## 3 Thermography Data Collection and Preparation
### Transformation Process for Aligning Real and Synthetic Thermographic Image Datasets  
The real thermographic image generated from the actual specimen RD60-35 and the corresponding synthetic thermographic image generated from the synthetic specimen SD60-35 were analyzed for similarity at the same time point (100 s) using a 3D surface graph and histogram. The 3D surface graph represents the elements of a two-dimensional real matrix as depth values, plotted along the x, y, and z axes. The thermographic image of the real specimen at time \(t\) is denoted as \(RI\), while the thermographic image of the synthetic specimen, generated by normalizing its temperature data, is denoted as \(SI\). Both \(RI\) and \(SI\) are represented as grayscale images with a single channel. Since each pixel in a grayscale image is assigned a scalar \(z\) value, it can be represented using a 3D surface graph. The histogram visually illustrates the distribution of the \(z\) values from the 3D surface graph [24]. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Material** &
\begin{tabular}{c} **Density** \\ **(kg/m\({}^{2}\))** \\ \end{tabular} & **Thermal Conductivity** (W/m\({}^{2}\)C) & **Specific Heat** (J/kg\({}^{2}\)C) \\ \hline \multirow{2}{*}{CFRP [22]} & \multirow{2}{*}{1540} & Thermal Conductivity\(\mathrm{yx}\) = 9.00 & \multirow{2}{*}{1040} \\  & Thermal Conductivity\(\mathrm{y}\) = 0.77 & & \\  & Thermal Conductivity\(\mathrm{yz}\) = 0.70 & & \\ \hline \multirow{2}{*}{GFRP [23]} & \multirow{2}{*}{1600} & Thermal Conductivity\(\mathrm{yx}\) = 0.55 & \multirow{2}{*}{1310} \\  & Thermal Conductivity\(\mathrm{y}\) = 0.55 & & \\ \hline Air & 1.225 & 0.025 & 1005 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Properties of the Materials. Figure 4: Comparison between Real Specim (RD78-35) and Corresponding Synthetic Specim (RD78-35). Figure 5a shows the thermographic image \(RI\) of the real specimen, obtained at \(t=100\), with normalization applied. The pixel values of \(RI\) are treated as the depth in the z-direction and reconstructed into a 3D surface graph, along with a histogram representing the distribution of the \(z\) values. The curved temperature distribution observed in the 3D surface graph of \(RI\) can be attributed to the curvature inherent in the real blade. Since the specimen was fabricated by cutting a portion of the CFRP used in manufacturing the real blade, the blade's curvature remains. This residual curvature led to heat loss in areas that were not in direct contact during the heating process. Figure 5b presents the thermographic image \(SI\) of the synthetic specimen, generated by normalizing the temperature into a 3D surface graph, with a histogram displaying the distribution of the \(z\) values. The median of the \(z\) values for \(RI\) is 50, with an average of 58, while the median of the \(z\) values for \(SI\) is 151, with an average of 148. By comparing the 3D surface graph and histogram, the analysis of the images obtained from the real specimen RD60-35 and the corresponding synthetic specimen SD60-35 reveals that the \(z\) value distributions of the real thermographic image \(RI\) in Figure 5a and the synthetic thermographic image \(SI\) in Figure 5b differ significantly. The difference in the \(z\) value distributions between the real thermographic image and the synthetic thermographic image, both processed using the same normalization method, can be attributed to the disparity between real and simulated data. Therefore, additional preprocessing is necessary for the synthetic specimen thermographic image \(SI\) to minimize this disparity and better align it with the real specimen thermographic image \(RI\). The preprocessing procedure for the synthetic specimen thermographic image \(SI\) is shown in Figure 6. The synthetic specimen temperature data passes through the same normalization module applied to the real specimen thermographic data, resulting in the synthetic specimen thermographic image \(SI\).