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. Author manuscript; available in PMC: 2021 Jan 1.
Published in final edited form as: Prog Biophys Mol Biol. 2019 Sep 13;150:160–183. doi: 10.1016/j.pbiomolbio.2019.09.002

Figure 2. Schematic of the proposed adjustment to the SSNR formula for cases with unmeasured regions of Fourier space.

Figure 2.

The shaded areas represent the P values on a Fourier sphere that have been measured for a target value, T, in the measured region. The variance in the measured region is down-weighted by the total sampling, Sp, which is N times the per-particle sampling, sp. Meanwhile, the unshaded region represents Q unmeasured values. In (A) the unmeasured voxels are assigned zero variance, whereas in (B) the voxels are assigned variance consistent with the already measured voxels, resulting in two different expressions for SSNR. The expression in (A) limits to arbitrarily large values as the number of particles increases, whereas in (B) the expression saturates.