{TAIL ~ The focus information} of each solder ball is used to determine the distance to {HEAD ~ the tips} of each solder ball 
{ TAIL ~ The focus information } of each solder ball is used to determine the distance to { HEAD ~ the tips } of each solder ball
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH