This program checks for NULL tracks in the seven tracks of
a Viking image cube. If the percentage of pixels in a
line of a track meets or exceeds the THRESHLD value, then that
track is considered bad and the program will replace all
NULL values in that track. It does this replacement by using
valid pixels from each side of the track to perform an interpolation
to calculate the new pixel value.
The threshhold percentage value for determining a bad track.
If the percentage of pixels in a line of a track meets or exceeds
the THRESHLD value, then that track is considered bad. Defaults to 90.0.