a first set of zero coefficients extending along a direction traversing said filter through {HEAD ~ a center position} to form {TAIL ~ a first side} and a second side 
to form
a first set of zero coefficients extending along a direction traversing said filter through { HEAD ~ a center position } to form { TAIL ~ a first side } and a second side
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH