Fig. 2

Quantitative validation of the super-resolved capability of direct-SIM. a Fluorescent beads of 100-nm diameter were imaged by our home-built 2D-SIM setup, and SR images were reconstructed using HiFi-SIM and direct-SIM. b Magnified images of the white-box region in (a). c Intensity profiles along the yellow line in (b). d Full-width at half-maxima (FWHMs) of the profiles of 10 beads in the images of widefield, HiFi-SIM, and direct-SIM. e Error map of direct-SIM obtained by SQUIRREL analysis. f “Line” patterns in Argolight slide were imaged by DeltaVision OMX with 50 ms exposure. The equivalent widefield image is shown on the top row, and the SR images were reconstructed by GE SoftWoRx, HiFi-SIM, and direct-SIM (\(\alpha { = }0.8\)), respectively. g Fourier spectra of the images in (f). h Magnified images of the white-box region in (f). i Intensity profiles along the red lines in (h), showing that two lines with 90 nm separation were resolved by direct-SIM. Scale bars, 2 μm in (a), 0.2 μm in (b), 3 μm in (f) and 1 μm in (h)