Fig. 2

Single-pixel PESRS. a The raw PESRS image of aggregated Au NPs substrate with adsorbed adenine. The color of each pixel represents the average total spectral channels intensity from each PESRS spectrum. b The raw single pixel spectra obtained from spot 1 and 2, which are indicated in a. c The PESRS image of adsorbed adenine on aggregated Au NPs substrate. The color of each pixel represents the peak area at 733 cm⁻¹ after background subtraction. d The background-removed single-pixel spectra obtained from spot 1 and 2 which are indicated in c. e The BM4D-denoised PESRS image of adsorbed adenine on aggregated Au NPs substrate. The color of each pixel represents the peak area at 733 cm⁻¹ after BM4D denoising and background subtraction. f The BM4D-denoised single-pixel spectra obtained from spot 1 and 2 which are indicated in e. Image area: 30 μm × 30 μm.