BP 32F - Back Projection - 3D, Sampled, Interpolated in Fourier space ||*

PURPOSE

Calculates two randomly selected sample and a total-3D reconstruction using back-projection interpolated in Fourier space. This operation is the same as 'BP 3F' with the addition of the two randomly selected sample reconstructions.

SEE ALSO

BP 3F	[Back Projection - 3D, Interpolated in Fourier space ||*]
BP 3F OLD	[Older Back Projection - 3D, Interpolated in Fourier space ||*]
BP 32F OLD	[Older Back Projection - 3D, Sampled, interpolated in Fourier space ||*]
BP CG	[Back Projection - 3D, Conjugate gradients ||*]
BP R2	[Back Projection - 2D, weighting of image series ||]
BP RP	[Back Projection - 3D, iterative, with constraints, ||*]
BP S2	[Back Projection - 2D, single tilt iterative, constrained ||]
RB 32F	[Rotate, Shift, Sampled, Back Projection in Fourier space |]

USAGE

.OPERATION: BPD 32F

.TEMPLATE FOR IMAGE FILES (E.G. STK@****): PROJ***
[Enter a template for input image files to be back projected. This template can alternatively refer to a series of single images (e.g. img***), or to a series of stacked images (e.g stack3@***), or to a whole stack of images ending in '@' (e.g. stk@). Templates containing an asterisk will have the astericks substituted with a number for the file. (The MPI version can not use a selection file for image numbers).]

If the template contains an asterisk the following question will appear:

.ENTER FILE NUMBERS OR SELECTION DOC. FILE NAME: 1-700 OR IMAGE_SEL
[Enter projection file numbers or the name of the document file containing projection file numbers in the first column.]

.ANGLES DOC FILE: ANGLES27
[Enter the name of the document file containing Eulerian angles for the projections used (psi, theta, phi).]

.SYMMETRIES DOC FILE: symmetries
[Enter the name of the document file containing Eulerian angles defining symmetries (psi, theta, phi). The angles should be such that when used in operation 'RT 3D' transform the volume into itself. The identity operation (angles 0,0,0) MUST be included.
The symmetries are enforced in two steps: projections related by the symmetry operations are added in Fourier space to the volume; in order to reduce the residual artifacts, additional real-space symmetrization is applied.
If there are no symmetries, enter symbol "*".]

.RECONSTRUCTED VOLUME: VOLUME001
[Name for the output volume calculated using all input projections specified in the selection document file.]

.FIRST SAMPLE VOLUME: VOLUME1001
[Name for the output volume calculated from a randomly selected set formed from half of the input projections.]

.SECOND SAMPLE VOLUME: VOLUME2001
[Name for the output volume calculated from remaining half of the input projections.]

NOTES

1. 5x5x5 Keiser-Bessel interpolation scheme is used.

2. Projections do not have to have power-of-2 dimensions.

3. Sample volumes can be used to evaluate the resolution. The division of projection data set is performed in a random manner. Therefore, the two sample volumes will be different if the command is repeated on the same data set.

4. If you do not have enough memory available in your computer to use this operation, substitute 'BP 3F' instead and invoke it three times to create the complete and sampled output volumes.

5. This operation parallelized for use with MPI.

6. Implemented by Paul Penczek and ArDean Leith.

SUBROUTINES

WIW32D

CALLER

VTIL2