Broad-line active galaxy (Plate-MJD-Fiber 541-51959-519): PCA and VAE reconstructions of the Hβ and O III 4959 emission lines (left) and Hα, N II 6550/6585, and S II 6718/6733 emission lines (right). The median S/N of the spectrum is 30 in the left panel and 47 in the right panel. The VAE reconstructs the amplitude and width of the lines with four parameters, while the lines in the PCA reconstruction are too narrow, even with 10 parameters.