ITK  4.6.0
Insight Segmentation and Registration Toolkit
Filtering/CannyEdgeDetectionImageFilter.cxx
/*=========================================================================
*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
// Software Guide : BeginLatex
//
// This example introduces the use of the
// \doxygen{CannyEdgeDetectionImageFilter}. This filter is widely used for
// edge detection since it is the optimal solution satisfying the constraints
// of good sensitivity, localization and noise robustness.
//
// \index{itk::CannyEdgeDetectionImageFilter|textbf}
//
// Software Guide : EndLatex
// Software Guide : BeginLatex
//
// The first step required for using this filter is to include its header file
//
// \index{itk::CannyEdgeDetectionImageFilter!header}
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
// Software Guide : EndCodeSnippet
int main(int argc, char* argv[])
{
if( argc < 3 )
{
std::cerr << "Usage: " << std::endl;
std::cerr << argv[0] << " inputImage outputImage [variance upperThreshold lowerThreshold]" << std::endl;
return EXIT_FAILURE;
}
const char * inputFilename = argv[1];
const char * outputFilename = argv[2];
float variance = 2.0;
float upperThreshold = 0.0;
float lowerThreshold = 0.0;
if( argc > 3 )
{
variance = atof( argv[3] );
}
if( argc > 4 )
{
upperThreshold = atof( argv[4] );
}
if( argc > 5 )
{
lowerThreshold = atof( argv[5] );
}
std::cout << "Variance = " << variance << std::endl;
std::cout << "UpperThreshold = " << upperThreshold << std::endl;
std::cout << "LowerThreshold = " << lowerThreshold << std::endl;
typedef unsigned char CharPixelType; // IO
typedef double RealPixelType; // Operations
const unsigned int Dimension = 2;
typedef itk::Image<CharPixelType, Dimension> CharImageType;
typedef itk::Image<RealPixelType, Dimension> RealImageType;
// Software Guide : BeginLatex
//
// This filter operates on image of pixel type float. It is then necessary
// to cast the type of the input images that are usually of integer type.
// The \doxygen{CastImageFilter} is used here for that purpose. Its image
// template parameters are defined for casting from the input type to the
// float type using for processing.
//
// Software Guide : EndLatex
// Software Guide : BeginCodeSnippet
CastToRealFilterType;
// Software Guide : EndCodeSnippet
// Software Guide : BeginLatex
//
// The \doxygen{CannyEdgeDetectionImageFilter} is instantiated using the float image type.
//
// \index{itk::CannyEdgeDetectionImageFilter|textbf}
//
// Software Guide : EndLatex
//Setting the IO
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
CastToRealFilterType::Pointer toReal = CastToRealFilterType::New();
RescaleFilter::Pointer rescale = RescaleFilter::New();
//Setting the ITK pipeline filter
CannyFilter::Pointer cannyFilter = CannyFilter::New();
reader->SetFileName( inputFilename );
writer->SetFileName( outputFilename );
//The output of an edge filter is 0 or 1
rescale->SetOutputMinimum( 0 );
rescale->SetOutputMaximum( 255 );
toReal->SetInput( reader->GetOutput() );
cannyFilter->SetInput( toReal->GetOutput() );
cannyFilter->SetVariance( variance );
cannyFilter->SetUpperThreshold( upperThreshold );
cannyFilter->SetLowerThreshold( lowerThreshold );
rescale->SetInput( cannyFilter->GetOutput() );
writer->SetInput( rescale->GetOutput() );
try
{
writer->Update();
}
catch( itk::ExceptionObject & err )
{
std::cout << "ExceptionObject caught !" << std::endl;
std::cout << err << std::endl;
return EXIT_FAILURE;
}
return EXIT_SUCCESS;
}