[Insight-users] Generate gaussian noise image

[Laurent Chauvin]

It actually works but you have to force the filter to only use 1 thread.

I think otherwise all threads got the same "random" values, which generate
same output for all threads.
My guess is the image is divided in 'lines' or 'column', each of them
managed by a separated thread. If all threads have same random values, then
the output will be patterned.

If it's possible to have different random values for each threads, then it
should be possible to run it with multiple threads.
I think one possibility would be to use a timestamp as seed for the
NormalVariateGenerator filter.
I tried with GetTimeStamp(), but this is the same timestamp for all threads.
I tried with GetNumberOfThreads(), but still the same number for all
threads.
I tried with GetMTime(), same.
I tried with 'this', but this is the same pointer too.

I'm not sure which variable could be different in each thread.

Thank you.
-Laurent


On Thu, Mar 6, 2014 at 3:56 PM, Laurent Chauvin <lchauvin at bwh.harvard.edu>wrote:

> I tried to use the itkAdditiveGaussianNoiseFilter, but on the output image
> I obtain, the noise seems really patterned.
>
> I compiled the code from the article, and run exactly the same example
> with same parameters and I don't have the same results as on the article.
> As I mentionned, the noise I obtain seems really patterned.
>
> I enclosed the picture I obtain after running the 'gauss' example with the
> same parameters as the article.
>
> Is it possible that the 'NormalVariateGenerator' used in the
> AdditiveGaussianNoiseFilter changed since the article has been written ?
> I noticed that the gaussian filter does not call Initialize of the
> NormalVariateGenerator, but I tried to add it, and it doesn't make any
> difference.
>
> Thank you.
> -Laurent
>
>
> On Thu, Mar 6, 2014 at 1:19 PM, Laurent Chauvin <lchauvin at bwh.harvard.edu>wrote:
>
>> I didn't look in the article for now.
>>
>> I was first trying to compile the code. There is a minor modification to
>> do to be compatible with ITKv4, but otherwise it's pretty straight forward.
>> So far I only tested itkAdditiveGaussianNoiseFilter.
>>
>> Thank you.
>> -Laurent
>>
>>
>> On Thu, Mar 6, 2014 at 1:11 PM, Bradley Lowekamp <blowekamp at mail.nih.gov>wrote:
>>
>>> It would be great if you could to a brief review of the IJ article to
>>> facilitate integrating it into ITK.
>>>
>>> Brad
>>>
>>> On Mar 6, 2014, at 12:17 PM, Laurent Chauvin <lchauvin at bwh.harvard.edu>
>>> wrote:
>>>
>>> Thank you Bradley.
>>>
>>> Indeed I saw this article, but as it is from 2010, I thought maybe now
>>> it would have been integrated into ITK.
>>> I will look into that.
>>>
>>> Thank you.
>>> -Laurent
>>>
>>>
>>> On Thu, Mar 6, 2014 at 11:59 AM, Bradley Lowekamp <
>>> blowekamp at mail.nih.gov> wrote:
>>>
>>>> Have a look at this insight journal article:
>>>>
>>>> http://www.insight-journal.org/browse/publication/721
>>>>
>>>> I would also find this quite useful, and have been thinking about
>>>> adding it to ITK.
>>>> Brad
>>>> On Mar 6, 2014, at 11:55 AM, Laurent Chauvin <lchauvin at bwh.harvard.edu>
>>>> wrote:
>>>>
>>>> Hello,
>>>>
>>>> I'm trying to develop a filter, but in order to test it, I need to add
>>>> some gaussian noise to my image.
>>>> I looked for it but I couldn't find a ITK filter to generate noise.
>>>>
>>>> Is there a way to do this ?
>>>>
>>>> Thank you very much.
>>>> -Laurent
>>>>
>>>> --
>>>> Laurent Chauvin, MS
>>>> Surgical Navigation and Robotics Laboratory, Radiology Department
>>>> Brigham And Women's Hospital, Harvard Medical School
>>>> http://wiki.ncigt.org/index.php/User:Lchauvin
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>>>
>>>
>>>
>>> --
>>> Laurent Chauvin, MS
>>> Surgical Navigation and Robotics Laboratory, Radiology Department
>>> Brigham And Women's Hospital, Harvard Medical School
>>> http://wiki.ncigt.org/index.php/User:Lchauvin
>>>
>>>
>>>
>>
>>
>> --
>> Laurent Chauvin, MS
>> Surgical Navigation and Robotics Laboratory, Radiology Department
>> Brigham And Women's Hospital, Harvard Medical School
>> http://wiki.ncigt.org/index.php/User:Lchauvin
>>
>
>
>
> --
> Laurent Chauvin, MS
> Surgical Navigation and Robotics Laboratory, Radiology Department
> Brigham And Women's Hospital, Harvard Medical School
> http://wiki.ncigt.org/index.php/User:Lchauvin
>



-- 
Laurent Chauvin, MS
Surgical Navigation and Robotics Laboratory, Radiology Department
Brigham And Women's Hospital, Harvard Medical School
http://wiki.ncigt.org/index.php/User:Lchauvin
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