A stenographer records a conversation but misses a few lines. Later, she fills them in from context without rewriting the whole text. That's how the new URA-SIM method works for microscopes.
URA-SIM takes fewer snapshots — for example, just 5 instead of 9. It reconstructs the missing frames by estimating how the stripe brightness changes. Then the full set of frames is processed in the usual way, yielding an image as sharp as if all snapshots had been taken. On living cells with mitochondria, the method allows imaging every 20 seconds or even every second without damaging the cell.
In standard 2D-SIM, one super-resolved image requires 9 raw images, but URA-SIM gets by with just five, a saving of nearly half.