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