The method comprises: providing a source image comprising a plurality of pixels, each pixel having a source value, providing an inverted threshold value for each pixel of the plurality of pixels, and generating thereof a temporary image comprising {HEAD ~ a temporary value} for {TAIL ~ each pixel} of the plurality of pixels 
The method comprises : providing a source image comprising a plurality of pixels , each pixel having a source value , providing an inverted threshold value for each pixel of the plurality of pixels , and generating thereof a temporary image comprising { HEAD ~ a temporary value } for { TAIL ~ each pixel } of the plurality of pixels
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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH