Figure 3.

Quantitative analysis of signal, noise and bias in denoised images. (a) Histograms of SNRs before (blue) and after (orange) denoising and SNBRs after denoising (green) for images from the T20S proteasome data set. Smooth lines represent kernel density estimates of the distribution. The x axis is on a logarithmic scale. (b) Spatial frequency-dependent variance (power) of the signal (blue), bias (orange) and noise. Noise power is calculated before (purple) and after (green) denoising. The y axis is on a logarithmic scale. Curves represent the mean of the quantities for all images in the T20S proteasome data set. Shaded regions show one standard deviation above and below each mean curve. All quantities were calculated as described in Sections S2 and S3.