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Commit 12907906 authored by Davis King's avatar Davis King
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This doesn't change the behavior of segment_image(). I just refactored it to 

avoid duplicate code and generally cleaned things up a little.
parent 20eb9c35
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Showing with 152 additions and 217 deletions
dlib/image_transforms/segment_image.h
View file @ 12907906
......@@ -16,15 +16,8 @@ namespace dlib
namespace impl
{
struct graph_image_segmentation_data
{
graph_image_segmentation_data() : component_size(1), internal_diff(0) {}
unsigned long component_size;
unsigned short internal_diff;
};
template <typename T>
inline T edge_diff(
inline T edge_diff_uint(
const T& a,
const T& b
)
......@@ -35,71 +28,119 @@ namespace dlib
return b - a;
}
struct segment_image_edge_data
// ----------------------------------------
template <typename T, typename enabled = void>
struct edge_diff_funct
{
typedef double diff_type;
template <typename pixel_type>
double operator()(
const pixel_type& a,
const pixel_type& b
) const
{
return length(pixel_to_vector<double>(a) - pixel_to_vector<double>(b));
}
};
template <>
struct edge_diff_funct<uint8,void>
{
typedef uint8 diff_type;
uint8 operator()( const uint8& a, const uint8& b) const { return edge_diff_uint(a,b); }
};
template <>
struct edge_diff_funct<uint16,void>
{
typedef uint16 diff_type;
uint16 operator()( const uint16& a, const uint16& b) const { return edge_diff_uint(a,b); }
};
template <>
struct edge_diff_funct<uint32,void>
{
typedef uint32 diff_type;
uint32 operator()( const uint32& a, const uint32& b) const { return edge_diff_uint(a,b); }
};
template <>
struct edge_diff_funct<double,void>
{
segment_image_edge_data (){}
typedef double diff_type;
double operator()( const double& a, const double& b) const { return std::abs(a-b); }
};
segment_image_edge_data (
template <typename T>
struct edge_diff_funct<T, typename enable_if<is_matrix<T> >::type>
{
typedef double diff_type;
double operator()(
const T& a,
const T& b
) const
{
return length(a-b);
}
};
// ------------------------------------------------------------------------------------
template <typename T>
struct graph_image_segmentation_data_T
{
graph_image_segmentation_data_T() : component_size(1), internal_diff(0) {}
unsigned long component_size;
T internal_diff;
};
// ------------------------------------------------------------------------------------
template <typename T>
struct segment_image_edge_data_T
{
segment_image_edge_data_T (){}
segment_image_edge_data_T (
const rectangle& rect,
const point& p1,
const point& p2,
const unsigned short& diff_
const T& diff_
) :
idx1(p1.y()*rect.width() + p1.x()),
idx2(p2.y()*rect.width() + p2.x()),
diff(diff_)
{}
bool operator<(const segment_image_edge_data_T& item) const
{ return diff < item.diff; }
unsigned long idx1;
unsigned long idx2;
unsigned short diff;
T diff;
};
}
// ----------------------------------------------------------------------------------------
// ------------------------------------------------------------------------------------
// This is an overload of segment_image() that is optimized to segment images with 8bit
// pixels very quickly. We do this by using a radix sort instead of quicksort.
template <
typename in_image_type,
typename out_image_type
>
// This is an overload of get_pixel_edges() that is optimized to segment images
// with 8bit or 16bit pixels very quickly. We do this by using a radix sort
// instead of quicksort.
template <typename in_image_type, typename T>
typename enable_if_c<is_same_type<typename in_image_type::type,uint8>::value ||
is_same_type<typename in_image_type::type,uint16>::value>::type
segment_image (
get_pixel_edges (
const in_image_type& in_img,
out_image_type& out_img,
const double k = 200,
const unsigned long min_size = 10
std::vector<segment_image_edge_data_T<T> >& sorted_edges
)
{
using namespace dlib::impl;
typedef typename in_image_type::type ptype;
// make sure requires clause is not broken
DLIB_ASSERT(is_same_object(in_img, out_img) == false,
"\t void segment_image()"
<< "\n\t The input images can't be the same object."
);
COMPILE_TIME_ASSERT(is_unsigned_type<typename out_image_type::type>::value);
out_img.set_size(in_img.nr(), in_img.nc());
// don't bother doing anything if the image is too small
if (in_img.nr() < 2 || in_img.nc() < 2)
{
assign_all_pixels(out_img,0);
return;
}
disjoint_subsets sets;
sets.set_size(in_img.size());
std::vector<graph_image_segmentation_data> data(in_img.size());
typedef T diff_type;
std::vector<unsigned long> counts(std::numeric_limits<ptype>::max()+1, 0);
edge_diff_funct<ptype> edge_diff;
border_enumerator be(get_rect(in_img), 1);
// we are going to do a radix sort on the edge weights. So the first step
// is to accumulate them into count.
