[vtkusers] About surface extraction

[Rong Xu]

Dear Everyone:

I encountered a problem on surface extraction. I want to extract a 3d fetal
facial surface from 3D ultrasound image. So I tried two methods to extract
3D surface. First method is, I detect each edge of fetal facial surface
from each 2D slice, and then the 3D surface is composed of extracted edges
from each slice. Second method is to use vtkContourFilter to extract 3D
surface directly and saved as poly data. However, I found the coordinates
of poly data from two methods are different. The coordinates of poly data
from the first method is relative to original 3D US data, but the
coordinates of poly data from the second method are scaled compared with
original 3D US data.

But I want to apply the second method to get the same coordinates of poly
data as the first method, because the first method is cumbersome to extract
3D surface. So does anyone have any ideas about this problem?

Thank you very much for your advice!

-- 

---------------------
Best Regards!

===============================================
Rong Xu,  Ph.D Student
Ohya Lab
Graduate School of Global Information and Telecommunication
Studies (GITS), Waseda University
1-6-1 Nishi Waseda, Shinjuku-ku, Tokyo, Japan (¨“169-8050)

Tel:          +81-80-4208-1207
E-mail:     xurong1981 at gmail.com
               xurong at fuji.waseda.jp
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