Name

prj - calculate a set of 2-D projection of a 3-D volume using three Eulerian angles and two shifts using the gridding technique

Usage

[proj] = prj(vol, params, [stack])

Input

vol

input volume, all dimensions have to be the same (nx=ny=nz)

params

a list of input parameters given as a list [i][phi, theta, psi, sx, sy], projection in calculated using the three Eulerian angles and then shifted by sx,sy

Output

proj

either: an in-core stack of generated 2-D projections

stack

or: file name of a disk file into which the projections will be stored. If this name is given, the in-core projection stack is not generated/returned.

• The projections have the following attributes set:
  • phi, theta, psi, -s2x, -s2y, ctf_applied=0

• The Eulerian angles are set to the input values, the shifts are set with inverted signs, so the 3D reconstruction can be directly calculated using the generated projections.

Method

Fourier space interpolation.

Reference

Penczek, P.A., Renka, R. and Schomberg, H.: Gridding-based direct Fourier inversion of the three-dimensional ray transform. J. Opt. Soc. Am. A. 21:499-509, 2004.

Author / Maintainer

Pawel A. Penczek

Keywords

category 1

TRANSFORMS

category 2

FOURIER

Files

projection.py

See also

prep_vol, prgs, prg

Maturity

stable

works for most people, has been tested; test cases/examples available.

Bugs

None. It is perfect.