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/*=========================================================================
Program: ORFEO Toolbox
Language: C++
Date: $Date$
Version: $Revision$
Copyright (c) Centre National d'Etudes Spatiales. All rights reserved.
See OTBCopyright.txt for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#ifndef otbImageToEdgePathFilter_txx
#define otbImageToEdgePathFilter_txx
#include "otbImageToEdgePathFilter.h"
#include "otbMacro.h"
#include "itkConstantPadImageFilter.h"
#include "itkConstShapedNeighborhoodIterator.h"
#include "itkImageRegionConstIteratorWithIndex.h"
namespace otb
{
/*
* Constructor.
*/
template <class TInputImage, class TOutputPath>
ImageToEdgePathFilter<TInputImage, TOutputPath>
::ImageToEdgePathFilter()
{
m_ForegroundValue = PixelType(255);
}
/**
* Main computation method.
*/
template <class TInputImage, class TOutputPath>
void
ImageToEdgePathFilter<TInputImage, TOutputPath>
::GenerateData(void)
{
const InputImageType * inputImage = this->GetInput();
OutputPathType * outputPath = this->GetOutput();
otbMsgDebugMacro(<< "Foreground value : " << m_ForegroundValue);
PixelType initPadConstant(0);
if (initPadConstant == m_ForegroundValue)
{
initPadConstant = 1;
}
typedef itk::ConstantPadImageFilter<InputImageType, InputImageType> PadFilterType;
typedef itk::ConstShapedNeighborhoodIterator<InputImageType> IteratorType;
typedef itk::ImageRegionConstIteratorWithIndex<InputImageType> LinearIteratorType;
// Padding to deal with near the border objects.
typename PadFilterType::Pointer pad = PadFilterType::New();
pad->SetInput(inputImage);
pad->SetConstant(initPadConstant);
SizeType padSize;
padSize[ 0 ] = 1;
padSize[ 1 ] = 1;
pad->SetPadUpperBound(padSize);
pad->SetPadLowerBound(padSize);
pad->Update();
// Iterate on the image to get a starting point
LinearIteratorType linIter(pad->GetOutput(), pad->GetOutput()->GetLargestPossibleRegion());
linIter.GoToBegin();
bool flag = true;
while (flag && !linIter.IsAtEnd())
{
if (linIter.Get() == m_ForegroundValue)
{
flag = false;
}
else
{
++linIter;
}
}
typename InputImageType::IndexType start = linIter.GetIndex();
// outputPath->AddVertex(start);
// Neighborhood definition
typename IteratorType::RadiusType radius;
radius.Fill(1);
IteratorType it(radius, pad->GetOutput(), pad->GetOutput()->GetLargestPossibleRegion());
const typename IteratorType::OffsetType LEFT = {{-1, 0}};
const typename IteratorType::OffsetType RIGHT = {{1, 0}};
const typename IteratorType::OffsetType UP = {{0, -1}};
const typename IteratorType::OffsetType DOWN = {{0, 1}};
const typename IteratorType::OffsetType LEFTUP = {{-1, -1}};
const typename IteratorType::OffsetType RIGHTDOWN = {{1, 1}};
const typename IteratorType::OffsetType RIGHTUP = {{1, -1}};
const typename IteratorType::OffsetType LEFTDOWN = {{-1, 1}};
const typename IteratorType::OffsetType CENTER = {{0, 0}};
it.ClearActiveList();
it.ActivateOffset(LEFT);
it.ActivateOffset(RIGHT);
it.ActivateOffset(UP);
it.ActivateOffset(DOWN);
it.ActivateOffset(CENTER);
it.ActivateOffset(RIGHTUP);
it.ActivateOffset(RIGHTDOWN);
it.ActivateOffset(LEFTUP);
it.ActivateOffset(LEFTDOWN);
// The rotation vector allows getting the clock-wise next pixel
std::vector<typename IteratorType::OffsetType> rotation;
rotation.push_back(RIGHT);
rotation.push_back(RIGHTDOWN);
rotation.push_back(DOWN);
rotation.push_back(LEFTDOWN);
rotation.push_back(LEFT);
rotation.push_back(LEFTUP);
rotation.push_back(UP);
rotation.push_back(RIGHTUP);
// Set up the iterator
it.SetLocation(start);
ContinuousIndexType newVertex = it.GetIndex(CENTER);
if (it.GetPixel(RIGHT) == m_ForegroundValue) newVertex[0] -= 0.5;
if (it.GetPixel(LEFT) == m_ForegroundValue) newVertex[0] += 0.5;
if (it.GetPixel(UP) == m_ForegroundValue) newVertex[1] += 0.5;
if (it.GetPixel(DOWN) == m_ForegroundValue) newVertex[1] -= 0.5;
outputPath->AddVertex(newVertex);
otbMsgDebugMacro(<< "START: " << start);
// stopping flag
flag = true;
int nbMove = 0;
// nexstart gives a clue of where to begin searching in next step of the search
int nextStart = 0;
// While the search has not eended
while (flag)
{
// move is used to walk the neighnorhood clock-wise
int move = nextStart;
// edgeFound indicate that the edge has been found.
bool EdgeFound = false;
// LastWasPositive indicate whether the previous pixel belong to the object or not
bool LastWasPositive(false);
// While unexplored pixels remain and no edge was found
while ((move < nextStart + 8) && (!EdgeFound))
{
//otbMsgDevMacro(<<"SEARCH: "<<move%8<<" "<<it.GetPixel(rotation[move%8])<<" LAST: "<<LastWasPositive);
// If last pixel was not in the object and the current is, we have found the edge
if ((!LastWasPositive) && (it.GetPixel(rotation[move % 8]) == m_ForegroundValue))
{
EdgeFound = true;
}
else
{
// Else goes on
LastWasPositive = (it.GetPixel(rotation[move % 8]) == m_ForegroundValue);
move++;
}
}
// Once the search has been completed, if an edge pixel was found
if (EdgeFound)
{
// Update the output path
it += rotation[move % 8];
nextStart = (move + 5) % 8;
newVertex = it.GetIndex(CENTER);
if (it.GetPixel(RIGHT) == m_ForegroundValue) newVertex[0] -= 0.5;
if (it.GetPixel(LEFT) == m_ForegroundValue) newVertex[0] += 0.5;
if (it.GetPixel(UP) == m_ForegroundValue) newVertex[1] += 0.5;
if (it.GetPixel(DOWN) == m_ForegroundValue) newVertex[1] -= 0.5;
outputPath->AddVertex(newVertex);
otbMsgDebugMacro(<< newVertex);
// If we came back to our start point after a sufficient number of moves
if ((it.GetIndex(CENTER) == start) && (nbMove >= 2))
{
// search end
flag = false;
}
else
{
// else
for (int i = 0; i < 8; ++i)
{
// If we came back near our starting pointer after a sufficient number of moves
if ((it.GetIndex(rotation[i]) == start) && (nbMove >= 2))
{
// search end
flag = false;
}
}
}
}
// else
else
{
// search ended, no pixel can be added to the edge path.
flag = false;
}
nbMove++;
}
}
template <class TInputImage, class TOutputPath>
void
ImageToEdgePathFilter<TInputImage, TOutputPath>
::PrintSelf(std::ostream& os, itk::Indent indent) const
{
Superclass::PrintSelf(os, indent);
os << "Foreground value : " << m_ForegroundValue << std::endl;
}
} // end namespace otb
#endif
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