Fire accidents in the concrete structures affect the safety of human beings and structural components. Due to higher temperatures, thermal cracks are conceived in concrete elements. Crack identification, localization, and quantification are the three major components in the damage assessment system. This paper aims to detect thermal cracks of fire‐affected concrete structures using ripplet transform‐based computer vision method. Initially, the concrete images are decomposed with discrete ripplet transform (DRT). The low frequency sub‐bands are approximated with column filtering‐based gray level difference metric. It removes the uneven concrete background. Ripplet coefficient variance parameter (RCVP) is used to differentiate the crack pixels from noisy pixels which is used to eliminate the noises. Finally, in the reconstructed image, the major and minor thermal cracks are detected. The obtained thermal cracks are quantified with the crack properties of length, width, area, and perimeter. The novelty of the proposed method relays on the usage of ripplet transform for the detection of thermal cracks for different concrete grades and different durations of temperature profile. The experimental results are compared with four transform domain state‐of‐the‐method crack detection methods. The proposed method yields better results in terms of the accuracy and average execution time.

中文翻译：

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基于波纹变换的结构混凝土热裂纹检测与定量化新方法

混凝土结构中的火灾事故会影响人类和结构部件的安全。由于温度升高，混凝土构件中会产生热裂纹。裂纹识别，定位和量化是损坏评估系统的三个主要组成部分。本文旨在使用基于涟漪变换的计算机视觉方法检测受火灾影响的混凝土结构的热裂纹。最初，使用离散纹波变换（DRT）分解具体图像。低频子带可通过基于列滤波的灰度差异度量来近似。它消除了不均匀的具体背景。涟漪系数方差参数（RCVP）用于区分裂纹像素和噪声像素，从而消除噪声。最后，在重建的图像中，检测到主要和次要的热裂纹。用长度，宽度，面积和周长的裂纹特性量化获得的热裂纹。所提出方法的新颖性在于使用波纹变换检测不同混凝土等级和温度曲线持续时间下的热裂纹。将实验结果与四种变换域方法状态裂纹检测方法进行了比较。提出的方法在准确性和平均执行时间方面产生更好的结果。所提出方法的新颖性在于使用波纹变换检测不同混凝土等级和温度曲线持续时间下的热裂纹。将实验结果与四种变换域方法状态裂纹检测方法进行了比较。提出的方法在准确性和平均执行时间方面产生更好的结果。所提出方法的新颖性在于使用波纹变换检测不同混凝土等级和温度曲线持续时间下的热裂纹。将实验结果与四种变换域方法状态裂纹检测方法进行了比较。提出的方法在准确性和平均执行时间方面产生更好的结果。