[ITK Community] Image buffer pointer

[Gib Bogle]

Well, obviously this was the problem.  Initially I was working with a separate allocated buffer, then to save memory I started modifying the image "in place".  I was slow to realize that this actually makes the image writing very simple - I just need

writer->SetInput(im_u8);


I have learned something useful about itk::ImportImageFilter anyway. :)
Gib
________________________________
From: Community [community-bounces at itk.org] on behalf of Gib Bogle [g.bogle at auckland.ac.nz]
Sent: Monday, 17 March 2014 10:44 p.m.
To: Luis Ibanez
Cc: community at itk.org
Subject: Re: [ITK Community] Image buffer pointer

Hi Luis,

I implemented this method, and it works.  But there is a problem.  When I exit the program I get this:

The program has unexpectedly finished.

E:\LN_structure\vessel-tools\Qt\equaliser-build\equaliser.exe exited with code -1073741819

The output file was written successfully, but somehow the program (perhaps the stack) is left in a bad state.  Could it be a problem that buffer in this statement

importFilter->SetImportPointer( buffer, numberOfPixels, importImageFilterWillOwnTheBuffer );

is this:

buffer = (unsigned char *)(im_u8->GetBufferPointer());

where im_u8 is an image that I previously read in?



________________________________
From: Luis Ibanez [luis.ibanez at kitware.com]
Sent: Monday, 17 March 2014 5:29 p.m.
To: Gib Bogle
Cc: community at itk.org
Subject: Re: [ITK Community] Image buffer pointer


Gib

The itkImportImageFilter

http://www.itk.org/Wiki/ITK/Examples/IO/ImportImageFilter

Might be what you are looking for.

Hope this helps

   Luis

On Mar 17, 2014 12:24 AM, "Gib Bogle" <g.bogle at auckland.ac.nz<mailto:g.bogle at auckland.ac.nz>> wrote:
Hi,

I am doing manipulations on images by directly accessing the image buffer.  When I want to create a new image I currently employ a rather crude method.  I allocate a buffer of the right size, create the image in the buffer, then because I do not know how to make itk::Image use this buffer address I allocate the image buffer and copy from my buffer to the new image buffer:

         unsigned char *p_u8;

    typedef itk::Image<unsigned char,3> ImageType_u8;

    ImageType_u8::Pointer im_u8 = ImageType_u8::New();

    ImageType_u8::SizeType imsize;

    ImageType_u8::IndexType imstart;

    ImageType_u8::RegionType imregion;

    imsize[0] = width;

    imsize[1] = height;

    imsize[2] = depth;

    imstart[0] = 0;

    imstart[1] = 0;

    imstart[2] = 0;

    imregion.SetSize(imsize);

    imregion.SetIndex(imstart);

    im_u8->SetRegions(imregion);

    im_u8->Allocate();

    p_u8 = (unsigned char *)(im_u8->GetBufferPointer());

    // copy buffer to p_u8

    memcpy(p_u8,buffer,(size_t)(width*height*depth));

This works but is obviously inefficient.  Previously the inefficiency didn't bother me,
but now that I'm working with big tiff images I am running out of memory.  Is there a way to create an Image

and make it use a buffer that has already been allocated?

Thanks
Gib


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