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# vigra/labelimage.hxx

    00001 /************************************************************************/
    00002 /*                                                                      */
    00003 /*               Copyright 1998-2002 by Ullrich Koethe                  */
    00004 /*       Cognitive Systems Group, University of Hamburg, Germany        */
    00005 /*                                                                      */
    00006 /*    This file is part of the VIGRA computer vision library.           */
    00007 /*    ( Version 1.6.0, Aug 13 2008 )                                    */
    00008 /*    The VIGRA Website is                                              */
    00009 /*        http://kogs-www.informatik.uni-hamburg.de/~koethe/vigra/      */
    00010 /*    Please direct questions, bug reports, and contributions to        */
    00011 /*        ullrich.koethe@iwr.uni-heidelberg.de    or                    */
    00012 /*        vigra@informatik.uni-hamburg.de                               */
    00013 /*                                                                      */
    00014 /*    Permission is hereby granted, free of charge, to any person       */
    00015 /*    obtaining a copy of this software and associated documentation    */
    00016 /*    files (the "Software"), to deal in the Software without           */
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    00019 /*    sell copies of the Software, and to permit persons to whom the    */
    00020 /*    Software is furnished to do so, subject to the following          */
    00021 /*    conditions:                                                       */
    00022 /*                                                                      */
    00023 /*    The above copyright notice and this permission notice shall be    */
    00024 /*    included in all copies or substantial portions of the             */
    00025 /*    Software.                                                         */
    00026 /*                                                                      */
    00027 /*    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND    */
    00028 /*    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES   */
    00029 /*    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND          */
    00030 /*    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT       */
    00031 /*    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,      */
    00032 /*    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING      */
    00033 /*    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR     */
    00034 /*    OTHER DEALINGS IN THE SOFTWARE.                                   */
    00035 /*                                                                      */
    00036 /************************************************************************/
    00037
    00038
    00039 #ifndef VIGRA_LABELIMAGE_HXX
    00040 #define VIGRA_LABELIMAGE_HXX
    00041
    00042 #include <vector>
    00043 #include <functional>
    00044 #include "utilities.hxx"
    00045 #include "stdimage.hxx"
    00046
    00047 namespace vigra {
    00048
    00049 /** \addtogroup Labeling Connected Components Labeling
    00050      The 2-dimensional connected components algorithms may use either 4 or 8 connectivity.
    00051      By means of a functor the merge criterium can be defined arbitrarily.
    00052 */
    00053 //@{
    00054
    00055 /********************************************************/
    00056 /*                                                      */
    00057 /*                        labelImage                    */
    00058 /*                                                      */
    00059 /********************************************************/
    00060
    00061 /** \brief Find the connected components of a segmented image.
    00062
    00063     <b> Declarations:</b>
    00064
    00065     pass arguments explicitly:
    00066     \code
    00067     namespace vigra {
    00068         template <class SrcIterator, class SrcAccessor,
    00069                   class DestIterator, class DestAccessor>
    00070         unsigned int labelImage(SrcIterator upperlefts,
    00071                                 SrcIterator lowerrights, SrcAccessor sa,
    00072                                 DestIterator upperleftd, DestAccessor da,
    00073                                 bool eight_neighbors);
    00074
    00075         template <class SrcIterator, class SrcAccessor,
    00076                   class DestIterator, class DestAccessor,
    00077                   class EqualityFunctor>
    00078         unsigned int labelImage(SrcIterator upperlefts,
    00079                                 SrcIterator lowerrights, SrcAccessor sa,
    00080                                 DestIterator upperleftd, DestAccessor da,
    00081                                 bool eight_neighbors, EqualityFunctor equal);
    00082     }
    00083     \endcode
    00084
    00085     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00086     \code
    00087     namespace vigra {
    00088         template <class SrcIterator, class SrcAccessor,
    00089                   class DestIterator, class DestAccessor>
    00090         unsigned int labelImage(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00091                                 pair<DestIterator, DestAccessor> dest,
    00092                                 bool eight_neighbors);
    00093
    00094         template <class SrcIterator, class SrcAccessor,
    00095                   class DestIterator, class DestAccessor,
    00096                   class EqualityFunctor>
    00097         unsigned int labelImage(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00098                                 pair<DestIterator, DestAccessor> dest,
    00099                                 bool eight_neighbors, EqualityFunctor equal)
    00100     }
    00101     \endcode
    00102
    00103     Connected components are defined as regions with uniform pixel
    00104     values. Thus, <TT>SrcAccessor::value_type</TT> either must be
    00105     equality comparable (first form), or an EqualityFunctor must be
    00106     provided that realizes the desired predicate (second form). The
    00107     destination's value type should be large enough to hold the labels
    00108     without overflow. Region numbers will be a consecutive sequence
    00109     starting with one and ending with the region number returned by
    00110     the function (inclusive). The parameter '<TT>eight_neighbors</TT>'
    00111     determines whether the regions should be 4-connected or
    00112     8-connected. The function uses accessors.
