[Insight-users] Sigmoid Filter

[Abayiz]

Hello,

I am using sigmoid filter in ITK to obtain an edge map of a 3D dicom volume. It works quite fine, but what confuses me is, it gives out an extra edge exactly  in the middle of the two edges. How this could be possible? 

I also attached an image of it, the thin white line (edge) in the black region is the confusing point. The given parameters are: alpha=-3, beta=3. 


Hope to receive your helpful suggestions. Thanks in advance. 
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