SPIHT Coding Example: Pass 1, Sorting Step (5)
S = (0,0), (0,1), (1,0), (1,1),
(0,2), (0,3), (1,2), (1,3),
(2,0), (2,1), (3,0), (3,1)
Z = (R,2,0), (R,2,1), (R,3,0),
(R,2,0) is not significant
S = (0,0), (0,1), (1,0), (1,1),
(0,2), (0,3), (1,2), (1,3),
(2,0), (2,1), (3,0), (3,1)
Z = (R,2,1), (R,3,0), (R,3,1), (R,1,1)