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BP LOCAL - calculate a Back Projection/3D weighting function

(from images faling in to a specific LOCAL area in)
(a correspondence-analysis- or nonlinear map. 9/1/94)

PURPOSE

Reconstructions + transfer or weighting functions for local map areas can be calculated. This way, sevearl reconstructions may be added, their transferfunctions added and the inverse of the summed transfer functions can be applied to the summed up projections. (see procedure DECTRAPAD.SYS)

SEE ALSO

BP 3 [(ART Back Projection - 3D)]
BP 3D [(3D Reconstruction - using three Eulerian angles]
BP 3E [Back Projection in X-Y planes]
BP GW [3D reconstruction with general weighting]
BP MEM2 [2D reconstruction by Max. Entropy Method]
BP RP [Iterative Reconstruction With Constraints]
BP R2 [R**2 weighting for 2D]
BP S2 [2D Single-tilt Iterative Recon. With Constraints]
BP W2 [2D filtered, weighted back projection]
BP WX [Weighted Back Projection]
BP WY [Weighted Back Projection]
BP XY [Back Projection in X-Y planes]

USAGE

.OPERATION: BP LOCAL

.INPUT DOCUMENT FILE: IMCDOC001
[Enter the name of the document file that contains a copy of the imc-file (from CA S) or the 2D file (from CA MAP)

.INPUT DOCUMENT FILE: IMCDOC001

.SQUARE NUMBERS: 23,24,25,32,33,34,35
[Enter the numbers of the squares in the visual map from which (combined) a reconstruction should be calculated]

.TILT IMAGE FILE TEMPLATE: TMB***
[Enter the file name template of the tilt images that are to be used]

.X,Y-DIMENSION OF REAL SPACE 3D: 64,64

.Z-DIMENSION: 64
[Enter the dimensions of the 3D volume]

.PROJECTION MASK RADIUS, RAY LENGHT: 30,60
[Enter the radius of the circular mask that implicitely will be applied to the projections. Enter the length of the back-projections rays (normally about the object diameter)]

.3D TRANSFER FUNCTION, *IF NOT DESIRED, FILE: TRANSFER001
[Enter name of file to receive the 3D transferfunction. * if no transferfunction is to be calculated]

If transferfunction is requested:

.(S)INC-FCT.,(G)AUSS-FCT.,(M)IXED: M
[Enter if transferfunction should be calculated as a superposition of Sinc-functions, Gaussian functions, or a combination of both.]

If M was answered:

.SIGMA: .5
[Enter value for sigma in the gaussian function. Units are pixels in the Fourier transform.]

.2 X PADDED TRANSFER FUNCTION? (Y/N=DEF): Y
[Answer "y" if the transferfunction is to be calculated in a 3d volume with twice the x-y-z-dimensions of the real space 3D such that it can be applied to the padded 3D (its better to answer Y)]

.SIMPLE BACK-PROJECTION FILE, * IF NOT DESIRED: SIM3D001
[Enter name of the file that is to receive the 3D backprojection volume. * if no back-projection requested]

.ENLARGEMENT FACTOR: 1
[Enter enlargement factor relating the 3D and the projection. (like in BP XY)]

SUBROUTINES

TDLOCAL, TRANS3D, MIRBP3A

CALLER

VTIL2

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