the target wavelength range, second peak wavelengths at each of which the optical transmittance is at a local maximum, at least one of the second peak wavelengths being different from the first peak wavelengths, and a second band-limiting filter restricting transmission of light in a second sub-wavelength range that is a part of the target wavelength range and that is different from the first sub-wavelength range.