ITK  6.0.0
Insight Toolkit
itkFrequencyShiftedFFTLayoutImageRegionConstIteratorWithIndex.h
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1/*=========================================================================
2 *
3 * Copyright NumFOCUS
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 * https://www.apache.org/licenses/LICENSE-2.0.txt
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 *
17 *=========================================================================*/
18#ifndef itkFrequencyShiftedFFTLayoutImageRegionConstIteratorWithIndex_h
19#define itkFrequencyShiftedFFTLayoutImageRegionConstIteratorWithIndex_h
20
22
23namespace itk
24{
114template <typename TImage>
116 : public ImageRegionConstIteratorWithIndex<TImage>
117{
118public:
119
123
125 using typename Superclass::IndexType;
126 using typename Superclass::SizeType;
127 using typename Superclass::OffsetType;
128 using typename Superclass::RegionType;
129 using typename Superclass::ImageType;
130 using typename Superclass::PixelContainer;
132 using typename Superclass::InternalPixelType;
133 using typename Superclass::PixelType;
134 using typename Superclass::AccessorType;
135
136 using FrequencyType = typename ImageType::SpacingType;
137 using FrequencyValueType = typename ImageType::SpacingValueType;
141 {
142 this->Init();
143 }
144
148 : ImageRegionConstIteratorWithIndex<TImage>(ptr, region)
149 {
150 this->Init();
151 }
152
161 {
162 this->Init();
163 }
164
165 /*
166 * Image Index [0, N - 1] returns [-N/2 + 1, -1] (negative) union [0 to N/2] (positive). So index N/2 + 1 returns the
167 * bin 0. It is a shift by -N/2 + 1, from [0, N-1] to [-N/2 + 1, N/2] If first index of the image is not zero, it
168 * stills returns values in the same range.
169 */
172 {
173 IndexType freqInd{};
174 for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
175 {
176 freqInd[dim] = this->m_PositionIndex[dim] - this->m_ZeroFrequencyIndex[dim];
177 }
178 return freqInd;
179 }
180
191 FrequencyType
193 {
194 FrequencyType freq;
195 IndexType freqInd = this->GetFrequencyBin();
198 for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
199 {
200 freq[dim] = this->m_FrequencyOrigin[dim] + this->m_FrequencySpacing[dim] * freqInd[dim];
201 }
202 return freq;
203 }
204
205 FrequencyValueType
207 {
208 FrequencyValueType w2(0);
209 FrequencyType w(this->GetFrequency());
210
211 for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
212 {
213 w2 += w[dim] * w[dim];
214 }
215 return w2;
216 }
217
224 itkGetConstReferenceMacro(ZeroFrequencyIndex, IndexType);
225
227 itkGetConstReferenceMacro(FrequencyOrigin, FrequencyType);
228
235 itkGetConstReferenceMacro(FrequencySpacing, FrequencyType);
236
239 void
241 {
242 this->m_ActualXDimensionIsOdd = value;
243 }
244 itkGetMacro(ActualXDimensionIsOdd, bool);
245 itkBooleanMacro(ActualXDimensionIsOdd);
248private:
251 void
253 {
254 IndexType minIndex = this->m_Image->GetLargestPossibleRegion().GetIndex();
255 SizeType sizeImage = this->m_Image->GetLargestPossibleRegion().GetSize();
256 for (unsigned int dim = 0; dim < ImageType::ImageDimension; ++dim)
257 {
258 this->m_ZeroFrequencyIndex[dim] =
259 static_cast<FrequencyValueType>(minIndex[dim] + std::floor(sizeImage[dim] / 2.0));
260 // Set frequency metadata.
261 // Origin of frequencies is zero in the standard layout of a FFT output.
262 this->m_FrequencyOrigin[dim] = 0.0;
263 // SamplingFrequency = 1.0 / SpatialImageSpacing
264 // Freq_BinSize = SamplingFrequency / Size
265 this->m_FrequencySpacing[dim] = 1.0 / (this->m_Image->GetSpacing()[dim] * sizeImage[dim]);
266 }
267 }
274};
275} // end namespace itk
276#endif
A multi-dimensional iterator templated over image type that walks pixels within a region and is speci...
A base class for multi-dimensional iterators templated over image type that are designed to efficient...
typename PixelContainer::Pointer PixelContainerPointer
typename TImage::InternalPixelType InternalPixelType
typename TImage::PixelContainer PixelContainer
A multi-dimensional iterator templated over image type that walks an image region and is specialized ...
The "itk" namespace contains all Insight Segmentation and Registration Toolkit (ITK) classes....