Figure 3.20 - Reconstructive radial opening
If the base of the disjunctive opening is a set of linear structuring elements of varying angles, then the filter is called reconstructive radial opening. Figure 3.20 shows an illustration of the application of a radial opening and a reconstructive radial opening with angles varying from 0 to 180 deg with 2-deg steps. The filter detects all the pieces containing a long straight line.
1 import ia870 as MT 2 import numpy as np 3 from handson.lib import iaropen 4 5 A = adreadgray('pieces_bw.tif') > 0 6 B = iaropen(A,28,np.arange(0,179,2)) 7 C = MT.iainfrec(B,A,MT.iasebox()) 8 9 adshow(MT.iapad(MT.ianeg(A)), '(a) input image') 10 adshow(MT.iapad(MT.ianeg(B)), '(b) radial opening') 11 adshow(MT.iapad(MT.ianeg(C)), '(c) reconstructive radial opening')