[Insight-users] Distance between surfaces

[Arnaud Gelas]

Hi Koen,

if you want an approximation of the minimal distance between the two 
surfaces one cheap and "fast" solution would be to consider point sets 
and found the shortest distance between these two sets. Note this is 
only an approximation and it won't help you if you need to check if the 
two surface intersects...

If an approximation is ok for you, you could do the following:
use a kd-tree where you store one of the two surface (let's say A).
Then for the first point of the other surface (B) you search for the 
closest point on the (A) and you get the distance dist.
Then for the next point you search all closest neighbor given the 
distance dist. If there are any you update dist as the minimum of these 
neighbors, else you don't change dist. You iterate.

HTH
Arnaud

Leila Baghdadi wrote:
> Koen,
>
> one idea would be to convert your surfaces to binary mask images
> ( itkTriangleMeshToBinaryImageFilter) and then compare images voxel by
> voxel, 
>
> HTH
>
> Leila
>
> On Tue, 2009-06-09 at 18:08 +0200, Koen Vermeer wrote:
>   
>> Hi,
>>
>> My experience with ITK is still rather limited, so I'm looking for help
>> on which approach would be the best for my problem.
>>
>> In a 3D volume (note that my pixels are not isotropic), I have two 2D
>> surfaces (represented by a set of points, or a level set, or whatever
>> the solution requires). I am looking for a way to determine the minimum
>> distance between these two surfaces, for each point on these surfaces.
>>
>> I was thinking about propagating one surface and recording some kind of
>> distance map on the location of the second surface. Would something like
>> a distance map be the most appropriate operator, a fast marching filter,
>> or something else?
>>
>> Any comments are appreciated; if more information is required, I'd be
>> more than happy to elaborate on the problem!
>>
>> Best,
>> Koen
>>
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