Chamfer Mask:
( 1,  0,  0,  0,   7)
( 1,  1,  0,  0,  10)
( 1,  1,  1,  0,  12)
( 1,  1,  1,  1,  13)

Computed Lut Mask:
( 1,  0,  0,  0,   7)
( 1,  1,  0,  0,  10)
( 1,  1,  1,  0,  12)
( 1,  1,  1,  1,  13)

Look-Up Table: values which differ from LMC (L = 128, R <= 888)
Lut[][    7 ] =     8    11    13    14 
Lut[][   10 ] =    15    18    20    21 
Lut[][   12 ] =    18    21    23    24 
Lut[][   17 ] =    22    25    27    28 
Lut[][   19 ] =    25    28    30    31