    00113
    00114     Return:  the number of regions found (= largest region label)
    00115
    00116     <b> Usage:</b>
    00117
    00118         <b>\#include</b> <<a href="labelimage_8hxx-source.html">vigra/labelimage.hxx</a>><br>
    00119     Namespace: vigra
    00120
    00121     \code
    00122     vigra::BImage src(w,h);
    00123     vigra::IImage labels(w,h);
    00124
    00125     // threshold at 128
    00126     vigra::transformImage(srcImageRange(src), destImage(src),
    00127        vigra::Threshold<vigra::BImage::PixelType, vigra::BImage::PixelType>(
    00128                                                     128, 256, 0, 255));
    00129
    00130     // find 4-connected regions
    00131     vigra::labelImage(srcImageRange(src), destImage(labels), false);
    00132     \endcode
    00133
    00134     <b> Required Interface:</b>
    00135
    00136     \code
    00137     SrcImageIterator src_upperleft, src_lowerright;
    00138     DestImageIterator dest_upperleft;
    00139
    00140     SrcAccessor src_accessor;
    00141     DestAccessor dest_accessor;
    00142
    00143     SrcAccessor::value_type u = src_accessor(src_upperleft);
    00144
    00145     u == u                  // first form
    00146
    00147     EqualityFunctor equal;      // second form
    00148     equal(u, u)                 // second form
    00149
    00150     int i;
    00151     dest_accessor.set(i, dest_upperleft);
    00152     \endcode
    00153
    00154 */
    00155 doxygen_overloaded_function(template <...> unsigned int labelImage)
    00156
    00157 template <class SrcIterator, class SrcAccessor,
    00158           class DestIterator, class DestAccessor,
    00159           class EqualityFunctor>
    00160 unsigned int labelImage(SrcIterator upperlefts,
    00161                         SrcIterator lowerrights, SrcAccessor sa,
    00162                         DestIterator upperleftd, DestAccessor da,
    00163                         bool eight_neighbors, EqualityFunctor equal)
    00164 {
    00165     int w = lowerrights.x - upperlefts.x;
    00166     int h = lowerrights.y - upperlefts.y;
    00167     int x,y,i;
    00168
    00169     static const Diff2D neighbor[] = {
    00170         Diff2D(-1,0),  // left
    00171         Diff2D(-1,-1), // topleft
    00172         Diff2D(0,-1),  // top
    00173         Diff2D(1,-1)   // topright
    00174     };
    00175
    00176     static const int left = 0, /* unused:  topleft = 1, */ top = 2, topright = 3;
    00177     int step = eight_neighbors ? 1 : 2;
    00178
    00179     SrcIterator ys(upperlefts);
    00180     SrcIterator xs(ys);
    00181
    00182     // temporary image to store region labels
    00183     IImage labelimage(w, h);
    00184
    00185     IImage::Iterator yt = labelimage.upperLeft();
    00186     IImage::Iterator xt(yt);
    00187
    00188     // Kovalevsky's clever idea to use
    00189     // image iterator and scan order iterator simultaneously
    00190     IImage::ScanOrderIterator label = labelimage.begin();
    00191
    00192     // pass 1: scan image from upper left to lower right
    00193     // to find connected components
    00194
    00195     // Each component will be represented by a tree of pixels. Each
    00196     // pixel contains the scan order address of its parent in the
    00197     // tree.  In order for pass 2 to work correctly, the parent must
    00198     // always have a smaller scan order address than the child.
    00199     // Therefore, we can merge trees only at their roots, because the
    00200     // root of the combined tree must have the smallest scan order
    00201     // address among all the tree's pixels/ nodes.  The root of each
    00202     // tree is distinguished by pointing to itself (it contains its
    00203     // own scan order address). This condition is enforced whenever a
    00204     // new region is found or two regions are merged
    00205
    00206
    00207     for(y = 0; y != h; ++y, ++ys.y, ++yt.y)
    00208     {
    00209         xs = ys;
    00210         xt = yt;
    00211
    00212         int endNeighbor = (y == 0) ? left : (eight_neighbors ? topright : top);
    00213
    00214         for(x = 0; x != w; ++x, ++xs.x, ++xt.x)
    00215         {
    00216             int beginNeighbor = (x == 0) ? top : left;
    00217             if(x == w-1 && endNeighbor == topright) endNeighbor = top;
    00218
    00219             for(i=beginNeighbor; i<=endNeighbor; i+=step)
    00220             {
    00221                 if(equal(sa(xs), sa(xs, neighbor[i])))
    00222                 {
    00223                     int neighborLabel = xt[neighbor[i]];
    00224
    00225                     for(int j=i+2; j<=endNeighbor; j+=step)
    00226                     {
    00227                         if(equal(sa(xs), sa(xs, neighbor[j])))
    00228                         {
    00229                             int neighborLabel1 = xt[neighbor[j]];
    00230
    00231                             if(neighborLabel != neighborLabel1)
    00232                             {
    00233                                 // find roots of the region trees
    00234                                 while(neighborLabel != label[neighborLabel])
    00235                                 {
    00236                                     neighborLabel = label[neighborLabel];
    00237                                 }
    00238                                 while(neighborLabel1 != label[neighborLabel1])
    00239                                 {
    00240                                     neighborLabel1 = label[neighborLabel1];
    00241                                 }
    00242
    00243                                 // merge the trees
    00244                                 if(neighborLabel1 < neighborLabel)
    00245                                 {
    00246                                     label[neighborLabel] = neighborLabel1;
    00247                                     neighborLabel = neighborLabel1;
    00248                                 }
    00249                                 else if(neighborLabel < neighborLabel1)
    00250                                 {
    00251                                     label[neighborLabel1] = neighborLabel;
    00252                                 }
    00253                             }
    00254                             break;
    00255                         }
    00256                     }
    00257                     *xt = neighborLabel;
    00258                     break;
    00259                 }
    00260
    00261             }
    00262             if(i > endNeighbor)
    00263             {
    00264                 // new region
    00265                 // The initial label of a new region equals the
    00266                 // scan order address of it's first pixel.
    00267                 // This is essential for correct operation of the algorithm.
    00268                 *xt = x + y*w;
    00269             }
    00270         }
    00271     }
    00272
    00273     // pass 2: assign one label to each region (tree)
    00274     // so that labels form a consecutive sequence 1, 2, ...
    00275     DestIterator yd(upperleftd);
    00276
    00277     unsigned int count = 0;
    00278     i = 0;
    00279     for(y=0; y != h; ++y, ++yd.y)
    00280     {
    00281         DestIterator xd(yd);
    00282         for(x = 0; x != w; ++x, ++xd.x, ++i)
    00283         {
    00284             if(label[i] == i)
    00285             {
    00286                 label[i] = ++count;
    00287             }
    00288             else
    00289             {
    00290                 label[i] = label[label[i]];
    00291             }
    00292             da.set(label[i], xd);
    00293         }
    00294     }
    00295     return count;
    00296 }
    00297
    00298 template <class SrcIterator, class SrcAccessor,
    00299           class DestIterator, class DestAccessor,
    00300           class EqualityFunctor>
    00301 inline
    00302 unsigned int labelImage(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00303                         pair<DestIterator, DestAccessor> dest,
    00304                         bool eight_neighbors, EqualityFunctor equal)
    00305 {
    00306     return labelImage(src.first, src.second, src.third,
    00307                       dest.first, dest.second, eight_neighbors, equal);
    00308 }
    00309
    00310 template <class SrcIterator, class SrcAccessor,
    00311           class DestIterator, class DestAccessor>
    00312 inline
    00313 unsigned int labelImage(SrcIterator upperlefts,
    00314                         SrcIterator lowerrights, SrcAccessor sa,
    00315                         DestIterator upperleftd, DestAccessor da,
    00316                         bool eight_neighbors)
    00317 {
    00318     return labelImage(upperlefts, lowerrights, sa,
    00319                  upperleftd, da, eight_neighbors,
    00320                  std::equal_to<typename SrcAccessor::value_type>());
    00321 }
    00322
    00323 template <class SrcIterator, class SrcAccessor,
    00324           class DestIterator, class DestAccessor>
    00325 inline
    00326 unsigned int labelImage(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00327                         pair<DestIterator, DestAccessor> dest,
    00328                         bool eight_neighbors)
    00329 {
    00330     return labelImage(src.first, src.second, src.third,
    00331                  dest.first, dest.second, eight_neighbors,
    00332                  std::equal_to<typename SrcAccessor::value_type>());
    00333 }
    00334
    00335 /********************************************************/
    00336 /*                                                      */
    00337 /*             labelImageWithBackground                 */
    00338 /*                                                      */
    00339 /********************************************************/
    00340
    00341 /** \brief Find the connected components of a segmented image,
    00342     excluding the background from labeling.
    00343
    00344     <b> Declarations:</b>
    00345
    00346     pass arguments explicitly:
    00347     \code
    00348     namespace vigra {
    00349         template <class SrcIterator, class SrcAccessor,
    00350                   class DestIterator, class DestAccessor,
    00351                   class ValueType>
    00352         int labelImageWithBackground(SrcIterator upperlefts,
    00353                        SrcIterator lowerrights, SrcAccessor sa,
    00354                        DestIterator upperleftd, DestAccessor da,
    00355                        bool eight_neighbors,
    00356                        ValueType background_value );
    00357
    00358         template <class SrcIterator, class SrcAccessor,
    00359                   class DestIterator, class DestAccessor,
    00360                   class ValueType, class EqualityFunctor>
    00361         int labelImageWithBackground(SrcIterator upperlefts,
    00362                        SrcIterator lowerrights, SrcAccessor sa,
    00363                        DestIterator upperleftd, DestAccessor da,
    00364                        bool eight_neighbors,
    00365                        ValueType background_value, EqualityFunctor equal);
    00366     }
    00367     \endcode
    00368
    00369     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00370     \code
    00371     namespace vigra {
    00372         template <class SrcIterator, class SrcAccessor,
    00373                   class DestIterator, class DestAccessor,
    00374                   class ValueType>
    00375         int labelImageWithBackground(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00376                                      pair<DestIterator, DestAccessor> dest,
    00377                                      bool eight_neighbors,
    00378                                      ValueType background_value);
    00379
    00380         template <class SrcIterator, class SrcAccessor,
    00381                   class DestIterator, class DestAccessor,
    00382                   class ValueType, class EqualityFunctor>
    00383         int labelImageWithBackground(triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00384                                      pair<DestIterator, DestAccessor> dest,
    00385                                      bool eight_neighbors,
    00386                                      ValueType background_value, EqualityFunctor equal);
    00387     }
    00388     \endcode
    00389
    00390     Connected components are defined as regions with uniform pixel
    00391     values. Thus, <TT>SrcAccessor::value_type</TT> either must be
    00392     equality comparable (first form), or an EqualityFunctor must be
    00393     provided that realizes the desired predicate (second form). All
    00394     pixel equal to the given '<TT>background_value</TT>' are ignored
    00395     when determining connected components and remain untouched in the
    00396     destination image and
    00397
    00398     The destination's value type should be large enough to hold the
    00399     labels without overflow. Region numbers will be a consecutive
    00400     sequence starting with one and ending with the region number
    00401     returned by the function (inclusive). The parameter
    00402     '<TT>eight_neighbors</TT>' determines whether the regions should
    00403     be 4-connected or 8-connected. The function uses accessors.
    00404
    00405     Return:  the number of regions found (= largest region label)
    00406
    00407     <b> Usage:</b>
    00408
    00409         <b>\#include</b> <<a href="labelimage_8hxx-source.html">vigra/labelimage.hxx</a>><br>
    00410     Namespace: vigra
    00411
    00412     \code
    00413     vigra::BImage src(w,h);
    00414     vigra::IImage labels(w,h);
    00415
    00416     // threshold at 128
    00417     vigra::transformImage(srcImageRange(src), destImage(src),
    00418         vigra::Threshold<vigra::BImage::PixelType, vigra::BImage::PixelType>(
    00419                                                     128, 256, 0, 255));
    00420
    00421     // find 4-connected regions of foreground (= white pixels) only
    00422     vigra::labelImageWithBackground(srcImageRange(src), destImage(labels),
    00423                              false, 0);
    00424     \endcode
    00425
    00426     <b> Required Interface:</b>
    00427
    00428     \code
    00429     SrcImageIterator src_upperleft, src_lowerright;
    00430     DestImageIterator dest_upperleft;
    00431
    00432     SrcAccessor src_accessor;
    00433     DestAccessor dest_accessor;
    00434
    00435     SrcAccessor::value_type u = src_accessor(src_upperleft);
    00436     ValueType background_value;
    00437
    00438     u == u                  // first form
    00439     u == background_value   // first form
    00440
    00441     EqualityFunctor equal;      // second form
    00442     equal(u, u)                 // second form
    00443     equal(u, background_value)  // second form
    00444
    00445     int i;
    00446     dest_accessor.set(i, dest_upperleft);
    00447     \endcode
    00448
    00449 */
    00450 doxygen_overloaded_function(template <...> unsigned int labelImageWithBackground)
    00451
    00452 template <class SrcIterator, class SrcAccessor,
    00453           class DestIterator, class DestAccessor,
    00454           class ValueType, class EqualityFunctor>
    00455 unsigned int labelImageWithBackground(
    00456     SrcIterator upperlefts,
    00457     SrcIterator lowerrights, SrcAccessor sa,
    00458     DestIterator upperleftd, DestAccessor da,
    00459     bool eight_neighbors,
    00460     ValueType background_value, EqualityFunctor equal)
    00461 {
    00462     int w = lowerrights.x - upperlefts.x;
    00463     int h = lowerrights.y - upperlefts.y;
    00464     int x,y,i;
    00465
    00466     static const Diff2D neighbor[] = {
    00467         Diff2D(-1,0),  // left
    00468         Diff2D(-1,-1), // topleft
    00469         Diff2D(0,-1),  // top
    00470         Diff2D(1,-1)   // topright
    00471     };
    00472
    00473     static const int left = 0, /* unused:  topleft = 1,*/ top = 2, topright = 3;
    00474     int step = eight_neighbors ? 1 : 2;
    00475
    00476     SrcIterator ys(upperlefts);
    00477     SrcIterator xs(ys);
    00478
    00479     // temporary image to store region labels
    00480     IImage labelimage(w, h);
    00481     IImage::ScanOrderIterator label = labelimage.begin();
    00482     IImage::Iterator yt = labelimage.upperLeft();
    00483     IImage::Iterator  xt(yt);
    00484
    00485     // pass 1: scan image from upper left to lower right
    00486     // find connected components
    00487
    00488     for(y = 0; y != h; ++y, ++ys.y, ++yt.y)
    00489     {
    00490         xs = ys;
    00491         xt = yt;
    00492
    00493         int endNeighbor = (y == 0) ? left : (eight_neighbors ? topright : top);
    00494
    00495         for(x = 0; x != w; ++x, ++xs.x, ++xt.x)
    00496         {
    00497             if(equal(sa(xs), background_value))
    00498             {
    00499                 *xt = -1;
    00500             }
    00501             else
    00502             {
    00503                 int beginNeighbor = (x == 0) ? top : left;
    00504                 if(x == w-1 && endNeighbor == topright) endNeighbor = top;
    00505
    00506                 for(i=beginNeighbor; i<=endNeighbor; i+=step)
    00507                 {
    00508                     if(equal(sa(xs), sa(xs, neighbor[i])))
    00509                     {
    00510                         int neighborLabel = xt[neighbor[i]];
    00511
    00512                         for(int j=i+2; j<=endNeighbor; j+=step)
    00513                         {
    00514                             if(equal(sa(xs), sa(xs, neighbor[j])))
    00515                             {
    00516                                 int neighborLabel1 = xt[neighbor[j]];
    00517
    00518                                 if(neighborLabel != neighborLabel1)
    00519                                 {
    00520                                     // find roots of the region trees
    00521                                     while(neighborLabel != label[neighborLabel])
    00522                                     {
    00523                                         neighborLabel = label[neighborLabel];
    00524                                     }
    00525                                     while(neighborLabel1 != label[neighborLabel1])
    00526                                     {
    00527                                         neighborLabel1 = label[neighborLabel1];
    00528                                     }
    00529
    00530                                     // merge the trees
    00531                                     if(neighborLabel1 < neighborLabel)
    00532                                     {
    00533                                         label[neighborLabel] = neighborLabel1;
    00534                                         neighborLabel = neighborLabel1;
    00535                                     }
    00536                                     else if(neighborLabel < neighborLabel1)
    00537                                     {
    00538                                         label[neighborLabel1] = neighborLabel;
    00539                                     }
    00540                                 }
    00541                                 break;
    00542                             }
    00543                         }
    00544                         *xt = neighborLabel;
    00545                         break;
    00546                     }
    00547
    00548                 }
    00549                 if(i > endNeighbor)
    00550                 {
    00551                     // new region
    00552                     // The initial label of a new region equals the
    00553                     // scan order address of it's first pixel.
    00554                     // This is essential for correct operation of the algorithm.
    00555                     *xt = x + y*w;
    00556                 }
    00557             }
    00558         }
    00559     }
    00560
    00561     // pass 2: assign contiguous labels to the regions
    00562     DestIterator yd(upperleftd);
    00563
    00564     int count = 0;
    00565     i = 0;
    00566     for(y=0; y != h; ++y, ++yd.y)
    00567     {
    00568         DestIterator xd(yd);
    00569         for(x = 0; x != w; ++x, ++xd.x, ++i)
    00570         {
    00571             if(label[i] == -1) continue;
    00572
    00573             if(label[i] == i)
    00574             {
    00575                 label[i] = count++;
    00576             }
    00577             else
    00578             {
    00579                 label[i] = label[label[i]];
    00580             }
    00581             da.set(label[i]+1, xd);
    00582         }
    00583     }
    00584
    00585     return count;
    00586 }
    00587 template <class SrcIterator, class SrcAccessor,
    00588           class DestIterator, class DestAccessor,
    00589           class ValueType, class EqualityFunctor>
    00590 inline
    00591 unsigned int labelImageWithBackground(
    00592     triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00593     pair<DestIterator, DestAccessor> dest,
    00594     bool eight_neighbors,
    00595     ValueType background_value, EqualityFunctor equal)
    00596 {
    00597     return labelImageWithBackground(src.first, src.second, src.third,
    00598                                     dest.first, dest.second,
    00599                                     eight_neighbors, background_value, equal);
    00600 }
    00601
    00602 template <class SrcIterator, class SrcAccessor,
    00603           class DestIterator, class DestAccessor,
    00604           class ValueType>
    00605 inline
    00606 unsigned int labelImageWithBackground(
    00607     triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00608     pair<DestIterator, DestAccessor> dest,
    00609     bool eight_neighbors,
    00610     ValueType background_value)
    00611 {
    00612     return labelImageWithBackground(src.first, src.second, src.third,
    00613                             dest.first, dest.second,
    00614                             eight_neighbors, background_value,
    00615                             std::equal_to<typename SrcAccessor::value_type>());
    00616 }
    00617
    00618 template <class SrcIterator, class SrcAccessor,
    00619           class DestIterator, class DestAccessor,
    00620           class ValueType>
    00621 inline
    00622 unsigned int labelImageWithBackground(
    00623     SrcIterator upperlefts,
    00624     SrcIterator lowerrights, SrcAccessor sa,
    00625     DestIterator upperleftd, DestAccessor da,
    00626     bool eight_neighbors,
    00627     ValueType background_value)
    00628 {
    00629     return labelImageWithBackground(upperlefts, lowerrights, sa,
    00630                             upperleftd, da,
    00631                             eight_neighbors, background_value,
    00632                             std::equal_to<typename SrcAccessor::value_type>());
    00633 }
    00634
    00635 /********************************************************/
    00636 /*                                                      */
    00637 /*            regionImageToCrackEdgeImage               */
    00638 /*                                                      */
    00639 /********************************************************/
    00640
    00641 /** \brief Transform a labeled image into a crack edge image.
    00642
    00643     <b> Declarations:</b>
    00644
    00645     pass arguments explicitly:
    00646     \code
    00647     namespace vigra {
    00648         template <class SrcIterator, class SrcAccessor,
    00649                   class DestIterator, class DestAccessor, class DestValue>
    00650         void regionImageToCrackEdgeImage(
    00651                        SrcIterator sul, SrcIterator slr, SrcAccessor sa,
    00652                        DestIterator dul, DestAccessor da,
    00653                        DestValue edge_marker)
    00654     }
    00655     \endcode
    00656
    00657     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00658     \code
    00659     namespace vigra {
    00660         template <class SrcIterator, class SrcAccessor,
    00661                   class DestIterator, class DestAccessor, class DestValue>
    00662         void regionImageToCrackEdgeImage(
    00663                    triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00664                    pair<DestIterator, DestAccessor> dest,
    00665                    DestValue edge_marker)
    00666     }
    00667     \endcode
    00668
    00669     This algorithm inserts border pixels (so called "crack edges")
    00670     between regions in a labeled image like this (<TT>a</TT> and
    00671     <TT>c</TT> are the original labels, and <TT>0</TT> is the value of
    00672     <TT>edge_marker</TT> and denotes the inserted edges):
    00673
    00674     \code
    00675        original image     insert zero- and one-cells
    00676
    00677                                          a 0 c c c
    00678           a c c                          a 0 0 0 c
    00679           a a c               =>         a a a 0 c
    00680           a a a                          a a a 0 0
    00681                                          a a a a a
    00682     \endcode
    00683
    00684     The algorithm assumes that the original labeled image contains
    00685     no background. Therefore, it is suitable as a post-processing
    00686     operation of \ref labelImage() or \ref seededRegionGrowing().
    00687
    00688     The destination image must be twice the size of the original
    00689     (precisely, <TT>(2*w-1)</TT> by <TT>(2*h-1)</TT> pixels). The
    00690     source value type (<TT>SrcAccessor::value-type</TT>) must be
    00691     equality-comparable.
    00692
    00693     <b> Usage:</b>
    00694
    00695         <b>\#include</b> <<a href="labelimage_8hxx-source.html">vigra/labelimage.hxx</a>><br>
    00696     Namespace: vigra
    00697
    00698     \code
    00699     vigra::BImage src(w,h);
    00700     vigra::IImage labels(w,h);
    00701     vigra::IImage cellgrid(2*w-1, 2*h-1);
    00702
    00703     // threshold at 128
    00704     vigra::transformImage(srcImageRange(src), destImage(src),
    00705        vigra::Threshold<vigra::BImage::PixelType, vigra::BImage::PixelType>(
    00706                                                     128, 256, 0, 255));
    00707
    00708     // find 4-connected regions
    00709     vigra::labelImage(srcImageRange(src), destImage(labels), false);
    00710
    00711     // create cell grid image, mark edges with 0
    00712     vigra::regionImageToCrackEdgeImage(srcImageRange(labels), destImage(cellgrid), 0);
    00713     \endcode
    00714
    00715     <b> Required Interface:</b>
    00716
    00717     \code
    00718     ImageIterator src_upperleft, src_lowerright;
    00719     ImageIterator dest_upperleft;
    00720
    00721     SrcAccessor src_accessor;
    00722     DestAccessor dest_accessor;
    00723
    00724     SrcAccessor::value_type u = src_accessor(src_upperleft);
    00725
    00726     u != u
    00727
    00728     DestValue edge_marker;
    00729     dest_accessor.set(edge_marker, dest_upperleft);
    00730     \endcode
    00731
    00732     <b> Preconditions:</b>
    00733
    00734     The destination image must have twice the size of the source:
    00735     \code
    00736     w_dest = 2 * w_src - 1
    00737     h_dest = 2 * h_src - 1
    00738     \endcode
    00739 */
    00740 doxygen_overloaded_function(template <...> void regionImageToCrackEdgeImage)
    00741
    00742 template <class SrcIterator, class SrcAccessor,
    00743           class DestIterator, class DestAccessor, class DestValue>
    00744 void regionImageToCrackEdgeImage(
    00745                SrcIterator sul, SrcIterator slr, SrcAccessor sa,
    00746                DestIterator dul, DestAccessor da,
    00747                DestValue edge_marker)
    00748 {
    00749     int w = slr.x - sul.x;
    00750     int h = slr.y - sul.y;
    00751     int x,y;
    00752
    00753     static const Diff2D right(1,0);
    00754     static const Diff2D left(-1,0);
    00755     static const Diff2D bottomright(1,1);
    00756     static const Diff2D bottom(0,1);
    00757     static const Diff2D top(0,-1);
    00758
    00759     SrcIterator iy = sul;
    00760     DestIterator dy = dul;
    00761
    00762     for(y=0; y<h-1; ++y, ++iy.y, dy.y+=2)
    00763     {
    00764         SrcIterator ix = iy;
    00765         DestIterator dx = dy;
    00766