......@@ -127,7 +168,8 @@ namespace dlib
}
const unsigned long num_edges = shrink_rect(area,1).area()*4 + in_img.nr()*2*3 - 4 + (in_img.nc()-2)*2*3;
std::vector<segment_image_edge_data> sorted_edges(num_edges);
typedef segment_image_edge_data_T<T> segment_image_edge_data;
sorted_edges.resize(num_edges);
// integrate counts. The idea is to have sorted_edges[counts[i]] be the location that edges
// with an edge_diff of i go. So counts[0] == 0, counts[1] == number of 0 edge diff edges, etc.
......@@ -152,25 +194,25 @@ namespace dlib
const ptype pix = in_img[r][c];
if (area.contains(c-1,r))
{
const ptype diff = edge_diff(pix, in_img[r ][c-1]);
const diff_type diff = edge_diff(pix, in_img[r ][c-1]);
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c-1,r),diff);
}
if (area.contains(c+1,r))
{
const ptype diff = edge_diff(pix, in_img[r ][c+1]);
const diff_type diff = edge_diff(pix, in_img[r ][c+1]);
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c+1,r),diff);
}
if (area.contains(c ,r-1))
{
const ptype diff = edge_diff(pix, in_img[r-1][c ]);
const diff_type diff = edge_diff(pix, in_img[r-1][c ]);
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c ,r-1),diff);
}
if (area.contains(c ,r+1))
{
const ptype diff = edge_diff(pix, in_img[r+1][c ]);
const diff_type diff = edge_diff(pix, in_img[r+1][c ]);
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c ,r+1),diff);
}
}
......@@ -182,7 +224,7 @@ namespace dlib
{
const point p(c,r);
const ptype pix = in_img[r][c];
ptype diff;
diff_type diff;
diff = edge_diff(pix, in_img[r ][c+1]);
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c+1,r),diff);
......@@ -194,179 +236,26 @@ namespace dlib
sorted_edges[counts[diff]++] = segment_image_edge_data(area,p,point(c ,r+1),diff);
}
}
// now start connecting blobs together to make a minimum spanning tree.
for (unsigned long i = 0; i < sorted_edges.size(); ++i)
{
const unsigned long idx1 = sorted_edges[i].idx1;
const unsigned long idx2 = sorted_edges[i].idx2;
unsigned long set1 = sets.find_set(idx1);
unsigned long set2 = sets.find_set(idx2);
if (set1 != set2)
{
const ptype diff = sorted_edges[i].diff;
const ptype tau1 = static_cast<ptype>(std::floor(k/data[set1].component_size));
const ptype tau2 = static_cast<ptype>(std::floor(k/data[set2].component_size));
const ptype mint = std::min(data[set1].internal_diff + tau1,
data[set2].internal_diff + tau2);
if (diff <= mint)
{
const unsigned long new_set = sets.merge_sets(set1, set2);
data[new_set].component_size = data[set1].component_size + data[set2].component_size;
data[new_set].internal_diff = diff;
}
}
}
// now merge any really small blobs
if (min_size != 0)
{
for (unsigned long i = 0; i < sorted_edges.size(); ++i)
{
const unsigned long idx1 = sorted_edges[i].idx1;
const unsigned long idx2 = sorted_edges[i].idx2;
unsigned long set1 = sets.find_set(idx1);
unsigned long set2 = sets.find_set(idx2);
if (set1 != set2 && (data[set1].component_size < min_size || data[set2].component_size < min_size))
{
const unsigned long new_set = sets.merge_sets(set1, set2);
data[new_set].component_size = data[set1].component_size + data[set2].component_size;
const ptype diff = sorted_edges[i].diff;
data[new_set].internal_diff = diff;
}
}
}
unsigned long idx = 0;
for (long r = 0; r < out_img.nr(); ++r)
{
for (long c = 0; c < out_img.nc(); ++c)
{
out_img[r][c] = sets.find_set(idx++);
}
}
}
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
namespace impl
{
template <typename T, typename enabled = void>
struct edge_diff_funct
{
template <typename pixel_type>
double operator()(
const pixel_type& a,
const pixel_type& b
) const
{
return length(pixel_to_vector<double>(a) - pixel_to_vector<double>(b));
}
};
// ----------------------------------------------------------------------------------------
template <typename T>
struct edge_diff_funct<T, typename enable_if<is_matrix<T> >::type>
{
double operator()(
const T& a,
const T& b
) const
{
return length(a-b);
}
};
template <typename T>
struct graph_image_segmentation_data2
{
graph_image_segmentation_data2() : component_size(1), internal_diff(0) {}
unsigned long component_size;
T internal_diff;
};
template <typename T>
struct segment_image_edge_data2
{
segment_image_edge_data2 (){}
segment_image_edge_data2 (
const rectangle& rect,
const point& p1,
const point& p2,
const T& diff_
) :
idx1(p1.y()*rect.width() + p1.x()),
idx2(p2.y()*rect.width() + p2.x()),
diff(diff_)
{}
bool operator<(const segment_image_edge_data2& item) const
{ return diff < item.diff; }
unsigned long idx1;
unsigned long idx2;
T diff;
};
}
// This is the general purpose version of segment_image(). It handles all pixel types.
