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Commit 35d4f998 authored by Vadim Pisarevsky's avatar Vadim Pisarevsky
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Merge pull request #5748 from songyuncen:fix#5745

parents 6dd5e774 02bb2878
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modules/imgproc/src/shapedescr.cpp
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......@@ -43,163 +43,171 @@
namespace cv
{
static int intersectLines( double x1, double dx1, double y1, double dy1,
double x2, double dx2, double y2, double dy2, double *t2 )
// inner product
static float innerProduct(Point2f &v1, Point2f &v2)
{
double d = dx1 * dy2 - dx2 * dy1;
int result = -1;
if( d != 0 )
{
*t2 = ((x2 - x1) * dy1 - (y2 - y1) * dx1) / d;
result = 0;
}
return result;
return v1.x * v2.y - v1.y * v2.x;
}
static bool findCircle( Point2f pt0, Point2f pt1, Point2f pt2,
Point2f* center, float* radius )
static void findCircle3pts(Point2f *pts, Point2f &center, float &radius)
{
double x1 = (pt0.x + pt1.x) * 0.5;
double dy1 = pt0.x - pt1.x;
double x2 = (pt1.x + pt2.x) * 0.5;
double dy2 = pt1.x - pt2.x;
double y1 = (pt0.y + pt1.y) * 0.5;
double dx1 = pt1.y - pt0.y;
double y2 = (pt1.y + pt2.y) * 0.5;
double dx2 = pt2.y - pt1.y;
double t = 0;
if( intersectLines( x1, dx1, y1, dy1, x2, dx2, y2, dy2, &t ) >= 0 )
// two edges of the triangle v1, v2
Point2f v1 = pts[1] - pts[0];
Point2f v2 = pts[2] - pts[0];
if (innerProduct(v1, v2) == 0.0f)
{
center->x = (float) (x2 + dx2 * t);
center->y = (float) (y2 + dy2 * t);
*radius = (float)norm(*center - pt0);
return true;
// v1, v2 colineation, can not determine a unique circle
// find the longtest distance as diameter line
float d1 = (float)norm(pts[0] - pts[1]);
float d2 = (float)norm(pts[0] - pts[2]);
float d3 = (float)norm(pts[1] - pts[2]);
if (d1 >= d2 && d1 >= d3)
{
center = (pts[0] + pts[1]) / 2.0f;
radius = (d1 / 2.0f);
}
else if (d2 >= d1 && d2 >= d3)
{
center = (pts[0] + pts[2]) / 2.0f;
radius = (d2 / 2.0f);
}
else if (d3 >= d1 && d3 >= d2)
{
center = (pts[1] + pts[2]) / 2.0f;
radius = (d3 / 2.0f);
}
}
else
{
// center is intersection of midperpendicular lines of the two edges v1, v2
// a1*x + b1*y = c1 where a1 = v1.x, b1 = v1.y
// a2*x + b2*y = c2 where a2 = v2.x, b2 = v2.y
Point2f midPoint1 = (pts[0] + pts[1]) / 2.0f;
float c1 = midPoint1.x * v1.x + midPoint1.y * v1.y;
Point2f midPoint2 = (pts[0] + pts[2]) / 2.0f;
float c2 = midPoint2.x * v2.x + midPoint2.y * v2.y;
float det = v1.x * v2.y - v1.y * v2.x;
float cx = (c1 * v2.y - c2 * v1.y) / det;
float cy = (v1.x * c2 - v2.x * c1) / det;
center.x = (float)cx;
center.y = (float)cy;
cx -= pts[0].x;
cy -= pts[0].y;
radius = (float)(std::sqrt(cx *cx + cy * cy));
}
center->x = center->y = 0.f;
*radius = 0;
return false;
}
const float EPS = 1.0e-4f;
static double pointInCircle( Point2f pt, Point2f center, float radius )
static void findEnclosingCircle3pts_orLess_32f(Point2f *pts, int count, Point2f &center, float &radius)
{
double dx = pt.x - center.x;
double dy = pt.y - center.y;
return (double)radius*radius - dx*dx - dy*dy;
}
switch (count)
{
case 1:
center = pts[0];
radius = 0.0f;
break;
case 2:
center.x = (pts[0].x + pts[1].x) / 2.0f;
center.y = (pts[0].y + pts[1].y) / 2.0f;
radius = (float)(norm(pts[0] - pts[1]) / 2.0);
break;
case 3:
findCircle3pts(pts, center, radius);
break;
default:
break;
}
radius += EPS;
}
