[Insight-users] Generate gaussian noise image

Thu Mar 6 16:32:30 EST 2014

I haven't looked at the classes closely. But would expect these filters have a user settable seed, to make the results reproduce able, and be the same independent with the number of threads.

The trick would be to have each thread has a random number generator object, then at the beginning of each line seed it with a combination of the user defined seed, and the starting index of the scan-line ( perhaps multiplied by a prime number).

Hope that some help... I just have some ideas in my head about some ways to do it...

Brad

On Mar 6, 2014, at 4:26 PM, Laurent Chauvin <lchauvin at bwh.harvard.edu> wrote:

> 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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