Differences between revisions 15 and 16
 ⇤ ← Revision 15 as of 2007-05-30 16:14:35 → Size: 2018 Editor: penczek Comment: ← Revision 16 as of 2013-07-01 13:12:58 → ⇥ Size: 2018 Editor: localhost Comment: converted to 1.6 markup Deletions are marked like this. Additions are marked like this. Line 40: Line 40: ["recons3d_sirt"] [[recons3d_sirt]]

# Name

recons3d_wbp - calculate 3-D reconstruction from a set of projections using weighted back-projection method (general or exact filter) or perform a simple backprojection

# Usage

vol = recons3d_wbp(stack, list_proj, method [, symmetry, const])

## Input

stack

name of the stack file or an in-core stack containing projection data, projections have to be squares, i.e., nx=ny.

list_proj
list of projections to be included in the reconstruction.
symmetry
point-group symmetry to be enforced, each projection will enter the reconstruction in all symmetry-related directions. The possibilities are
• "cn"
• "dn"
• "i"
• "c1" (no symmetry) is the default.
method

method used in WBP reconstruction, could either be general, exact, or empty string " ". The last indicates simple backprojection.

const

for general, it should correspond to the SNR of the reconstruction, the default is 1.0E4; for exact, it should be the diameter of the structure in pixels.

## Output

vol
the 3-D reconstructed volume

## Method

general
the weighting function is constructed as a sum of Gaussian function of distances between projection pixels in Fourier space, as described in: M. Radermacher, Weighted Back-Projection Methods. (p.102) In: Electron Tomography. Ed.: J. Frank, 1992.
exact
the weighting function is constructed as a sum of "overlaps" between Fourier transforms of projections, as described in: G. Harauz and M. van Heel, Exact filters for general geometry three dimensional reconstruction.Optik 73 (1986) 146-156. The smaller the diameter, the stronger the lowpass filtration effect on the reconstructed object.
" "
the projections are backprojected, no weighting applied

Pawel A. Penczek

category 1
INVERSION
category 2
FOURIER

# Files

reconstruction.py

alpha

# Bugs

None. It is perfect.

recons3d_wbp (last edited 2013-07-01 13:12:58 by localhost)