[Insight-users] Fwd: Average of multiple image files

[Kannan U V]

Hi David,
Here is  the code I wrote to average randomly generated tiles. I get a
blank image (filled with zeros) as the averageImage. But the random images
are different. I think I am doing something wrong in

    dividendImage->SetRequestedRegion (nullFilter->GetOutput());

but I not able to figure out how.


void createAverageImage () {

  cout << "In createAverageImage()" << endl;

  ImageType::SizeType outputSize;
  outputSize[0] = 10;
  outputSize[1] = 10;

  itk::RandomImageSource<ImageType>::Pointer randomImageSource =
    itk::RandomImageSource<ImageType>::New();
  randomImageSource->SetSize(outputSize);
  AddImageFilterType::Pointer addImageFilter = AddImageFilterType::New();
  DivideImageFilterType::Pointer divideImageFilter =
DivideImageFilterType::New();
  AverageImageWriterType::Pointer averageImageWriter =
AverageImageWriterType::New();

  NullFilterType::Pointer nullFilter = NullFilterType::New();
  ImageReaderType::Pointer reader = ImageReaderType::New();
  CastFilterType::Pointer castFilter = CastFilterType::New();
  AddImageFilterType::Pointer addFilter = AddImageFilterType::New();
  AverageImageOutputFilterType::Pointer averageImageOutputFilterType =
AverageImageOutputFilterType::New();
  SumImageType::Pointer divisorImage = SumImageType::New();
  SumImageType::Pointer dividendImage = SumImageType::New();

  // Set region size of dividend and divisor images
  SumImageType::SizeType sumOutputSize;
  sumOutputSize[0] = 10;
  sumOutputSize[1] = 10;
  SumImageType::IndexType start;
  start[0] = 0;
  start[1] = 0;

  SumImageType::RegionType region;
  region.SetIndex(start);
  region.SetSize(sumOutputSize);

  // Set divisor image to total number of images
  cout << "Allocating divisorImage" << endl;
  divisorImage->SetRegions(region);
  divisorImage->Allocate();
  divisorImage->FillBuffer(10.0);

 // Set dividend image to zero
  cout << "Allocating dividendImage" << endl;
  dividendImage->SetRegions(region);
  dividendImage->Allocate();
  dividendImage->FillBuffer(0.0);

  string *imFileName = new string("");
  string outputImageDir("./imageFiles/");
  for (int iTile = 0; iTile < 10; iTile++) {
    randomImageSource->SetNumberOfThreads(iTile); // to produce non-random
results
  //for (int iTile = 0; iTile < (int) imageFileName.size(); iTile++) {
    cout << "Processing Image = " << iTile;
    stringstream ss;
    ss << iTile << ".tif";
    string *imFileName = new string("");
    imFileName->clear();
    imFileName->append(outputImageDir);
    //imFileName->append("/");
    imFileName->append("FileName");
    imFileName->append(ss.str().c_str());
    cout << ", Image name : " <<  imFileName->c_str() << endl;
    reader->SetFileName (imFileName->c_str());
    castFilter->SetInput (randomImageSource->GetOutput());
    addFilter->SetInput1 (castFilter->GetOutput());
    addFilter->SetInput2 (dividendImage);
    nullFilter->SetInput (addFilter->GetOutput());
    dividendImage->SetRequestedRegion (nullFilter->GetOutput());
    reader->Update();
    addFilter->Update();
 }

  divideImageFilter->SetInput1(dividendImage);
  divideImageFilter->SetInput2(divisorImage);

  //averageImageWriter->SetInput(divideImageFilter->GetOutput());
  averageImageOutputFilterType->SetInput (dividendImage);
  //averageImageWriter->SetInput(averageImageOutputFilterType->GetOutput());
  averageImageWriter->SetInput(dividendImage);
  string *averageImageFileName = new string("");
  averageImageFileName->clear();
  //averageImageFileName->append(outputImageDir);
  averageImageFileName->append("./");
  averageImageFileName->append("AverageImage.img");
  averageImageWriter->SetFileName (averageImageFileName->c_str());
  cout << "Average Image name : " <<  averageImageFileName->c_str() << endl;
  averageImageWriter->Update();

    nullFilter->Update();
}


On Mon, Aug 20, 2012 at 12:45 PM, David Doria <daviddoria at gmail.com> wrote:

> > Hi,
> > I want to create an average image of multiple files. I am reading all
> files
> > and create a dividend image that is a sum of all images and then use the
> > divide image filter and divide the dividend float image with a constant
> > image having pixel values equal to the number of images summed up. I am
> > having issues adding multiple images to the dividend image. Below is the
> > function I have written. I see that SetRequestedRegion is a virtual
> > function.
>
> Most functions in ITK are virtual functions :) Can you explain the
> problem you having? Or better, provide the smallest compilable,
> self-contained example of the problem. That is, rather than reading
> images from files, generate some random images programmatically and
> then call your function with them.
>
> David
>



-- 
Thanks,
Kannan
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20120824/74cb76b9/attachment.htm>