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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 5. Estimation of the PSSNR from masked FRC calculations.

Figure 5

A. FRC calculations for a 100-image data set (as in Fig. 2), split into halves and averaged to produce two noisy particle estimates. In the masked FRC calculations, we applied either a binary mask (identical to Figure 3B) or a smoothed mask. The smoothed mask was obtained by expanding the border of the binary mask with a cosine-edge smoothing function (Grigorieff, 2007) such that 〈env2〉 increased by approximately 50%.

B. FRC calculations from A, but with the smoothed-mask calculation rescaled by Equation (19).

C. FRC calculations from A, but with the non-masked calculation rescaled by Equation (19).