CV_IMPL void
cvMinEnclosingCircle( CvSeq * sequence, CvPoint2D32f * _center, float *_radius )
{
const int max_iters = 20;
CvSeqReader reader;
int i, k, count;
CvPoint *pt_left, *pt_right, *pt_top, *pt_bottom;
CvPoint pt;
CvPoint2D32f center = { 0, 0 };
CvPoint2D32f pts[8];
float radius = 0;
if( _center )
_center->x = _center->y = 0.f;
if( _radius )
*_radius = 0;
CV_FUNCNAME( "cvMinEnclosingCircle" );
__BEGIN__;
if( !sequence || !_center || !_radius )
CV_ERROR_FROM_STATUS( CV_NULLPTR_ERR );
if( sequence->total <= 0 )
CV_ERROR_FROM_STATUS( CV_BADSIZE_ERR );
if( !CV_IS_SEQ_POINT_SET( sequence ))
CV_ERROR_FROM_STATUS( CV_BADFLAG_ERR );
CV_CALL( cvStartReadSeq( sequence, &reader, 0 ));
pt_left = pt_right = pt_top = pt_bottom = (CvPoint *) (reader.ptr);
CV_READ_SEQ_ELEM( pt, reader );
count = sequence->total;
for( i = 1; i < count; i++ )
{
CvPoint *pt_ptr = (CvPoint *) (reader.ptr);
CvPoint pt;
CV_READ_SEQ_ELEM( pt, reader );
if( pt.x < pt_left->x )
pt_left = pt_ptr;
if( pt.x > pt_right->x )
pt_right = pt_ptr;
if( pt.y < pt_top->y )
pt_top = pt_ptr;
if( pt.y > pt_bottom->y )
pt_bottom = pt_ptr;
}
pts[0] = icvCvtPoint32s_32f( *pt_left );
pts[1] = icvCvtPoint32s_32f( *pt_right );
pts[2] = icvCvtPoint32s_32f( *pt_top );
pts[3] = icvCvtPoint32s_32f( *pt_bottom );
for( k = 0; k < max_iters; k++ )
{
icvFindEnslosingCicle4pts_32f( pts, ¢er, &radius );
cvStartReadSeq( sequence, &reader, 0 );
for( i = 0; i < count; i++ )
{
CvPoint pt;
CvPoint2D32f ptfl;
CV_READ_SEQ_ELEM( pt, reader );
ptfl = icvCvtPoint32s_32f( pt );
if( !icvIsPtInCircle( ptfl, center, radius ))
{
pts[3] = ptfl;
break;
}
}
if( i == count )
break;
}
__CLEANUP__;
__END__;
*_center = center;
*_radius = radius;
}
CV_IMPL int
cvMinEnclosingCircle( const void* array, CvPoint2D32f * _center, float *_radius )
{
const int max_iters = 100;
const float eps = FLT_EPSILON*2;
CvPoint2D32f center = { 0, 0 };
float radius = 0;
int result = 0;
if( _center )
_center->x = _center->y = 0.f;
if( _radius )
*_radius = 0;
CV_FUNCNAME( "cvMinEnclosingCircle" );
__BEGIN__;
CvSeqReader reader;
int i, k, count;
CvPoint2D32f pts[8];
CvContour contour_header;
CvSeqBlock block;
CvSeq* sequence = 0;
int is_float;
if( !_center || !_radius )
CV_ERROR( CV_StsNullPtr, "Null center or radius pointers" );
if( CV_IS_SEQ(array) )
{
sequence = (CvSeq*)array;
if( !CV_IS_SEQ_POINT_SET( sequence ))
CV_ERROR( CV_StsBadArg, "The passed sequence is not a valid contour" );
}
else
{
CV_CALL( sequence = cvPointSeqFromMat(
CV_SEQ_KIND_GENERIC, array, &contour_header, &block ));
}
if( sequence->total <= 0 )
CV_ERROR_FROM_STATUS( CV_BADSIZE_ERR );
