opencv/modules/imgproc/test/test_fitellipse.cpp
Vadim Pisarevsky 8abb312c20
Merge pull request #17417 from vpisarev:fix_fitellipse
* improved fitEllipse and fitEllipseDirect accuracy in singular or close-to-singular cases (see issue #9923)

* scale points using double precision

* added normalization to fitEllipseAMS as well; fixed Java test case by raising the tolerance (it's unclear what is the correct result in this case).

* improved point perturbation a bit. make the code a little bit more clear

* trying to fix Java fitEllipseTest by slightly raising the tolerance threshold

* synchronized C++ version of Java's fitEllipse test

* removed trailing whitespaces
2020-06-01 18:01:20 +00:00

106 lines
3.6 KiB
C++

// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2016, Itseez, Inc, all rights reserved.
#include "test_precomp.hpp"
namespace opencv_test { namespace {
// return true if point lies inside ellipse
static bool check_pt_in_ellipse(const Point2f& pt, const RotatedRect& el) {
Point2f to_pt = pt - el.center;
double pt_angle = atan2(to_pt.y, to_pt.x);
double el_angle = el.angle * CV_PI / 180;
double x_dist = 0.5 * el.size.width * cos(pt_angle + el_angle);
double y_dist = 0.5 * el.size.height * sin(pt_angle + el_angle);
double el_dist = sqrt(x_dist * x_dist + y_dist * y_dist);
return cv::norm(to_pt) < el_dist;
}
// Return true if mass center of fitted points lies inside ellipse
static bool fit_and_check_ellipse(const vector<Point2f>& pts) {
RotatedRect ellipse = fitEllipseDirect(pts); // fitEllipseAMS() also works fine
Point2f mass_center;
for (size_t i = 0; i < pts.size(); i++) {
mass_center += pts[i];
}
mass_center /= (float)pts.size();
return check_pt_in_ellipse(mass_center, ellipse);
}
TEST(Imgproc_FitEllipse_Issue_4515, accuracy) {
vector<Point2f> pts;
pts.push_back(Point2f(327, 317));
pts.push_back(Point2f(328, 316));
pts.push_back(Point2f(329, 315));
pts.push_back(Point2f(330, 314));
pts.push_back(Point2f(331, 314));
pts.push_back(Point2f(332, 314));
pts.push_back(Point2f(333, 315));
pts.push_back(Point2f(333, 316));
pts.push_back(Point2f(333, 317));
pts.push_back(Point2f(333, 318));
pts.push_back(Point2f(333, 319));
pts.push_back(Point2f(333, 320));
EXPECT_TRUE(fit_and_check_ellipse(pts));
}
TEST(Imgproc_FitEllipse_Issue_6544, accuracy) {
vector<Point2f> pts;
pts.push_back(Point2f(924.784f, 764.160f));
pts.push_back(Point2f(928.388f, 615.903f));
pts.push_back(Point2f(847.4f, 888.014f));
pts.push_back(Point2f(929.406f, 741.675f));
pts.push_back(Point2f(904.564f, 825.605f));
pts.push_back(Point2f(926.742f, 760.746f));
pts.push_back(Point2f(863.479f, 873.406f));
pts.push_back(Point2f(910.987f, 808.863f));
pts.push_back(Point2f(929.145f, 744.976f));
pts.push_back(Point2f(917.474f, 791.823f));
EXPECT_TRUE(fit_and_check_ellipse(pts));
}
TEST(Imgproc_FitEllipse_Issue_10270, accuracy) {
vector<Point2f> pts;
float scale = 1;
Point2f shift(0, 0);
pts.push_back(Point2f(0, 1)*scale+shift);
pts.push_back(Point2f(0, 2)*scale+shift);
pts.push_back(Point2f(0, 3)*scale+shift);
pts.push_back(Point2f(2, 3)*scale+shift);
pts.push_back(Point2f(0, 4)*scale+shift);
// check that we get almost vertical ellipse centered around (1, 3)
RotatedRect e = fitEllipse(pts);
EXPECT_LT(std::min(fabs(e.angle-180), fabs(e.angle)), 10.);
EXPECT_NEAR(e.center.x, 1, 1);
EXPECT_NEAR(e.center.y, 3, 1);
EXPECT_LT(e.size.width*3, e.size.height);
}
TEST(Imgproc_FitEllipse_JavaCase, accuracy) {
vector<Point2f> pts;
float scale = 1;
Point2f shift(0, 0);
pts.push_back(Point2f(0, 0)*scale+shift);
pts.push_back(Point2f(1, 1)*scale+shift);
pts.push_back(Point2f(-1, 1)*scale+shift);
pts.push_back(Point2f(-1, -1)*scale+shift);
pts.push_back(Point2f(1, -1)*scale+shift);
// check that we get almost vertical ellipse centered around (1, 3)
RotatedRect e = fitEllipse(pts);
EXPECT_NEAR(e.center.x, 0, 0.01);
EXPECT_NEAR(e.center.y, 0, 0.01);
EXPECT_NEAR(e.size.width, sqrt(2.)*2, 0.4);
EXPECT_NEAR(e.size.height, sqrt(2.)*2, 0.4);
}
}} // namespace