## PJ 3G - Project - 3D volume using Eulerian angles, Gridded interpolation ||

(05/22/08)

PURPOSE

Computes projection(s) of a 3D volume according to three Eulerian angles. Uses non-uniform Fourier interpolation (gridding).

 PJ 3Q [Project - 3D volume using Eulerian angles, trilinear interpolation ||] PJ 3Q RR [Project - 3D volume using Eulerian angles & create rings file ||] RT SQ [Rotate and Shift - image, Quadratic interpolation ||]

USAGE

.OPERATION: PJ 3G

.INPUT VOLUME: vol001
[Enter the name of the volume whose projections are to be computed. This must be a cube.]

.ANGLE NUMBERS OR SELECTION DOC. FILE NAME: 1-700 or SEL001
[Enter selected angle numbers or name of a document file containing the selected angle numbers. Projections will only be calculated for the selected sets of angles from the following angles doc. file. (If you use a selection doc. file heer then the selected numbers are taken from the first register in the doc. file.)]

.ANGLES DOC. FILE: ANGLES
[Enter the name of the document file containing the Eulerian angles for the projections. The angles have to be given in the order: psi, theta, phi. The meaning of the angles is the same as in operation 'RT SQ'. Projections will be calculated for every entry specified in the previous question.]

.TEMPLATE FOR OUTPUT PROJECTIONS: PRJ****
[Enter the template for the output files which will contain the 2-D projections.]

NOTES

1. The projection always has dimensions NX x NY.

2. 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.

3. Psi, theta, & phi angles are placed in file header starting at location: 100

4. Implemented by: P.Penczek.

SUBROUTINES

PJ3G, WIW3G

CALLER

VTIL2