[Insight-users] Re: Exporting an array

[Frédéric Stevens]

I will give you more details about how I did.
It is a function with (int argc, IDL_VPTR argv[]) as arguments
First argument is an array passed thanks to IDL
At the moment, I'm working on 16 bits DICOM (short type) with size : 512*512
and using them works fine
All the problem I have is to return the array modified back to IDL, here is
my code :


typedef  short InputPixelType;
typedef  short OutputPixelType;
const unsigned int Dimension = 2;
typedef itk::Image< InputPixelType,  Dimension >   InputImageType;
typedef itk::Image< OutputPixelType, Dimension >   OutputImageType;

IDL_VPTR src,dest;   // variables to import / export the picture from / to
IDL
InputPixelType *src_d,*dest_d;
src = argv[0];   // array 512*512
src_d = (InputPixelType *)src->value.s.arr->data; // way to get the data
from the IDL variable


// So now I'm using the ImportImageFilter using this array as Input and it
works perfectly fine

typedef itk::ImportImageFilter< InputPixelType, Dimension >
ImportFilterType;
ImportFilterType::Pointer importFilter = ImportFilterType::New();
ImportFilterType::SizeType  size;
size[0]  = 512;  // size along X
size[1]  = 512;  // size along Y
ImportFilterType::IndexType start;
start.Fill( 0 );
ImportFilterType::RegionType region;
region.SetIndex( start );
region.SetSize(  size  );
importFilter->SetRegion( region );
double origin[ Dimension ];
origin[0] = 0.0;    // X coordinate
origin[1] = 0.0;    // Y coordinate
importFilter->SetOrigin( origin );
double spacing[ Dimension ];
spacing[0] = 0.21484;    // along X direction
spacing[1] = 0.21484;    // along Y direction
importFilter->SetSpacing( spacing );
const unsigned int numberOfPixels =  size[0] * size[1];
const bool importImageFilterWillOwnTheBuffer = false;
importFilter->SetImportPointer( (InputPixelType *)src_d,
numberOfPixels,importImageFilterWillOwnTheBuffer );

// Just for test I was using a binarythresholdfilter and it is working with
it

typedef itk::BinaryThresholdImageFilter< InputImageType, OutputImageType >
FilterType;
FilterType::Pointer filter = FilterType::New();
const OutputPixelType outsideValue = 0;
const OutputPixelType insideValue  = 255;
filter->SetOutsideValue( outsideValue );
filter->SetInsideValue( insideValue );
const InputPixelType lowerThreshold = 0;
const InputPixelType upperThreshold = 500;
filter->SetLowerThreshold( lowerThreshold );
filter->SetUpperThreshold( upperThreshold );
filter->SetInput( importFilter->GetOutput() );

// Okay so until now, everything is fine. I can say it works because I used
a FileWriter and checked the picture after passing in the filter with :

typedef itk::ImageFileWriter< OutputImageType >  WriterType;
WriterType::Pointer writer = WriterType::New();
writer->SetInput( filter->GetOutput() );
writer->SetFileName( "e:\\test.dcm" );

try
{
    writer->Update();
}
catch (itk::ExceptionObject & e)
{
    sprintf(statusbuffer, "Error");
    IDL_Message(IDL_M_NAMED_GENERIC,IDL_MSG_INFO, statusbuffer);
    return src;
 }

// Now is the part where I try to export it back to IDL

I tried both with ImportImageContainer without succeeding :

typedef itk::ImportImageContainer<InputPixelType, InputPixelType >
ImportContainerType;
ImportContainerType::Pointer importFilter2 = ImportContainerType::New();
importFilter2->SetImportPointer( (InputPixelType *)filter->GetOutput(),
numberOfPixels,false);

dest_d = (InputPixelType *) IDL_MakeTempArray(IDL_TYP_INT,dest->value.arr-
>n_dim,dest->value.arr->dim,IDL_ARR_INI_INDEX,&paf);  // this allows to
create an array with the same dimensions. each element of the array is set
to the value of its index.  (it works I get an array with the right
dimensions and with the values back)

dest_d = (InputPixelType *)importFilter2->GetBufferPointer();  // I try to
get the array from the binary filter

return dest;  // return the IDL_VPTR variable to IDL containing the array.
The result in IDL is the array with each element is set to the value of its
index as if the GetBufferPointer didn't have any effect on the variable. I
tried also with the GetImportPointer but the result is the same.

I tried in a similar way with the ImportImageFilter but the result was still
the same.

I hope that you understand better my problem like this and would really be
glad to be helped because I have tried for a long time studying the problem
without succeeding.

Regards,

Frédéric



On 5/21/07, Frédéric Stevens <frederic.stevens at gmail.com> wrote:
>
> Hi,
>
> I have successfully imported an array using ImportImageFilter, used some
> filters on it and I can write it on the hard disk using ImageFileWriter.
> Instead of creating a new file, I would like to return this array in the
> same way as I imported it. (I am using an image imported from IDL and I
> would like to export it back with the filters applied).
> Is there a function that allows to do this operation  ?
>
> Many thanks,
>
> Frédéric
>
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