Fig. 5.
Quantitation of denoising effects on low-light images of fluorescent latex beads. (A) The same bead is measured in 3D at four different excitation intensities (10-3I0, 10-4I0, 10-5I0, and 4 × 10-6I0). Single Z sections through the 3D stack are shown and analyzed. The raw images (Left) lose signal-to-noise as excitation intensity decreases, whereas this is mostly recovered in the denoised images (Right). (B) Line profiles through the beads demonstrate overall maintenance of peak width measured by Gaussian fitting, until the noisiest condition (bottom), in which the raw image does not give a fit at all, and the denoised image shows peak broadening. (C) Peak intensities corrected for excitation intensity display sensitivity to signal-to-noise ratio. A field of fluorescent beads was imaged 60 times, subjected to denoising, and both raw and denoised images were time-averaged to enable comparisons. (Left) Excitation-corrected raw peak intensities increase as excitation decreases, whereas denoised peak intensities are more stable. Error bars show variation (± 1 standard deviation) in individual bead intensities. (Right) Ratios of denoised to raw peak intensities are plotted as mean ± standard deviation (n = 19 fluorescent beads).