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lthin.c File Reference

grayscale leveling thinning More...

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Detailed Description

grayscale leveling thinning

Usage: lthin in.pgm <imcond.pgm|null> connex niter out.pgm

Description: Grayscale leveling thinning (refs. [BEC97, CBB01]). The parameter connex gives the connectivity used for the minima; possible choices are 4, 8 in 2D and 6, 26 in 3D. Let F be the function corresponding to the input image in.pgm. Let G be the function corresponding to the input image imcond.pgm, or the null function if the keyword null is used. The algorithm is the following:

Repeat niter times:
    L = {(p,a) such that T--(p,F) = 1 and a = alpha-(p,F)}
    While L not empty
       extract a couple (p,a) from L
       F(p) = max{ a, alpha-(p,F), G(p) }    
Result: F

If niter is set to -1, then the operator iterates until stability.

References:
[BEC97] G. Bertrand, J. C. Everat and M. Couprie: "Image segmentation through operators based upon topology", Journal of Electronic Imaging, Vol. 6, No. 4, pp. 395-405, 1997.
[CBB01] M. Couprie, F.N. Bezerra, Gilles Bertrand: "Topological operators for grayscale image processing", Journal of Electronic Imaging, Vol. 10, No. 4, pp. 1003-1015, 2001.

Types supported: byte 2D, byte 3D.

Category: topogray

Author:

Michel Couprie

Example:

lthin ur1 null 4 -1 ur1_lthin minima ur1_lthin 4 ur1_lthin_m

ur1	ur1_lthin	ur1_lthin_m

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