static int findEnslosingCicle4pts_32f( Point2f* pts, Point2f& _center, float& _radius )
template<typename PT>
static void findThirdPoint(const PT *pts, int i, int j, Point2f &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;
Point2f center;
Point2f min_center;
float radius, min_radius = FLT_MAX;
Point2f res_pts[4];
center = min_center = pts[0];
radius = 1.f;
center.x = (float)(pts[j].x + pts[i].x) / 2.0f;
center.y = (float)(pts[j].y + pts[i].y) / 2.0f;
float dx = (float)(pts[j].x - pts[i].x);
float dy = (float)(pts[j].y - pts[i].y);
radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
for( i = 0; i < 4; i++ )
for( j = i + 1; j < 4; j++ )
for (int k = 0; k < j; ++k)
{
dx = center.x - (float)pts[k].x;
dy = center.y - (float)pts[k].y;
if (norm(Point2f(dx, dy)) < radius)
{
float dist = (float)norm(pts[i] - pts[j]);
if( max_dist < dist )
{
max_dist = dist;
idxs[0] = i;
idxs[1] = j;
}
continue;
}
if( max_dist > 0 )
{
k = 2;
for( i = 0; i < 4; i++ )
else
{
for( j = 0; j < k; j++ )
if( i == idxs[j] )
break;
if( j == k )
idxs[k++] = i;
Point2f ptsf[3];
ptsf[0] = (Point2f)pts[i];
ptsf[1] = (Point2f)pts[j];
ptsf[2] = (Point2f)pts[k];
findEnclosingCircle3pts_orLess_32f(ptsf, 3, center, radius);
}
}
}
center = Point2f( (pts[idxs[0]].x + pts[idxs[1]].x)*0.5f,
(pts[idxs[0]].y + pts[idxs[1]].y)*0.5f );
radius = (float)(norm(pts[idxs[0]] - center)*1.03);
if( radius < 1.f )
radius = 1.f;
if( pointInCircle( pts[idxs[2]], center, radius ) >= 0 &&
pointInCircle( pts[idxs[3]], center, radius ) >= 0 )
template<typename PT>
void findSecondPoint(const PT *pts, int i, Point2f &center, float &radius)
{
center.x = (float)(pts[0].x + pts[i].x) / 2.0f;
center.y = (float)(pts[0].y + pts[i].y) / 2.0f;
float dx = (float)(pts[0].x - pts[i].x);
float dy = (float)(pts[0].y - pts[i].y);
radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
for (int j = 1; j < i; ++j)
{
dx = center.x - (float)pts[j].x;
dy = center.y - (float)pts[j].y;
if (norm(Point2f(dx, dy)) < radius)
{
k = 2; //rand()%2+2;
continue;
}
else
{
mi = -1;
for( i = 0; i < 4; i++ )
{
if( findCircle( pts[shuffles[i][0]], pts[shuffles[i][1]],
pts[shuffles[i][2]], &center, &radius ) )
{
radius *= 1.03f;
if( radius < 2.f )
radius = 2.f;
if( pointInCircle( pts[shuffles[i][3]], center, radius ) >= 0 &&
min_radius > radius )
{
min_radius = radius;
min_center = center;
mi = i;
}
}
}
CV_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];
findThirdPoint(pts, i, j, center, radius);
}
}
}
_center = center;
_radius = radius;
/* reorder output points */
for( i = 0; i < 4; i++ )
res_pts[i] = pts[idxs[i]];
template<typename PT>
static void findMinEnclosingCircle(const PT *pts, int count, Point2f &center, float &radius)
{
center.x = (float)(pts[0].x + pts[1].x) / 2.0f;
center.y = (float)(pts[0].y + pts[1].y) / 2.0f;
float dx = (float)(pts[0].x - pts[1].x);
float dy = (float)(pts[0].y - pts[1].y);
radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
for( i = 0; i < 4; i++ )
for (int i = 2; i < count; ++i)
{
pts[i] = res_pts[i];
CV_Assert( pointInCircle( pts[i], center, radius ) >= 0 );
dx = (float)pts[i].x - center.x;
dy = (float)pts[i].y - center.y;
float d = (float)norm(Point2f(dx, dy));
if (d < radius)
{
continue;
}
else
{
findSecondPoint(pts, i, center, radius);
}
}
return k;
}
}
} // namespace cv
// see Welzl, Emo. Smallest enclosing disks (balls and ellipsoids). Springer Berlin Heidelberg, 1991.
