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. Author manuscript; available in PMC: 2020 Apr 7.
Published in final edited form as: Nat Methods. 2019 Oct 7;16(11):1146–1152. doi: 10.1038/s41592-019-0580-y

Figure 5. Effect of using the full local 3D CTF for template matching in tomograms.

Figure 5

During template matching, Warp multiplies the rotated 3D reference by the local 3D CTF before correlating it to a local portion of the tomogram volume, as opposed to multiplying it by a binary missing wedge mask. This produces sharper correlation peaks.

(a) XY slice through a tomogram reconstructed from EMPIAR-10045 data. The faint shapes of 80S ribosomes are visible.

(b) XY slice through the correlation volume at the same location as (a), using a binary missing wedge mask. White indicates higher correlation. The peaks are broad and hard to distinguish against the background.

(c) XY slice through the correlation volume at the same location as (a), using the full local 3D CTF. White indicates higher correlation. The peaks are sharper, leading to higher template matching accuracy.

(d) Rotational average of a 48 px window around all correlation peaks, mean-subtracted and normalized against the respective correlation background. 3D CTF-aware template matching (+CTF) produces peaks rising 2.7 times higher above the background compared to binary missing wedge masks (–CTF).