Optical Gas Imaging Noise Reduction via Frame Averaging

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Solution Overview

Problem

Infrared imaging systems face challenges in effectively detecting gas clouds due to small changes in infrared images that may be below the noise threshold, and motion or thermal changes within the camera scene can lead to false detection or non-detection of gases, making it difficult to use these systems effectively in the field.

Innovation Solution

A real-time optical gas imaging system that uses a thermal imaging camera to generate filtered background and foreground images by averaging multiple frames, and then compares these to create an optical gas image, reducing noise and improving the signal-to-noise ratio to enhance gas detection accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If infrared imaging is used to detect gas clouds, then gas detection capability is provided, but the small changes in infrared images caused by gas clouds fall below the noise threshold making detection difficult

Engineering Contradiction:

Improvegas detection sensitivityVSAvoidsignal-to-noise ratio

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system performs preliminary actions by capturing multiple background images before gas detection and capturing multiple foreground images during detection. These preliminary captures allow the system to establish baseline thermal patterns and reduce random noise through statistical processing, thereby improving the reliability of subsequent gas detection measurements.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system merges multiple infrared image captures (both background and foreground images) into composite images through averaging or other statistical operations. This combining approach reduces random noise and enhances the signal-to-noise ratio, making subtle gas cloud detections more reliable while maintaining measurement precision.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of operation

If thermal camera is used for gas detection, then gas presence can be identified, but motion of the camera or thermal changes within the camera scene cause false detection or non-detection

Engineering Contradiction:

Improvegas detection functionalityVSAvoiddetection accuracy

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs preliminary capture of multiple background images under normal operating conditions before actual gas detection begins. This establishes a baseline that accounts for camera thermal drift and scene variations, allowing the system to distinguish between normal operational changes and actual gas cloud presence, thereby improving detection accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by continuously comparing foreground images against the established background baseline. This comparison mechanism provides real-time feedback that helps distinguish between camera motion artifacts and actual gas detection signals, improving reliability while maintaining ease of operation.

Inventive Principle:

Principle #23Feedback

3Reliability

If multiple image filtering processes are applied to reduce noise, then signal-to-noise ratio improves, but processing time and computational complexity increase

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidimage processing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system applies partial filtering by averaging only a specific number of background and foreground images rather than processing all possible captures. This selective approach achieves sufficient noise reduction for reliable gas detection while limiting processing time and computational resources, balancing reliability improvement with time efficiency.

Inventive Principle:

Principle #16Partial or excessive action

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 effectively reduces noise in infrared images, allowing for more accurate detection of gas clouds by highlighting changes in the scene, even in the presence of motion or thermal fluctuations, thereby improving the reliability of gas recognition.

Implementation Method 1

an infrared camera module configured to capture an infrared image of a target scene

Methodology Applied

Scientific EffectInfrared radiation detection: Infrared Radiation

Implementation Method 2

combining infrared image data from a first plurality of images... using a first filtering process... combining infrared image data from a second plurality of images... using a second filtering process

Methodology Applied

Scientific EffectSignal averaging:

Data Source

PatentEP3404401B1Optical gas imaging systems and methods

Publication Date: 2023.02.22 FLUKE CORP

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AI summary

Systems, cameras, and software for performing optical gas imaging using thermal imaging. Processors are programmed with instructions for a method of detecting gas that includes creating a filtered background image, a filtered foreground image, and optical gas image data, and generating a display image. The filtered background image and filtered foreground images may be created by combining infrared image data from a plurality of images captured by an infrared camera module using filtering processes. The optical gas image data may be created by comparing the filtered background image and the filtered foreground image. An image may be generated that includes the optical gas image data for presentation on a display.