[Insight-users] About Hough Circle Filter and PNG file

[Jiangtao Li]

Hi, all,

For this topic, I need to say that this is the problem of my BMP file which
is Black circle with While white outside, so when using Hough Filter, please
make sure that Intensity values of Feature parts should above the value of
outside part.


Regards!

Jiangtao Li


2010/5/10 Luis Ibanez <luis.ibanez at kitware.com>

> Hi Jiangtao,
>
> Thanks for sharing your findings.
>
> Hoever, they seen quite strange.
>
> The Hough filter works with an image of scalars,
> so your conversion from RGBA is changing some
> secondary characteristic of the image.
>
> Can you please post that input image in a public
> web site ?
>
> We need to look at the image in order to figure
> out the source of the problem,
>
>
>      Thanks
>
>
>            Luis
>
>
> --------------------------------------------------
> On Wed, May 5, 2010 at 12:00 AM, Jiangtao Li <nelfylee at gmail.com> wrote:
> > Dear All,
> >
> > When I use below code to save sampled image as a PNG file (RGBA), and
> then
> > read it again, the Hough Circle Filter works!
> > I found Hough Filter only support the image pixel has 4 components, well,
> if
> > so, I will change my image to 4 components first,
> > I change it back to Gray image by RGBToLuminanceImageFilter for Hough
> > filter, however, Hough filter gives wrong result again.
> >
> > typedef itk::Image<itk::RGBAPixel<unsigned char>> RGBAImage;
> > typedef itk::ComposeRGBAImageFilter<ImageUChar2D, RGBAImage>
> > ComposeRGBAImageFilter;
> > ComposeRGBAImageFilter::Pointer rgba = ComposeRGBAImageFilter::New();
> >   rgba->SetInput(0, resampler->GetOutput());
> > rgba->SetInput(1, resampler->GetOutput());
> > rgba->SetInput(2, resampler->GetOutput());
> > rgba->SetInput(3, dup->GetOutput());
> >   rgba->Update();
> > // typedef itk::ImageFileWriter<RGBAImage> ImageFileWriter2;
> > // ImageFileWriter2::Pointer writer = ImageFileWriter2::New();
> > // writer->SetInput(rgba->GetOutput());
> > // writer->SetFileName("E:/Resample.png");
> > // writer->Update();
> > // typedef itk::ImageFileReader<ImageUChar2D> ImageFileReader;
> > // ImageFileReader::Pointer reader = ImageFileReader::New();
> > // reader->SetFileName("E:/Resample.png");
> > // reader->Update();
> > typedef itk::RGBToLuminanceImageFilter<RGBAImage, ImageUChar2D>
> > RGBToLuminanceImageFilter;
> > RGBToLuminanceImageFilter::Pointer rgba2gray =
> > RGBToLuminanceImageFilter::New();
> > rgba2gray->SetInput(rgba->GetOutput());
> > rgba2gray->Update();
> > typedef itk::HoughTransform2DCirclesImageFilter<unsigned char, float>
> > HoughTransformFilterType;
> > HoughTransformFilterType::Pointer hough =
> HoughTransformFilterType::New();
> > hough->SetInput(rgba2gray->GetOutput());
> > hough->SetNumberOfCircles(1);
> > hough->SetMinimumRadius(10);
> > hough->SetMaximumRadius(300);
> > hough->SetVariance(5);
> > hough->SetSigmaGradient(1);
> > hough->SetDiscRadiusRatio(2);
> > hough->Update();
> >
> >
> > Any ideas? I really need your help. thank you very much !
> >
> > Best Regards!
> >
> >
> > Jiangtao
> > --
> > From Jiangtao Li @ Seoul National University
> >
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