[vtkusers] help for rendering a large amount of images

[Henry Blanco]

Thanks David for your soon reply. My problem is to load and render
thousands of medical images, organized into series, by using VTK, but
considering strong limitations in terms of RAM (e.g., only 128 or 256 MB
of RAM available).

To achieve this task, we have tried to use the "vtkImageDataStreamer"
class, but we have failed. This class seems to load the whole volume
into memory, therefore loading 2000 CT images (1GB) into memory may fail
if we just consider 128 MB of RAM.

We are thinking to split the whole volume into K blocks and to load
a block of images into memory just when it's needed. The illusion of
having the whole volume loaded in memory could be achieved by
uploading/downloading one or more blocks of images to/from memory when
needed. We're wondering whether exists some vtk classes which can be
used to picture a view different than the original one (e.g., sagittal,
coronal, or even oblique view) without loading the whole volume of
images into memory. 

Henry

On mar, 2015-11-03 at 12:33 -0500, Henry Blanco wrote:
> Thanks David for your soon reply. Ok, my problem is to load and render thousands of medical images,
> organized into series, by using VTK, but considering strong limitations
> in terms of RAM (e.g., only 128 or 256 MB of RAM available).
> 
> To achieve this task, we have tried to use the "vtkImageDataStreamer"
> class, but we have failed. This class seems to load the whole volume into
> memory, therefore loading 2000 CT images (1GB) into memory may fail if
> we consider just 128 MB of RAM.
> 
> We are thinking to partition the whole volume into K blocks and to load
> a block of images into memory just when it's needed. The illusion of
> having the whole volume loaded in memory could be achieved by
> uploading/downloading one or more blocks of images to/from memory when
> needed. I'm wondering whether exist some vtk classes which can be used
> to picture a different view than the original (e.g., sagittal, coronal,
> or even oblique) without loading the whole volume of images. 
> 
> Henry
> 
> On lun, 2015-11-02 at 17:29 -0700, David Gobbi wrote:
> > What kind of views will you need?  Do you just have to view the
> > original
> > slices?  If so, then the VTK pipeline's streaming will make the job
> > easy.
> > If you need orthogonal or oblique views, things are more difficult.
> > Also,
> > how is the data stored on disk?  If the whole volume is stored on disk
> > as a single flat file, then you can memory map the file.
> > 
> > 
> >  - David
> > 
> > On Mon, Nov 2, 2015 at 4:10 PM, Henry Blanco <henry.blanco at cbiomed.cu>
> > wrote:
> >         Hello guys, I need some hints on how to render a large amount
> >         of images
> >         (e.g., thousands of images) using just few RAM resources
> >         (e.g., 128 MB)
> >         using the vtkImageReslice class for the whole volume.
> >         
> >         Thanks in advance
> >         
> >         Henry
> 
>