<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:12pt"><DIV>hello dear list;</DIV>
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<DIV>I have a 3D image (.raw) and I specified 150 point on it (X,Y,Z). For each points I have calculated normal vectors. Through a normal vector I got 50 samples( 50 grey scale values) by tri-linearintepolation . I would like to calculate these 50 samples' derivative( this is like a edge detection) . Is there a method to calculate these 50 grey scale values derivative? I hope I wrote my problem understandably.</DIV>
<DIV>Thanks</DIV>
<DIV>Tony</DIV></div><br>
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