MA Z - Mask - image in Z direction

PURPOSE

Masks a volume in Z direction.

SEE ALSO

MA	[Mask - image/volume with a circular mask]
MA L	[Mask - line across image]
MA X	[Mask - image in X direction]
MA Y	[Mask - image in Y direction]
MM	[Mask Multiplication]

USAGE

.OPERATION: MA Z

.INPUT FILE: PIC001
[Enter the name of the file to be masked.]

.OUTPUT FILE: IMG032
[Enter the name of the output file.]

.OUTER & INNER RADII: 12.0
[Enter the radius of the mask circle, in pixels.]

.(D)isk, (C)osine, (G)aussian edge, or (T)rue Gaussian: D/C/G/T
[Enter 'D' for a sharp profile cutoff, (for 2D image only).
Enter 'C' or 'G' for a piece-wise mask (no modification inside the mask range, and cosine/Gaussian-shaped falloff from this range outwards).
Enter 'T' for a true Gaussian mask.]

.(A)V, (P)REC AV, (C)IRCUMF, OR (E)XTERNAL: P
[Enter 'A' if the background is to be the average of the picture before masking.
Enter 'P' if the background is to be the average after masking.
Enter 'E' if the background is to be specified EXTERNALLY.
Enter 'C' if you want the background to be determined by averaging along the border of the mask].

If 'E' was entered, SPIDER asks:

.ENTER BACKGROUND: 3.0
[Enter the desired background.]

If using a 2-D image SPIDER asks.

.MASK CENTER COORDINATES (IX, IY): 50, 15
[Enter the coordinates of the mask center. Note that you have to specify coordinates equal to NX/2+1, NY/2+1 if you want the mask center to coincide with the nominal image center.]

If using a 3-D volume SPIDER asks.

.MASK CENTER COORDINATES (IX, IY, IZ): 50, 15, 45
[Enter the coordinates of the mask center. Note that you have to specify coordinates equal to NX/2+1, NY/2+1,NZ/2+1 if you want the mask center to coincide with the nominal image center.]

If a 'C' was specified in response to the '(C)osine, (D)isk or (G)aussian:' prompt, SPIDER asks:

.WIDTH: 3.5
[Enter the width of the cosine falloff function.]

If a 'G' was specified in response to the '(C)osine, (D)isk or (G)aussian:' prompt, SPIDER asks:

.HALFWIDTH: 3.5
[Enter the halfwidth of the Gaussian falloff function.]

EXAMPLE Usage

SUBROUTINES

MASK

CALLER

UTIL2