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# vigra/labelvolume.hxx

    00001 /************************************************************************/
    00002 /*                                                                      */
    00003 /*     Copyright 2006-2007 by F. Heinrich, B. Seppke, 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    */
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    00021 /*    conditions:                                                       */
    00022 /*                                                                      */
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    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       */
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    00035 /*                                                                      */
    00036 /************************************************************************/
    00037
    00038 #ifndef VIGRA_LABELVOLUME_HXX
    00039 #define VIGRA_LABELVOLUME_HXX
    00040
    00041
    00042 #include "voxelneighborhood.hxx"
    00043 #include "multi_array.hxx"
    00044
    00045 namespace vigra{
    00046
    00047 /** \addtogroup Labeling Connected Components Labeling
    00048      The 3-dimensional connected components algorithms may use either 6 or 26 connectivity.
    00049      By means of a functor the merge criterium can be defined arbitrarily.
    00050 */
    00051 //@{
    00052
    00053 /********************************************************/
    00054 /*                                                      */
    00055 /*                        labelVolume                   */
    00056 /*                                                      */
    00057 /********************************************************/
    00058
    00059 /** \brief Find the connected components of a segmented volume.
    00060
    00061     <b> Declarations:</b>
    00062
    00063     pass arguments explicitly:
    00064     \code
    00065     namespace vigra {
    00066
    00067         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00068                   class DestIterator, class DestAccessor,
    00069                   class Neighborhood3D>
    00070         unsigned int labelVolume(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00071                                  DestIterator d_Iter, DestAccessor da,
    00072                                  Neighborhood3D neighborhood3D);
    00073
    00074         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00075                           class DestIterator, class DestAccessor,
    00076                           class Neighborhood3D, class EqualityFunctor>
    00077         unsigned int labelVolume(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00078                                  DestIterator d_Iter, DestAccessor da,
    00079                                  Neighborhood3D neighborhood3D, EqualityFunctor equal);
    00080
    00081     }
    00082     \endcode
    00083
    00084     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00085     \code
    00086     namespace vigra {
    00087
    00088         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00089                   class DestIterator, class DestAccessor,
    00090                   class Neighborhood3D>
    00091         unsigned int labelVolume(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00092                                  pair<DestIterator, DestAccessor> dest,
    00093                                  Neighborhood3D neighborhood3D);
    00094
    00095         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00096                  class DestIterator, class DestAccessor,
    00097                  class Neighborhood3D, class EqualityFunctor>
    00098         unsigned int labelVolume(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00099                                  pair<DestIterator, DestAccessor> dest,
    00100                                  Neighborhood3D neighborhood3D, EqualityFunctor equal);
    00101
    00102     }
    00103     \endcode
    00104
    00105     use with 3D-Six-Neighborhood:
    00106     \code
    00107     namespace vigra {
    00108
    00109         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00110                   class DestIterator, class DestAccessor>
    00111         unsigned int labelVolumeSix(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00112                                     pair<DestIterator, DestAccessor> dest);
    00113
    00114     }
    00115     \endcode
    00116
    00117     Connected components are defined as regions with uniform voxel
    00118     values. Thus, <TT>SrcAccessor::value_type</TT> either must be
    00119     equality comparable (first form), or an EqualityFunctor must be
    00120     provided that realizes the desired predicate (second form). The
    00121     destination's value type should be large enough to hold the labels
    00122     without overflow. Region numbers will be a consecutive sequence
    00123     starting with one and ending with the region number returned by
    00124     the function (inclusive).
    00125
    00126     Return:  the number of regions found (= largest region label)
    00127
    00128     <b> Usage:</b>
    00129
    00130     <b>\#include</b> <<a href="labelvolume_8hxx-source.html">vigra/labelvolume.hxx</a>><br>
    00131     Namespace: vigra
    00132
    00133     \code
    00134     typedef vigra::MultiArray<3,int> IntVolume;
    00135     IntVolume src(IntVolume::difference_type(w,h,d));
    00136     IntVolume dest(IntVolume::difference_type(w,h,d));
    00137
    00138     // find 6-connected regions
    00139     int max_region_label = vigra::labelVolumeSix(srcMultiArrayRange(src), destMultiArray(dest));
    00140
    00141     // find 26-connected regions
    00142     int max_region_label = vigra::labelVolume(srcMultiArrayRange(src), destMultiArray(dest), NeighborCode3DTwentySix());
    00143     \endcode
    00144
    00145     <b> Required Interface:</b>
    00146
    00147     \code
    00148     SrcIterator src_begin;
    00149     SrcShape shape;
    00150     DestIterator dest_begin;
    00151
    00152     SrcAccessor src_accessor;
    00153     DestAccessor dest_accessor;
    00154
    00155     SrcAccessor::value_type u = src_accessor(src_begin);
    00156
    00157     u == u                      // first form
    00158
    00159     EqualityFunctor equal;      // second form
    00160     equal(u, u)                 // second form
    00161
    00162     int i;
    00163     dest_accessor.set(i, dest_begin);
    00164     \endcode
    00165
    00166 */
    00167 doxygen_overloaded_function(template <...> unsigned int labelVolume)
    00168
    00169 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00170           class DestIterator, class DestAccessor,
    00171           class Neighborhood3D>
    00172 unsigned int labelVolume(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00173                          DestIterator d_Iter, DestAccessor da,
    00174                          Neighborhood3D neighborhood3D)
    00175 {
    00176         return labelVolume(s_Iter, srcShape, sa, d_Iter, da, neighborhood3D, std::equal_to<typename SrcAccessor::value_type>());
    00177 }
    00178
    00179 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00180           class DestIterator, class DestAccessor,
    00181           class Neighborhood3D>
    00182 unsigned int labelVolume(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00183                          pair<DestIterator, DestAccessor> dest,
    00184                          Neighborhood3D neighborhood3D)
    00185 {
    00186     return labelVolume(src.first, src.second, src.third, dest.first, dest.second, neighborhood3D, std::equal_to<typename SrcAccessor::value_type>());
    00187 }
    00188
    00189 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00190           class DestIterator, class DestAccessor,
    00191           class Neighborhood3D, class EqualityFunctor>
    00192 unsigned int labelVolume(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00193                          pair<DestIterator, DestAccessor> dest,
    00194                          Neighborhood3D neighborhood3D, EqualityFunctor equal)
    00195 {
    00196     return labelVolume(src.first, src.second, src.third, dest.first, dest.second, neighborhood3D, equal);
    00197 }
    00198
    00199 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00200           class DestIterator, class DestAccessor,
    00201           class Neighborhood3D, class EqualityFunctor>
    00202 unsigned int labelVolume(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00203                          DestIterator d_Iter, DestAccessor da,
    00204                          Neighborhood3D, EqualityFunctor equal)
    00205 {
    00206
    00207     //basically needed for iteration and border-checks
    00208     int w = srcShape[0], h = srcShape[1], d = srcShape[2];
    00209     int x,y,z, i;
    00210
    00211     //declare and define Iterators for all three dims at src
    00212     SrcIterator zs = s_Iter;
    00213     SrcIterator ys(zs);
    00214     SrcIterator xs(ys);
    00215
    00216     // temporary image to store region labels
    00217     typedef vigra::MultiArray<3,int> LabelVolume;
    00218     typedef LabelVolume::traverser LabelTraverser;
    00219
    00220     LabelVolume labelvolume(srcShape);
    00221
    00222     //Declare traversers for all three dims at target
    00223     LabelTraverser zt = labelvolume.traverser_begin();
    00224     LabelTraverser yt(zt);
    00225     LabelTraverser xt(yt);
    00226
    00227     // Kovalevsky's clever idea to use
    00228     // image iterator and scan order iterator simultaneously
    00229     // memory order indicates label
    00230     LabelVolume::iterator label = labelvolume.begin();
    00231
    00232     // initialize the neighborhood traversers
    00233
    00234 #if 0
    00235     NeighborOffsetTraverser<Neighborhood3D> nc(Neighborhood3D::CausalFirst);
    00236     NeighborOffsetTraverser<Neighborhood3D> nce(Neighborhood3D::CausalLast);
    00237 #endif /* #if 0 */
    00238
    00239     NeighborOffsetCirculator<Neighborhood3D> nc(Neighborhood3D::CausalFirst);
    00240     NeighborOffsetCirculator<Neighborhood3D> nce(Neighborhood3D::CausalLast);
    00241     ++nce;
    00242     // pass 1: scan image from upper left front to lower right back
    00243     // to find connected components
    00244
    00245     // Each component will be represented by a tree of pixels. Each
    00246     // pixel contains the scan order address of its parent in the
    00247     // tree.  In order for pass 2 to work correctly, the parent must
    00248     // always have a smaller scan order address than the child.
