MA - Mask - image/volume with a circular mask

PURPOSE

Masks an image/volume with a circular mask of specified radii. Pixels in the area inside the inner circle and the area outside the outer circle are set to a specified background.

SEE ALSO

MA L	[Mask - line across image]
MA X	[Mask - image in X direction]
MA Y	[Mask - image in Y direction]
MA Z	[Mask - image in Z direction]
MM	[Mask Multiplication]
MM C	[Mask Multiplication - Continuous]

USAGE

.OPERATION: MA

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

.OUTPUT FILE: PIC002
[Enter the name of the output file.]

.OUTER & INNER RADII: 12.0, 0.0
[Enter the radii of the outer and inner mask circles, in pixels. Pixels in areas outside the outer radius and inside the inner radius are set to background. Enter zero inner radius for no inner radius masking. Enter zero outer radius for inner masking only.]

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

.(A)V, (P)REV AV, (C)IRCUMF, OR (E)XTERNAL: P
[Enter 'A' to set background to the average before masking.
Enter 'P' to set background to the average after masking.
Enter 'C' to set background to average along the border of the mask.
. Enter 'E' to specify the background. ]

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 (OR <CR> FOR IMAGE CENTER): 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 spider image center.]

If using a volume SPIDER asks.

.MASK CENTER COORDINATES IX,IY,IZ (OR <CR> FOR IMAGE CENTER): 50, 15, 45
[Enter the coordinates of the mask center. A <CR> gives the coordinates of the SPIDER image center: NX/2+1,NY/2+1,NZ/2+1.]

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