[Insight-users] Using MetaIO for trees of TubeSpatialObjects

[Dan Mueller]

Hi all,

I have some questions regarding the itk::SpatialObject classes.

I have a simple application which creates a tree of itk::TubeSpatialObjects (please find source code attached).   
This application creates tube1 and tube1_1, calls tube1->AddSpatialObject(tube1_1), and uses the itk::MetaTubeConverter to save the object as a Meta file (*.mhd).

However, the itk::MetaTubeConverter does not write the itk:SpatialObject child nodes to the Meta file (see output Meta file below).

How do I save the entire tube network to a Meta file?
Am I missing something with the itk::SpatialObject::AddSpatialObject(..) call? I have tried using itk::TubeSpatialObject::SetParentPoint(..) and itk::TubeSpatialObject::SetRoot(..) but I can't seem to make them work either. Should I be using a different Meta converter class, like itk::MetaGroupConverter? Am I on the right track, or did I miss the point somewhere?

Any help would be appreciated!


Output Meta file (note that only tube1 is written):
--------------------
ObjectType = Tube
NDims = 3
Color = 1 0 0 1
TransformMatrix = 1 0 0 0 1 0 0 0 1
Offset = 0 0 0
CenterOfRotation = 0 0 0
ElementSpacing = 1 1 1
Root = False
PointDim = x y z r v1x v1y v1z v2x v2y v2z tx ty tz red green blue alpha id
NPoints = 5
Points = 
10.5 10 15 4 0 0 0 0 0 0 0 0 0 1 0 0 1 -1 
50 30.5 30 2 0 0 0 0 0 0 0 0 0 1 0 0 1 -1 
65 45.5 30 3 0 0 0 0 0 0 0 0 0 1 0 0 1 -1 
100 115 60 2 0 0 0 0 0 0 0 0 0 1 0 0 1 -1 
170 60 200 1.55 0 0 0 0 0 0 0 0 0 1 0 0 1 -1 
--------------------

Note: I am using Windows XP, ITK v2.4.1, VC++ 2003. 

Cheers

Dan Mueller [d.mueller at qut.edu.au]

School of Engineering Systems
Faculty of Built Environment and Engineering
Queensland University of Technology (QUT)
Brisbane, Queensland, Australia
CRICOS No.: 00213J
-------------- next part --------------
#include "itkImage.h"
#include "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkGroupSpatialObject.h"
#include "itkLineSpatialObject.h"
#include "itkEllipseSpatialObject.h"
#include "itkLineSpatialObjectPoint.h"
#include "itkTubeSpatialObject.h"
#include "itkTubeSpatialObjectPoint.h"
#include "itkMetaTubeConverter.h"

int main(int argc, char * argv[])
{
    try
    {
        //Check the input arguments:
		//	0 = Application name
		//	1 = Output meta file path
        if (argc != 2)
        {
            std::cerr << "Usage: " << std::endl;
            std::cerr << argv[0] << " OutputMetaFile" << std::endl;
            return EXIT_FAILURE;
        }

        //Declare pixel and image types
        const unsigned int Dimension = 3;
		typedef unsigned char						PixelType;
        typedef itk::Image<PixelType, Dimension>	ImageType;

        //Declare SpatialObject types
		typedef itk::GroupSpatialObject<Dimension>		GroupType;
		typedef itk::EllipseSpatialObject<Dimension>	EllipseType;
		typedef itk::LineSpatialObject<Dimension>		LineType;
		typedef itk::LineSpatialObjectPoint<Dimension>	LinePointType;
		typedef itk::TubeSpatialObject<Dimension>		TubeType;
		typedef itk::TubeSpatialObjectPoint<Dimension>	TubePointType;

		//Create some tube points
		TubePointType point1_1;
		point1_1.SetPosition(10.5, 10.0, 15.0);
		point1_1.SetRadius(4.0);

		TubePointType point1_2;
		point1_2.SetPosition(50, 30.5, 30.0);
		point1_2.SetRadius(2.0);

		TubePointType point1_3;
		point1_3.SetPosition(65.0, 45.5, 30.0);
		point1_3.SetRadius(3.0);

		TubePointType point1_4;
		point1_4.SetPosition(100.0, 115.0, 60.0);
		point1_4.SetRadius(2.0);

		TubePointType point1_5;
		point1_5.SetPosition(170.0, 60.0, 200.0);
		point1_5.SetRadius(1.55);

		TubePointType point1_1_1;
		point1_1_1.SetPosition(100.0, 115.0, 60.0);
		point1_1_1.SetRadius(2.0);

		TubePointType point1_1_2;
		point1_1_2.SetPosition(65.0, 130.0, 60.0);
		point1_1_2.SetRadius(1.0);

		TubePointType point1_1_3;
		point1_1_3.SetPosition(35.0, 130.0, 90.0);
		point1_1_3.SetRadius(3.5);

		//Create "root" tube
		TubeType::Pointer tube1 = TubeType::New();
		tube1->GetPoints().push_back(point1_1);
		tube1->GetPoints().push_back(point1_2);
		tube1->GetPoints().push_back(point1_3);
		tube1->GetPoints().push_back(point1_4);
		tube1->GetPoints().push_back(point1_5);

		//Create the "child" tube
		TubeType::Pointer tube1_1 = TubeType::New();
		tube1_1->GetPoints().push_back(point1_1_1);
		tube1_1->GetPoints().push_back(point1_1_2);
		tube1_1->GetPoints().push_back(point1_1_3);
		
		//Add child tube to root tube
		tube1->SetRoot(true);
		tube1->AddSpatialObject(tube1_1);
		tube1->SetRoot(true);
		tube1_1->SetParentPoint(3); //point1_4 is the parent point of tube1_1
		
		//Print some debug info
		char buffer[10];
		std::cout << "Tube1 (the root) has " << itoa(tube1->GetNumberOfChildren(), buffer, 10) << " child\\children" << std::endl;
		std::cout << "Tube1_1 (the child) HasParent=" << tube1_1->HasParent()<< std::endl;

		//Write SpatialObject to Meta file
		itk::MetaTubeConverter<Dimension> metaWriter;
		metaWriter.WriteMeta(tube1, argv[1]);
    }
    catch (itk::ExceptionObject & err)
    { 
        std::cout << "ExceptionObject caught !" << std::endl; 
        std::cout << err << std::endl; 
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;

}//end main()