Compact Lidar Opacity Measurement System
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Solution Overview
Problem
Current methods for remote opacity measurement of visible emissions, such as EPA Method 9 and lidar, are either labor-intensive, prone to human bias, or require bulky, power-hungry equipment that is not easily transportable or eye-safe, limiting their practicality for compliance with environmental regulations.
Innovation Solution
A compact, handheld lidar system with a low-average-power pulsed laser transmitter and low-power signal processing hardware, allowing for eye-safe, battery-operable operation, which reduces power consumption and enables accurate opacity measurement of both stationary and non-stationary sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional lidar systems are used for opacity measurement, then measurement accuracy is improved, but device portability and power consumption deteriorate
Solution Approach 1:
The system segments the optical detection function into a separate handheld lidar unit from the emission source, allowing the measurement device to be compact and portable while maintaining measurement accuracy through dedicated optical components and signal processing algorithms
Solution Approach 2:
The patent changes operational parameters by using low-average-power pulsed laser transmission instead of continuous high-power operation, and employs sensitive photodetectors with signal amplification to detect weak backscatter signals, achieving both portability and measurement precision
2Measurement precision
If high-power laser transmitters are used, then measurement range and accuracy are improved, but eye safety deteriorates
Solution Approach 1:
The system uses periodic pulsed laser transmission at low average power instead of continuous high-power operation, transmitting brief pulses that provide sufficient backscatter signal for measurement while keeping the average power below eye safety thresholds
Solution Approach 2:
The patent replaces mechanical eye-safe attenuators with optical signal processing techniques, using sensitive detectors and signal amplification to achieve accurate measurements from low-power pulses without requiring physical attenuation mechanisms
3Device complexity
If visual determination methods are used, then equipment complexity is reduced, but measurement objectivity and data reliability deteriorate
Solution Approach 1:
The patent replaces human visual assessment with automated optical detection and electronic signal processing, using photodetectors to objectively measure backscatter signal attenuation and compute opacity values, eliminating human bias while maintaining operational simplicity
Solution Approach 2:
The handheld lidar unit performs self-calibration and automated opacity calculation through integrated signal processing algorithms that compare backscatter signals with and without the emission plume present, providing objective measurements without requiring external reference standards or manual calibration procedures
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 system achieves significant reduction in power consumption, enabling a portable and accurate opacity measurement system that meets regulatory standards, providing real-time data and improved compliance with environmental regulations.
Implementation Method 1
A basic lidar system consists of an optical transmitter, an optical receiver, and associated signal processing and control electronics. In a pulsed lidar system, the optical transmitter sends optical pulses in a collimated light path through the atmosphere towards a target of interest. A small fraction of that transmitted light is backscattered to the optical receiver by atmospheric constituents, particles, or objects within light path.
Implementation Method 2
The receiver collects the backscattered light onto a detector that converts that light into an electronic signal.
Data Source
AI summary
Disclosed herein is a novel system and method for the remote characterization of visible emissions, and more particularly, to compact, optical sensors which can remotely measure the opacity of a visible emission plume from a stationary source. Assessing visible emissions is important for compliance with environmental regulations and to support the regulatory reporting needs of Federal and State inspectors. By reducing the power consumption of the laser source and the signal processing, a compact, handheld or hand portable, battery-operable opacity measurement system can be realized while allowing eye-safe operation. The system and method may also be applied to non-stationary sources.