[Insight-users] ITK Filter in an Osirix plugin

[Luis Ibanez]

Hi Quent,

The likely source of the problem is the line


       // After the copy, I need to decrement the pointer
       // It doesn't work if I don't ...
       localBuffer -= numberOfPixels;


You shouldn't need to do that after you call

       // Buffer containing the data
       float * localBuffer = new float[numberOfPixels];
       memcpy(localBuffer, [viewerController volumePtr], numberOfPixels);


since memcpy doesn't change your localBuffer pointer.


You may have to do some verification of your
"volumePtr" variable.


Also, you may find useful to look at the Tutorials

     http://www.itk.org/ITK/help/tutorials.html


in particular to:

"Getting Started V: Integrating ITK in your Application."
http://www.itk.org/CourseWare/Training/GettingStarted-V.pdf



     Regards,


          Luis


--------------------------------------------------------------------
On Mon, May 10, 2010 at 4:04 AM, Quent <quentin.bezsilko at gmail.com> wrote:
>
> Hi all,
> I'm working on an osirix plugin and I've already succeeded in importing the
> data from the Osirix viewer to itk to create an itk::ImportImageFilter
> object.
> What I need to do now is to create a filter on this importFilter. I've
> already tried to create a MeanImageFilter but it simply did not work because
> of a segmentation fault caused by a call to a dynamic_cast function. The
> problem is I did not call any such function.
>
> After creating the filter, I'll have to bring the pixels from the filter
> back to the Osirix viewer and see the modifications made by the filter. For
> this part, I know how I will proceed to do it.
>
> I think the ImportImageFiter object works fine because no error was produced
> while I was running the program with gdb and without the MeanImageFilter.
> Here is the source code :
>
> - (long) filterImage:(NSString*) menuName{
>
>       // Duplication of the Osirix viewer
>        ViewerController * new2DViewer = [self duplicateCurrent2DViewerWindow];
>        id waitWindow = [viewerController startWaitWindow:@"Essai modification de
> l'image"];
>
>        // Defining the variables for the ImportFilter
>        typedef itk::Image <float, 3> ImageType;
>
>        ImageType::RegionType region;
>        ImageType::SizeType size;
>
>        double spacing[3];
>
>        typedef itk::Image <float, 3> InputImageType;
>        typedef itk::Image <float, 3> OutputImageType;
>
>        typedef itk::ImportImageFilter <float, 3> ImportFilterType;
>        ImportFilterType::Pointer importFilter = ImportFilterType::New();
>
>        typedef itk::ImageFileReader <InputImageType> ReaderType;
>        typedef itk::ImageFileWriter <ImageType> WriterType;
>
>        WriterType::Pointer writer = WriterType::New();
>        ReaderType::Pointer reader = ReaderType::New();
>
>        NSArray * pixList = [new2DViewer pixList];
>        DCMPix * curPix = [pixList objectAtIndex:0];
>
>        int height = [curPix pheight];
>        int width = [curPix pwidth];
>        int depth = [pixList count];
>
>        size[0] = width; size[1] = height; size[2] = depth;
>        region.SetSize(size);
>
>        ImageType::IndexType start;
>        start.Fill(0);
>        region.SetIndex(start);
>
>        const unsigned int numberOfPixels = height * width * depth;
>
>        double spaceX = [curPix pixelSpacingX];
>        double spaceY = [curPix pixelSpacingY];
>        double spaceZ = [curPix sliceInterval];
>
>        if(spaceZ == 0){
>                spaceZ = [curPix sliceThickness];
>        }
>
>        spacing[0] = spaceX; spacing[1] = spaceY; spacing[2] = spaceZ;
>
>        double ox = [curPix originX];
>        double oy = [curPix originY];
>        double oz = [curPix originZ];
>
>        double origin[3];
>        origin[0] = ox; origin[1] = oy; origin[2] = oz;
>
>        // Buffer containing the data
>        float * localBuffer = new float[numberOfPixels];
>        memcpy(localBuffer, [viewerController volumePtr], numberOfPixels);
>
>        // After the copy, I need to decrement the pointer
>        // It doesn't work if I don't ...
>        localBuffer -= numberOfPixels;
>
>        importFilter->SetRegion(region);
>        importFilter->SetSpacing(spacing);
>        importFilter->SetOrigin(origin);
>        importFilter->SetImportPointer(localBuffer, numberOfPixels, false);
>
>        // Creating the ImportFilter
>        try{
>                importFilter->Update();
>                NSRunCriticalAlertPanel(@"importFilter->Update()", @"OK", nil, nil, nil);
>        }
>        catch(itk::ExceptionObject & err){
>                FILE * fichier = fopen("/Users/u703inserm/Desktop/fichier.txt", "w");
>                if(fichier != NULL){
>                        fputs("Exception ImportFilter", fichier);
>                        fputs(err.GetDescription(), fichier);
>                }
>        }
>        // Works fine until there
>
>        // Here starts the problem
>        // Application of a filter : MeanImageFilter (Osirix crashes)
>        typedef itk::MeanImageFilter <ImageType, ImageType> FilterType;
>        FilterType::Pointer filter = FilterType::New();
>        filter->SetInput(importFilter->GetOutput());
>
>        try{
>                filter->Update();
>        }
>        catch (itk::ExceptionObject & err) {
>                FILE * fichier = fopen("/Users/u703inserm/Desktop/fichier.txt", "w");
>                if(fichier != NULL){
>                        fputs("Exception ImportFilter", fichier);
>                        fputs(err.GetDescription(), fichier);
>                }
>        }
>
>        [new2DViewer endWaitWindow:waitWindow];
>        [new2DViewer needsDisplayUpdate];
>        return 0;
> }
>
> And the error is :
>
> Program received signal EXC_BAD_ACCESS, Could not access memory.
> Reason: KERN_INVALID_ADDRESS at address: 0x6e6b6e4d
> 0x92cbafe6 in __dynamic_cast ()
>
> I appreciate any help,
> Thanks
> Quentin
>
> --
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>
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