void cv::minEnclosingCircle( InputArray _points, Point2f& _center, float& _radius )
{
int max_iters = 100;
const float eps = FLT_EPSILON*2;
bool result = false;
Mat points = _points.getMat();
int i, j, k, count = points.checkVector(2);
int count = points.checkVector(2);
int depth = points.depth();
Point2f center;
float radius = 0.f;
......@@ -215,78 +223,50 @@ void cv::minEnclosingCircle( InputArray _points, Point2f& _center, float& _radiu
const Point* ptsi = points.ptr<Point>();
const Point2f* ptsf = points.ptr<Point2f>();
Point2f pt = is_float ? ptsf[0] : Point2f((float)ptsi[0].x,(float)ptsi[0].y);
Point2f pts[4] = {pt, pt, pt, pt};
for( i = 1; i < count; i++ )
// point count <= 3
if (count <= 3)
{
pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
if( pt.x < pts[0].x )
pts[0] = pt;
if( pt.x > pts[1].x )
pts[1] = pt;
if( pt.y < pts[2].y )
pts[2] = pt;
if( pt.y > pts[3].y )
pts[3] = pt;
Point2f ptsf3[3];
for (int i = 0; i < count; ++i)
{
ptsf3[i] = (is_float) ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
}
findEnclosingCircle3pts_orLess_32f(ptsf3, count, center, radius);
_center = center;
_radius = radius;
return;
}
for( k = 0; k < max_iters; k++ )
if (is_float)
{
double min_delta = 0, delta;
Point2f farAway(0,0);
/*only for first iteration because the alg is repared at the loop's foot*/
if( k == 0 )
findEnslosingCicle4pts_32f( pts, center, radius );
for( i = 0; i < count; i++ )
findMinEnclosingCircle<Point2f>(ptsf, count, center, radius);
#if 0
for (size_t m = 0; m < count; ++m)
{
pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
delta = pointInCircle( pt, center, radius );
if( delta < min_delta )
float d = (float)norm(ptsf[m] - center);
if (d > radius)
{
min_delta = delta;
farAway = pt;
}
}
result = min_delta >= 0;
if( result )
break;
Point2f 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( i = 3; i >= 0; i-- )
{
for( j = 0; j < 4; j++ )
ptsCopy[j] = i != j ? pts[j] : farAway;
findEnslosingCicle4pts_32f( ptsCopy, center, radius );
if( pointInCircle( pts[i], center, radius ) >= 0)
{
// replaced one again in the new circle?
pts[i] = farAway;
break;
printf("error!\n");
}
}
#endif
}
if( !result )
else
{
radius = 0.f;
for( i = 0; i < count; i++ )
findMinEnclosingCircle<Point>(ptsi, count, center, radius);
#if 0
for (size_t m = 0; m < count; ++m)
{
pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
float dx = center.x - pt.x, dy = center.y - pt.y;
float t = dx*dx + dy*dy;
radius = MAX(radius, t);
double dx = ptsi[m].x - center.x;
double dy = ptsi[m].y - center.y;
double d = std::sqrt(dx * dx + dy * dy);
if (d > radius)
{
printf("error!\n");
}
}
radius = (float)(std::sqrt(radius)*(1 + eps));
#endif
}
_center = center;
_radius = radius;
}
......
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