Distribution of t-SNE visualisation domain. Spectra and features are represented visually using the t-SNE algorithm. The top-left and bottom-right panels show the visualised domain distribution of the synthetic spectra and observed spectra before and after cross-domain translation. The top-right and bottom-left show the corresponding feature distributions of the synthetic spectra and observed spectra extracted by the content encoder and the style encoder. The 𝒳-axis and y-axis coordinates represent the positions of data points in the new coordinate system after dimensionality reduction. The positions after dimensionality reduction can reflect the similarity between data points.