template <
typename in_image_type,
typename out_image_type
>
// This is the general purpose version of get_pixel_edges(). It handles all pixel types.
template <typename in_image_type, typename T>
typename disable_if_c<is_same_type<typename in_image_type::type,uint8>::value ||
is_same_type<typename in_image_type::type,uint16>::value>::type
segment_image (
get_pixel_edges (
const in_image_type& in_img,
out_image_type& out_img,
const double k = 200,
const unsigned long min_size = 10
std::vector<segment_image_edge_data_T<T> >& sorted_edges
)
{
using namespace dlib::impl;
typedef double diff_type;
typedef typename in_image_type::type ptype;
edge_diff_funct<ptype> edge_diff;
// make sure requires clause is not broken
DLIB_ASSERT(is_same_object(in_img, out_img) == false,
"\t void segment_image()"
<< "\n\t The input images can't be the same object."
);
COMPILE_TIME_ASSERT(is_unsigned_type<typename out_image_type::type>::value);
out_img.set_size(in_img.nr(), in_img.nc());
// don't bother doing anything if the image is too small
if (in_img.nr() < 2 || in_img.nc() < 2)
{
assign_all_pixels(out_img,0);
return;
}
disjoint_subsets sets;
sets.set_size(in_img.size());
std::vector<graph_image_segmentation_data2<diff_type> > data(in_img.size());
const rectangle area = get_rect(in_img);
typedef segment_image_edge_data2<diff_type> segment_image_edge_data;
std::vector<segment_image_edge_data> sorted_edges;
sorted_edges.reserve(area.area()*4);
typedef typename in_image_type::type ptype;
edge_diff_funct<ptype> edge_diff;
typedef T diff_type;
typedef segment_image_edge_data_T<T> segment_image_edge_data;
border_enumerator be(get_rect(in_img), 1);
......@@ -424,7 +313,52 @@ namespace dlib
std::sort(sorted_edges.begin(), sorted_edges.end());
}
// ------------------------------------------------------------------------------------
} // end of namespace impl
// ----------------------------------------------------------------------------------------
template <
typename in_image_type,
typename out_image_type
>
void segment_image (
const in_image_type& in_img,
out_image_type& out_img,
const double k = 200,
const unsigned long min_size = 10
)
{
using namespace dlib::impl;
typedef typename in_image_type::type ptype;
typedef typename edge_diff_funct<ptype>::diff_type diff_type;
// make sure requires clause is not broken
DLIB_ASSERT(is_same_object(in_img, out_img) == false,
"\t void segment_image()"
<< "\n\t The input images can't be the same object."
);
COMPILE_TIME_ASSERT(is_unsigned_type<typename out_image_type::type>::value);
out_img.set_size(in_img.nr(), in_img.nc());
// don't bother doing anything if the image is too small
if (in_img.nr() < 2 || in_img.nc() < 2)
{
assign_all_pixels(out_img,0);
return;
}
disjoint_subsets sets;
sets.set_size(in_img.size());
std::vector<segment_image_edge_data_T<diff_type> > sorted_edges;
get_pixel_edges(in_img, sorted_edges);
std::vector<graph_image_segmentation_data_T<diff_type> > data(in_img.size());
// now start connecting blobs together to make a minimum spanning tree.
for (unsigned long i = 0; i < sorted_edges.size(); ++i)
......@@ -465,6 +399,7 @@ namespace dlib
{
const unsigned long new_set = sets.merge_sets(set1, set2);
data[new_set].component_size = data[set1].component_size + data[set2].component_size;
//data[new_set].internal_diff = sorted_edges[i].diff;
}
}
}
......
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