image scaling

#include "itkImage.h"
#include "itkImageFileWriter.h"
#include "itkImageFileReader.h"
#include "itkMinimumMaximumImageCalculator.h"
#include "itkImageRegionIterator.h"
#include <iostream>
#include <string>
#include <stdlib.h>
#include <fstream>

using namespace std;

const unsigned int ImageDimension = 4;
typedef double  PixelType;
typedef itk::Image< PixelType, ImageDimension > ImageType;
typedef itk::ImageFileReader< ImageType > ReaderType;
typedef itk::ImageFileWriter< ImageType > WriterType;

ImageType::Pointer randomscaler(ImageType::Pointer inputimage, ImageType::RegionType iterregion)
{

    typedef itk::MinimumMaximumImageCalculator <ImageType>  ImageCalculatorFilterType;
    ImageCalculatorFilterType::Pointer imageCalculatorFilter = ImageCalculatorFilterType::New ();

    imageCalculatorFilter->SetImage( inputimage );
    imageCalculatorFilter->Compute();

    PixelType Imin = imageCalculatorFilter->GetMinimum();
    PixelType Imax = imageCalculatorFilter->GetMaximum();
    PixelType Omin = 0;
    PixelType Omax = 1;

    typedef itk::ImageRegionIterator< ImageType > IteratorType;
    IteratorType imageIterator(inputimage,iterregion);

    imageIterator.GoToBegin();

    std::cout << "image iterator at end?" << imageIterator.IsAtEnd() << std::endl; //gives 1 always

    while(!imageIterator.IsAtEnd())
    {
        PixelType inputPixel = imageIterator.Get();
        PixelType outputPixel = (inputPixel-Imin)*((Omax-Omin)/(Imax-Imin))+Omin;
        imageIterator.Set(outputPixel);
        ++imageIterator;
    }

    ImageType::Pointer outputimage = inputimage;

    return outputimage;
}

int main(int argc , char *argv[])
{
    if( argc < 3 )
    {
        std::cerr << "Usage: " << std::endl;
        std::cerr << argv[1] << " inputImageFile" << std::endl;
        std::cerr << argv[2] << " outputImageFile" << std::endl;
        return EXIT_FAILURE;
    }

    ReaderType::Pointer reader = ReaderType::New();

    reader->SetFileName(argv[1]);
    reader->Update();

    ImageType::Pointer image = reader->GetOutput();
    ImageType::RegionType region = image->GetLargestPossibleRegion();
    ImageType::SizeType size = region.GetSize();

    ImageType::IndexType volumestart;
    volumestart = image->GetLargestPossibleRegion().GetIndex();

    int nrofloops = size[ImageDimension-1];

    size[ImageDimension-1] = 0;

    region.SetSize(size);

    ImageType::Pointer scaledImage;
    scaledImage = image;

    for(int i=0; i < nrofloops; i++)
    {
        volumestart[ImageDimension-1] = i;
        region.SetIndex(volumestart);
        scaledImage = randomscaler(scaledImage, region);
    }

    return 0;
}