mirror of
https://github.com/opencv/opencv.git
synced 2024-12-15 09:49:13 +08:00
613 lines
13 KiB
ReStructuredText
613 lines
13 KiB
ReStructuredText
Planar Subdivisions
|
|
===================
|
|
|
|
.. highlight:: c
|
|
|
|
|
|
|
|
.. index:: CvSubdiv2D
|
|
|
|
.. _CvSubdiv2D:
|
|
|
|
CvSubdiv2D
|
|
----------
|
|
|
|
`id=0.0330142359402 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/CvSubdiv2D>`__
|
|
|
|
.. ctype:: CvSubdiv2D
|
|
|
|
|
|
|
|
Planar subdivision.
|
|
|
|
|
|
|
|
|
|
::
|
|
|
|
|
|
|
|
#define CV_SUBDIV2D_FIELDS() \
|
|
CV_GRAPH_FIELDS() \
|
|
int quad_edges; \
|
|
int is_geometry_valid; \
|
|
CvSubdiv2DEdge recent_edge; \
|
|
CvPoint2D32f topleft; \
|
|
CvPoint2D32f bottomright;
|
|
|
|
typedef struct CvSubdiv2D
|
|
{
|
|
CV_SUBDIV2D_FIELDS()
|
|
}
|
|
CvSubdiv2D;
|
|
|
|
|
|
..
|
|
|
|
Planar subdivision is the subdivision of a plane into a set of
|
|
non-overlapped regions (facets) that cover the whole plane. The above
|
|
structure describes a subdivision built on a 2d point set, where the points
|
|
are linked together and form a planar graph, which, together with a few
|
|
edges connecting the exterior subdivision points (namely, convex hull points)
|
|
with infinity, subdivides a plane into facets by its edges.
|
|
|
|
For every subdivision there exists a dual subdivision in which facets and
|
|
points (subdivision vertices) swap their roles, that is, a facet is
|
|
treated as a vertex (called a virtual point below) of the dual subdivision and
|
|
the original subdivision vertices become facets. On the picture below
|
|
original subdivision is marked with solid lines and dual subdivision
|
|
with dotted lines.
|
|
|
|
|
|
|
|
.. image:: ../pics/subdiv.png
|
|
|
|
|
|
|
|
OpenCV subdivides a plane into triangles using Delaunay's
|
|
algorithm. Subdivision is built iteratively starting from a dummy
|
|
triangle that includes all the subdivision points for sure. In this
|
|
case the dual subdivision is a Voronoi diagram of the input 2d point set. The
|
|
subdivisions can be used for the 3d piece-wise transformation of a plane,
|
|
morphing, fast location of points on the plane, building special graphs
|
|
(such as NNG,RNG) and so forth.
|
|
|
|
|
|
.. index:: CvQuadEdge2D
|
|
|
|
.. _CvQuadEdge2D:
|
|
|
|
CvQuadEdge2D
|
|
------------
|
|
|
|
`id=0.774421357321 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/CvQuadEdge2D>`__
|
|
|
|
.. ctype:: CvQuadEdge2D
|
|
|
|
|
|
|
|
Quad-edge of planar subdivision.
|
|
|
|
|
|
|
|
|
|
::
|
|
|
|
|
|
|
|
/* one of edges within quad-edge, lower 2 bits is index (0..3)
|
|
and upper bits are quad-edge pointer */
|
|
typedef long CvSubdiv2DEdge;
|
|
|
|
/* quad-edge structure fields */
|
|
#define CV_QUADEDGE2D_FIELDS() \
|
|
int flags; \
|
|
struct CvSubdiv2DPoint* pt[4]; \
|
|
CvSubdiv2DEdge next[4];
|
|
|
|
typedef struct CvQuadEdge2D
|
|
{
|
|
CV_QUADEDGE2D_FIELDS()
|
|
}
|
|
CvQuadEdge2D;
|
|
|
|
|
|
|
|
..
