[Insight-users] Failed to allocate memory

[Nithiananthan, Sajendra]

Luis,

So the memory usage I observed was much larger than would be expected (see
below).
As I mentioned, I was importing the images into ITK, so the increased memory
usage might be a problem further up the pipeline.

-Sajendra N.

> -----Original Message-----
> From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
> 
> Hi Sajendra,
> 
> Yes,
> 2.5 Gb sounds about right for the amount of RAM memory that
> you would need for running this filter.
> 
> Note however that a process in Windows 32bits system cannot
> allocate more than 2Gb of RAM.
>     Regards,
> 
>         Luis
> -------------------------------
> Nithiananthan, Sajendra wrote:
> > Luis,
> > 
> > The pixel type is "float", 4 bytes/pixel. So the image size 
> is approximately
> > 100 million pixels, or 400MB.
> > I chose to represent the deformation field with a vector of 
> floats, so they
> > are three times as big, or about 1.2GB.
> > Specifically:
> >     const unsigned int DIMENSION = 3;
> >     typedef itk::Image<float, DIMENSION>	ImageType;
> >     //representation of the deformation field:
> >     typedef itk::Vector<float, DIMENSION>   VectorPixelType;
> >     typedef itk::Image<VectorPixelType, DIMENSION>  
> DeformationFieldType;
> > 
> > So to represent the fixed image, moving image, deformation 
> field, and output
> > image, I would expect usage about 2.5GB?
> > 
> > -Sajendra
> > 
> > 
> > 
> > 
> >>-----Original Message-----
> >>From: Luis Ibanez [mailto:luis.ibanez at kitware.com]
> >>Subject: Re: [Insight-users] Failed to allocate memory
> >>
> >>Hi Sajendra,
> >>
> >>What was the image size (in pixels) ?
> >>
> >> From a 400Mb image, if we assume that you are using "signed short"
> >>as pixel type, then we are probably talking about:
> >>
> >>                       200 Million pixels
> >>
> >>Demons will internally construct a deformation field with a 
> 3D vector
> >>of doubles per pixel. That will be:
> >>
> >>               2e8 x 3 x 8 bytes = 4.9 Gigabytes.
> >>
> >>To this you will have to add the 400Mb of the output image.
> >>
> >>
> >>Therefore your observed memory actually looks small for 
> this problem.
> >>
> >>
> >>    Regards,
> >>
> >>
> >>
> >>       Luis
> >>
> >>
> >>
> >>-------------------------------
> >>Nithiananthan, Sajendra wrote:
> >>
> >>>I was in a situation similar to the OP, Zhihong, trying to 
> >>
> >>use ITK based
> >>
> >>>Demons registration on larger images (~400MB). It failed 
> >>
> >>spectacularly  on
> >>
> >>>32 bit Windows. Compiling and running on a 64 bit machine 
> solved the
> >>>problem.
> >>>The peak memory was about 4.5 GB, which seems high (no 
> >>
> >>histogram matching or
> >>
> >>>casting used). I had imported the images into ITK from VTK 
> >>
> >>so perhaps that
> >>
> >>>explains some of the increased memory usage. Either way, it 
> >>
> >>did run well and
> >>
> >>>gave me the results I would have expected (compared the 
> >>
> >>output for a smaller
> >>
> >>>image to that from a 32bit machine). I will hopefully 
> >>
> >>confirm later that
> >>
> >>>nothing strange is happening with memory usage.
> >>>
> >>>Thank you for your input
> >>>-Sajendra
> >>>
> >>>
> >>>
> > 
> > 

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