SURFLIB_CALC_DUAL_BEAM

Calculates a chopped map from a single beam map

Description:

This routine can be used to added a chopped beam response to a single beam image. When NBEAMS=2 this routine calculates a middle-beam dual-beam map by calculating the difference between the left and right beams for each pixel in the map.

When NBEAMS=3 a triple beam map is constructed where the central beam is the difference between the central beam and the average of the positions a chop distance away on either side.

All pixels off the edge of the image are assumed to have flux 0 and variance 0.

Bad pixels are assumed to be equivalent to flux of 0 and variance 0, although for the triple beam image a bad pixel is retained if it coincide with the middle beam position.

Invocation

CALL SURFLIB_CALC_CHOPPED_IMAGE( NBEAMS, CHOP_THR, CHOP_PA, DIM1, DIM2, IN_DATA, OUT_DATA, USEVAR, IN_VAR, OUT_VAR, STATUS)

Arguments

NBEAMS = INTEGER (Given)
Number of beams to add. (2 or 3)
CHOP_THR = REAL (Given)
Chop throw in pixels
CHOP_PA = REAL (Given)
Chop position angle (east of north) in degrees
DIM1 = INTEGER (Given)
First dimension of image
DIM2 = INTEGER (Given)
Second dimension of image [can not use DIMS as an array since the linux fortran compiler doesnt like it]
IN_DATA = REAL (Given)
Input single-beam image
OUT_DATA = REAL (Returned)
Output dual-beam image
USEVAR = LOGICAL (Given)
Are we processing a variance array?
IN_VAR = REAL (Given)
Input variance image (if USEVAR=TRUE)
OUT_VAR = REAL (Returned)
Output variance image (if USEVAR=TRUE)
STATUS = INTEGER (Given and Returned)
Global status

Copyright

Copyright ©1995,1996,1997,1998,1999 Particle Physics and Astronomy Research Council. All Rights Reserved.