63fb46d6_bster_US___Patent_applications__Description
[Patent application number] 20110051197 [Published] 03-03-2011 [Description] 
BITMAPPED BASED TRAPPING METHODS, APPARATUS AND SYSTEMS - Provided are bitmap based trapping methods, apparatus and systems. According to one exemplary method, black trapping color image data is performed by estimating the continuous tone values associated with non-black pixels near a qualified black pixel and subsequently, the estimated continuous tone values are halftoned at the qualified black pixel locations and ORed with the original bitmap data.
Xing Li, Webster US - Patent applications