3D Gas-Mapping Imager for Fast High-Sensitivity Leak Detection
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Solution Overview
Problem
Existing wavelength modulation spectroscopy (WMS) sensors face limitations in generating high-sensitivity gas concentration imagery due to slow measurement rates, lack of spatial registration, and inability to generate quantitative concentration analysis over large areas, especially in complex topographical scenes.
Innovation Solution
A measurement system combining wavelength modulation spectroscopy with laser detection and ranging, using a spatially-scanning transmitter, encoder, and processor to create spatially mapped gas absorption imagery, incorporating geo-registration and methods to reduce measurement noise and errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If wavelength modulation spectroscopy is used for high-sensitivity gas concentration measurements, then measurement sensitivity is improved, but measurement speed deteriorates (0.1s acquisition time)
Solution Approach 1:
The patent segments the measurement process by using multiple detectors arranged in an array, allowing simultaneous measurement of gas concentrations across different spatial locations. This parallel measurement approach maintains high sensitivity through WMS while improving overall productivity by measuring multiple points concurrently rather than sequentially
Solution Approach 2:
The patent implements periodic modulation of the laser wavelength at high frequencies, enabling rapid gas concentration measurements. The periodic wavelength modulation allows the system to achieve both high sensitivity through spectroscopic techniques and high speed by operating at modulation frequencies that enable fast detection cycles
2Length of stationary object
If WMS sensors are used for remote sensing, then measurement range is improved, but spatial resolution and imagery generation capability deteriorate
Solution Approach 1:
The patent introduces an intermediary imaging lens system that couples the laser beam to a focal plane array detector. This intermediary optical system maintains the long measurement range capability of remote sensing while enabling spatial resolution by forming an image of the measurement path onto the detector array, thereby achieving both remote sensing and spatial registration
Solution Approach 2:
The patent transitions from point measurements to spatially-resolved measurements by adding the spatial dimension through an imaging lens system. The lens creates a one-to-one correspondence between spatial positions in the measurement path and detector elements, enabling imagery generation while maintaining remote sensing capability
3Ease of operation
If hand-held WMS sensors are used for leak detection, then portability is improved, but measurement area coverage and quantitative analysis capability deteriorate
Solution Approach 1:
The patent merges the advantages of hand-held portability with the capabilities of fixed installations by integrating a focal plane array detector system into a portable platform. This combination enables the sensor to cover large measurement areas through parallel detection while maintaining the ease of operation and mobility of hand-held devices
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 rapid and accurate generation of path-averaged gas concentration imagery with reduced systematic errors, suitable for large-area gas detection applications.
Implementation Method 1
a wavelength modulation spectroscopy portion configured to measure a gas absorption of laser light over a distance to a surface
Implementation Method 2
measure a gas absorption of laser light
Implementation Method 3
a laser detection and ranging portion configured to measure a distance from a sensor to the surface
Implementation Method 4
a spatially-scanning transmitter configured to transmit laser light
Data Source
AI summary
Measurement apparatuses and methods are disclosed for generating high-precision and -accuracy gas concentration maps that can be overlaid with 3D topographic images by rapidly scanning one or several modulated laser beams with a spatially-encoded transmitter over a scene to build-up imagery. Independent measurements of the topographic target distance and path-integrated gas concentration are combined to yield a map of the path-averaged concentration between the sensor and each point in the image. This type of image is particularly useful for finding localized regions of elevated (or anomalous) gas concentration making it ideal for large-area leak detection and quantification applications including: oil and gas pipeline monitoring, chemical processing facility monitoring, and environmental monitoring.