opencv/modules/imgproc/src/convhull.cpp
2016-01-02 21:06:51 +01:00

741 lines
22 KiB
C++

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#include "precomp.hpp"
#include <iostream>
namespace cv
{
template<typename _Tp>
static int Sklansky_( Point_<_Tp>** array, int start, int end, int* stack, int nsign, int sign2 )
{
int incr = end > start ? 1 : -1;
// prepare first triangle
int pprev = start, pcur = pprev + incr, pnext = pcur + incr;
int stacksize = 3;
if( start == end ||
(array[start]->x == array[end]->x &&
array[start]->y == array[end]->y) )
{
stack[0] = start;
return 1;
}
stack[0] = pprev;
stack[1] = pcur;
stack[2] = pnext;
end += incr; // make end = afterend
while( pnext != end )
{
// check the angle p1,p2,p3
_Tp cury = array[pcur]->y;
_Tp nexty = array[pnext]->y;
_Tp by = nexty - cury;
if( CV_SIGN( by ) != nsign )
{
_Tp ax = array[pcur]->x - array[pprev]->x;
_Tp bx = array[pnext]->x - array[pcur]->x;
_Tp ay = cury - array[pprev]->y;
_Tp convexity = ay*bx - ax*by; // if >0 then convex angle
if( CV_SIGN( convexity ) == sign2 && (ax != 0 || ay != 0) )
{
pprev = pcur;
pcur = pnext;
pnext += incr;
stack[stacksize] = pnext;
stacksize++;
}
else
{
if( pprev == start )
{
pcur = pnext;
stack[1] = pcur;
pnext += incr;
stack[2] = pnext;
}
else
{
stack[stacksize-2] = pnext;
pcur = pprev;
pprev = stack[stacksize-4];
stacksize--;
}
}
}
else
{
pnext += incr;
stack[stacksize-1] = pnext;
}
}
return --stacksize;
}
template<typename _Tp>
struct CHullCmpPoints
{
bool operator()(const Point_<_Tp>* p1, const Point_<_Tp>* p2) const
{ return p1->x < p2->x || (p1->x == p2->x && p1->y < p2->y); }
};
void convexHull( InputArray _points, OutputArray _hull, bool clockwise, bool returnPoints )
{
Mat points = _points.getMat();
int i, total = points.checkVector(2), depth = points.depth(), nout = 0;
int miny_ind = 0, maxy_ind = 0;
CV_Assert(total >= 0 && (depth == CV_32F || depth == CV_32S));
if( total == 0 )
{
_hull.release();
return;
}
returnPoints = !_hull.fixedType() ? returnPoints : _hull.type() != CV_32S;
bool is_float = depth == CV_32F;
AutoBuffer<Point*> _pointer(total);
AutoBuffer<int> _stack(total + 2), _hullbuf(total);
Point** pointer = _pointer;
Point2f** pointerf = (Point2f**)pointer;
Point* data0 = points.ptr<Point>();
int* stack = _stack;
int* hullbuf = _hullbuf;
CV_Assert(points.isContinuous());
for( i = 0; i < total; i++ )
pointer[i] = &data0[i];
// sort the point set by x-coordinate, find min and max y
if( !is_float )
{
std::sort(pointer, pointer + total, CHullCmpPoints<int>());
for( i = 1; i < total; i++ )
{
int y = pointer[i]->y;
if( pointer[miny_ind]->y > y )
miny_ind = i;
if( pointer[maxy_ind]->y < y )
maxy_ind = i;
}
}
else
{
std::sort(pointerf, pointerf + total, CHullCmpPoints<float>());
for( i = 1; i < total; i++ )
{
float y = pointerf[i]->y;
if( pointerf[miny_ind]->y > y )
miny_ind = i;
if( pointerf[maxy_ind]->y < y )
maxy_ind = i;
}
}
if( pointer[0]->x == pointer[total-1]->x &&
pointer[0]->y == pointer[total-1]->y )
{
hullbuf[nout++] = 0;
}
else
{
// upper half
int *tl_stack = stack;
int tl_count = !is_float ?
Sklansky_( pointer, 0, maxy_ind, tl_stack, -1, 1) :
Sklansky_( pointerf, 0, maxy_ind, tl_stack, -1, 1);
int *tr_stack = stack + tl_count;
int tr_count = !is_float ?
