Merge pull request #5748 from songyuncen:fix#5745
This commit is contained in:
Vadim Pisarevsky
commit
35d4f998fd
@ -43,163 +43,171 @@
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namespace cv
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{
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static int intersectLines( double x1, double dx1, double y1, double dy1,
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double x2, double dx2, double y2, double dy2, double *t2 )
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// inner product
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static float innerProduct(Point2f &v1, Point2f &v2)
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{
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double d = dx1 * dy2 - dx2 * dy1;
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int result = -1;
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if( d != 0 )
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{
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*t2 = ((x2 - x1) * dy1 - (y2 - y1) * dx1) / d;
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result = 0;
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}
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return result;
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return v1.x * v2.y - v1.y * v2.x;
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}
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static bool findCircle( Point2f pt0, Point2f pt1, Point2f pt2,
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Point2f* center, float* radius )
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static void findCircle3pts(Point2f *pts, Point2f ¢er, float &radius)
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{
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double x1 = (pt0.x + pt1.x) * 0.5;
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double dy1 = pt0.x - pt1.x;
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double x2 = (pt1.x + pt2.x) * 0.5;
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double dy2 = pt1.x - pt2.x;
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double y1 = (pt0.y + pt1.y) * 0.5;
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double dx1 = pt1.y - pt0.y;
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double y2 = (pt1.y + pt2.y) * 0.5;
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double dx2 = pt2.y - pt1.y;
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double t = 0;
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// two edges of the triangle v1, v2
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Point2f v1 = pts[1] - pts[0];
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Point2f v2 = pts[2] - pts[0];
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if( intersectLines( x1, dx1, y1, dy1, x2, dx2, y2, dy2, &t ) >= 0 )
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if (innerProduct(v1, v2) == 0.0f)
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{
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center->x = (float) (x2 + dx2 * t);
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center->y = (float) (y2 + dy2 * t);
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*radius = (float)norm(*center - pt0);
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return true;
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// v1, v2 colineation, can not determine a unique circle
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// find the longtest distance as diameter line
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float d1 = (float)norm(pts[0] - pts[1]);
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float d2 = (float)norm(pts[0] - pts[2]);
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float d3 = (float)norm(pts[1] - pts[2]);
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if (d1 >= d2 && d1 >= d3)
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{
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center = (pts[0] + pts[1]) / 2.0f;
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radius = (d1 / 2.0f);
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}
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else if (d2 >= d1 && d2 >= d3)
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{
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center = (pts[0] + pts[2]) / 2.0f;
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radius = (d2 / 2.0f);
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}
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else if (d3 >= d1 && d3 >= d2)
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{
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center = (pts[1] + pts[2]) / 2.0f;
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radius = (d3 / 2.0f);
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}
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}
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else
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{
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// center is intersection of midperpendicular lines of the two edges v1, v2
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// a1*x + b1*y = c1 where a1 = v1.x, b1 = v1.y
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// a2*x + b2*y = c2 where a2 = v2.x, b2 = v2.y
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Point2f midPoint1 = (pts[0] + pts[1]) / 2.0f;
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float c1 = midPoint1.x * v1.x + midPoint1.y * v1.y;
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Point2f midPoint2 = (pts[0] + pts[2]) / 2.0f;
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float c2 = midPoint2.x * v2.x + midPoint2.y * v2.y;
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float det = v1.x * v2.y - v1.y * v2.x;
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float cx = (c1 * v2.y - c2 * v1.y) / det;
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float cy = (v1.x * c2 - v2.x * c1) / det;
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center.x = (float)cx;
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center.y = (float)cy;
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cx -= pts[0].x;
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cy -= pts[0].y;
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radius = (float)(std::sqrt(cx *cx + cy * cy));
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}
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}
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const float EPS = 1.0e-4f;
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static void findEnclosingCircle3pts_orLess_32f(Point2f *pts, int count, Point2f ¢er, float &radius)
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{
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switch (count)
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{
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case 1:
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center = pts[0];
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radius = 0.0f;
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break;
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case 2:
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center.x = (pts[0].x + pts[1].x) / 2.0f;
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center.y = (pts[0].y + pts[1].y) / 2.0f;
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radius = (float)(norm(pts[0] - pts[1]) / 2.0);
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break;
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case 3:
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findCircle3pts(pts, center, radius);
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break;
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default:
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break;
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}
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center->x = center->y = 0.f;
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*radius = 0;
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return false;
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radius += EPS;
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}
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static double pointInCircle( Point2f pt, Point2f center, float radius )
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template<typename PT>
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static void findThirdPoint(const PT *pts, int i, int j, Point2f ¢er, float &radius)
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{
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double dx = pt.x - center.x;
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double dy = pt.y - center.y;
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return (double)radius*radius - dx*dx - dy*dy;
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}
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center.x = (float)(pts[j].x + pts[i].x) / 2.0f;
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center.y = (float)(pts[j].y + pts[i].y) / 2.0f;
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float dx = (float)(pts[j].x - pts[i].x);
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float dy = (float)(pts[j].y - pts[i].y);
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radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
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static int findEnslosingCicle4pts_32f( Point2f* pts, Point2f& _center, float& _radius )
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{
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int shuffles[4][4] = { {0, 1, 2, 3}, {0, 1, 3, 2}, {2, 3, 0, 1}, {2, 3, 1, 0} };
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int idxs[4] = { 0, 1, 2, 3 };
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int i, j, k = 1, mi = 0;
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float max_dist = 0;
