Comparison of SPIDER Back Projection Operations


Usefull Reference: Fundamentals of three-dimensional reconstruction from projections. Penczek PA. Methods Enzymol. 2010; 482: 1-33


In SPIDER operations that reconstuct a volume from its projections are grouped under back projection irrespective of whether the method entails a actual 'back projection' step.

Definitions:

SIRT
Simultaneous Iterative Reconstruction Technique
WBP
Weighted Back Projection
FBS
Fourier Based Spline
Operation Operation Subset volumes Input angles Symmetries Method Interpolation Weighting Notes Source code
'BP 3F' 'BP 32F' 3 + Direct Fourier 5x5x5 Kaiser-Bessel - 1 or 3 output volumes, MPI available bp3f.f, bp32f.f, oneline.f
'BP CG' 'BP CG 3' 3 - SIRT - Conjugate gradient WBP Linear or FBS - 1 or 3 output volumes, MPI available bpcg.f, prepcub_s.f, hiang.f, rprq.f, prjcq.f, bckpj.f
'BP RP' 'BP RP 3' 3 + SIRT - Constrained WBP - - MPI available bprp.f, redprq.f, hiang.f, asta.f, bckpj.f, prjcq.f
'BP 3N' - 3 + Direct Fourier Nearest neighbor - -- nn4.f
'BP 3D' - 3 - WBP - Choice of: Gaussian, none, triangular overlap Also used for tomography bcq.f, buildm.f, cang.f, bpcqp.f, bpcmp.f, bpcq.f, bpcm.f, wtf.f, wtm.f
'BP W2' - Single - WBP - Parzen For tomography. Faster then 'BP S2'. wgbp2.f, rdpa.f, fftr_q.f
'BP S2' - Single - SIRT - Constrained WBP - - For tomography. Slower than 'BP W2' bps2.f, bpcq.f, prjs2.f, prjc2.f, prjc0.f, repr2_s.f, cppb.f, smt3.f, ...
'BP R2' - None - - R**2 or R*, Parzen --- Weights only, No back projection! Use with 'BP RP'. bpwr.f, bpwr_q.f

Reconstruction resolution:

Using 5030 ribosome images of size 130x130 pixels:

Operation Resolution Time
     'BP CG'      17.95531
     'BP 3F' / 'BP 32F'      23.96128
     'BP 3N' / 'BP 32F'      23.99 25
However on perfectly aligned phantom projections the volume from 'BP 3G' appears to be sharper to the eye.


Source file: bp_overview.html     Updated: 3 Oct 2012     ArDean Leith


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