hdilatball.c File Reference

topologically controlled dilation More...

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Detailed Description

topologically controlled dilation

Usage: hdilatball in.pgm radius dist connex out.pgm

Description: Performs a topologically controlled dilation, that is, a homotopic thickening constrained by the dilation of the input object.

The parameter radius gives the radius of the ball which is used as structuring element for the dilation.

The parameter dist is a numerical code indicating the distance which is used to compute the dilation. The possible choices are:

• 0: approximate euclidean distance
• 1: approximate quadratic euclidean distance
• 2: chamfer distance
• 3: exact quadratic euclidean distance
• 4: 4-distance in 2d
• 8: 8-distance in 2d
• 6: 6-distance in 3d
• 18: 18-distance in 3d
• 26: 26-distance in 3d

The parameter connex indicates the connectivity of the binary object. Possible choices are 4, 8 in 2d and 6, 26 in 3d.

Let X be the set corresponding to the input image in.pgm, and let Xbar denote its complementary set. The algorithm is the following:

I = dilatball(X, dist, r)
Repeat:
    Select a point x in [Xbar inter I] such that dist(x,X) is minimal
    If x is simple for X then
        X = X union {x}
	I = I \ {x}
Until [Xbar inter I] = emptyset
Result: X

Types supported: byte 2d, byte 3d

Category: topobin

Author:

Michel Couprie