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Point2f center;
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Point2f min_center;
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float radius, min_radius = FLT_MAX;
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Point2f res_pts[4];
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center = min_center = pts[0];
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radius = 1.f;
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for( i = 0; i < 4; i++ )
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for( j = i + 1; j < 4; j++ )
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{
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float dist = (float)norm(pts[i] - pts[j]);
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if( max_dist < dist )
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{
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max_dist = dist;
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idxs[0] = i;
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idxs[1] = j;
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}
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}
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if( max_dist > 0 )
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for (int k = 0; k < j; ++k)
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{
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k = 2;
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for( i = 0; i < 4; i++ )
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dx = center.x - (float)pts[k].x;
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dy = center.y - (float)pts[k].y;
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if (norm(Point2f(dx, dy)) < radius)
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{
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for( j = 0; j < k; j++ )
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if( i == idxs[j] )
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break;
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if( j == k )
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idxs[k++] = i;
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}
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center = Point2f( (pts[idxs[0]].x + pts[idxs[1]].x)*0.5f,
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(pts[idxs[0]].y + pts[idxs[1]].y)*0.5f );
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radius = (float)(norm(pts[idxs[0]] - center)*1.03);
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if( radius < 1.f )
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radius = 1.f;
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if( pointInCircle( pts[idxs[2]], center, radius ) >= 0 &&
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pointInCircle( pts[idxs[3]], center, radius ) >= 0 )
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{
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k = 2; //rand()%2+2;
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continue;
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}
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else
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{
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mi = -1;
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for( i = 0; i < 4; i++ )
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{
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if( findCircle( pts[shuffles[i][0]], pts[shuffles[i][1]],
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pts[shuffles[i][2]], ¢er, &radius ) )
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{
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radius *= 1.03f;
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if( radius < 2.f )
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radius = 2.f;
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if( pointInCircle( pts[shuffles[i][3]], center, radius ) >= 0 &&
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min_radius > radius )
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{
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min_radius = radius;
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min_center = center;
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mi = i;
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}
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}
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}
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CV_Assert( mi >= 0 );
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if( mi < 0 )
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mi = 0;
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k = 3;
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center = min_center;
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radius = min_radius;
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for( i = 0; i < 4; i++ )
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idxs[i] = shuffles[mi][i];
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Point2f ptsf[3];
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ptsf[0] = (Point2f)pts[i];
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ptsf[1] = (Point2f)pts[j];
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ptsf[2] = (Point2f)pts[k];
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findEnclosingCircle3pts_orLess_32f(ptsf, 3, center, radius);
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}
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}
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}
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_center = center;
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_radius = radius;
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/* reorder output points */
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for( i = 0; i < 4; i++ )
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res_pts[i] = pts[idxs[i]];
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template<typename PT>
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void findSecondPoint(const PT *pts, int i, Point2f ¢er, float &radius)
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{
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center.x = (float)(pts[0].x + pts[i].x) / 2.0f;
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center.y = (float)(pts[0].y + pts[i].y) / 2.0f;
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float dx = (float)(pts[0].x - pts[i].x);
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float dy = (float)(pts[0].y - pts[i].y);
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radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
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for( i = 0; i < 4; i++ )
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for (int j = 1; j < i; ++j)
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{
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pts[i] = res_pts[i];
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CV_Assert( pointInCircle( pts[i], center, radius ) >= 0 );
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dx = center.x - (float)pts[j].x;
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dy = center.y - (float)pts[j].y;
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if (norm(Point2f(dx, dy)) < radius)
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{
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continue;
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}
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else
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{
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findThirdPoint(pts, i, j, center, radius);
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}
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}
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return k;
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}
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}
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template<typename PT>
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static void findMinEnclosingCircle(const PT *pts, int count, Point2f ¢er, float &radius)
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{
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center.x = (float)(pts[0].x + pts[1].x) / 2.0f;
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center.y = (float)(pts[0].y + pts[1].y) / 2.0f;
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float dx = (float)(pts[0].x - pts[1].x);
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float dy = (float)(pts[0].y - pts[1].y);
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radius = (float)norm(Point2f(dx, dy)) / 2.0f + EPS;
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for (int i = 2; i < count; ++i)
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{
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dx = (float)pts[i].x - center.x;
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dy = (float)pts[i].y - center.y;
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float d = (float)norm(Point2f(dx, dy));
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if (d < radius)
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{
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continue;
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}
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else
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{
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findSecondPoint(pts, i, center, radius);
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}
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}
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}
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} // namespace cv
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// see Welzl, Emo. Smallest enclosing disks (balls and ellipsoids). Springer Berlin Heidelberg, 1991.
