Name

prl - calculate a set of 2-D projection of a 3-D volume using three Eulerian angles and two shifts using linear interpolation

Usage

[proj =] prj(vol, params [, radius, 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, s2x, s2y], projection in calculated using the three Eulerian angles and then shifted by s2x,s2y

radius

integer radius of a sphere - projection is calculated using voxels within this sphere. Note: if the average of the structure within the sphere is not zero, the projection will contain a projection of a sphere (an artifact).

Output

proj

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

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

linear interpolation.

Author / Maintainer

Pawel A. Penczek

Keywords

category 1

TRANSFORMS

category 2

spatial

Files

projection.py

See also

project, prj, prg

Maturity

stable

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

Bugs

None. It is perfect.