Multi-Band Light Detection with Uniform Filter Sensitivity
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Solution Overview
Problem
Hyperspectral cameras face challenges in reducing the influence of noise during image reconstruction, which increases reconstruction errors.
Innovation Solution
A light detection apparatus with a filter array and optical filters designed to modulate light on a wavelength-by-wavelength basis, combined with an image processing apparatus, reduces noise by leveraging compressed sensing techniques to reconstruct high-resolution multi-wavelength images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If compressed sensing is applied to reconstruct hyperspectral images, then higher resolution and wavelength expansion are achieved, but noise influence increases reconstruction errors
Solution Approach 1:
The patent changes the parameter of optical filter transmittance to optimize the effective sensitivity distribution. By controlling the transmittance values and their distribution across different pixels, the system achieves more uniform signal levels that are less susceptible to noise, thereby reducing reconstruction errors while maintaining high resolution
Solution Approach 2:
The patent performs preliminary optimization of the filter array design before actual imaging. By pre-calculating and setting the transmittance parameters of optical filters to achieve uniform effective sensitivity, the system prepares the optimal configuration in advance to minimize noise impact during the reconstruction process
2Measurement precision
If optical filters with narrow bandwidth are used for each wavelength band, then spectral resolution is improved, but signal intensity decreases and noise becomes more significant
Solution Approach 1:
The patent optimizes the transmittance parameter of optical filters to balance bandwidth and signal intensity. By adjusting the transmittance values, the system maintains narrow bandwidth for spectral resolution while ensuring sufficient light transmission to keep signal intensity adequate and noise influence manageable
Solution Approach 2:
The system pre-optimizes the filter transmittance parameters before imaging to achieve the desired balance between spectral resolution and signal intensity, ensuring that each wavelength band has appropriate filter characteristics that maximize signal while maintaining resolution
3Productivity
If multiple wavelength bands are superimposed on each pixel signal, then spectral information compression is achieved, but noise from multiple bands accumulates
Solution Approach 1:
The patent changes the distribution parameters of effective sensitivity across pixels to achieve uniform signal levels. This uniformity prevents noise accumulation during superposition because each pixel contributes comparable signal strength, allowing multiple wavelength bands to be compressed without excessive noise buildup
Solution Approach 2:
The patent creates homogeneity in the effective sensitivity distribution across all pixels by optimizing filter transmittance. This homogeneous distribution ensures that when multiple wavelength bands are superimposed, the noise from each band is weighted equally and does not accumulate disproportionately, maintaining signal-to-noise ratio
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 apparatus effectively minimizes noise-related reconstruction errors, enhancing the quality of hyperspectral images by improving sensitivity and resolution.
Implementation Method 1
information on four or more wavelength bands included in a target wavelength range is superimposed on a signal outputted from the light detection element, let μi be an average of values of an effective sensitivity of an i-th pixel (i=1, 2, . . . , N) among the N pixels in the target wavelength range based on a wavelength dependency of a transmittance of the optical filter included in the i-th pixel
Implementation Method 2
a light detection element detecting light having passed through the optical filter
Data Source
AI summary
A light detection apparatus includes N pixels the number of which is N. Each of the N pixels includes an optical filter and a light detection element that detects light having passed through the optical filter. Information on four or more wavelength bands included in a target wavelength range is superimposed on a signal outputted from the light detection element. Let μi be an average of values of an effective sensitivity of an i-th pixel (i=1, 2, . . . , N) among the N pixels in the target wavelength range based on a wavelength dependency of a transmittance of the optical filter included in the i-th pixel and a wavelength dependency of a detection sensitivity of the light detection element included in the i-th pixel. Let μmin be a minimum value among μ1 to μN. Given these definitions, a predetermined expression is satisfied.