    00249     // Therefore, we can merge trees only at their roots, because the
    00250     // root of the combined tree must have the smallest scan order
    00251     // address among all the tree's pixels/ nodes.  The root of each
    00252     // tree is distinguished by pointing to itself (it contains its
    00253     // own scan order address). This condition is enforced whenever a
    00254     // new region is found or two regions are merged
    00255     i=0;
    00256     for(z = 0; z != d; ++z, ++zs.dim2(), ++zt.dim2())
    00257     {
    00258         ys = zs;
    00259         yt = zt;
    00260
    00261         for(y = 0; y != h; ++y, ++ys.dim1(), ++yt.dim1())
    00262         {
    00263             xs = ys;
    00264             xt = yt;
    00265
    00266             for(x = 0; x != w; ++x, ++xs.dim0(), ++xt.dim0(), ++i)
    00267             {
    00268                 *xt = i; // default: new region
    00269
    00270                 //queck whether there is a special borde threatment to be used or not
    00271                 AtVolumeBorder atBorder = isAtVolumeBorderCausal(x,y,z,w,h,z);
    00272
    00273                 //We are not at the border!
    00274                 if(atBorder == NotAtBorder)
    00275                 {
    00276
    00277
    00278 #if 0
    00279                     nc = NeighborOffsetTraverser<Neighborhood3D>(Neighborhood3D::CausalFirst);
    00280 #endif /* #if 0 */
    00281
    00282                     nc = NeighborOffsetCirculator<Neighborhood3D>(Neighborhood3D::CausalFirst);
    00283
    00284                     do
    00285                     {
    00286                         // if colors are equal
    00287                         if(equal(*xs, xs[*nc]))
    00288                         {
    00289                             int neighborLabel = xt[*nc];
    00290
    00291                             // find the root label of a label tree
    00292                             while(neighborLabel != label[neighborLabel])
    00293                             {
    00294                                 neighborLabel = label[neighborLabel];
    00295                             }
    00296
    00297                             if(neighborLabel < *xt) // always keep the smallest among the possible neighbor labels
    00298                             {
    00299                                 label[*xt] = neighborLabel;
    00300                                 *xt = neighborLabel;
    00301                             }
    00302                             else
    00303                             {
    00304                                 label[neighborLabel] = *xt;
    00305                             }
    00306                         }
    00307                         ++nc;
    00308                     }while(nc!=nce);
    00309                 }
    00310                 //we are at a border - handle this!!
    00311                 else
    00312                 {
    00313
    00314 #if 0
    00315                     nc = NeighborOffsetTraverser<Neighborhood3D>(Neighborhood3D::nearBorderDirectionsCausal(atBorder,0));
    00316 #endif /* #if 0 */
    00317
    00318                     nc = NeighborOffsetCirculator<Neighborhood3D>(Neighborhood3D::nearBorderDirectionsCausal(atBorder,0));
    00319                     int j=0;
    00320                     while(nc.direction() != Neighborhood3D::Error)
    00321                     {
    00322                         //   colors equal???
    00323                         if(equal(*xs, xs[*nc]))
    00324                         {
    00325                             int neighborLabel = xt[*nc];
    00326
    00327                             // find the root label of a label tree
    00328                             while(neighborLabel != label[neighborLabel])
    00329                             {
    00330                                 neighborLabel = label[neighborLabel];
    00331                             }
    00332
    00333                             if(neighborLabel < *xt) // always keep the smallest among the possible neighbor labels
    00334                             {
    00335                                 label[*xt] = neighborLabel;
    00336                                 *xt = neighborLabel;
    00337                             }
    00338                             else
    00339                             {
    00340                                 label[neighborLabel] = *xt;
    00341                             }
    00342                         }
    00343                         nc.turnTo(Neighborhood3D::nearBorderDirectionsCausal(atBorder,++j));
    00344                     }
    00345                 }
    00346             }
    00347         }
    00348     }
    00349
    00350     // pass 2: assign one label to each region (tree)
    00351     // so that labels form a consecutive sequence 1, 2, ...
    00352     DestIterator zd = d_Iter;
    00353
    00354     unsigned int count = 0;
    00355
    00356     i= 0;
    00357
    00358     for(z=0; z != d; ++z, ++zd.dim2())
    00359     {
    00360         DestIterator yd(zd);
    00361
    00362         for(y=0; y != h; ++y, ++yd.dim1())
    00363         {
    00364             DestIterator xd(yd);
    00365
    00366             for(x = 0; x != w; ++x, ++xd.dim0(), ++i)
    00367             {
    00368                 if(label[i] == i)
    00369                 {
    00370                         label[i] = count++;
    00371                 }
    00372                 else
    00373                 {
    00374                         label[i] = label[label[i]]; // compress trees
    00375                 }
    00376                 da.set(label[i]+1, xd);
    00377             }
    00378         }
    00379     }
    00380     return count;
    00381 }
    00382
    00383 /********************************************************/
    00384 /*                                                      */
    00385 /*                    labelVolumeSix                    */
    00386 /*                                                      */
    00387 /********************************************************/
    00388
    00389 /** \brief Find the connected components of a segmented volume
    00390      using the 6-neighborhood.
    00391
    00392      See \ref labelVolume() for detailed documentation.
    00393
    00394 */
    00395 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00396           class DestIterator, class DestAccessor>
    00397 unsigned int labelVolumeSix(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00398                             pair<DestIterator, DestAccessor> dest)
    00399 {
    00400     return labelVolume(src.first, src.second, src.third, dest.first, dest.second, NeighborCode3DSix(), std::equal_to<typename SrcAccessor::value_type>());
    00401 }
    00402
    00403
    00404
    00405
    00406 /********************************************************/
    00407 /*                                                      */
    00408 /*               labelVolumeWithBackground              */
    00409 /*                                                      */
    00410 /********************************************************/
    00411
    00412 /** \brief Find the connected components of a segmented volume,
    00413      excluding the background from labeling.
    00414
    00415     <b> Declarations:</b>
    00416
    00417     pass arguments explicitly:
    00418     \code
    00419     namespace vigra {
    00420
    00421         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00422                           class DestIterator, class DestAccessor,
    00423                           class Neighborhood3D, class ValueType>
    00424         unsigned int labelVolumeWithBackground(    SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00425                                                           DestIterator d_Iter, DestAccessor da,
    00426                                                           Neighborhood3D neighborhood3D, ValueType background_value);
    00427
    00428         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00429                           class DestIterator, class DestAccessor,
    00430                           class Neighborhood3D, class ValueType, class EqualityFunctor>
    00431         unsigned int labelVolumeWithBackground(    SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00432                                                             DestIterator d_Iter, DestAccessor da,
    00433                                                           Neighborhood3D neighborhood3D, ValueType background_value,
    00434                                                             EqualityFunctor equal);
    00435
    00436     }
    00437     \endcode
    00438
    00439     use argument objects in conjunction with \ref ArgumentObjectFactories :
    00440     \code
    00441     namespace vigra {
    00442
    00443         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00444                           class DestIterator, class DestAccessor,
    00445                           class Neighborhood3D, class ValueType>
    00446         unsigned int labelVolumeWithBackground(    triple<SrcIterator, SrcShape, SrcAccessor> src,
    00447                                                           pair<DestIterator, DestAccessor> dest,
    00448                                                           Neighborhood3D neighborhood3D, ValueType background_value);
    00449
    00450         template <class SrcIterator, class SrcAccessor,class SrcShape,
    00451                           class DestIterator, class DestAccessor,
    00452                           class Neighborhood3D, class ValueType, class EqualityFunctor>
    00453         unsigned int labelVolumeWithBackground(    triple<SrcIterator, SrcShape, SrcAccessor> src,
    00454                                                         pair<DestIterator, DestAccessor> dest,
    00455                                                         Neighborhood3D neighborhood3D, ValueType background_value,
    00456                                                         EqualityFunctor equal);
    00457
    00458     }
    00459     \endcode
    00460
    00461     Connected components are defined as regions with uniform voxel
    00462     values. Thus, <TT>SrcAccessor::value_type</TT> either must be
    00463     equality comparable (first form), or an EqualityFunctor must be
    00464     provided that realizes the desired predicate (second form). All
    00465     voxel equal to the given '<TT>background_value</TT>' are ignored
    00466     when determining connected components and remain untouched in the
    00467     destination volume.
    00468
    00469     The destination's value type should be large enough to hold the
    00470     labels without overflow. Region numbers will be a consecutive
    00471     sequence starting with one and ending with the region number
    00472     returned by the function (inclusive).
    00473
    00474     Return:  the number of regions found (= largest region label)
    00475
    00476     <b> Usage:</b>
    00477
    00478     <b>\#include</b> <<a href="labelvolume_8hxx-source.html">vigra/labelvolume.hxx</a>><br>
    00479     Namespace: vigra
    00480
    00481     \code
    00482     typedef vigra::MultiArray<3,int> IntVolume;
    00483     IntVolume src(IntVolume::difference_type(w,h,d));
    00484     IntVolume dest(IntVolume::difference_type(w,h,d));
    00485
    00486     // find 6-connected regions
    00487     int max_region_label = vigra::labelVolumeWithBackground(
    00488     srcMultiArrayRange(src), destMultiArray(dest), NeighborCode3DSix(), 0);
    00489     \endcode
    00490
    00491     <b> Required Interface:</b>
    00492
    00493     \code
    00494     SrcIterator src_begin;
    00495     SrcShape shape;
    00496     DestIterator dest_begin;
    00497
    00498     SrcAccessor src_accessor;
    00499     DestAccessor dest_accessor;
    00500
    00501     SrcAccessor::value_type u = src_accessor(src_begin);
    00502
    00503     u == u                      // first form
    00504
    00505     EqualityFunctor equal;      // second form
    00506     equal(u, u)                 // second form
    00507
    00508     int i;
    00509     dest_accessor.set(i, dest_begin);
    00510     \endcode
    00511
    00512 */
    00513 doxygen_overloaded_function(template <...> unsigned int labelVolumeWithBackground)
    00514
    00515 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00516           class DestIterator, class DestAccessor,
    00517           class Neighborhood3D,
    00518           class ValueType>
    00519 unsigned int labelVolumeWithBackground(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00520                                        DestIterator d_Iter, DestAccessor da,
    00521                                        Neighborhood3D neighborhood3D, ValueType backgroundValue)
    00522 {
    00523     return labelVolumeWithBackground(s_Iter, srcShape, sa, d_Iter, da, neighborhood3D, backgroundValue, std::equal_to<typename SrcAccessor::value_type>());
    00524 }
    00525
    00526 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00527           class DestIterator, class DestAccessor,
    00528           class Neighborhood3D,
    00529           class ValueType>
    00530 unsigned int labelVolumeWithBackground(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00531                                        pair<DestIterator, DestAccessor> dest,
    00532                                        Neighborhood3D neighborhood3D, ValueType backgroundValue)
    00533 {
    00534     return labelVolumeWithBackground(src.first, src.second, src.third, dest.first, dest.second, neighborhood3D, backgroundValue, std::equal_to<typename SrcAccessor::value_type>());
    00535 }
    00536
    00537 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00538           class DestIterator, class DestAccessor,
    00539           class Neighborhood3D,
    00540           class ValueType, class EqualityFunctor>
    00541 unsigned int labelVolumeWithBackground(triple<SrcIterator, SrcShape, SrcAccessor> src,
    00542                                        pair<DestIterator, DestAccessor> dest,
    00543                                        Neighborhood3D neighborhood3D, ValueType backgroundValue, EqualityFunctor equal)
    00544 {
    00545     return labelVolumeWithBackground(src.first, src.second, src.third, dest.first, dest.second, neighborhood3D, backgroundValue, equal);
    00546 }
    00547
    00548 template <class SrcIterator, class SrcAccessor,class SrcShape,
    00549           class DestIterator, class DestAccessor,
