[Insight-users] Problem implementing GradientAnisotropicDiffusionImageFilter

[Bill Lorensen]

The advantage of the itk class is that the conductance you provide is
independent of the image intensity range.

On Wed, Dec 2, 2009 at 10:12 AM, O'Connor, Michael
<Michael.OConnor at umassmed.edu> wrote:
> 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
>>>>>
>>>
>>>
>>>
>>
>
>
>