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. Author manuscript; available in PMC: 2009 Nov 1.
Published in final edited form as: J Struct Biol. 2009 Mar 6;166(2):126–132. doi: 10.1016/j.jsb.2009.02.012

Figure 1.

Figure 1

Principle of SNR measurement by double experiments, each of which results in a pair of images. a) Image pairs with the same orientation (i.e., oriented to the same reference) result from separate processing pathways with different structural noise, shot noise, and digitization noise. The cross-correlation coefficient αstruct is computed from this comparison, yielding SNR αcomp_struct. b) Image pairs from two exposures of the same imaging field have different shot noise and digitization noise (but same structural noise), yielding cross-correlation coefficient ρexp and SNR αcomp_exp. c) Image pairs obtained by twice scanning the same micrograph have the same structural and shot noise, but different digitization noise, yielding ρscan and αtrue_scan. See text for details.