Fig. 7

Octant portion of the chamfer polygon generated by a 7×7 mask. l₁:(d−3a)y+ax=r, l₂:(3c−2d)y+(d−c)x=r, l₃:(2e−3c)y+(2c−e)x=r, and l₄:(3b−e)y+(e−2b)x=r. ∠AOE=45^∘ and corner points are \(A(\frac {r}{a},0)\), \(B(\frac {3r}{d},\frac {r}{d})\), \(C(\frac {2r}{c},\frac {r}{c})\), \(D(\frac {3r}{e},\frac {2r}{e})\), \(E(\frac {r}{b},\frac {r}{b})\), \(P(\frac {r}{d-c},0)\), \(Q(\frac {r}{2c-e},0)\), and \(R(\frac {r}{e-2b},0)\)