Thermal Sensor Emissivity Compensation via Dual-Image Overlay

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Solution Overview

Problem

Typical IR camera sensor devices fail to accurately measure the temperature of target objects due to their inability to account for the specific emissivity of the object's surface, leading to inaccurate temperature conversions.

Innovation Solution

A method and sensor device that process thermal image data by using a neural network to detect objects of interest, identify their surface characteristics, and apply respective emissivity-based conversion functions to accurately convert pixel values to temperature values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a predetermined conversion function with fixed emissivity value is used for temperature conversion, then the device complexity is reduced and operation is simplified, but the measurement precision deteriorates due to inability to account for actual surface emissivity

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary detection of surface characteristics (shiny, painted, rusty, etc.) before temperature conversion, and pre-selects appropriate emissivity values from stored lookup tables based on the detected surface type. This preliminary classification enables accurate temperature measurement without real-time complex calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses its own visible light imaging capability to detect surface characteristics of the target object, and automatically selects appropriate emissivity values without requiring external input or manual intervention. The sensor device serves itself by utilizing its dual imaging modes (visible and thermal) for automatic emissivity compensation.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If emissivity-based conversion functions are applied to different objects, then the measurement precision improves, but the device complexity increases due to need for multiple conversion functions and emissivity determination

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidadaptability to different surface conditions
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The system applies different emissivity values to different regions of the thermal image based on local surface characteristics detected in the visible light image. Each detected object or region receives a customized emissivity value appropriate to its specific surface properties, enabling locally optimized temperature measurement accuracy.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The system dynamically changes the emissivity parameter based on detected surface characteristics. By identifying surface types (shiny metal, painted metal, rusty metal, etc.) and selecting corresponding emissivity values from lookup tables, the system adapts the conversion parameter to match actual physical conditions of different objects.

Inventive Principle:
Principle #35Parameter changes

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 enables accurate temperature measurements that take into account the emissivity of the objects, improving the precision of thermal condition monitoring in sensor devices.

Implementation Method 1

an infrared (IR) camera sensor device may be positioned near a target object and may detect the infrared radiation emitted from the target object

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

The second image capturing thermal distribution across the scene

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3751245B1Smart sensor measurement system
Publication Date: 2025.05.07 AIR PROD & CHEM INC
  • EP3751245B1 patent drawingFigure 1
  • EP3751245B1 patent drawingFigure 2
  • EP3751245B1 patent drawingFigure 3

AI summary

A first camera captures a first image of a scene, and a second camera captures a second image capturing thermal distribution across the scene. The first image is processed to detect one or more objects of interest in the scene and to identify respective surface characteristics of the objects. The first image is overlaid with the second image to identify regions of interest in the second image corresponding to the objects of interest in the first image. Values of pixels that belong to respective regions of interest in the second image are converted to temperature values using respective conversion functions that reflect respective emissivity values determined by the identified respective surface characteristics of the corresponding objects of interest in the first image. The temperature values are analyzed to monitor thermal conditions of the one or more objects of interest in the scene.