Freeman Chain Code

Gives Freeman chain code 8-connected representation of a boundary

usage:
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[cc] = chaincode(b,u)

INPUT:
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b - boundary as np-by-2 array
unwrap - (optional, default=false) unwrap code

OUTPUT:
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cc is a structure with the following fields:
cc.code - 8-connected Freeman chain code 1-by-np
cc.x0,cc.y0 - coordinates of start point
cc.ucode - unwrapped 8-connected Freeman chain code