[Insight-users] GradientImageFilter vs GradientRecursiveGaussianImageFilter

[Ting Chen]

Hi! Pieter, thanks a lot for finding out the inconsistency. For my own
application, I think the itkGradientImageFilter should be changed to
be consistant with the itkGradientRecursiveGuassianImageFilter, I hope the
inconsistency can be fixed as soon as possible.

ting

-----Original Message-----
From: Will Schroeder <will.schroeder@kitware.com>
To: Pieter Vos <pieterv@nat-239.azn.nl>; insight-users@public.kitware.com
<insight-users@public.kitware.com>
Date: Thursday, April 25, 2002 6:44 AM
Subject: Re: [Insight-users] GradientImageFilter vs
GradientRecursiveGaussianImageFilter


>Hi Pieter-
>
>I believe that I am speaking for the whole group of ITK developers here: we
>very much appreciate your patient evaluation of ITK. Your work goes a long
>way to making the system realize its true potential and towards building
>the ITK community. Thank you.
>
>We will correct the inconsistency.
>
>Will
>
>At 11:54 AM 4/25/2002 +0200, Pieter Vos wrote:
>>Hello,
>>
>>I compaired the outputs of the filter GradientImageFilter and the
>>GradientRecursiveGaussianImageFilter.
>>Both filters had the same 3D image: a black image with a white spot in the
>>middle. The vectoroutputs however, where not the same:
>>
>>The vectors of the GradientImageFilter where pointing away form the spot.
>>
>>------------------
>>|
>>|       ^
>>|       |
>>|    <-   ->
>>|    <-   ->
>>|       |
>>|
>>|
>>------------------
>>
>>And the vectors of the GradientRecursiveGaussian where pointing to the
>>white spot:
>>
>>------------------
>>|
>>|
>>|        |
>>|    ->     <-
>>|    ->     <-
>>|        ^
>>|        |
>>|
>>------------------
>>
>>The second picture is as how it should be.
>>
>>So, am I forgetting some basic theory (and should I study again)
>>or should the outcome of the GradientImageFilter not be the opposite?
>>
>>Please help.
>>
>>Greetings,
>>
>>--
>>Pieter Vos
>>UMC Radboud Nijmegen
>>The Netherlands
>>mailto:pieterv@radiology.azn.nl
>>
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>
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