By sampling only localized land imagery the claimed method computes black points that are more robust against the localized effects of atmospheric and land reflection effects than {HEAD ~ black points} computed from {TAIL ~ wider areas} 
By sampling only localized land imagery the claimed method computes black points that are more robust against the localized effects of atmospheric and land reflection effects than { HEAD ~ black points } computed from { TAIL ~ wider areas }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL