[8f0f49]: src / foreign / vigra / symmetry.hxx Maximize Restore History

Download this file

symmetry.hxx    266 lines (214 with data), 9.6 kB

  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
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
/************************************************************************/
/* */
/* Copyright 1998-2002 by Ullrich Koethe */
/* Cognitive Systems Group, University of Hamburg, Germany */
/* */
/* This file is part of the VIGRA computer vision library. */
/* ( Version 1.4.0, Dec 21 2005 ) */
/* The VIGRA Website is */
/* http://kogs-www.informatik.uni-hamburg.de/~koethe/vigra/ */
/* Please direct questions, bug reports, and contributions to */
/* koethe@informatik.uni-hamburg.de or */
/* vigra@kogs1.informatik.uni-hamburg.de */
/* */
/* Permission is hereby granted, free of charge, to any person */
/* obtaining a copy of this software and associated documentation */
/* files (the "Software"), to deal in the Software without */
/* restriction, including without limitation the rights to use, */
/* copy, modify, merge, publish, distribute, sublicense, and/or */
/* sell copies of the Software, and to permit persons to whom the */
/* Software is furnished to do so, subject to the following */
/* conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the */
/* Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES */
/* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND */
/* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT */
/* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, */
/* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING */
/* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR */
/* OTHER DEALINGS IN THE SOFTWARE. */
/* */
/************************************************************************/
#ifndef VIGRA_SYMMETRY_HXX
#define VIGRA_SYMMETRY_HXX
#include <vigra/utilities.hxx>
#include <vigra/numerictraits.hxx>
#include <vigra/stdimage.hxx>
#include <vigra/convolution.hxx>
namespace vigra {
/** \addtogroup SymmetryDetection Symmetry Detection
Measure the local symmetry at each pixel.
*/
//@{
/********************************************************/
/* */
/* radialSymmetryTransform */
/* */
/********************************************************/
/** \brief Find centers of radial symmetry in an image.
This algorithm implements the Fast Radial Symmetry Transform according to
[G. Loy, A. Zelinsky: <em> "A Fast Radial Symmetry Transform for Detecting
Points of Interest"</em>, in: A. Heyden et al. (Eds.): Proc. of 7th European
Conf. on Computer Vision, Part 1, pp. 358-368, Springer LNCS 2350, 2002].
Minima of the algorithm response mark dark blobs, maxima correspond to light blobs.
The "radial strictness parameter" is fixed at <TT>alpha</tt> = 2.0, the
spatial spreading of the raw response is done by a Gaussian convolution
at <tt>0.25*scale</TT> (these values are recommendations from the paper).
Loy and Zelinsky additionally propose to add the operator response from several
scales (see usage example below).
<b> Declarations:</b>
pass arguments explicitly:
\code
namespace vigra {
template <class SrcIterator, class SrcAccessor,
class DestIterator, class DestAccessor>
void
radialSymmetryTransform(SrcIterator sul, SrcIterator slr, SrcAccessor as,
DestIterator dul, DestAccessor ad,
double scale)
}
\endcode
use argument objects in conjunction with \ref ArgumentObjectFactories:
\code
namespace vigra {
template <class SrcIterator, class SrcAccessor,
class DestIterator, class DestAccessor>
inline
void radialSymmetryTransform(
triple<SrcIterator, SrcIterator, SrcAccessor> src,
pair<DestIterator, DestAccessor> dest,
double scale)
}
\endcode
<b> Usage:</b>
