[Insight-users] Generate gaussian noise image

Thu Mar 6 16:40:24 EST 2014

Do you mean ask the user to input a number (always different) for each
thread ?

Thank you.
-Laurent

On Thu, Mar 6, 2014 at 4:32 PM, Bradley Lowekamp <blowekamp at mail.nih.gov>wrote:

> 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
>
>
>

-- 
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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