[Insight-users] Fwd: reading jpg files

[Jie Zhu]

I added reader->update() and it worked. Thanks.

Jie


On Wed, 15 Sep 2004 15:49:50 -0600 (MDT), Joshua Cates
<cates at sci.utah.edu> wrote:
> Hello Jie,
> 
> In this code you are never calling Update on the
> image file reader so you are iterating through
> an uninitialized image (of arbitrary values).  See
> Section 4.1.2 of the ITK Software Guide
> (www.itk.org/ItkSoftwareGuide.pdf) for more detailed
> information on file readers.
> 
> hope this helps,
> 
> Josh.
> ----------------
> Josh Cates
> Scientific Computing and Imaging Institute
> University of Utah
> http://www.sci.utah.edu/~cates
> 
> 
> 
> 
> On Wed, 15 Sep 2004, Jie Zhu wrote:
> 
> > Hi All,
> > I am new to itk, and I need to use it with JPEG files. I wrote a
> > simple program putting the jpeg file in  image and tested to see if
> > image.GetPixel() returns the correct value of the pixels. But the
> > result I get looks like:
> > 205
> > 205
> > 205
> > 205
> > ...
> > Although the input image have a variety of pixel values, the pixel
> > values GetPixel() return are all 205 or "=" if I dont convert it to
> > (int). Can somebody please help me and tell me what I'm doing wrong.
> > Thank you.
> > Jie
> >
> > Below is the code
> > -------------------------------------------------------------------------------------------------------------
> >  typedef itk::Image<unsigned char,2>            ImageType;
> >
> >  typedef itk::ImageFileReader< ImageType >  ReaderType;
> >
> >  ReaderType::Pointer reader = ReaderType::New();
> >
> >  const char * inputFilename  = argv[1];
> >  const char * outputFilename = argv[2];
> >
> >  reader->SetFileName( inputFilename  );
> >  writer->SetFileName( outputFilename );
> >
> >  ImageType::Pointer image = reader->GetOutput();
> >
> >  //set regions in input image
> >  ImageType::RegionType region;
> >  ImageType::RegionType::SizeType size;
> >  ImageType::RegionType::IndexType index;;
> >  index[ 0 ] = 0;
> >  index[ 1 ] = 0;
> >  size[ 0 ] = 255;
> >  size[ 1 ] = 255;
> >
> >  region.SetSize( size );
> >  region.SetIndex( index );
> >
> >  image->SetRegions( region );
> >  image->Allocate();
> >
> >  //creat linear iterators
> >  //typedef itk::ImageRegionConstIterator< ImageType > ConstIteratorType;
> >
> >  typedef itk::ImageLinearConstIteratorWithIndex< ImageType >
> > ConstIteratorType;
> >  ConstIteratorType inputIt( image, image->GetRequestedRegion() );
> >  inputIt.SetDirection(0);
> >
> >   //iteration
> >  for ( inputIt.GoToBegin(); ! inputIt.IsAtEnd();
> >         inputIt.NextLine())
> >    {
> >    inputIt.GoToBeginOfLine();
> >    while ( ! inputIt.IsAtEndOfLine() )
> >      {
> >      ImageType::PixelType   pixelValue = image->GetPixel( indx );
> >      std::cout<<(int)pixelValue<<" "<<std::endl;
> >       ++inputIt;
> >
> >      }
> >    }
> >
> > --
> > Jie Zhu
> > Cornell University
> >
> >
> >
> >
> > --
> > Jie Zhu
> > Cornell University
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >
> 
> 



-- 
Jie Zhu
Cornell University