CV_CALL( cvStartReadSeq( sequence, &reader, 0 ));
count = sequence->total;
is_float = CV_SEQ_ELTYPE(sequence) == CV_32FC2;
if( !is_float )
{
CvPoint *pt_left, *pt_right, *pt_top, *pt_bottom;
CvPoint pt;
pt_left = pt_right = pt_top = pt_bottom = (CvPoint *)(reader.ptr);
CV_READ_SEQ_ELEM( pt, reader );
for( i = 1; i < count; i++ )
{
CvPoint* pt_ptr = (CvPoint*)reader.ptr;
CV_READ_SEQ_ELEM( pt, reader );
if( pt.x < pt_left->x )
pt_left = pt_ptr;
if( pt.x > pt_right->x )
pt_right = pt_ptr;
if( pt.y < pt_top->y )
pt_top = pt_ptr;
if( pt.y > pt_bottom->y )
pt_bottom = pt_ptr;
}
pts[0] = cvPointTo32f( *pt_left );
pts[1] = cvPointTo32f( *pt_right );
pts[2] = cvPointTo32f( *pt_top );
pts[3] = cvPointTo32f( *pt_bottom );
}
else
{
CvPoint2D32f *pt_left, *pt_right, *pt_top, *pt_bottom;
CvPoint2D32f pt;
pt_left = pt_right = pt_top = pt_bottom = (CvPoint2D32f *) (reader.ptr);
CV_READ_SEQ_ELEM( pt, reader );
for( i = 1; i < count; i++ )
{
CvPoint2D32f* pt_ptr = (CvPoint2D32f*)reader.ptr;
CV_READ_SEQ_ELEM( pt, reader );
if( pt.x < pt_left->x )
pt_left = pt_ptr;
if( pt.x > pt_right->x )
pt_right = pt_ptr;
if( pt.y < pt_top->y )
pt_top = pt_ptr;
if( pt.y > pt_bottom->y )
pt_bottom = pt_ptr;
}
pts[0] = *pt_left;
pts[1] = *pt_right;
pts[2] = *pt_top;
pts[3] = *pt_bottom;
}
for( k = 0; k < max_iters; k++ )
{
double min_delta = 0, delta;
CvPoint2D32f ptfl;
icvFindEnslosingCicle4pts_32f( pts, ¢er, &radius );
cvStartReadSeq( sequence, &reader, 0 );
for( i = 0; i < count; i++ )
{
if( !is_float )
{
ptfl.x = (float)((CvPoint*)reader.ptr)->x;
ptfl.y = (float)((CvPoint*)reader.ptr)->y;
}
else
{
ptfl = *(CvPoint2D32f*)reader.ptr;
}
CV_NEXT_SEQ_ELEM( sequence->elem_size, reader );
delta = icvIsPtInCircle( ptfl, center, radius );
if( delta < min_delta )
{
min_delta = delta;
pts[3] = ptfl;
}
}
result = min_delta >= 0;
if( result )
break;
}
if( !result )
{
cvStartReadSeq( sequence, &reader, 0 );
radius = 0.f;
for( i = 0; i < count; i++ )
{
CvPoint2D32f ptfl;
float t, dx, dy;
if( !is_float )
{
ptfl.x = (float)((CvPoint*)reader.ptr)->x;
ptfl.y = (float)((CvPoint*)reader.ptr)->y;
}
else
{
ptfl = *(CvPoint2D32f*)reader.ptr;
}
CV_NEXT_SEQ_ELEM( sequence->elem_size, reader );
dx = center.x - ptfl.x;
dy = center.y - ptfl.y;
t = dx*dx + dy*dy;
radius = MAX(radius,t);
}
radius = (float)(sqrt(radius)*(1 + eps));
result = 1;
}
__END__;
*_center = center;
*_radius = radius;
return result;
}
int
icvFindEnslosingCicle4pts_32f( CvPoint2D32f * pts, CvPoint2D32f * _center, float *_radius )
{
int shuffles[4][4] = { {0, 1, 2, 3}, {0, 1, 3, 2}, {2, 3, 0, 1}, {2, 3, 1, 0} };
int idxs[4] = { 0, 1, 2, 3 };
int i, j, k = 1, mi = 0;
