How to compute curvature from chain code in image processing?

Question

How do I get from chart a (chain code) to chart b (curvature)?

0, 0, 2, 0, 1, 0, 7, 6, 0, 0 --> 0, 2, -2, 1, -1, -1, -1, 2, 0

Answer 1

From figure (a); the chain code comes out to be as follows:

According to [2] - page 186; the curvature is calculated by toe following psuedo code:

c = d - di

for all di such that d remains within a limit of ±2 (critical point of a chain code)

if c < 2 then c+7
if c > 2 then c-7

So this gives the required result (b).

Reference: Google Books