Background In the deformation measurement of high-temperature structures, image degradation caused by thermal radiation and random errors introduced by heat haze restrict the accuracy and effectiveness of deformation measurement. Objective The purpose of this study is to suppress thermal radiation and heat haze using fusion-restoration image processing methods, thereby improving the accuracy and effectiveness of Digital Image Correlation (DIC) in the measurement of high-temperature deformation. Methods For image degradation caused by thermal radiation, based on the image layered representation, the image is decomposed into positive and negative channels for parallel processing, and then optimized for quality by multi-exposure image fusion. To counteract the high-frequency, random errors introduced by heat haze, we adopt the Feature Similarity Index (FSIM) as the objective function to guide the iterative optimization of model parameters, and the grayscale average algorithm is applied to equalize anomalous gray values, thereby reducing measurement error. Results The proposed multi-exposure image fusion algorithm effectively suppresses image degradation caused by complex illumination conditions, boosting the effective computation area from 26 % to 50 % for under-exposed images and from 32 % to 40 % for over-exposed images without degrading measurement accuracy in the experiment. Meanwhile, the image restoration combined with the grayscale average algorithm reduces static thermal deformation measurement errors. The error in <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\varepsilon _{xx}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mrow> <mi mathvariant="italic">xx</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> is reduced by 85.3%, while the errors in <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\varepsilon _{yy}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>ε</mi> <mrow> <mi mathvariant="italic">yy</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\gamma _{xy}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>γ</mi> <mrow> <mi mathvariant="italic">xy</mi> </mrow> </msub> </math></EquationSource> </InlineEquation> are reduced by 36.0% and 36.4%, respectively. Conclusions We present image processing methods to suppress the interference of thermal radiation and heat haze in high-temperature deformation measurement using DIC. The experimental results verify that the proposed method can effectively improve image quality, reduce deformation measurement errors, and has potential application value in thermal deformation measurement.

Fusion-Restoration Image Processing Algorithm to Improve the High-Temperature Deformation Measurement

期刊论文
发表日期：

2026年2月19日

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B. Guan,
D. Tan,
J. Tao,
A. Su,
Y. Shang,
Q. Yu

摘要

Background

In the deformation measurement of high-temperature structures, image degradation caused by thermal radiation and random errors introduced by heat haze restrict the accuracy and effectiveness of deformation measurement.

Objective

The purpose of this study is to suppress thermal radiation and heat haze using fusion-restoration image processing methods, thereby improving the accuracy and effectiveness of Digital Image Correlation (DIC) in the measurement of high-temperature deformation.

Methods

For image degradation caused by thermal radiation, based on the image layered representation, the image is decomposed into positive and negative channels for parallel processing, and then optimized for quality by multi-exposure image fusion. To counteract the high-frequency, random errors introduced by heat haze, we adopt the Feature Similarity Index (FSIM) as the objective function to guide the iterative optimization of model parameters, and the grayscale average algorithm is applied to equalize anomalous gray values, thereby reducing measurement error.

Results

The proposed multi-exposure image fusion algorithm effectively suppresses image degradation caused by complex illumination conditions, boosting the effective computation area from 26 % to 50 % for under-exposed images and from 32 % to 40 % for over-exposed images without degrading measurement accuracy in the experiment. Meanwhile, the image restoration combined with the grayscale average algorithm reduces static thermal deformation measurement errors. The error in $\varepsilon _{xx}$ $ε_{xx}$ is reduced by 85.3%, while the errors in $\varepsilon _{yy}$ $ε_{yy}$ and $\gamma _{xy}$ $γ_{xy}$ are reduced by 36.0% and 36.4%, respectively.

Conclusions

We present image processing methods to suppress the interference of thermal radiation and heat haze in high-temperature deformation measurement using DIC. The experimental results verify that the proposed method can effectively improve image quality, reduce deformation measurement errors, and has potential application value in thermal deformation measurement.