BP 32F OLD - Older Back Projection - 3D, Sampled, interpolated in Fourier space ||*

PURPOSE

Calculates two randomly selected half- and a total-3D reconstructions using interpolation in Fourier space. This operation is exactly same as 'BP 3F' with the addition of the two randomly selected half reconstructions. This operation is an older version of current 'BP 32F'

SEE ALSO

BP 32F	[Back Projection - 3D, Sampled, Interpolated in Fourier space ||*]
BP 3F	[Back Projection - 3D, Interpolated in Fourier space ||*]
BP 3F OLD	[Older Back Projection - 3D, Interpolated in Fourier space ||*]
BP CG	[Back Projection - 3D, Conjugate gradients ||*]

USAGE

.OPERATION: BP 32F OLD

.ENTER TEMPLATE FOR 2-D IMAGE FILE: PROJ001
[Enter the name of any projection from the set.]

.ENTER FILE NUMBERS OR SELECTION DOC. FILE NAME: 1-700 OR IMAGES127
[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 3-D FILE: VOLUME001
[Name of the output volume calculated using all input projections specified in the selection document file.]

.RECONSTRUCTED FIRST HALF 3-D FILE: VOLUME1001
[Name of the output volume calculated using first half of randomly selected set of input projections.]

.RECONSTRUCTED SECOND HALF 3-D FILE: VOLUME2001
[Name of the output volume calculated using second hald of randomly selected set of input projections.]

NOTES

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

2. The projections do not have to have power-of-2 dimensions.

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

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

5. This operation parallelized for use with MPI.

6. Implemented by Paul Penczek.

SUBROUTINES

WIW32D

CALLER

VTIL2