    00767         for(x=0; x<w-1; ++x, ++ix.x, dx.x+=2)
    00768         {
    00769             da.set(sa(ix), dx);
    00770             da.set(sa(ix), dx, bottomright);
    00771
    00772             if(sa(ix, right) != sa(ix))
    00773             {
    00774                 da.set(edge_marker, dx, right);
    00775             }
    00776             else
    00777             {
    00778                 da.set(sa(ix), dx, right);
    00779             }
    00780             if(sa(ix, bottom) != sa(ix))
    00781             {
    00782                 da.set(edge_marker, dx, bottom);
    00783             }
    00784             else
    00785             {
    00786                 da.set(sa(ix), dx, bottom);
    00787             }
    00788
    00789         }
    00790
    00791         da.set(sa(ix), dx);
    00792         if(sa(ix, bottom) != sa(ix))
    00793         {
    00794             da.set(edge_marker, dx, bottom);
    00795         }
    00796         else
    00797         {
    00798             da.set(sa(ix), dx, bottom);
    00799         }
    00800     }
    00801
    00802     SrcIterator ix = iy;
    00803     DestIterator dx = dy;
    00804
    00805     for(x=0; x<w-1; ++x, ++ix.x, dx.x+=2)
    00806     {
    00807         da.set(sa(ix), dx);
    00808         if(sa(ix, right) != sa(ix))
    00809         {
    00810             da.set(edge_marker, dx, right);
    00811         }
    00812         else
    00813         {
    00814             da.set(sa(ix), dx, right);
    00815         }
    00816     }
    00817     da.set(sa(ix), dx);
    00818
    00819     dy = dul + Diff2D(1,1);
    00820
    00821     // find missing 0-cells
    00822     for(y=0; y<h-1; ++y, dy.y+=2)
    00823     {
    00824         DestIterator dx = dy;
    00825
    00826         for(x=0; x<w-1; ++x, dx.x+=2)
    00827         {
    00828             static const Diff2D dist[] = {right, top, left, bottom };
    00829
    00830             int i;
    00831             for(i=0; i<4; ++i)
    00832             {
    00833                 if(da(dx, dist[i]) == edge_marker) break;
    00834             }
    00835
    00836             if(i < 4) da.set(edge_marker, dx);
    00837         }
    00838     }
    00839 }
    00840
    00841 template <class SrcIterator, class SrcAccessor,
    00842           class DestIterator, class DestAccessor, class DestValue>
    00843 inline
    00844 void regionImageToCrackEdgeImage(
    00845            triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00846            pair<DestIterator, DestAccessor> dest,
    00847            DestValue edge_marker)
    00848 {
    00849     regionImageToCrackEdgeImage(src.first, src.second, src.third,
    00850                                         dest.first, dest.second,
    00851                                         edge_marker);
    00852 }
    00853
    00854 /********************************************************/
    00855 /*                                                      */
    00856 /*                regionImageToEdgeImage                */
    00857 /*                                                      */
    00858 /********************************************************/
    00859
    00860 /** \brief Transform a labeled image into an edge image.
    00861
    00862     <b> Declarations:</b>
    00863
    00864     pass arguments explicitly:
    00865     \code
    00866     namespace vigra {
    00867         template <class SrcIterator, class SrcAccessor,
    00868                   class DestIterator, class DestAccessor, class DestValue>
    00869         void regionImageToEdgeImage(
    00870                        SrcIterator sul, SrcIterator slr, SrcAccessor sa,
    00871                        DestIterator dul, DestAccessor da,
    00872                        DestValue edge_marker)
    00873     }
    00874     \endcode
    00875
    00876     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00877     \code
    00878     namespace vigra {
    00879         template <class SrcIterator, class SrcAccessor,
    00880                   class DestIterator, class DestAccessor, class DestValue>
    00881         void regionImageToEdgeImage(
    00882                    triple<SrcIterator, SrcIterator, SrcAccessor> src,
    00883                    pair<DestIterator, DestAccessor> dest,
    00884                    DestValue edge_marker)
    00885     }
    00886     \endcode
    00887
    00888     This algorithm marks all pixels with the given <TT>edge_marker</TT>
    00889     which belong to a different region (label) than their right or lower
    00890     neighbors:
    00891
    00892     \code
    00893        original image                     edges
    00894                                  (assuming edge_marker == 1)
    00895
    00896           a c c                            1 1 *
    00897           a a c               =>           * 1 1
    00898           a a a                            * * *
    00899     \endcode
    00900
    00901     The non-edge pixels of the destination image will not be touched.
    00902     The source value type (<TT>SrcAccessor::value-type</TT>) must be
    00903     equality-comparable.
    00904
    00905     <b> Usage:</b>
    00906
    00907         <b>\#include</b> <<a href="labelimage_8hxx-source.html">vigra/labelimage.hxx</a>><br>
    00908     Namespace: vigra
    00909
    00910     \code
    00911     vigra::BImage src(w,h);
    00912     vigra::IImage labels(w,h);
    00913     vigra::IImage edges(w, h);
    00914     edges = 255;  // init background (non-edge) to 255
    00915
    00916     // threshold at 128
    00917     vigra::transformImage(srcImageRange(src), destImage(src),
    00918       vigra::Threshold<vigra::BImage::PixelType, vigra::BImage::PixelType>(
    00919                                                     128, 256, 0, 255));
    00920
    00921     // find 4-connected regions
    00922     vigra::labelImage(srcImageRange(src), destImage(labels), false);
    00923
    00924     // create edge image, mark edges with 0
    00925     vigra::regionImageToEdgeImage(srcImageRange(labels), destImage(edges), 0);
    00926     \endcode
    00927
    00928     <b> Required Interface:</b>
    00929
    00930     \code
    00931     ImageIterator src_upperleft, src_lowerright;
    00932     ImageIterator dest_upperleft;
    00933
    00934     SrcAccessor src_accessor;
    00935     DestAccessor dest_accessor;
    00936
    00937     SrcAccessor::value_type u = src_accessor(src_upperleft);
    00938
    00939     u != u
    00940
    00941     DestValue edge_marker;
    00942     dest_accessor.set(edge_marker, dest_upperleft);
    00943     \endcode
    00944
    00945 */
    00946 doxygen_overloaded_function(template <...> void regionImageToEdgeImage)
    00947
    00948 template <class SrcIterator, class SrcAccessor,
    00949           class DestIterator, class DestAccessor, class DestValue>
    00950 void regionImageToEdgeImage(
    00951                SrcIterator sul, SrcIterator slr, SrcAccessor sa,
    00952                DestIterator dul, DestAccessor da,
    00953                DestValue edge_marker)
    00954 {
    00955     int w = slr.x - sul.x;
    00956     int h = slr.y - sul.y;
    00957     int x,y;
    00958
    00959     static const Diff2D right(1,0);
    00960     static const Diff2D left(-1,0);
    00961     static const Diff2D bottomright(1,1);
    00962     static const Diff2D bottom(0,1);
    00963     static const Diff2D top(0,-1);
    00964
    00965     SrcIterator iy = sul;
    00966     DestIterator dy = dul;
    00967
    00968     for(y=0; y<h-1; ++y, ++iy.y, ++dy.y)
    00969     {
    00970         SrcIterator ix = iy;
    00971         DestIterator dx = dy;
    00972
    00973         for(x=0; x<w-1; ++x, ++ix.x, ++dx.x)
    00974         {
    00975             if(sa(ix, right) != sa(ix))
    00976             {
    00977                 da.set(edge_marker, dx);
    00978             }
    00979             if(sa(ix, bottom) != sa(ix))
    00980             {
    00981                 da.set(edge_marker, dx);
    00982             }
    00983         }
    00984
    00985         if(sa(ix, bottom) != sa(ix))
    00986         {
    00987             da.set(edge_marker, dx);
    00988         }
    00989     }
    00990
    00991     SrcIterator ix = iy;
    00992     DestIterator dx = dy;
    00993
    00994     for(x=0; x<w-1; ++x, ++ix.x, ++dx.x)
    00995     {
    00996         if(sa(ix, right) != sa(ix))
    00997         {
    00998             da.set(edge_marker, dx);
    00999         }
    01000     }
    01001 }
    01002
    01003 template <class SrcIterator, class SrcAccessor,
    01004           class DestIterator, class DestAccessor, class DestValue>
    01005 inline
    01006 void regionImageToEdgeImage(
    01007            triple<SrcIterator, SrcIterator, SrcAccessor> src,
    01008            pair<DestIterator, DestAccessor> dest,
    01009            DestValue edge_marker)
    01010 {
    01011     regionImageToEdgeImage(src.first, src.second, src.third,
    01012                                         dest.first, dest.second,
    01013                                         edge_marker);
    01014 }
    01015
    01016 //@}
    01017
    01018 } // namespace vigra
    01019
    01020 #endif // VIGRA_LABELIMAGE_HXX

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python VIGRA 1.6.0 (13 Aug 2008)