Thermal Tomography for 3D Subsurface Effusivity Imaging
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Solution Overview
Problem
Current thermal imaging methods are limited to 2D surface analysis, unable to provide a distribution of subsurface material properties and require specific material system configurations, making them unsuitable for inhomogeneous materials like multilayer systems.
Innovation Solution
A method that converts temporal surface temperature data into a spatial 3D distribution of thermal effusivity using pulsed thermal imaging, allowing for fast 3D imaging of subsurface material properties without relying on pre-defined material models, by processing infrared data to form 3D images within minutes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional 2D thermal imaging methods are used to determine subsurface parameters, then the analysis is simpler and faster, but the method can only determine limited parameters at each surface position and cannot provide a distribution of subsurface material properties
Solution Approach 1:
The patent transforms temporal temperature data into spatial depth distribution by introducing a time-to-depth mapping relationship. The deconvolution algorithm converts the temporal domain signal into a spatial domain representation, effectively adding a depth dimension to the traditional 2D surface imaging, thereby achieving 3D visualization of subsurface thermal effusivity distribution
2Adaptability or versatility
If physical models with pre-defined material system configurations are used, then the analysis method is more straightforward, but the method cannot handle inhomogeneous materials like multilayer systems
Solution Approach 1:
The patent transforms the material property of interest from thermal conductivity to thermal effusivity, which has a more direct relationship with the measured temperature signal. This parameter transformation simplifies the mathematical relationship between the measured data and the subsurface properties, enabling the method to handle diverse material systems including multilayer and inhomogeneous materials without requiring complex material models
Solution Approach 2:
The deconvolution algorithm automatically adapts to different material configurations by processing the temporal temperature signal to extract depth distribution information. The method does not require pre-definition of material layer structures or homogeneous assumptions, as the algorithm self-adjusts to reveal the actual subsurface thermal effusivity distribution regardless of material complexity
3Measurement precision
If temporal surface temperature data is processed to determine subsurface parameters, then the measurement is nondestructive and fast, but the method cannot provide detailed 3D images of material interiors
Solution Approach 1:
The patent uses pulsed thermal excitation to periodically heat the sample surface, creating a time-resolved temperature signal that encodes subsurface structural information. The periodic pulsed heating enables the extraction of depth-dependent thermal effusivity distribution through temporal signal analysis, achieving 3D imaging capability while maintaining fast nondestructive measurement
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 accurate 3D imaging of subsurface defects and material properties, overcoming limitations of conventional 2D methods by providing detailed, high-resolution images of material interiors, suitable for both layered and inhomogeneous materials.
Implementation Method 1
providing a pulse of thermal energy to heat a first surface of the sample
Implementation Method 2
an infrared camera positioned near the first surface of the sample for taking a rapid series of thermal images
Data Source
AI summary
A computer-implemented method for automated thermal computed tomography includes providing an input of heat, for example, with a flash lamp, onto the surface of a sample. The amount of heat and the temperature rise necessary are dependent on the thermal conductivity and the thickness of the sample being inspected. An infrared camera takes a rapid series of thermal images of the surface of the article, at a selected rate, which can vary from 100 to 2000 frames per second. Each infrared frame tracks the thermal energy as it passes from the surface through the material. Once the infrared data is collected, a data acquisition and control computer processes the collected infrared data to form a three-dimensional (3D) thermal effusivity image.