    00550           class Neighborhood3D,
    00551           class ValueType, class EqualityFunctor>
    00552 unsigned int labelVolumeWithBackground(SrcIterator s_Iter, SrcShape srcShape, SrcAccessor sa,
    00553                                        DestIterator d_Iter, DestAccessor da,
    00554                                        Neighborhood3D,
    00555                                        ValueType backgroundValue, EqualityFunctor equal)
    00556 {
    00557
    00558     //basically needed for iteration and border-checks
    00559     int w = srcShape[0], h = srcShape[1], d = srcShape[2];
    00560     int x,y,z, i;
    00561
    00562     //declare and define Iterators for all three dims at src
    00563     SrcIterator zs = s_Iter;
    00564     SrcIterator ys(zs);
    00565     SrcIterator xs(ys);
    00566
    00567     // temporary image to store region labels
    00568     typedef vigra::MultiArray<3,int> LabelVolume;
    00569     typedef LabelVolume::traverser LabelTraverser;
    00570
    00571     LabelVolume labelvolume(srcShape);
    00572
    00573     //Declare traversers for all three dims at target
    00574     LabelTraverser zt = labelvolume.traverser_begin();
    00575     LabelTraverser yt(zt);
    00576     LabelTraverser xt(yt);
    00577
    00578     // Kovalevsky's clever idea to use
    00579     // image iterator and scan order iterator simultaneously
    00580     // memory order indicates label
    00581     LabelVolume::iterator label = labelvolume.begin();
    00582
    00583     // initialize the neighborhood traversers
    00584
    00585 #if 0
    00586     NeighborOffsetTraverser<Neighborhood3D> nc(Neighborhood3D::CausalFirst);
    00587     NeighborOffsetTraverser<Neighborhood3D> nce(Neighborhood3D::CausalLast);
    00588 #endif /* #if 0 */
    00589
    00590     NeighborOffsetCirculator<Neighborhood3D> nc(Neighborhood3D::CausalFirst);
    00591     NeighborOffsetCirculator<Neighborhood3D> nce(Neighborhood3D::CausalLast);
    00592     ++nce;
    00593     // pass 1: scan image from upper left front to lower right back
    00594     // to find connected components
    00595
    00596     // Each component will be represented by a tree of pixels. Each
    00597     // pixel contains the scan order address of its parent in the
    00598     // tree.  In order for pass 2 to work correctly, the parent must
    00599     // always have a smaller scan order address than the child.
    00600     // Therefore, we can merge trees only at their roots, because the
    00601     // root of the combined tree must have the smallest scan order
    00602     // address among all the tree's pixels/ nodes.  The root of each
    00603     // tree is distinguished by pointing to itself (it contains its
    00604     // own scan order address). This condition is enforced whenever a
    00605     // new region is found or two regions are merged
    00606     i=0;
    00607     int backgroundAddress=-1;
    00608     for(z = 0; z != d; ++z, ++zs.dim2(), ++zt.dim2())
    00609     {
    00610         ys = zs;
    00611         yt = zt;
    00612
    00613         for(y = 0; y != h; ++y, ++ys.dim1(), ++yt.dim1())
    00614         {
    00615             xs = ys;
    00616             xt = yt;
    00617
    00618             for(x = 0; x != w; ++x, ++xs.dim0(), ++xt.dim0(), ++i)
    00619             {
    00620                 if(equal(*xs, backgroundValue)){
    00621                         if(backgroundAddress==-1) backgroundAddress = i;
    00622                         label[i]=backgroundAddress;
    00623                 }
    00624                 else{
    00625                     *xt = i; // default: new region
    00626
    00627                     //queck whether there is a special borde threatment to be used or not
    00628                     AtVolumeBorder atBorder = isAtVolumeBorderCausal(x,y,z,w,h,z);
    00629
    00630                     //We are not at the border!
    00631                     if(atBorder == NotAtBorder)
    00632                     {
    00633
    00634
    00635 #if 0
    00636                         nc = NeighborOffsetTraverser<Neighborhood3D>(Neighborhood3D::CausalFirst);
    00637 #endif /* #if 0 */
    00638
    00639                         nc = NeighborOffsetCirculator<Neighborhood3D>(Neighborhood3D::CausalFirst);
    00640
    00641                         do
    00642                         {
    00643                             // if colors are equal
    00644                             if(equal(*xs, xs[*nc]))
    00645                             {
    00646                                 int neighborLabel = xt[*nc];
    00647
    00648                                 // find the root label of a label tree
    00649                                 while(neighborLabel != label[neighborLabel])
    00650                                 {
    00651                                     neighborLabel = label[neighborLabel];
    00652                                 }
    00653
    00654                                 if(neighborLabel < *xt) // always keep the smallest among the possible neighbor labels
    00655                                 {
    00656                                     label[*xt] = neighborLabel;
    00657                                     *xt = neighborLabel;
    00658                                 }
    00659                                 else
    00660                                 {
    00661                                     label[neighborLabel] = *xt;
    00662                                 }
    00663                             }
    00664                             ++nc;
    00665                         }while(nc!=nce);
    00666                     }
    00667                     //we are at a border - handle this!!
    00668                     else
    00669                     {
    00670
    00671 #if 0
    00672                         nc = NeighborOffsetTraverser<Neighborhood3D>(Neighborhood3D::nearBorderDirectionsCausal(atBorder,0));
    00673 #endif /* #if 0 */
    00674
    00675                         nc = NeighborOffsetCirculator<Neighborhood3D>(Neighborhood3D::nearBorderDirectionsCausal(atBorder,0));
    00676                         int j=0;
    00677                         while(nc.direction() != Neighborhood3D::Error)
    00678                         {
    00679                             //   colors equal???
    00680                             if(equal(*xs, xs[*nc]))
    00681                             {
    00682                                 int neighborLabel = xt[*nc];
    00683
    00684                                 // find the root label of a label tree
    00685                                 while(neighborLabel != label[neighborLabel])
    00686                                 {
    00687                                     neighborLabel = label[neighborLabel];
    00688                                 }
    00689
    00690                                 if(neighborLabel < *xt) // always keep the smallest among the possible neighbor labels
    00691                                 {
    00692                                     label[*xt] = neighborLabel;
    00693                                     *xt = neighborLabel;
    00694                                 }
    00695                                 else
    00696                                 {
    00697                                     label[neighborLabel] = *xt;
    00698                                 }
    00699                             }
    00700                             nc.turnTo(Neighborhood3D::nearBorderDirectionsCausal(atBorder,++j));
    00701                         }
    00702                     }
    00703                 }
    00704             }
    00705         }
    00706     }
    00707
    00708     // pass 2: assign one label to each region (tree)
    00709     // so that labels form a consecutive sequence 1, 2, ...
    00710     DestIterator zd = d_Iter;
    00711
    00712     unsigned int count = 0;
    00713
    00714     i= 0;
    00715
    00716     for(z=0; z != d; ++z, ++zd.dim2())
    00717     {
    00718         DestIterator yd(zd);
    00719
    00720         for(y=0; y != h; ++y, ++yd.dim1())
    00721         {
    00722             DestIterator xd(yd);
    00723
    00724             for(x = 0; x != w; ++x, ++xd.dim0(), ++i)
    00725             {
    00726                 if(label[i] == backgroundAddress){
    00727                     label[i]=0;
    00728                     continue;
    00729                 }
    00730
    00731                 if(label[i] == i)
    00732                 {
    00733                     label[i] = count++;
    00734                 }
    00735                 else
    00736                 {
    00737                     label[i] = label[label[i]]; // compress trees
    00738                 }
    00739                 da.set(label[i]+1, xd);
    00740             }
    00741         }
    00742     }
    00743     return count;
    00744 }
    00745
    00746 //@}
    00747
    00748 } //end of namespace vigra
    00749
    00750 #endif //VIGRA_LABELVOLUME_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)