Filter Array Transmittance Variation for Hyperspectral Reconstruction
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Solution Overview
Problem
Existing hyperspectral cameras using compressed sensing suffer from significant reconstruction errors due to inappropriate optical filter array configurations, which affect the quality of reconstructed images.
Innovation Solution
Designing a filter array with optical filters that have uniform mean transmittance and standard deviation greater than a certain value, considering the wavelength dependency of the image sensor, to reduce reconstruction errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional optical filter arrays are used in hyperspectral cameras, then the device can capture multiwavelength information, but significant reconstruction errors occur due to inappropriate filter configurations
Solution Approach 1:
The patent applies parameter changes by optimizing the transmittance characteristics of optical filters. Specifically, it sets the standard deviation of transmittance values to be greater than a predetermined threshold and controls the ratio between standard deviation and mean value, transforming the filter array from a conventional configuration to one with statistically optimized parameters that enhance compressed sensing reconstruction accuracy
Solution Approach 2:
The patent implements local quality by creating spatial variation in filter transmittance properties across the filter array. Different regions of the array have filters with locally optimized transmittance characteristics, ensuring that each local region contributes optimally to the compressed sensing measurement matrix while maintaining overall system performance
2Loss of information
If optical filters with varying transmittance characteristics are used, then spectral information can be captured, but reconstruction errors increase due to inappropriate transmittance distribution
Solution Approach 1:
The patent transforms the transmittance parameter distribution of optical filters from conventional uniform or arbitrary values to a statistically optimized distribution. By setting standard deviation greater than a predetermined value and controlling the coefficient of variation, the filter array achieves optimal information capture while minimizing reconstruction errors in compressed sensing
3Reliability
If a filter array with optimized transmittance standard deviation is designed, then reconstruction errors are reduced, but the device complexity increases due to precise transmittance control requirements
Solution Approach 1:
The patent simplifies the design process by specifying concrete parameter thresholds (standard deviation greater than predetermined value, coefficient of variation greater than predetermined ratio) rather than requiring complex optimization algorithms. This transforms a potentially complex design problem into a straightforward parameter selection process that maintains high reconstruction reliability
Solution Approach 2:
The patent enables the filter array to self-optimize its performance through inherent statistical properties of the transmittance distribution. By designing filters with appropriate standard deviation and mean value ratios, the system automatically achieves optimal compressed sensing reconstruction without requiring external adjustment or complex control mechanisms
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 proposed filter array configuration enhances the convergence of reconstruction solutions and reduces errors in hyperspectral image reconstruction, resulting in higher-quality images.
Implementation Method 1
The filter array includes optical filters whose light transmittances in each of the N wavelength bands differ from each other
Implementation Method 2
an image sensor that detects light that has passed through the optical filters
Data Source
AI summary
A filter array, which is to be used in a photodetection system that generates image data of each of N wavelength bands (where N is an integer greater than or equal to 4), includes optical filters whose light transmittances in each of the N wavelength bands differ from each other. (σ1/μ1)≥0.1, . . . , and (σN/μN)≥0.1, where μi is a mean value of transmittances, corresponding one-to-one to the optical filters, with respect to light of an i-th wavelength band (where i is an integer greater than or equal to 1 and less than or equal to N) among the N wavelength bands, and where σi is a standard deviation of the transmittances, corresponding one-to-one to the optical filters, with respect to the light of the i-th wavelength band.