Uses an ARD file to set some pixels of a given image to bad

#### Description:

Allows the user to input the name of an NDF image file and and ARD file. The ARD file is used to specify which parts of the image will NOT be used. An output NDF is then created which is the same as the input file except that all pixels specified by the ARD file have been assigned the value Bad.

#### Usage:

MASK IN ARDFIL OUT

#### Parameters:

##### ARDFIL = _CHAR (Read)
The name of the ARD file containing a description of the parts of the image to be masked out i.e. set to bad.
##### IN = _NDF (Read)
The name of the source NDF.
##### OUT = _NDF (Write)
The name of the output NDF.

#### Examples:

mask in=ic3374 ardfil=^ardfile.txt out=ic3374a
This example uses as the source image IC3374 and sets the pixels specified by the ARD description contained in ARDFILE.TXT to the bad value. The resultant image is output as IC3374A.