## PJ CYL - Project - 3D volume onto Cylinder

(09/02/04)

PURPOSE

Computes a projection of a 3D density distribution onto a cylinder surrounding the volume. The axis of the cylinder is assumed to be the Y axis. The origin is specified for each plane perpendicular to Y using a document file that contains the X,Z coordinates of the projection centers (intended for curved fibers). The cylinder is then unrolled into a 2D image.   Example.

 PJ 3 [Project - 3D volume using Eulerian angles, trilinear or FBS interpolation, single projection] PJ 3Q [Project - 3D volume using Eulerian angles, trilinear interpolation ||] PJ AT [Project - 3D volume using exponential Attenuation]

USAGE

.OPERATION: PJ CYL

.THREED FILE: PIC001
[Enter the name of the file whose projection is to be computed. Should be a cube!]

.OUTPUT FILE: CYL001
[Enter name for the output file]

.STARTING ANGLE: 90
[Enter starting angle. Zero is at 3 o'clock on cylinder.]

[Enter inner and outer radius of cylinder. From the outer radius the X-dimension of the output image is calculated as YDIM=Radius*2*PI, and the angular increment as 360/YDIM. If inner radius < 0, the program does a maximum projection instead of regular summation. If outer radius < 0, the program finds the distance of the last positive pixel along the radius from the center of the projection.]

The program prints out: ANGULAR INCREMENT: 3.75 DEGREES, X DIMENSION: 91

.NEW INCREMENT OR <RET>: 4.5
[Enter a new angular increment if you want to overwrite the one calculated. The file dimensions are automatically adjusted.]

.COLUMNS FOR X-CENTER, Z-CENTER: 1,2
[Enter the column numbers for the center coordinates in the document file.]

.DOCUMENT FILE: DOC001
[Enter the document file that contains the projection centers.]

SUBROUTINES

MRCP

CALLER

VTIL2