[Insight-users] distance to isosurface transform

[Sam Preston]

Hi all,

I've been looking for a filter that, for every point in the output
image, will compute the euclidean distance to the nearest point on an
isosurface of the input image.  Actually, I don't need it for every
point in the image, only for some arbitrary neighborhood around the
isosurface.  This is very similar to the
IsoContourDistanceImageFilter, but I need the distance computed for a
neighborhood greater than one pixel wide, and haven't found a filter
that can perform this operation in ITK.  I have a greyscale image, not
a binary image, and need the distance to be sub-voxel accurate.

If such a filter doesn't exist, my plan is to extract the
marching-cubes mesh of the isosurface, and for a neighborhood around
each pixel (where the neighborhood includes an intersection with the
isosurface), find the nearest distance to any of the extracted
triangles generated from cells in the neighborhood.

Does such a filter already exist, and if not, is my implementation
reasonable (even if not extremely fast)?

Thanks,

-Sam

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J. Samuel Preston
Research Assistant
Scientific Computing and Imaging Institute
University of Utah