Spectral Filter Array Correlation Layout for Hyperspectral Reconstruction
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Solution Overview
Problem
Existing hyperspectral imaging technologies face challenges in achieving accurate reconstruction of spectral images due to insufficient randomness in the wavelength direction of filter arrays, leading to inadequate wavelength information and decreased resolution.
Innovation Solution
The implementation of optical filters with controlled spectral transmittance differences and an image sensor that detects light passing through these filters, where the correlation coefficient between pixel values of different wavelength bands is optimized to ensure rij≥0.8 for adjacent bands and rij≤0.8 for non-adjacent bands, enhancing the sparsity and randomness in the wavelength direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional filter array is used with insufficient randomness in the wavelength direction, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision of spectral information and reconstruction accuracy of hyperspectral images deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the correlation coefficient parameters between adjacent and non-adjacent wavelength bands. Specifically, it sets the correlation coefficient between adjacent bands to be greater than or equal to 0.8, and between non-adjacent bands to be less than or equal to 0.8. This parameter optimization improves spectral reconstruction accuracy without requiring complete randomness, thus balancing measurement precision with manageable device complexity
Solution Approach 2:
The patent implements local quality by differentiating the correlation requirements for different wavelength band relationships. Instead of applying a uniform randomness requirement across all bands, it specifies different correlation thresholds: higher correlation (≥0.8) for adjacent bands to preserve spectral continuity, and lower correlation (≤0.8) for non-adjacent bands to maintain wavelength discrimination. This localized quality approach improves reconstruction accuracy while avoiding excessive device complexity
2Measurement precision
If the filter array is designed with high randomness in the wavelength direction, then the sparsity of wavelength information is improved and reconstruction accuracy is enhanced, but the difficulty of detecting and measuring spectral characteristics increases
Solution Approach 1:
The patent changes the parameter of correlation coefficient thresholds to optimize wavelength information quality. By setting specific thresholds (≥0.8 for adjacent bands, ≤0.8 for non-adjacent bands), it achieves sufficient sparsity for accurate reconstruction while maintaining detectability. This parameter optimization avoids the need for complete randomness that would make spectral detection overly difficult
3Measurement precision
If optical filters are designed with controlled spectral transmittance to optimize correlation coefficients, then the reconstruction accuracy of hyperspectral images is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by establishing specific correlation coefficient thresholds (≥0.8 for adjacent bands, ≤0.8 for non-adjacent bands) as manufacturing targets. These threshold parameters provide clear, quantifiable specifications for filter fabrication, balancing the need for high reconstruction accuracy with practical manufacturing precision capabilities. The thresholds are set to be achievable while still delivering significant performance improvement over conventional approaches
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 improves the reconstruction accuracy of hyperspectral images by ensuring that adjacent wavelength bands have high correlation while non-adjacent bands have lower correlation, thereby enhancing the sparsity and improving the overall image reconstruction quality.
Implementation Method 1
optical filters that are different from one another in spectral transmittance
Implementation Method 2
an image sensor that detects light that has passed through the optical filters
Data Source
AI summary
A device used in a system for generating spectral images corresponding to four or more wavelength bands includes optical filters different in spectral transmittance and an image sensor that detects light through the optical filters, in which when the wavelength bands are given numbers in an ascending or descending order of a central wavelength, the image sensor outputs i-th mask data by detecting only light corresponding to an i-th wavelength band and outputs j-th mask data by detecting only light corresponding to a j-th wavelength band among the wavelength bands, a correlation coefficient between the i-th and j-th mask data is greater than or equal to 0.8 in a combination where |i−j| is 1, and is equal to or less than 0.8 in at least one combination where |i−j| is greater than or equal to 2 and less than or equal to N−1.