|
|
|
|
Quad-edge is a basic element of subdivision containing four edges (e, eRot, reversed e and reversed eRot):
|
|
|
|
|
|
|
|
.. image:: ../pics/quadedge.png
|
|
|
|
|
|
|
|
|
|
.. index:: CvSubdiv2DPoint
|
|
|
|
.. _CvSubdiv2DPoint:
|
|
|
|
CvSubdiv2DPoint
|
|
---------------
|
|
|
|
`id=0.348865048627 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/CvSubdiv2DPoint>`__
|
|
|
|
.. ctype:: CvSubdiv2DPoint
|
|
|
|
|
|
|
|
Point of original or dual subdivision.
|
|
|
|
|
|
|
|
|
|
::
|
|
|
|
|
|
|
|
#define CV_SUBDIV2D_POINT_FIELDS()\
|
|
int flags; \
|
|
CvSubdiv2DEdge first; \
|
|
CvPoint2D32f pt; \
|
|
int id;
|
|
|
|
#define CV_SUBDIV2D_VIRTUAL_POINT_FLAG (1 << 30)
|
|
|
|
typedef struct CvSubdiv2DPoint
|
|
{
|
|
CV_SUBDIV2D_POINT_FIELDS()
|
|
}
|
|
CvSubdiv2DPoint;
|
|
|
|
|
|
..
|
|
|
|
|
|
|
|
|
|
|
|
* id
|
|
This integer can be used to index auxillary data associated with each vertex of the planar subdivision
|
|
|
|
|
|
|
|
.. index:: CalcSubdivVoronoi2D
|
|
|
|
.. _CalcSubdivVoronoi2D:
|
|
|
|
CalcSubdivVoronoi2D
|
|
-------------------
|
|
|
|
`id=0.780234504298 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/CalcSubdivVoronoi2D>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: void cvCalcSubdivVoronoi2D( CvSubdiv2D* subdiv )
|
|
|
|
Calculates the coordinates of Voronoi diagram cells.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param subdiv: Delaunay subdivision, in which all the points are already added
|
|
|
|
|
|
|
|
The function calculates the coordinates
|
|
of virtual points. All virtual points corresponding to some vertex of the
|
|
original subdivision form (when connected together) a boundary of the Voronoi
|
|
cell at that point.
|
|
|
|
|
|
.. index:: ClearSubdivVoronoi2D
|
|
|
|
.. _ClearSubdivVoronoi2D:
|
|
|
|
ClearSubdivVoronoi2D
|
|
--------------------
|
|
|
|
`id=0.598833189257 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/ClearSubdivVoronoi2D>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: void cvClearSubdivVoronoi2D( CvSubdiv2D* subdiv )
|
|
|
|
Removes all virtual points.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param subdiv: Delaunay subdivision
|
|
|
|
|
|
|
|
The function removes all of the virtual points. It
|
|
is called internally in
|
|
:ref:`CalcSubdivVoronoi2D`
|
|
if the subdivision
|
|
was modified after previous call to the function.
|
|
|
|
|
|
|
|
.. index:: CreateSubdivDelaunay2D
|
|
|
|
.. _CreateSubdivDelaunay2D:
|
|
|
|
CreateSubdivDelaunay2D
|
|
----------------------
|
|
|
|
`id=0.740903386025 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/CreateSubdivDelaunay2D>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2D* cvCreateSubdivDelaunay2D( CvRect rect, CvMemStorage* storage )
|
|
|
|
Creates an empty Delaunay triangulation.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param rect: Rectangle that includes all of the 2d points that are to be added to the subdivision
|
|
|
|
|
|
:param storage: Container for subdivision
|
|
|
|
|
|
|
|
The function creates an empty Delaunay
|
|
subdivision, where 2d points can be added using the function
|
|
:ref:`SubdivDelaunay2DInsert`
|
|
. All of the points to be added must be within
|
|
the specified rectangle, otherwise a runtime error will be raised.
|
|
|
|
Note that the triangulation is a single large triangle that covers the given rectangle. Hence the three vertices of this triangle are outside the rectangle
|
|
``rect``
|
|
.
|
|
|
|
|
|
.. index:: FindNearestPoint2D
|
|
|
|
.. _FindNearestPoint2D:
|
|
|
|
FindNearestPoint2D
|
|
------------------
|
|
|
|
`id=0.89077983265 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/FindNearestPoint2D>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DPoint* cvFindNearestPoint2D( CvSubdiv2D* subdiv, CvPoint2D32f pt )
|
|
|
|
Finds the closest subdivision vertex to the given point.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param subdiv: Delaunay or another subdivision
|
|
|
|
|
|
:param pt: Input point
|
|
|
|
|
|
|
|
The function is another function that
|
|
locates the input point within the subdivision. It finds the subdivision vertex that
|
|
is the closest to the input point. It is not necessarily one of vertices
|
|
of the facet containing the input point, though the facet (located using
|
|
:ref:`Subdiv2DLocate`
|
|
) is used as a starting
|
|
point. The function returns a pointer to the found subdivision vertex.
|
|
|
|
|
|
.. index:: Subdiv2DEdgeDst
|
|
|
|
.. _Subdiv2DEdgeDst:
|
|
|
|
Subdiv2DEdgeDst
|
|
---------------
|
|
|
|
`id=0.475748447952 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/Subdiv2DEdgeDst>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DPoint* cvSubdiv2DEdgeDst( CvSubdiv2DEdge edge )
|
|
|
|
Returns the edge destination.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param edge: Subdivision edge (not a quad-edge)
|
|
|
|
|
|
|
|
The function returns the edge destination. The
|
|
returned pointer may be NULL if the edge is from dual subdivision and
|
|
the virtual point coordinates are not calculated yet. The virtual points
|
|
can be calculated using the function
|
|
:ref:`CalcSubdivVoronoi2D`
|
|
.
|
|
|
|
|
|
.. index:: Subdiv2DGetEdge
|
|
|
|
.. _Subdiv2DGetEdge:
|
|
|
|
Subdiv2DGetEdge
|
|
---------------
|
|
|
|
`id=0.128594743275 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/Subdiv2DGetEdge>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DEdge cvSubdiv2DGetEdge( CvSubdiv2DEdge edge, CvNextEdgeType type )
|
|
|
|
Returns one of the edges related to the given edge.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param edge: Subdivision edge (not a quad-edge)
|
|
|
|
|
|
:param type: Specifies which of the related edges to return, one of the following:
|
|
|
|
|
|
|
|
|
|
* **CV_NEXT_AROUND_ORG** next around the edge origin ( ``eOnext`` on the picture below if ``e`` is the input edge)
|
|
|
|
|
|
* **CV_NEXT_AROUND_DST** next around the edge vertex ( ``eDnext`` )
|
|
|
|
|
|
* **CV_PREV_AROUND_ORG** previous around the edge origin (reversed ``eRnext`` )
|
|
|
|
|
|
* **CV_PREV_AROUND_DST** previous around the edge destination (reversed ``eLnext`` )
|
|
|
|
|
|
* **CV_NEXT_AROUND_LEFT** next around the left facet ( ``eLnext`` )
|
|
|
|
|
|
* **CV_NEXT_AROUND_RIGHT** next around the right facet ( ``eRnext`` )
|
|
|
|
|
|
* **CV_PREV_AROUND_LEFT** previous around the left facet (reversed ``eOnext`` )
|
|
|
|
|
|
* **CV_PREV_AROUND_RIGHT** previous around the right facet (reversed ``eDnext`` )
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
.. image:: ../pics/quadedge.png
|
|
|
|
|
|
|
|
The function returns one of the edges related to the input edge.
|
|
|
|
|
|
.. index:: Subdiv2DNextEdge
|
|
|
|
.. _Subdiv2DNextEdge:
|
|
|
|
Subdiv2DNextEdge
|
|
----------------
|
|
|
|
`id=0.250529497726 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/Subdiv2DNextEdge>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DEdge cvSubdiv2DNextEdge( CvSubdiv2DEdge edge )
|
|
|
|
Returns next edge around the edge origin
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param edge: Subdivision edge (not a quad-edge)
|
|
|
|
|
|
|
|
|
|
|
|
.. image:: ../pics/quadedge.png
|
|
|
|
|
|
|
|
The function returns the next edge around the edge origin:
|
|
``eOnext``
|
|
on the picture above if
|
|
``e``
|
|
is the input edge)
|
|
|
|
|
|
.. index:: Subdiv2DLocate
|
|
|
|
.. _Subdiv2DLocate:
|
|
|
|
Subdiv2DLocate
|
|
--------------
|
|
|
|
`id=0.195353110226 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/Subdiv2DLocate>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DPointLocation cvSubdiv2DLocate( CvSubdiv2D* subdiv, CvPoint2D32f pt, CvSubdiv2DEdge* edge, CvSubdiv2DPoint** vertex=NULL )
|
|
|
|
Returns the location of a point within a Delaunay triangulation.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param subdiv: Delaunay or another subdivision
|
|
|
|
|
|
:param pt: The point to locate
|
|
|
|
|
|
:param edge: The output edge the point falls onto or right to
|
|
|
|
|
|
:param vertex: Optional output vertex double pointer the input point coinsides with
|
|
|
|
|
|
|
|
The function locates the input point within the subdivision. There are 5 cases:
|
|
|
|
|
|
|
|
|
|
|
|
*
|
|
The point falls into some facet. The function returns
|
|
``CV_PTLOC_INSIDE``
|
|
and
|
|
``*edge``
|
|
will contain one of edges of the facet.
