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
|
/*=========================================================================
*
* 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.
*
*=========================================================================*/
#ifndef itkSobelEdgeDetectionImageFilter_hxx
#define itkSobelEdgeDetectionImageFilter_hxx
#include "itkSobelEdgeDetectionImageFilter.h"
#include "itkNeighborhoodOperatorImageFilter.h"
#include "itkSobelOperator.h"
#include "itkNaryAddImageFilter.h"
#include "itkMultiplyImageFilter.h"
#include "itkSqrtImageFilter.h"
namespace itk
{
template< typename TInputImage, typename TOutputImage >
void
SobelEdgeDetectionImageFilter< TInputImage, TOutputImage >
::GenerateInputRequestedRegion()
{
// call the superclass' implementation of this method. this should
// copy the output requested region to the input requested region
Superclass::GenerateInputRequestedRegion();
// get pointers to the input and output
InputImagePointer inputPtr =
const_cast< TInputImage * >( this->GetInput() );
if ( !inputPtr )
{
return;
}
// Build an operator so that we can determine the kernel size
SobelOperator< OutputPixelType, ImageDimension > oper;
oper.CreateDirectional();
// get a copy of the input requested region (should equal the output
// requested region)
typename TInputImage::RegionType inputRequestedRegion;
inputRequestedRegion = inputPtr->GetRequestedRegion();
// pad the input requested region by the operator radius
inputRequestedRegion.PadByRadius( oper.GetRadius() );
// crop the input requested region at the input's largest possible region
if ( inputRequestedRegion.Crop( inputPtr->GetLargestPossibleRegion() ) )
{
inputPtr->SetRequestedRegion(inputRequestedRegion);
return;
}
else
{
// Couldn't crop the region (requested region is outside the largest
// possible region). Throw an exception.
// store what we tried to request (prior to trying to crop)
inputPtr->SetRequestedRegion(inputRequestedRegion);
// build an exception
InvalidRequestedRegionError e(__FILE__, __LINE__);
e.SetLocation(ITK_LOCATION);
e.SetDescription("Requested region is (at least partially) outside the largest possible region.");
e.SetDataObject(inputPtr);
throw e;
}
}
template< typename TInputImage, typename TOutputImage >
void
SobelEdgeDetectionImageFilter< TInputImage, TOutputImage >
::GenerateData()
{
// Test whether the output pixel type (or its components) are not of type
// float or double:
if ( NumericTraits< OutputPixelType >::is_integer )
{
itkWarningMacro("Output pixel type MUST be float or double to prevent computational errors");
}
// Define the filter types used.
typedef NeighborhoodOperatorImageFilter< InputImageType,
OutputImageType > OpFilter;
typedef MultiplyImageFilter< OutputImageType,
OutputImageType,
OutputImageType > MultFilter;
typedef NaryAddImageFilter< OutputImageType, OutputImageType > AddFilter;
typedef SqrtImageFilter< OutputImageType, OutputImageType > SqrtFilter;
unsigned int i;
typename TOutputImage::Pointer output = this->GetOutput();
output->SetBufferedRegion( output->GetRequestedRegion() );
output->Allocate();
// Create the sobel operator
SobelOperator< OutputPixelType, ImageDimension > opers[ImageDimension];
ZeroFluxNeumannBoundaryCondition< TInputImage > nbc;
// Setup mini-pipelines along each axis.
typename OpFilter::Pointer opFilter[ImageDimension];
typename MultFilter::Pointer multFilter[ImageDimension];
typename AddFilter::Pointer addFilter = AddFilter::New();
typename SqrtFilter::Pointer sqrtFilter = SqrtFilter::New();
for ( i = 0; i < ImageDimension; ++i )
{
// Create the filters for this axis.
opFilter[i] = OpFilter::New();
multFilter[i] = MultFilter::New();
// Set boundary condition and operator for this axis.
opers[i].SetDirection(i);
opers[i].CreateDirectional();
opFilter[i]->OverrideBoundaryCondition(&nbc);
opFilter[i]->SetOperator(opers[i]);
// Setup the mini-pipeline for this axis.
opFilter[i]->SetInput( this->GetInput() );
multFilter[i]->SetInput1( opFilter[i]->GetOutput() );
multFilter[i]->SetInput2( opFilter[i]->GetOutput() );
// All axes' mini-pipelines come together in addFilter.
addFilter->SetInput( i, multFilter[i]->GetOutput() );
}
// calculate the gradient magnitude
sqrtFilter->SetInput( addFilter->GetOutput() );
// setup the mini-pipeline to calculate the correct regions and
// write to the appropriate bulk data block
sqrtFilter->GraftOutput( this->GetOutput() );
// execute the mini-pipeline
sqrtFilter->Update();
// graft the mini-pipeline output back onto this filter's output.
// this is needed to get the appropriate regions passed back.
this->GraftOutput( sqrtFilter->GetOutput() );
}
} // end namespace itk
#endif
|
