``nonmax suppression'' -- non-maximum suppression

purpose:

Zero out a voxel if it is not a local maximum in some sense.

For ``connectivity = 6'', a voxel will not be set to 0 if it is a local maximum in either the x , y, or z directions. For ``connectivity = 26'', the voxel must be a local maximum within its local 3x3x3 neighborhood.

The operation is typically used in conjunction with edges detection. For example, a typical edge-detection sequence is

1. Calculate edge strengths using the ``Kirsch edge operator'', zeroing out voxels having low-valued edge strengths.
2. Apply a 6-connected ``non-maxima suppression'' to the volume.

The result is a grayscale volume containing a thinned-down set of edges.

input:

An 8-bit volume.

output:

An 8-bit volume.

parameters:

Default parameters menu is

connectivity = 6
input from vol # = 0
copy output to vol # = 0

comments:

 

1. This operation takes a little more computation than a typical 3x3x3 local maximum (``max'').