Fig. 2: Analysis for PTO sample 1: BOARS with structural image patches and dKL kernel function.

a Downsampled PFM amplitude image of the PTO film, with exploration points for the spectral locations where the user voted only, b final learned target spectral structure after voting through explored spectra in (a, c). Plot of a with all the explored spectral locations overlaid d ground truth image, i.e., the structural similarity map as in Eq. (3), given the user-voted target spectral. e estimated structural similarity map (as represented by the colorbar in the right with the light region being higher values and the dark region being lower values) from the surrogate model, with all the explored spectral locations, f map (as represented by the colorbar in the right) of the model’s associated uncertainty. The samples color coding represents (red being higher values and blue being lower values) the color of the explored locations with the human-augmented objective function values in (a), automated objective function values in (c, e), and the objective ground truth image in (d). Within sub-figure (c), (i)–(iv) are the visualization of the spectra at some of the BO explored locations. The scale bar in (a) is 200 nm.