Sklansky_( pointer, total-1, maxy_ind, tr_stack, -1, -1) :
Sklansky_( pointerf, total-1, maxy_ind, tr_stack, -1, -1);
// gather upper part of convex hull to output
if( !clockwise )
{
std::swap( tl_stack, tr_stack );
std::swap( tl_count, tr_count );
}
for( i = 0; i < tl_count-1; i++ )
hullbuf[nout++] = int(pointer[tl_stack[i]] - data0);
for( i = tr_count - 1; i > 0; i-- )
hullbuf[nout++] = int(pointer[tr_stack[i]] - data0);
int stop_idx = tr_count > 2 ? tr_stack[1] : tl_count > 2 ? tl_stack[tl_count - 2] : -1;
// lower half
int *bl_stack = stack;
int bl_count = !is_float ?
Sklansky_( pointer, 0, miny_ind, bl_stack, 1, -1) :
Sklansky_( pointerf, 0, miny_ind, bl_stack, 1, -1);
int *br_stack = stack + bl_count;
int br_count = !is_float ?
Sklansky_( pointer, total-1, miny_ind, br_stack, 1, 1) :
Sklansky_( pointerf, total-1, miny_ind, br_stack, 1, 1);
if( clockwise )
{
std::swap( bl_stack, br_stack );
std::swap( bl_count, br_count );
}
if( stop_idx >= 0 )
{
int check_idx = bl_count > 2 ? bl_stack[1] :
bl_count + br_count > 2 ? br_stack[2-bl_count] : -1;
if( check_idx == stop_idx || (check_idx >= 0 &&
pointer[check_idx]->x == pointer[stop_idx]->x &&
pointer[check_idx]->y == pointer[stop_idx]->y) )
{
// if all the points lie on the same line, then
// the bottom part of the convex hull is the mirrored top part
// (except the exteme points).
bl_count = MIN( bl_count, 2 );
br_count = MIN( br_count, 2 );
}
}
for( i = 0; i < bl_count-1; i++ )
hullbuf[nout++] = int(pointer[bl_stack[i]] - data0);
for( i = br_count-1; i > 0; i-- )
hullbuf[nout++] = int(pointer[br_stack[i]] - data0);
}
if( !returnPoints )
Mat(nout, 1, CV_32S, hullbuf).copyTo(_hull);
else
{
_hull.create(nout, 1, CV_MAKETYPE(depth, 2));
Mat hull = _hull.getMat();
size_t step = !hull.isContinuous() ? hull.step[0] : sizeof(Point);
for( i = 0; i < nout; i++ )
*(Point*)(hull.ptr() + i*step) = data0[hullbuf[i]];
}
}
void convexityDefects( InputArray _points, InputArray _hull, OutputArray _defects )
{
Mat points = _points.getMat();
int i, j = 0, npoints = points.checkVector(2, CV_32S);
CV_Assert( npoints >= 0 );
if( npoints <= 3 )
{
_defects.release();
return;
}
Mat hull = _hull.getMat();
int hpoints = hull.checkVector(1, CV_32S);
CV_Assert( hpoints > 2 );
const Point* ptr = points.ptr<Point>();
const int* hptr = hull.ptr<int>();
std::vector<Vec4i> defects;
// 1. recognize co-orientation of the contour and its hull
bool rev_orientation = ((hptr[1] > hptr[0]) + (hptr[2] > hptr[1]) + (hptr[0] > hptr[2])) != 2;
// 2. cycle through points and hull, compute defects
int hcurr = hptr[rev_orientation ? 0 : hpoints-1];
CV_Assert( 0 <= hcurr && hcurr < npoints );
for( i = 0; i < hpoints; i++ )
{
int hnext = hptr[rev_orientation ? hpoints - i - 1 : i];
CV_Assert( 0 <= hnext && hnext < npoints );
Point pt0 = ptr[hcurr], pt1 = ptr[hnext];
double dx0 = pt1.x - pt0.x;
double dy0 = pt1.y - pt0.y;
double scale = dx0 == 0 && dy0 == 0 ? 0. : 1./std::sqrt(dx0*dx0 + dy0*dy0);
int defect_deepest_point = -1;
double defect_depth = 0;
bool is_defect = false;
j=hcurr;
for(;;)
{
// go through points to achieve next hull point
j++;
j &= j >= npoints ? 0 : -1;
if( j == hnext )
break;
