Tunable Spectral Calibration Target Using Segmented Mirrors
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Solution Overview
Problem
Current vicarious calibration methods for remote sensing systems are limited by the need for large, cumbersome targets with stable reflectance properties and do not account for spectral variations, making it difficult to validate sensor performance across various environmental conditions and backgrounds, especially for sensitive or hard-to-reproduce targets.
Innovation Solution
A system and method using a plurality of reflective mirrors with tunable radii of curvature and base diameters to create synthetic targets with specific spectral properties, allowing for precise spectral calibration and validation of remote sensing sensors by reflecting radiation across different wavelength ranges, enabling easier deployment and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional vicarious calibration methods use large diffuse reflectance targets, then radiometric calibration can be achieved, but the targets become cumbersome and require extensive support teams for deployment and maintenance
Solution Approach 1:
The calibration target is divided into multiple reflective mirrors, each reflecting radiation at different wavelengths. This segmentation allows the system to achieve spectral calibration without requiring a single large diffuse reflectance target, thereby reducing deployment complexity while maintaining calibration accuracy.
Solution Approach 2:
The patent uses mirrors with different spectral reflectance properties (analogous to color changes) to provide calibration at different wavelengths. Each mirror is designed to reflect specific wavelength ranges, enabling spectral calibration without the need for large diffuse targets, thus simplifying deployment while maintaining measurement precision.
2Measurement precision
If conventional calibration targets are used, then radiometric properties can be calibrated, but spectral variations are not accounted for
Solution Approach 1:
The calibration system is segmented into multiple mirrors, each designed to reflect specific wavelength ranges. This segmentation enables the system to provide both radiometric calibration (using overall reflectance) and spectral calibration (using wavelength-specific reflectance), thereby achieving adaptability across different calibration requirements without sacrificing radiometric precision.
Solution Approach 2:
The patent changes the spectral reflectance parameter of the calibration targets by using mirrors with different radii of curvature and base diameters. This parameter change enables the system to account for spectral variations while maintaining radiometric calibration accuracy, thereby improving adaptability to different spectral conditions.
3Device complexity
If spectral calibration is performed without accounting for spectral mixing, then calibration can be simplified, but validation accuracy decreases
Solution Approach 1:
The calibration target is segmented into multiple spectral components (different mirrors for different wavelengths). This segmentation allows the system to explicitly account for spectral mixing effects during calibration, thereby improving validation accuracy while maintaining reasonable procedural simplicity through the modular mirror configuration.
Solution Approach 2:
The patent changes the geometric parameters (radii of curvature and base diameters) of the mirrors to control spectral reflectance properties. This parameter change enables precise control over spectral mixing effects, allowing accurate calibration and validation without overly complex procedures, thus balancing simplicity with precision.
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 provides a flexible and efficient means for spectral calibration and validation, allowing for precise quantitative spectral relationships and improved sensor performance across diverse conditions, reducing the need for large, stable targets and enhancing the ability to detect targets with unique spectral properties.
Implementation Method 1
a plurality of reflective mirrors configured and arranged to reflect radiation from a source of radiation onto a remotely located radiation sensor
Data Source
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Figure 3A~3D
AI summary
A method and a system for spectral calibration of a remote sensing sensor and a synthetic target having a tunable spectral composition are described. The system or synthetic target includes a plurality of reflective mirrors arranged to reflect radiation from a source of radiation onto a remotely located radiation sensor. A first mirror in the plurality of mirrors is configured to reflect a first portion of the radiation in a first wavelength toward the remotely located radiation sensor. A second mirror in the plurality of mirrors is configured to reflect a second portion of the radiation in a second wavelength different from the first wavelength toward the remotely located radiation sensor. The first portion of the radiation and the second portion of the radiation can be selected to calibrate the remotely located radiation sensor so as to provide a quantitative spectral relationship between the radiation detected at the remotely located sensor and the radiation reflected by the plurality of mirrors.