In Situ Spectral Analysis via Swept-Frequency Laser
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Solution Overview
Problem
Conventional remote sensing technologies struggle to simultaneously determine the geometric shape and chemical composition of a target material across multiple wavelengths, requiring costly post-processing and incomplete spectral coverage due to limitations in lidar and passive spectral analysis techniques.
Innovation Solution
A system combining active hyperspectral imaging with simultaneous lidar measurements and a materials database for real-time adaptation of light frequency and spatial resolution, using a broad-band laser source and tunable filters to collect high-resolution spectral and spatial data, minimizing post-processing and maximizing resolution in areas of interest.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional lidar uses a single laser frequency to actively illuminate a target, then ranging information can be obtained, but chemical composition analysis cannot be accomplished
Solution Approach 1:
The patent segments the spectral analysis by using multiple discrete frequencies simultaneously collected through a spectrograph, allowing chemical composition analysis while maintaining ranging capability. The single laser frequency is segmented into multiple frequency components that can be individually analyzed for compositional information.
Solution Approach 2:
The patent merges lidar ranging functionality with hyperspectral imaging by simultaneously collecting multiple discrete frequencies through a spectrograph. This combination allows both geometric shape/location determination and chemical composition analysis to be achieved in a single integrated system without requiring separate instruments.
2Measurement precision
If passive spectral analysis uses naturally occurring electromagnetic radiation, then spectral samples can be collected, but considerable post-processing is required and spectral coverage is incomplete
Solution Approach 1:
The patent performs preliminary spectral processing by simultaneously collecting multiple discrete frequencies through a spectrograph during the acquisition phase. This preliminary action reduces the need for extensive post-processing by pre-organizing the spectral data in a structured manner that facilitates rapid analysis and interpretation.
Solution Approach 2:
The patent employs feedback mechanisms where real-time spectral information from the target material is used to dynamically adjust acquisition parameters. This feedback loop allows the system to optimize spectral coverage and resolution based on actual target characteristics, reducing unnecessary post-processing time.
3Measurement precision
If wide spectral bands are used to collect spectral data, then data acquisition is simplified, but spectral samples become blurred and resolution is reduced
Solution Approach 1:
The patent segments the spectral data into multiple discrete narrow bands (approximately 1 nm wide) that can be individually analyzed. This segmentation allows high spectral resolution to be achieved without requiring complex instrumentation, as each narrow band provides clear, unresolved spectral features for accurate chemical analysis.
4Area of stationary object
If atmospheric transit distance is increased to extend sensing range, then more target areas can be covered, but atmospheric absorption attenuates specific frequency bands
Solution Approach 1:
The patent changes the spectral parameters by selecting frequency bands that are less susceptible to atmospheric absorption. The system dynamically adjusts the spectral sampling to focus on windows where atmospheric transmission is higher, maintaining spectral accuracy even at extended sensing ranges.
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
Enables efficient collection of spectral data across hundreds of discrete wavelengths, reducing spatial distortion and errors, and providing accurate chemical composition analysis with minimized post-processing, while overcoming atmospheric attenuation limitations.
Implementation Method 1
a broad-band laser source, at least one tunable filter coupled to the source laser for generating a swept-frequency signal
Implementation Method 2
an optical device for splitting the swept-frequency signal into a first illumination signal and second illumination signal
Implementation Method 3
a first optical path for directing the first illumination signal unto the target material and receiving a reflected signal from the target material
Implementation Method 4
The control system performs a comparison of the spectral reference signal and the reflected signal, and adjusts the frequency and spatial resolution of the laser source based at least in part on the comparison
Data Source
AI summary
A system for remotely sensing a target material in situ include a broad-band laser source, at least one tunable filter coupled to the source laser for generating a swept-frequency signal an optical device for splitting the swept-frequency signal into a first illumination signal and second illumination signal, a first optical path for directing the first illumination signal unto the target material and receiving a reflected signal from the target material, a second optical path for receiving the second illumination signal and generating a spectral reference signal, and a controller coupled to the first optical path and the second optical path for adjusting the frequency and spatial resolution of the laser source based at least in part on a comparison of the spectral reference signal and the reflected signal.