All images were cropped images to the same dimensions (684 pixels × 305 pixels). The grayscale pixel images were stacked horizontally (similar results were obtained by stacking them vertically), resulting in 208620-dimensional vector data (because two-dimensional correlation is eliminated, unsupervised learning becomes stronger). ML was performed using the accompanying data, which dramatically reduced the computation costs (particularly random-access memory usage) compared to training, while maintaining the pixel coordinates and values (Figure ). However, this method is sensitive to spectral deviations. The SDBS number, International Union of Pure and Applied Chemistry (IUPAC) name, InChI, molecular formula, and molecular weight were used for hierarchical clustering, which employed the linkage function (method = "ward" and metric = "euclidean