[Insight-users] Problem implementing GradientAnisotropicDiffusionImageFilter

[O'Connor, Michael]

Hello Bill and Luis,
   With conductance = 6 the ITK data output do compare well with MATLAB.  Thanks for your help.  

Regards,
   Mike 


-----Original Message-----
From: Bill Lorensen [mailto:bill.lorensen at gmail.com]
Sent: Wed 12/2/2009 12:03 AM
To: O'Connor, Michael
Cc: Luis Ibanez; insight-users at itk.org
Subject: Re: [Insight-users] Problem implementing GradientAnisotropicDiffusionImageFilter
 
The average gradient in your data is about .0005.  So the conductance
of the itk code should be about the matlab conductance / .0005 which
is about .003 / .0005 = 6.

Try a conductance of 6  without scaling your data and see how it compares.

Bill


On Tue, Dec 1, 2009 at 11:36 PM, Bill Lorensen <bill.lorensen at gmail.com> wrote:
> In itk, the K divisor is average_gradient_squared *
> conductance_squared. I suspect that accounts for some of the
> difference.
>
> On Tue, Dec 1, 2009 at 9:01 PM, O'Connor, Michael
> <Michael.OConnor at umassmed.edu> wrote:
>> Hello Luis,
>>      The pixel spacing is .2 mm.   I did not SetSpacing in ITK code.
>> Thanks for the insight.   I will check that out.
>>
>> Regards,
>>    Michael
>>
>>
>> -----Original Message-----
>> From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
>> Sent: Tue 12/1/2009 7:56 PM
>> To: O'Connor, Michael
>> Cc: Bill Lorensen; insight-users at itk.org
>> Subject: Re: [Insight-users] Problem implementing
>> GradientAnisotropicDiffusionImageFilter
>>
>> Hi Michael,
>>
>> What is the pixel spacing of your image ?
>>
>> I believe that the ITK implementation may
>> be taking the pixel spacing into account
>> when using the value of conductance.
>>
>>
>>    Please let us know,
>>
>>
>>              Thanks
>>
>>
>>                        Luis
>>
>>
>> ------------------------------------------------------------------
>> On Tue, Dec 1, 2009 at 5:17 PM, O'Connor, Michael
>> <Michael.OConnor at umassmed.edu> wrote:
>>> Hi Bill,
>>>     I use the exact same file with ITK (the one attached to the previous
>>> email with MATLAB code).
>>>
>>> Regards,
>>>    Michael
>>>
>>>
>>> -----Original Message-----
>>> From: Bill Lorensen [mailto:bill.lorensen at gmail.com]
>>> Sent: Tue 12/1/2009 4:17 PM
>>> To: O'Connor, Michael
>>> Cc: insight-users at itk.org
>>> Subject: Re: [Insight-users] Problem implementing
>>> GradientAnisotropicDiffusionImageFilter
>>>
>>> Can you provide a png file or meta file, or whatever file you tried with
>>> itk?
>>>
>>> On Tue, Dec 1, 2009 at 4:08 PM, O'Connor, Michael
>>> <Michael.OConnor at umassmed.edu> wrote:
>>>> Hi Bill,
>>>>     Thanks.   Attached is simple MATLAB test code  + the MATLAB filter
>>>> function used (Dr. Guy Gilboa's code).   I've also take the liberty of
>>>> attaching a test image (specifically opened in MATLAB code).   The test
>>>> image is 400x400 float with background = 0.024 + additive Gaussian Noise
>>>> and
>>>> foreground (circle) = 0.031 + additive Gaussian Noise.   As said
>>>> previously
>>>> MATLAB code seems to work as expected as shown in plot.   In ITK there is
>>>> no
>>>> similar intraregion filtering (i.e. filtered image ~ input )
>>>>
>>>> Regards,
>>>>    Michael
>>>>
>>
>>
>>
>


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