[Insight-users] Tif RGB wrong way around?

[Lorensen, William E (Research)]

BMP is definitely writing the bytes out in the incorrect order. I'm fixing
it now...

-----Original Message-----
From: John Biddiscombe [mailto:jbiddiscombe at skippingmouse.co.uk]
Sent: Wednesday, July 21, 2004 8:43 AM
To: Lorensen, William E (Research); Julien Jomier; insight-users at itk.org
Subject: Re: [Insight-users] Tif RGB wrong way around?


The tiff import is much improved, however the attached images are the
original and the result of
tiffimageio->bmpWriter

The RGB at least coming through OK, but the RGB are again BGR. This can
easily be rectified in itkTIFFImageIO by changing
    red = *(source);
    green = *(source+1);
    blue = *(source+2);
to
    red = *(source+2);
    green = *(source+1);
    blue = *(source+0);
though this may not be the correct fix and perhaps the convertRGBAtoRGB
should have a new one like convertABGRtoRGB since it seems the RGBA are
stored the other way around in the tiff stream (?)

anyway, the attached images could be made into a unit test for RGB Import
Export. The test image contains the characters R,G,B written on the image
colour planes and so its easy to see when they are messed up.

Test code

typedef itk::RGBPixel<unsigned char> RGBPixelType2D;
typedef itk::Image< RGBPixelType2D, 2 > ImageRGB2DType;
typedef itk::ImageFileReader< ImageRGB2DType > ReaderType;
ReaderType::Pointer reader = ReaderType::New();
//
reader->SetFileName( filename );
//
try
{
  reader->Update();
}
catch( itk::ExceptionObject & err )
{
  std::cout << "ExceptionObject caught !" << std::endl;
  std::cout << err << std::endl;
  return NULL;
}
typedef itk::ImageFileWriter< ImageRGB2DType > WriterType;
WriterType::Pointer writer = WriterType::New();
//
writer->SetFileName("D:/Test.bmp");
writer->SetInput(reader->GetOutput());
writer->Update();

JB


----- Original Message ----- 
From: "Lorensen, William E (Research)" <lorensen at crd.ge.com>
To: "'John Biddiscombe'" <jbiddiscombe at skippingmouse.co.uk>; "Julien Jomier"
<jjomier at cs.unc.edu>; <insight-users at itk.org>
Sent: Monday, July 19, 2004 9:51 PM
Subject: RE: [Insight-users] Tif RGB wrong way around?


> We have found the problem. Nothing in the tiff stuff. It was a problem (a
> couple actually) in the ConvertBuffer code. There still are some issues
> regarding the handling of alpha channels, but I've checked in the changes
to
> fix the color problems.
>
> Bill
>
> -----Original Message-----
> From: John Biddiscombe [mailto:jbiddiscombe at skippingmouse.co.uk]
> Sent: Friday, July 09, 2004 11:03 AM
> To: John Biddiscombe; Julien Jomier; insight-users at itk.org
> Subject: Re: [Insight-users] Tif RGB wrong way around?
>
>
> After doing some digging I became convinced that there is nothing wrong
with
> the itk->vtk RGB pixels and so I tried exporting my TIFF as bmp using the
> following code. The exported Bitmap has RGB components the wrong way
around.
>
> I'm therefore reasonably confident that the TIFF reader is messing about.
>
> I'll modify my local version to give what I hope will be the correct
images
> and post a patch should anyone else have trouble.
>
> JB
>
>
> typedef itk::ImageFileReader< ImageTypeRGB2D > ReaderType;
> ReaderType::Pointer reader = ReaderType::New();
> //
> reader->SetFileName( filename );
> //
> try
> {
> reader->Update();
> }
> catch( itk::ExceptionObject & err )
> {
> std::cout << "ExceptionObject caught !" << std::endl;
> std::cout << err << std::endl;
> return NULL;
> }
> typedef itk::ImageFileWriter< ImageTypeRGB2D > WriterType;
> WriterType::Pointer writer = WriterType::New();
> //
> writer->SetFileName("D:/Test.bmp");
> writer->SetInput(reader->GetOutput());
> writer->Update();
> return reader->GetOutput();
>
>
> ----- Original Message ----- 
> From: "John Biddiscombe" <jbiddiscombe at skippingmouse.co.uk>
> To: "Julien Jomier" <jjomier at cs.unc.edu>; <insight-users at itk.org>
> Sent: Thursday, July 08, 2004 6:59 PM
> Subject: Re: [Insight-users] Tif RGB wrong way around?
>
>
> > Thanks. I should have thought of trying that! I'll look for a mistake in
> my
> > code somewhere.
> >
> > JB
> >
> > ----- Original Message ----- 
> > From: "Julien Jomier" <jjomier at cs.unc.edu>
> > To: "'John Biddiscombe'" <jbiddiscombe at skippingmouse.co.uk>;
> > <insight-users at itk.org>
> > Sent: Thursday, July 08, 2004 6:47 PM
> > Subject: RE: [Insight-users] Tif RGB wrong way around?
> >
> >
> > Hi John,
> >
> > I just tried to read a RGB tiff image and write it as JPEG and BMP using
> ITK
> > and the resulting image appears to be valid so I guess the channels are
in
> > the correct order when reading the file.
> >
> > Hope this helps,
> >
> > Julien
> >
> > > -----Original Message-----
> > > From: insight-users-bounces at itk.org
> > > [mailto:insight-users-bounces at itk.org] On Behalf Of John Biddiscombe
> > > Sent: Thursday, July 08, 2004 12:56 PM
> > > To: insight-users at itk.org
> > > Subject: [Insight-users] Tif RGB wrong way around?
> > >
> > >
> > > I've connected itk::TiffImageIO to a vtk pipeline and found that when
> > > reading RGB colour images the data looks as though its GBR
> > > instead of RGB.
> > > Red and blue channels swapped. I notice that the Tif test in
> > > testing/code/io
> > > uses a black and white image with R=G=B channels so this wouldn't be
> > > spotted.
> > >
> > > Can anyone else easily check if TiffImageIO is getting R and
> > > B the wrong way
> > > around? It might be me passing the data into vtk, but since I'm using
> > > SetImportVoidPointer directly and not modifying the actual
> > > pixels, it should
> > > be the same as when it was read.
> > >
> > > thanks
> > >
> > > JB
> > >
> > > _______________________________________________
> > > Insight-users mailing list
> > > Insight-users at itk.org
> > > http://www.itk.org/mailman/listinfo/insight-users
> > >
> >
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