function chinhat

Creates a chinese hat filter. This is defined by: Center position (x, y) and radius. Optional keywords are naxis1, naxis2 which determine the size of the array. If not set, the size of the array is determined from global variables.

Syntax
result = chinhat(X, Y, RADIUS [, naxis1=value] [, naxis2 = value])

Arguments
X:   The center of the chinese hat filter in the first dimension
Y:   The center of the chinese hat filter in the second dimension
RADIUS:   The radius of the chinese hat filter
naxis1=value:   Optional, the size of the resulting array in the first dimension
naxis2=value:   Optional, the size of the resulting array in the second dimension