<b>\#include</b> "<a href="symmetry_8hxx-source.html">vigra/symmetry.hxx</a>"<br>
Namespace: vigra
\code
vigra::BImage src(w,h), centers(w,h);
vigra::FImage symmetry(w,h);
// empty result image
centers.init(128);
symmetry.init(0.0);
// input width of edge detection filter
for(double scale = 2.0; scale <= 8.0; scale *= 2.0)
{
vigra::FImage tmp(w,h);
// find centers of symmetry
radialSymmetryTransform(srcImageRange(src), destImage(tmp), scale);
combineTwoImages(srcImageRange(symmetry), srcImage(tmp), destImage(symmetry),
std::plus<float>());
}
localMinima(srcImageRange(symmetry), destImage(centers), 0);
localMaxima(srcImageRange(symmetry), destImage(centers), 255);
\endcode
<b> Required Interface:</b>
\code
SrcImageIterator src_upperleft, src_lowerright;
DestImageIterator dest_upperleft;
SrcAccessor src_accessor;
DestAccessor dest_accessor;
// SrcAccessor::value_type must be a built-in type
SrcAccessor::value_type u = src_accessor(src_upperleft);
dest_accessor.set(u, dest_upperleft);
\endcode
*/
template <class SrcIterator, class SrcAccessor,
class DestIterator, class DestAccessor>
void
radialSymmetryTransform(SrcIterator sul, SrcIterator slr, SrcAccessor as,
DestIterator dul, DestAccessor ad,
double scale)
{
vigra_precondition(scale > 0.0,
"radialSymmetryTransform(): Scale must be > 0");
int w = slr.x - sul.x;
int h = slr.y - sul.y;
if(w <= 0 || h <= 0) return;
typedef typename
NumericTraits<typename SrcAccessor::value_type>::RealPromote TmpType;
typedef BasicImage<TmpType> TmpImage;
typedef typename TmpImage::Iterator TmpIterator;
TmpImage gx(w,h);
TmpImage gy(w,h);
IImage orientationCounter(w,h);
TmpImage magnitudeAccumulator(w,h);
gaussianGradient(srcIterRange(sul, slr, as),
destImage(gx), destImage(gy),
scale);
orientationCounter.init(0);
magnitudeAccumulator.init(NumericTraits<TmpType>::zero());
TmpIterator gxi = gx.upperLeft();
TmpIterator gyi = gy.upperLeft();
int y;
for(y=0; y<h; ++y, ++gxi.y, ++gyi.y)
{
typename TmpIterator::row_iterator gxr = gxi.rowIterator();
typename TmpIterator::row_iterator gyr = gyi.rowIterator();
for(int x = 0; x<w; ++x, ++gxr, ++gyr)
{
double angle = VIGRA_CSTD::atan2(-*gyr, *gxr);
double magnitude = VIGRA_CSTD::sqrt(*gxr * *gxr + *gyr * *gyr);
if(magnitude < NumericTraits<TmpType>::epsilon()*10.0)
continue;
int dx = NumericTraits<int>::fromRealPromote(scale * VIGRA_CSTD::cos(angle));
int dy = NumericTraits<int>::fromRealPromote(scale * VIGRA_CSTD::sin(angle));
int xx = x + dx;
int yy = y - dy;
if(xx >= 0 && xx < w && yy >= 0 && yy < h)
{
orientationCounter(xx, yy) += 1;
magnitudeAccumulator(xx, yy) += magnitude;
}
xx = x - dx;
yy = y + dy;
if(xx >= 0 && xx < w && yy >= 0 && yy < h)
{
orientationCounter(xx, yy) -= 1;
magnitudeAccumulator(xx, yy) -= magnitude;
}
}
}
int maxOrientation = 0;
TmpType maxMagnitude = NumericTraits<TmpType>::zero();
for(y=0; y<h; ++y)
{
for(int x = 0; x<w; ++x)
{
int o = VIGRA_CSTD::abs(orientationCounter(x,y));
if(o > maxOrientation)
maxOrientation = o;
TmpType m = VIGRA_CSTD::abs(magnitudeAccumulator(x,y));
if(m > maxMagnitude)
maxMagnitude = m;
}
}
for(y=0; y<h; ++y)
{
for(int x = 0; x<w; ++x)
{
double o = (double)orientationCounter(x, y) / maxOrientation;
magnitudeAccumulator(x, y) = o * o * magnitudeAccumulator(x, y) / maxMagnitude;
}
}
gaussianSmoothing(srcImageRange(magnitudeAccumulator), destIter(dul, ad), 0.25*scale);
}
template <class SrcIterator, class SrcAccessor,
class DestIterator, class DestAccessor>
inline
void radialSymmetryTransform(
triple<SrcIterator, SrcIterator, SrcAccessor> src,
pair<DestIterator, DestAccessor> dest,
double scale)
{
radialSymmetryTransform(src.first, src.second, src.third,
dest.first, dest.second,
scale);
}
//@}
} // namespace vigra
#endif /* VIGRA_SYMMETRY_HXX */