Figure 1.

Schematic illustration of the SMALL-LABS algorithm. (a) Simulated raw data (imaging frames), the mean of the entire movie, and the true background (all on the same grayscale) are shown. Frames 1–3 have fluorescent molecules, indicated with colored arrows; frames 4–25 are identical except for detection noise and only contain the background; the mean includes a faint image of the real molecules over the true background. (b) Molecule detection in the approximate background-subtracted movie is shown. Solid colored boxes indicate a detected molecule, and dashed colored boxes indicate the local background for that molecule in “off” frames. Box colors correspond to the arrows in (a). (c) The SMALL-LABS background subtraction process is shown. The true image of each molecule is obtained by locally subtracting the mean of the “off” frames from the raw image. To see this figure in color, go online.