// compute distance from current point to hull edge
double dx = ptr[j].x - pt0.x;
double dy = ptr[j].y - pt0.y;
double dist = fabs(-dy0*dx + dx0*dy) * scale;
if( dist > defect_depth )
{
defect_depth = dist;
defect_deepest_point = j;
is_defect = true;
}
}
if( is_defect )
{
int idepth = cvRound(defect_depth*256);
defects.push_back(Vec4i(hcurr, hnext, defect_deepest_point, idepth));
}
hcurr = hnext;
}
Mat(defects).copyTo(_defects);
}
template<typename _Tp>
static bool isContourConvex_( const Point_<_Tp>* p, int n )
{
Point_<_Tp> prev_pt = p[(n-2+n) % n];
Point_<_Tp> cur_pt = p[n-1];
_Tp dx0 = cur_pt.x - prev_pt.x;
_Tp dy0 = cur_pt.y - prev_pt.y;
int orientation = 0;
for( int i = 0; i < n; i++ )
{
_Tp dxdy0, dydx0;
_Tp dx, dy;
prev_pt = cur_pt;
cur_pt = p[i];
dx = cur_pt.x - prev_pt.x;
dy = cur_pt.y - prev_pt.y;
dxdy0 = dx * dy0;
dydx0 = dy * dx0;
// find orientation
// orient = -dy0 * dx + dx0 * dy;
// orientation |= (orient > 0) ? 1 : 2;
orientation |= (dydx0 > dxdy0) ? 1 : ((dydx0 < dxdy0) ? 2 : 3);
if( orientation == 3 )
return false;
dx0 = dx;
dy0 = dy;
}
return true;
}
bool isContourConvex( InputArray _contour )
{
Mat contour = _contour.getMat();
int total = contour.checkVector(2), depth = contour.depth();
CV_Assert(total >= 0 && (depth == CV_32F || depth == CV_32S));
if( total == 0 )
return false;
return depth == CV_32S ?
isContourConvex_(contour.ptr<Point>(), total ) :
isContourConvex_(contour.ptr<Point2f>(), total );
}
}
CV_IMPL CvSeq*
cvConvexHull2( const CvArr* array, void* hull_storage,
int orientation, int return_points )
{
union { CvContour* c; CvSeq* s; } hull;
hull.s = 0;
CvMat* mat = 0;
CvContour contour_header;
CvSeq hull_header;
CvSeqBlock block, hullblock;
CvSeq* ptseq = 0;
CvSeq* hullseq = 0;
if( CV_IS_SEQ( array ))
{
ptseq = (CvSeq*)array;
if( !CV_IS_SEQ_POINT_SET( ptseq ))
CV_Error( CV_StsBadArg, "Unsupported sequence type" );
if( hull_storage == 0 )
hull_storage = ptseq->storage;
}
else
{
ptseq = cvPointSeqFromMat( CV_SEQ_KIND_GENERIC, array, &contour_header, &block );
}
if( CV_IS_STORAGE( hull_storage ))
{
if( return_points )
{
hullseq = cvCreateSeq(CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE(ptseq)|
CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX,
sizeof(CvContour), sizeof(CvPoint),(CvMemStorage*)hull_storage );
}
else
{
hullseq = cvCreateSeq(
CV_SEQ_KIND_CURVE|CV_SEQ_ELTYPE_PPOINT|
CV_SEQ_FLAG_CLOSED|CV_SEQ_FLAG_CONVEX,
sizeof(CvContour), sizeof(CvPoint*), (CvMemStorage*)hull_storage );
}
}
else
{
if( !CV_IS_MAT( hull_storage ))
CV_Error(CV_StsBadArg, "Destination must be valid memory storage or matrix");
mat = (CvMat*)hull_storage;
if( (mat->cols != 1 && mat->rows != 1) || !CV_IS_MAT_CONT(mat->type))
CV_Error( CV_StsBadArg,
"The hull matrix should be continuous and have a single row or a single column" );
if( mat->cols + mat->rows - 1 < ptseq->total )
CV_Error( CV_StsBadSize, "The hull matrix size might be not enough to fit the hull" );
if( CV_MAT_TYPE(mat->type) != CV_SEQ_ELTYPE(ptseq) &&
CV_MAT_TYPE(mat->type) != CV_32SC1 )
CV_Error( CV_StsUnsupportedFormat,
"The hull matrix must have the same type as input or 32sC1 (integers)" );
hullseq = cvMakeSeqHeaderForArray(
CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED,
sizeof(hull_header), CV_ELEM_SIZE(mat->type), mat->data.ptr,
mat->cols + mat->rows - 1, &hull_header, &hullblock );
cvClearSeq( hullseq );
}
int hulltype = CV_SEQ_ELTYPE(hullseq);
int total = ptseq->total;
if( total == 0 )
{
if( mat )
CV_Error( CV_StsBadSize,
"Point sequence can not be empty if the output is matrix" );
return hull.s;
}
cv::AutoBuffer<double> _ptbuf;
cv::Mat h0;
cv::convexHull(cv::cvarrToMat(ptseq, false, false, 0, &_ptbuf), h0,
orientation == CV_CLOCKWISE, CV_MAT_CN(hulltype) == 2);
if( hulltype == CV_SEQ_ELTYPE_PPOINT )
{
const int* idx = h0.ptr<int>();
int ctotal = (int)h0.total();
for( int i = 0; i < ctotal; i++ )
{
void* ptr = cvGetSeqElem(ptseq, idx[i]);
cvSeqPush( hullseq, &ptr );
}
}
else
cvSeqPushMulti(hullseq, h0.ptr(), (int)h0.total());
if( mat )
{
if( mat->rows > mat->cols )
mat->rows = hullseq->total;
else
mat->cols = hullseq->total;
}
else
{
hull.s = hullseq;
hull.c->rect = cvBoundingRect( ptseq,
ptseq->header_size < (int)sizeof(CvContour) ||
&ptseq->flags == &contour_header.flags );
}
return hull.s;
}
/* contour must be a simple polygon */
/* it must have more than 3 points */
CV_IMPL CvSeq* cvConvexityDefects( const CvArr* array,
const CvArr* hullarray,
CvMemStorage* storage )
{
CvSeq* defects = 0;
int i, index;
CvPoint* hull_cur;
/* is orientation of hull different from contour one */
int rev_orientation;
CvContour contour_header;
CvSeq hull_header;
CvSeqBlock block, hullblock;
CvSeq *ptseq = (CvSeq*)array, *hull = (CvSeq*)hullarray;
CvSeqReader hull_reader;
CvSeqReader ptseq_reader;
CvSeqWriter writer;
int is_index;
if( CV_IS_SEQ( ptseq ))
{
if( !CV_IS_SEQ_POINT_SET( ptseq ))
CV_Error( CV_StsUnsupportedFormat,
"Input sequence is not a sequence of points" );
if( !storage )
storage = ptseq->storage;
}
else
{
ptseq = cvPointSeqFromMat( CV_SEQ_KIND_GENERIC, array, &contour_header, &block );
}
if( CV_SEQ_ELTYPE( ptseq ) != CV_32SC2 )
CV_Error( CV_StsUnsupportedFormat, "Floating-point coordinates are not supported here" );
if( CV_IS_SEQ( hull ))
{
int hulltype = CV_SEQ_ELTYPE( hull );
if( hulltype != CV_SEQ_ELTYPE_PPOINT && hulltype != CV_SEQ_ELTYPE_INDEX )
CV_Error( CV_StsUnsupportedFormat,
"Convex hull must represented as a sequence "
"of indices or sequence of pointers" );
if( !storage )
storage = hull->storage;
}
else
{
CvMat* mat = (CvMat*)hull;
if( !CV_IS_MAT( hull ))
CV_Error(CV_StsBadArg, "Convex hull is neither sequence nor matrix");
if( (mat->cols != 1 && mat->rows != 1) ||
!CV_IS_MAT_CONT(mat->type) || CV_MAT_TYPE(mat->type) != CV_32SC1 )
CV_Error( CV_StsBadArg,
"The matrix should be 1-dimensional and continuous array of int's" );
if( mat->cols + mat->rows - 1 > ptseq->total )
CV_Error( CV_StsBadSize, "Convex hull is larger than the point sequence" );
hull = cvMakeSeqHeaderForArray(
CV_SEQ_KIND_CURVE|CV_MAT_TYPE(mat->type)|CV_SEQ_FLAG_CLOSED,
sizeof(CvContour), CV_ELEM_SIZE(mat->type), mat->data.ptr,
mat->cols + mat->rows - 1, &hull_header, &hullblock );
}
is_index = CV_SEQ_ELTYPE(hull) == CV_SEQ_ELTYPE_INDEX;
if( !storage )
CV_Error( CV_StsNullPtr, "NULL storage pointer" );
defects = cvCreateSeq( CV_SEQ_KIND_GENERIC, sizeof(CvSeq), sizeof(CvConvexityDefect), storage );
