“…{p(x + dix∆x, y + diy∆y) = 1|0∆x|x − xe|, 0∆y|y − ye|}, (9) where p(x + ∆x, y + ∆y) is the binary value of points of expansion, it means reset the points in the region of expansion to be points of our final target object. d i can be found in the set {(-1,-1,),(0,-1),(1,-1),(1,0),(1,1),(0,1),(-1,1),(-1,0)}, which correspond to the label of direction {0,1,2,3,4,5,6,7}.…”