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void cv::minEnclosingCircle( InputArray _points, Point2f& _center, float& _radius )
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{
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int max_iters = 100;
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const float eps = FLT_EPSILON*2;
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bool result = false;
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Mat points = _points.getMat();
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int i, j, k, count = points.checkVector(2);
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int count = points.checkVector(2);
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int depth = points.depth();
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Point2f center;
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float radius = 0.f;
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@ -215,78 +223,50 @@ void cv::minEnclosingCircle( InputArray _points, Point2f& _center, float& _radiu
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const Point* ptsi = points.ptr<Point>();
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const Point2f* ptsf = points.ptr<Point2f>();
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Point2f pt = is_float ? ptsf[0] : Point2f((float)ptsi[0].x,(float)ptsi[0].y);
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Point2f pts[4] = {pt, pt, pt, pt};
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for( i = 1; i < count; i++ )
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// point count <= 3
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if (count <= 3)
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{
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pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
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if( pt.x < pts[0].x )
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pts[0] = pt;
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if( pt.x > pts[1].x )
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pts[1] = pt;
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if( pt.y < pts[2].y )
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pts[2] = pt;
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if( pt.y > pts[3].y )
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pts[3] = pt;
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Point2f ptsf3[3];
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for (int i = 0; i < count; ++i)
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{
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ptsf3[i] = (is_float) ? ptsf[i] : Point2f((float)ptsi[i].x, (float)ptsi[i].y);
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}
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findEnclosingCircle3pts_orLess_32f(ptsf3, count, center, radius);
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_center = center;
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_radius = radius;
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return;
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}
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for( k = 0; k < max_iters; k++ )
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if (is_float)
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{
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double min_delta = 0, delta;
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Point2f farAway(0,0);
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/*only for first iteration because the alg is repared at the loop's foot*/
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if( k == 0 )
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findEnslosingCicle4pts_32f( pts, center, radius );
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for( i = 0; i < count; i++ )
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findMinEnclosingCircle<Point2f>(ptsf, count, center, radius);
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#if 0
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for (size_t m = 0; m < count; ++m)
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{
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pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
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delta = pointInCircle( pt, center, radius );
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if( delta < min_delta )
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float d = (float)norm(ptsf[m] - center);
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if (d > radius)
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{
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min_delta = delta;
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farAway = pt;
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printf("error!\n");
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}
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}
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result = min_delta >= 0;
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if( result )
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break;
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Point2f ptsCopy[4];
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// find good replacement partner for the point which is at most far away,
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// starting with the one that lays in the actual circle (i=3)
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for( i = 3; i >= 0; i-- )
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#endif
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}
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else
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{
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findMinEnclosingCircle<Point>(ptsi, count, center, radius);
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#if 0
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for (size_t m = 0; m < count; ++m)
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{
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for( j = 0; j < 4; j++ )
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ptsCopy[j] = i != j ? pts[j] : farAway;
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findEnslosingCicle4pts_32f( ptsCopy, center, radius );
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if( pointInCircle( pts[i], center, radius ) >= 0)
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double dx = ptsi[m].x - center.x;
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double dy = ptsi[m].y - center.y;
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double d = std::sqrt(dx * dx + dy * dy);
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if (d > radius)
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{
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// replaced one again in the new circle?
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pts[i] = farAway;
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break;
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printf("error!\n");
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}
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}
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#endif
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}
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if( !result )
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{
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radius = 0.f;
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for( i = 0; i < count; i++ )
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{
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pt = is_float ? ptsf[i] : Point2f((float)ptsi[i].x,(float)ptsi[i].y);
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float dx = center.x - pt.x, dy = center.y - pt.y;
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float t = dx*dx + dy*dy;
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radius = MAX(radius, t);
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}
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radius = (float)(std::sqrt(radius)*(1 + eps));
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}
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_center = center;
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_radius = radius;
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}
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