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.


Simultaneous Iterative Reconstruction Technique
Weighted Back Projection
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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