
Digital Straightness and Polygonal Approximation 137
5
6
6
5
5
6
S
1
with chain code 0
5
10
6
10
6
10
5
10
5
10
6
(from lef t to right) (p = 5, q = 6, l = 5, r = 6) that
does not satisfy R3, s ince both the run lengths 5 and 6 have non-singular occurrences in
the code of run lengths: 566556. Thus, S
1
is not a DSS but an ADSS.
5
6
5
6
6
6
5
S
2
with chain code 0
5
10
6
10
5
10
6
10
6
10
6
10
5
(p = 5, q = 6, l = 5, r = 5) does not satisfy
R4, since in the run length code 5656665, the runs of 6 have lengths 1 and 3 that are not
consecutive. Here also, S
2
is not a DSS but an ADSS.
5
6
5
6
5
6
S
3
with chain code 0
5
10
6
10
5
10
6
10
5
10
6
(p = 5, q = 6, l = 5, r = 6) that satisfies (R1–R4)
and (c1, c2). So, S
3
is