{TAIL ~ a definition module} configured to define for each local region one or more local black points, wherein {HEAD ~ each local black point} corresponds to a single darkest pixel or local cluster of the darkest pixels in the given local region 
{ TAIL ~ a definition module } configured to define for each local region one or more local black points , wherein { HEAD ~ each local black point } corresponds to a single darkest pixel or local cluster of the darkest pixels in the given local region
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH