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. Author manuscript; available in PMC: 2012 Apr 1.
Published in final edited form as: J Struct Biol. 2011 Jul 2;176(1):60–74. doi: 10.1016/j.jsb.2011.06.010

Figure 2. Image restoration of a synthetic single-particle image using a conventional Wiener filter.

Figure 2

(A) Results of whole-image cross-correlation comparison between the noise-free reference image (Fig. 1A) and a Wiener-filtered composite of 100 256×256-pixel noisy images, each noisy image having a SNR of 0.003 but no CTF applied (as in Fig. 1B). In this figure, the SSNR term in the Wiener filter (Equation (4) ) has been varied above and below its known value in the image data set by multiplication with a scalar factor (“filter scale factor”), such that each x-value represents a slightly different incarnation of the filter and x=1 corresponds to the “true” Wiener filter. Note that in this plot the single-particle Wiener filter would correspond to a “filter scale factor” of 1/0.0328 = 30.5, for which the masked correlation to the perfect image was found to be 0.66 (not visible on the scale shown here). Inset in the lower right corner shows a magnified view of the particle region; inset in lower left corner shows the identical view of the noise-free particle, for comparison.

(B) Tight binary envelope function generated from the noise-free image in Fig. 1A. Inset is as in A.

(C) – (E) Output of the conventional Wiener filter for sets of 100 noisy images as in Fig. 1B, for the three different box sizes. Note that CCCmask-ref = 0.929 for the SP Wiener filter reconstruction. Inset is as in A.