float max_dist = 0;
CvPoint2D32f center;
CvPoint2D32f min_center;
float radius, min_radius = FLT_MAX;
CvPoint2D32f res_pts[4];
center = min_center = pts[0];
radius = 1.f;
for( i = 0; i < 4; i++ )
for( j = i + 1; j < 4; j++ )
{
float dist = icvDistanceL2_32f( pts[i], pts[j] );
if( max_dist < dist )
{
max_dist = dist;
idxs[0] = i;
idxs[1] = j;
}
}
if( max_dist == 0 )
goto function_exit;
k = 2;
for( i = 0; i < 4; i++ )
{
for( j = 0; j < k; j++ )
if( i == idxs[j] )
break;
if( j == k )
idxs[k++] = i;
}
center = icvMidPoint( pts[idxs[0]], pts[idxs[1]] );
radius = (float) (icvDistanceL2_32f( pts[idxs[0]], center ) * (1 + 0.03));
if( radius < 1.f )
radius = 1.f;
if( icvIsPtInCircle( pts[idxs[2]], center, radius ) &&
icvIsPtInCircle( pts[idxs[3]], center, radius ))
{
k = 2;
}
else
{
mi = -1;
for( i = 0; i < 4; i++ )
{
if( icvFindCircle( pts[shuffles[i][0]], pts[shuffles[i][1]],
pts[shuffles[i][2]], ¢er, &radius ) >= 0 )
{
radius *= 1.03f;
if( radius < 2.f )
radius = 2.f;
if( icvIsPtInCircle( pts[shuffles[i][3]], center, radius ) &&
min_radius > radius )
{
min_radius = radius;
min_center = center;
mi = i;
}
}
}
assert( mi >= 0 );
if( mi < 0 )
mi = 0;
k = 3;
center = min_center;
radius = min_radius;
for( i = 0; i < 4; i++ )
idxs[i] = shuffles[mi][i];
}
function_exit:
*_center = center;
*_radius = radius;
/* reorder output points */
for( i = 0; i < 4; i++ )
{
res_pts[i] = pts[idxs[i]];
}
for( i = 0; i < 4; i++ )
{
pts[i] = res_pts[i];
}
return k;
}
CV_IMPL int
cvMinEnclosingCircle( const void* array, CvPoint2D32f * _center, float *_radius )
{
const int max_iters = 100;
const float eps = FLT_EPSILON*2;
CvPoint2D32f center = { 0, 0 };
float radius = 0;
int result = 0;
if( _center )
_center->x = _center->y = 0.f;
if( _radius )
*_radius = 0;
CvSeqReader reader;
int k, count;
CvPoint2D32f pts[8];
CvContour contour_header;
CvSeqBlock block;
CvSeq* sequence = 0;
int is_float;
if( !_center || !_radius )
CV_Error( CV_StsNullPtr, "Null center or radius pointers" );
if( CV_IS_SEQ(array) )
{
sequence = (CvSeq*)array;
if( !CV_IS_SEQ_POINT_SET( sequence ))
CV_Error( CV_StsBadArg, "The passed sequence is not a valid contour" );
}
else
{
sequence = cvPointSeqFromMat(
CV_SEQ_KIND_GENERIC, array, &contour_header, &block );
}
if( sequence->total <= 0 )
CV_Error( CV_StsBadSize, "" );
cvStartReadSeq( sequence, &reader, 0 );
count = sequence->total;
is_float = CV_SEQ_ELTYPE(sequence) == CV_32FC2;
if( !is_float )
{
CvPoint *pt_left, *pt_right, *pt_top, *pt_bottom;
CvPoint pt;
pt_left = pt_right = pt_top = pt_bottom = (CvPoint *)(reader.ptr);
CV_READ_SEQ_ELEM( pt, reader );
for(int i = 1; i < count; i++ )