if( ptseq->total < 4 || hull->total < 3)
{
//CV_ERROR( CV_StsBadSize,
// "point seq size must be >= 4, convex hull size must be >= 3" );
return defects;
}
/* recognize co-orientation of ptseq and its hull */
{
int sign = 0;
int index1, index2, index3;
if( !is_index )
{
CvPoint* pos = *CV_SEQ_ELEM( hull, CvPoint*, 0 );
index1 = cvSeqElemIdx( ptseq, pos );
pos = *CV_SEQ_ELEM( hull, CvPoint*, 1 );
index2 = cvSeqElemIdx( ptseq, pos );
pos = *CV_SEQ_ELEM( hull, CvPoint*, 2 );
index3 = cvSeqElemIdx( ptseq, pos );
}
else
{
index1 = *CV_SEQ_ELEM( hull, int, 0 );
index2 = *CV_SEQ_ELEM( hull, int, 1 );
index3 = *CV_SEQ_ELEM( hull, int, 2 );
}
sign += (index2 > index1) ? 1 : 0;
sign += (index3 > index2) ? 1 : 0;
sign += (index1 > index3) ? 1 : 0;
rev_orientation = (sign == 2) ? 0 : 1;
}
cvStartReadSeq( ptseq, &ptseq_reader, 0 );
cvStartReadSeq( hull, &hull_reader, rev_orientation );
if( !is_index )
{
hull_cur = *(CvPoint**)hull_reader.prev_elem;
index = cvSeqElemIdx( ptseq, (char*)hull_cur, 0 );
}
else
{
index = *(int*)hull_reader.prev_elem;
hull_cur = CV_GET_SEQ_ELEM( CvPoint, ptseq, index );
}
cvSetSeqReaderPos( &ptseq_reader, index );
cvStartAppendToSeq( defects, &writer );
/* cycle through ptseq and hull with computing defects */
for( i = 0; i < hull->total; i++ )
{
CvConvexityDefect defect;
int is_defect = 0;
double dx0, dy0;
double depth = 0, scale;
CvPoint* hull_next;
if( !is_index )
hull_next = *(CvPoint**)hull_reader.ptr;
else
{
int t = *(int*)hull_reader.ptr;
hull_next = CV_GET_SEQ_ELEM( CvPoint, ptseq, t );
}
dx0 = (double)hull_next->x - (double)hull_cur->x;
dy0 = (double)hull_next->y - (double)hull_cur->y;
assert( dx0 != 0 || dy0 != 0 );
scale = 1./std::sqrt(dx0*dx0 + dy0*dy0);
defect.start = hull_cur;
defect.end = hull_next;
for(;;)
{
/* go through ptseq to achieve next hull point */
CV_NEXT_SEQ_ELEM( sizeof(CvPoint), ptseq_reader );
if( ptseq_reader.ptr == (schar*)hull_next )
break;
else
{
CvPoint* cur = (CvPoint*)ptseq_reader.ptr;
/* compute distance from current point to hull edge */
double dx = (double)cur->x - (double)hull_cur->x;
double dy = (double)cur->y - (double)hull_cur->y;
/* compute depth */
double dist = fabs(-dy0*dx + dx0*dy) * scale;
if( dist > depth )
{
depth = dist;
defect.depth_point = cur;
defect.depth = (float)depth;
is_defect = 1;
}
}
}
if( is_defect )
{
CV_WRITE_SEQ_ELEM( defect, writer );
}
hull_cur = hull_next;
if( rev_orientation )
{
CV_PREV_SEQ_ELEM( hull->elem_size, hull_reader );
}
else
{
CV_NEXT_SEQ_ELEM( hull->elem_size, hull_reader );
}
}
return cvEndWriteSeq( &writer );
}
CV_IMPL int
cvCheckContourConvexity( const CvArr* array )
{
CvContour contour_header;
CvSeqBlock block;
CvSeq* contour = (CvSeq*)array;
if( CV_IS_SEQ(contour) )
{
if( !CV_IS_SEQ_POINT_SET(contour))
CV_Error( CV_StsUnsupportedFormat,
"Input sequence must be polygon (closed 2d curve)" );
}
else
{
contour = cvPointSeqFromMat(CV_SEQ_KIND_CURVE|
CV_SEQ_FLAG_CLOSED, array, &contour_header, &block );
}
if( contour->total == 0 )
return -1;
cv::AutoBuffer<double> _buf;
return cv::isContourConvex(cv::cvarrToMat(contour, false, false, 0, &_buf)) ? 1 : 0;
}
/* End of file. */