1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
|
/*
* Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
*
* This file is part of Orfeo Toolbox
*
* https://www.orfeo-toolbox.org/
*
* 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
*
* 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.
*/
#include "otbMacro.h"
#include "otbImage.h"
#include "otbImageFileReader.h"
#include "otbImageFileWriter.h"
/* Example usage:
./HarrisExample Input/ROISpot5.png Output/ROISpot5Harris.png 1.5 2 0.1
*/
// This example illustrates the use of the \doxygen{otb}{HarrisImageFilter}.
//
// The first step required to use this filter is to include its header file.
#include "otbHarrisImageToPointSetFilter.h"
#include "itkRescaleIntensityImageFilter.h"
int main(int argc, char* argv[])
{
if (argc != 6)
{
std::cerr << "Usage: " << argv[0] << " inputImageFile ";
std::cerr << " outputHarrisImageFile sigmaD sigmaI alpha" << std::endl;
return EXIT_FAILURE;
}
const char* inputFilename = argv[1];
const char* outputFilename = argv[2];
double SigmaD((double)::atof(argv[3]));
double SigmaI((double)::atof(argv[4]));
double Alpha((double)::atof(argv[5]));
using InputPixelType = float;
const unsigned int Dimension = 2;
using OutputPixelType = unsigned char;
using InputImageType = otb::Image<InputPixelType, Dimension>;
using OutputImageType = otb::Image<OutputPixelType, Dimension>;
using ReaderType = otb::ImageFileReader<InputImageType>;
// The \doxygen{otb}{HarrisImageFilter} is templated over the
// input and output image types, so we start by
// defining:
using HarrisFilterType = otb::HarrisImageFilter<InputImageType, InputImageType>;
using RescalerType = itk::RescaleIntensityImageFilter<InputImageType, OutputImageType>;
using WriterType = otb::ImageFileWriter<OutputImageType>;
ReaderType::Pointer reader = ReaderType::New();
WriterType::Pointer writer = WriterType::New();
HarrisFilterType::Pointer harris = HarrisFilterType::New();
RescalerType::Pointer rescaler = RescalerType::New();
reader->SetFileName(inputFilename);
writer->SetFileName(outputFilename);
harris->SetInput(reader->GetOutput());
// The \doxygen{otb}{HarrisImageFilter} needs some parameters to
// operate. The derivative computation is performed by a
// convolution with the derivative of a Gaussian kernel of
// variance $\sigma_D$ (derivation scale) and
// the smoothing of the image is performed by convolving with a
// Gaussian kernel of variance $\sigma_I$ (integration
// scale). This allows the computation of the following matrix:
// \begin{equation}
// \mu(\mathbf{x},\sigma_I,\sigma_D) = \sigma_D^2 g(\sigma_I)\star
// \left[\begin{array}{cc} L_x^2(\mathbf{x},\sigma_D) &
// L_xL_y(\mathbf{x},\sigma_D)\\ L_xL_y(\mathbf{x},\sigma_D)&
// L_y^2(\mathbf{x},\sigma_D) \end{array}\right]
// \end{equation}
// The output of the detector is $$det(\mu) - \alpha trace^2(\mu).$$
harris->SetSigmaD(SigmaD);
harris->SetSigmaI(SigmaI);
harris->SetAlpha(Alpha);
rescaler->SetOutputMinimum(itk::NumericTraits<OutputPixelType>::min());
rescaler->SetOutputMaximum(itk::NumericTraits<OutputPixelType>::max());
rescaler->SetInput(harris->GetOutput());
writer->SetInput(rescaler->GetOutput());
writer->Update();
// Figure~\ref{fig:Harris} shows the result of applying the interest
// point detector to a small patch extracted from a Spot 5 image.
// \begin{figure}
// \center
// \includegraphics[width=0.25\textwidth]{ROISpot5.eps}
// \includegraphics[width=0.25\textwidth]{ROISpot5Harris.eps}
// \itkcaption[Harris Filter Application]{Result of applying the
// \doxygen{otb}{HarrisImageFilter} to a Spot 5 image.}
// \label{fig:Harris}
// \end{figure}
//
// The output of the \doxygen{otb}{HarrisImageFilter} is an image
// where, for each pixel, we obtain the intensity of the
// detection. Often, the user may want to get access to the set of
// points for which the output of the detector is higher than a
// given threshold. This can be obtained by using the
// \doxygen{otb}{HarrisImageToPointSetFilter}. This filter is only
// templated over the input image type, the output being a
// \doxygen{itk}{PointSet} with pixel type equal to the image pixel type.
using FunctionType = otb::HarrisImageToPointSetFilter<InputImageType>;
// We declare now the filter and a pointer to the output point set.
using OutputPointSetType = FunctionType::OutputPointSetType;
FunctionType::Pointer harrisPoints = FunctionType::New();
OutputPointSetType::Pointer pointSet = OutputPointSetType::New();
// The \doxygen{otb}{HarrisImageToPointSetFilter} takes the same
// parameters as the \doxygen{otb}{HarrisImageFilter} and an
// additional parameter : the threshold for the point selection.
harrisPoints->SetInput(0, reader->GetOutput());
harrisPoints->SetSigmaD(SigmaD);
harrisPoints->SetSigmaI(SigmaI);
harrisPoints->SetAlpha(Alpha);
harrisPoints->SetLowerThreshold(10);
pointSet = harrisPoints->GetOutput();
harrisPoints->Update();
// We can now iterate through the obtained pointset and access
// the coordinates of the points. We start by accessing the
// container of the points which is encapsulated into the point
// set (see section \ref{sec:PointSetSection} for more
// information on using \doxygen{itk}{PointSet}s) and declaring
// an iterator to it.
using ContainerType = OutputPointSetType::PointsContainer;
ContainerType* pointsContainer = pointSet->GetPoints();
using IteratorType = ContainerType::Iterator;
IteratorType itList = pointsContainer->Begin();
// And we get the points coordinates
while (itList != pointsContainer->End())
{
using OutputPointType = OutputPointSetType::PointType;
OutputPointType pCoordinate = (itList.Value());
otbLogMacro(Debug, << pCoordinate);
++itList;
}
return EXIT_SUCCESS;
}
|
