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RM INV3 Inverse - of 3D Radon transform or

PURPOSE

Computes the inverse 3D (Fourier-)Radon transform.

USAGE

.OPERATION: RM INV3

.INPUT FILE: 3DFRAD001
[Enter name of real of Fourier space 3D Radon transform.]

.IS THIS A FOURIER TRANSFORM (Y/N)?: Y
[If the input file is a Fourier transformed Radon transform answer Y. Currently there is no information in the file header of Radon transforms that identify if it is in real or Fourier space.]

.OUTPUT FILE: RECON001
[Enter name of output file.]

.INTERMEDIATE OUTPUT FILE: F_INTER001
[Enter name of file to store intermediate volume. This file is only being used if the memory requirements of the program are larger than the memory provided. If the file name, however, has an "_" (underline) in the second position, the intermediate output file is used regardless of memory size. This option can be quite helpful if intermediate results are of interrest. The content of this volume are the projections in a single axix tilt series around y.]

.ENTER X,Y DIMENSIONS: 64,64
[Enter the x and y dimensions of the backtransformed volume.]

.ENTER Z DIMENSION: 64

.OBJECT DIAMETER: 60
[Enter diameter of reconstructed object.]

.INCLUDE LOW-PASS FILTER(Y/N): N
[The underlying algorithm is a filtered backprojection. If "Y" is answered here, then the weighting funtion is multiplied with a Fermi filter (s. FF) with a radius corresponding to Crowther's formula.]

.OBJECT DIAMETER: 50
[Enter the diameter of the object in the output image. If this is not known, use the longer of the image dimensions.]

.WEIGHTING FUNCTION DOC-FILE: WDOC001
[Enter the name for a document file that will contain the weighting function. This can be used e.g. to produce a plot of this function. It will be well behaved up to the resolution limit defined by Bracewell's/Crowther's formula: N=pi*D/r.]

.INCLUDE LOW-PASS FILTER (Y/N)?: Y
[If Y is answered a fermi low-pass filter will be applied to the weighting function. The radius of this filter is calculated from Crowther's formula.]

NOTES

  1. Developed by: M.Radermacher

  2. Not Distributed!

SUBROUTINES

CALL3DRMINV, RMINV, FOURADINV, FOURAD, MRFOUR1

CALLER

UTIL5

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