Fig. 2: SIM reconstruction of variably spaced line pairs.

a Simulated line pairs with spacing ranging from 60 to 240 nm in steps of 30 nm at high SNR. We show the pseudo-widefield (Wf) image obtained by averaging raw data, and ground truth (GT) image, together with SIM reconstructions using Wiener filter (Wi), FISTA-SIM (Fi), and B-SIM (B). Scale bar 1.5 μm. Colored arrows indicate the line pair resolved according to the Sparrow criterion. b Line cuts corresponding to the white line in (a). All reconstruction methods resolve the 120 nm-spaced line pair. Both FISTA-SIM and B-SIM resolve the 90 nm-spaced line pair, but B-SIM does so with higher contrast. c Simulated line pairs as in (a), but at low SNR. d Line cuts corresponding to (c). All reconstruction methods resolve the 120 nm line pair, but only B-SIM resolves the 90 nm line pair. e Experimental images and reconstructions of variably spaced line pairs on an Argo-SIM calibration sample at high SNR. Line pairs have spacings of 60–330 nm in 30 nm steps. Scale bar 2.0 μm. f Line cuts corresponding to (e). All methods resolve the 120 nm-spaced line pair (right) with similar contrast, and no methods resolve the 90 nm line pair (left). g Experimental images as in (e), but at low SNR. Wiener and FISTA-SIM introduce reconstruction artifacts. h Line cuts corresponding to (h). Only B-SIM resolves the 120 nm spaced line pair.