Toolbox ia870 | List of Figures | Fig. 3.17 | Fig. 3.19

Figure 3.18 - Reconstructive opening top-hat


The top-hat concept can be applied to reconstructive opening producing the reconstructive opening top-hat:

In this case, the operator reveals the objects that do not exhibit a fitting criterion. For instance, to detect thin objects, one can use a disk of diameter larger than the thickest of the thin objects. Figure 3.18 illustrates this situation. The reconstructive opening has detected the suite-objects of the cards as a disk can be fit into them, and the reconstructive opening top-hat has detected the number-objects as a disk cannot be fit.

Demo Script

 1 import ia870 as MT
 3 f = adreadgray('MVBook/cards.png')>0
 4 A = MT.iaareaopen(MT.iaedgeoff(f),50)
 5 adshow(MT.iapad(MT.ianeg(A)),'(a) input image')
 7 B = MT.iasedisk(5)
 9 C = MT.iaopen(A,B)
10 adshow(MT.iapad(MT.ianeg(C)),'(b) opening by disk')
12 D = MT.iaopenrec(A,B,MT.iasebox())
13 adshow(MT.iapad(MT.ianeg(D)),'(c) reconstructive opening by disk')
15 E = MT.iaopenrecth(A,B,MT.iasebox())
16 adshow(MT.iapad(MT.ianeg(E)),'(d) reconstructive opening top-hat by disk')

(a) input image

(b) opening by disk

(c) reconstructive opening by disk

(d) reconstructive opening top-hat by disk