|
|
|
|
|
|
|
|
*
|
|
The point falls onto the edge. The function returns
|
|
``CV_PTLOC_ON_EDGE``
|
|
and
|
|
``*edge``
|
|
will contain this edge.
|
|
|
|
|
|
|
|
*
|
|
The point coincides with one of the subdivision vertices. The function returns
|
|
``CV_PTLOC_VERTEX``
|
|
and
|
|
``*vertex``
|
|
will contain a pointer to the vertex.
|
|
|
|
|
|
|
|
*
|
|
The point is outside the subdivsion reference rectangle. The function returns
|
|
``CV_PTLOC_OUTSIDE_RECT``
|
|
and no pointers are filled.
|
|
|
|
|
|
|
|
*
|
|
One of input arguments is invalid. A runtime error is raised or, if silent or "parent" error processing mode is selected,
|
|
``CV_PTLOC_ERROR``
|
|
is returnd.
|
|
|
|
|
|
|
|
.. index:: Subdiv2DRotateEdge
|
|
|
|
.. _Subdiv2DRotateEdge:
|
|
|
|
Subdiv2DRotateEdge
|
|
------------------
|
|
|
|
`id=0.808074440668 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/Subdiv2DRotateEdge>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DEdge cvSubdiv2DRotateEdge( CvSubdiv2DEdge edge, int rotate )
|
|
|
|
Returns another edge of the same quad-edge.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param edge: Subdivision edge (not a quad-edge)
|
|
|
|
|
|
:param rotate: Specifies which of the edges of the same quad-edge as the input one to return, one of the following:
|
|
|
|
|
|
* **0** the input edge ( ``e`` on the picture below if ``e`` is the input edge)
|
|
|
|
|
|
* **1** the rotated edge ( ``eRot`` )
|
|
|
|
|
|
* **2** the reversed edge (reversed ``e`` (in green))
|
|
|
|
|
|
* **3** the reversed rotated edge (reversed ``eRot`` (in green))
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
.. image:: ../pics/quadedge.png
|
|
|
|
|
|
|
|
The function returns one of the edges of the same quad-edge as the input edge.
|
|
|
|
|
|
.. index:: SubdivDelaunay2DInsert
|
|
|
|
.. _SubdivDelaunay2DInsert:
|
|
|
|
SubdivDelaunay2DInsert
|
|
----------------------
|
|
|
|
`id=0.318236209384 Comments from the Wiki <http://opencv.willowgarage.com/wiki/documentation/c/imgproc/SubdivDelaunay2DInsert>`__
|
|
|
|
|
|
|
|
|
|
.. cfunction:: CvSubdiv2DPoint* cvSubdivDelaunay2DInsert( CvSubdiv2D* subdiv, CvPoint2D32f pt)
|
|
|
|
Inserts a single point into a Delaunay triangulation.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
:param subdiv: Delaunay subdivision created by the function :ref:`CreateSubdivDelaunay2D`
|
|
|
|
|
|
:param pt: Inserted point
|
|
|
|
|
|
|
|
The function inserts a single point into a subdivision and modifies the subdivision topology appropriately. If a point with the same coordinates exists already, no new point is added. The function returns a pointer to the allocated point. No virtual point coordinates are calculated at this stage.
|
|
|