{
CvPoint* pt_ptr = (CvPoint*)reader.ptr;
CV_READ_SEQ_ELEM( pt, reader );
if( pt.x < pt_left->x )
pt_left = pt_ptr;
if( pt.x > pt_right->x )
pt_right = pt_ptr;
if( pt.y < pt_top->y )
pt_top = pt_ptr;
if( pt.y > pt_bottom->y )
pt_bottom = pt_ptr;
}
pts[0] = cvPointTo32f( *pt_left );
pts[1] = cvPointTo32f( *pt_right );
pts[2] = cvPointTo32f( *pt_top );
pts[3] = cvPointTo32f( *pt_bottom );
}
else
{
CvPoint2D32f *pt_left, *pt_right, *pt_top, *pt_bottom;
CvPoint2D32f pt;
pt_left = pt_right = pt_top = pt_bottom = (CvPoint2D32f *) (reader.ptr);
CV_READ_SEQ_ELEM( pt, reader );
for(int i = 1; i < count; i++ )
{
CvPoint2D32f* pt_ptr = (CvPoint2D32f*)reader.ptr;
CV_READ_SEQ_ELEM( pt, reader );
if( pt.x < pt_left->x )
pt_left = pt_ptr;
if( pt.x > pt_right->x )
pt_right = pt_ptr;
if( pt.y < pt_top->y )
pt_top = pt_ptr;
if( pt.y > pt_bottom->y )
pt_bottom = pt_ptr;
}
pts[0] = *pt_left;
pts[1] = *pt_right;
pts[2] = *pt_top;
pts[3] = *pt_bottom;
}
for( k = 0; k < max_iters; k++ )
{
double min_delta = 0, delta;
CvPoint2D32f ptfl, farAway = { 0, 0};
/*only for first iteration because the alg is repared at the loop's foot*/
if(k==0)
icvFindEnslosingCicle4pts_32f( pts, ¢er, &radius );
cvStartReadSeq( sequence, &reader, 0 );
for(int i = 0; i < count; i++ )
{
if( !is_float )
{
ptfl.x = (float)((CvPoint*)reader.ptr)->x;
ptfl.y = (float)((CvPoint*)reader.ptr)->y;
}
else
{
ptfl = *(CvPoint2D32f*)reader.ptr;
}
CV_NEXT_SEQ_ELEM( sequence->elem_size, reader );
delta = icvIsPtInCircle( ptfl, center, radius );
if( delta < min_delta )
{
min_delta = delta;
farAway = ptfl;
}
}
result = min_delta >= 0;
if( result )
break;
CvPoint2D32f ptsCopy[4];
/* find good replacement partner for the point which is at most far away,
starting with the one that lays in the actual circle (i=3) */
for(int i = 3; i >=0; i-- )
{
for(int j = 0; j < 4; j++ )
{
ptsCopy[j]=(i != j)? pts[j]: farAway;
}
icvFindEnslosingCicle4pts_32f(ptsCopy, ¢er, &radius );
if( icvIsPtInCircle( pts[i], center, radius )>=0){ // replaced one again in the new circle?
pts[i] = farAway;
break;
}
}
}
if( !result )
{
cvStartReadSeq( sequence, &reader, 0 );
radius = 0.f;
for(int i = 0; i < count; i++ )
{
CvPoint2D32f ptfl;
float t, dx, dy;
if( !is_float )
{
ptfl.x = (float)((CvPoint*)reader.ptr)->x;
ptfl.y = (float)((CvPoint*)reader.ptr)->y;
}
else
{
ptfl = *(CvPoint2D32f*)reader.ptr;
}
CV_NEXT_SEQ_ELEM( sequence->elem_size, reader );
dx = center.x - ptfl.x;
dy = center.y - ptfl.y;
t = dx*dx + dy*dy;
radius = MAX(radius,t);
}
radius = (float)(sqrt(radius)*(1 + eps));
result = 1;
}
*_center = center;
*_radius = radius;
return result;
}
