imgproc: fixed bug from intersectConvexConvex

Added checks for all of vertices from each contour instead of checking
only for the first vertex.

modules/imgproc/src/geometry.cpp

@@ -563,21 +563,41 @@ float cv::intersectConvexConvex( InputArray _p1, InputArray _p2, OutputArray _p1
             return 0.f;
         }
 
-        if( pointPolygonTest(_InputArray(fp1, n), fp2[0], false) >= 0 )
+        bool intersected = false;
+
+        // check if all of fp2's vertices is inside/on the edge of fp1.
+        int nVertices = 0;
+        for (int i=0; i<m; ++i)
+            nVertices += pointPolygonTest(_InputArray(fp1, n), fp2[i], false) >= 0;
+
+        // if all of fp2's vertices is inside/on the edge of fp1.
+        if (nVertices == m)
         {
+            intersected = true;
             result = fp2;
             nr = m;
         }
-        else if( pointPolygonTest(_InputArray(fp2, m), fp1[0], false) >= 0 )
+        else // otherwise check if fp2 is inside fp1.
         {
-            result = fp1;
-            nr = n;
+            nVertices = 0;
+            for (int i=0; i<n; ++i)
+                nVertices += pointPolygonTest(_InputArray(fp2, m), fp1[i], false) >= 0;
+
+            // // if all of fp1's vertices is inside/on the edge of fp2.
+            if (nVertices == n)
+            {
+                intersected = true;
+                result = fp1;
+                nr = n;
+            }
         }
-        else
+
+        if (!intersected)
         {
             _p12.release();
             return 0.f;
         }
+
         area = (float)contourArea(_InputArray(result, nr), false);
     }
 

modules/imgproc/test/test_intersectconvexconvex.cpp

+// 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.
+
+#include "test_precomp.hpp"
+
+namespace opencv_test { namespace {
+
+
+TEST(Imgproc_IntersectConvexConvex, no_intersection)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(290, 126));
+    convex1.push_back(cv::Point(284, 132));
+    convex1.push_back(cv::Point(281, 133));
+    convex1.push_back(cv::Point(256, 124));
+    convex1.push_back(cv::Point(249, 116));
+    convex1.push_back(cv::Point(234, 91));
+    convex1.push_back(cv::Point(232, 86));
+    convex1.push_back(cv::Point(232, 79));
+    convex1.push_back(cv::Point(251, 69));
+    convex1.push_back(cv::Point(257, 68));
+    convex1.push_back(cv::Point(297, 85));
+    convex1.push_back(cv::Point(299, 87));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(192, 236));
+    convex2.push_back(cv::Point(190, 245));
+    convex2.push_back(cv::Point(177, 260));
+    convex2.push_back(cv::Point(154, 271));
+    convex2.push_back(cv::Point(142, 270));
+    convex2.push_back(cv::Point(135, 263));
+    convex2.push_back(cv::Point(131, 254));
+    convex2.push_back(cv::Point(132, 240));
+    convex2.push_back(cv::Point(172, 213));
+    convex2.push_back(cv::Point(176, 216));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    EXPECT_TRUE(intersection.empty());
+    EXPECT_NEAR(area, 0, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, no_intersection_with_1_vertex_on_edge_1)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(0, 210));
+    convex2.push_back(cv::Point(-30, 210));
+    convex2.push_back(cv::Point(-37, 170));
+    convex2.push_back(cv::Point(-7, 172));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    EXPECT_TRUE(intersection.empty());
+    EXPECT_NEAR(area, 0, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, no_intersection_with_1_vertex_on_edge_2)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(740, 210));
+    convex2.push_back(cv::Point(750, 100));
+    convex2.push_back(cv::Point(790, 250));
+    convex2.push_back(cv::Point(800, 500));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    EXPECT_TRUE(intersection.empty());
+    EXPECT_NEAR(area, 0, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_with_1_vertex_on_edge)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(30, 210));
+    convex2.push_back(cv::Point(0,210));
+    convex2.push_back(cv::Point(7, 172));
+    convex2.push_back(cv::Point(37, 170));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(0, 210));
+    expected_intersection.push_back(cv::Point(7, 172));
+    expected_intersection.push_back(cv::Point(37, 170));
+    expected_intersection.push_back(cv::Point(30, 210));
+
+    EXPECT_EQ(intersection, expected_intersection);
+    EXPECT_NEAR(area, 1163, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_with_2_vertices_on_edge)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(30, 210));
+    convex2.push_back(cv::Point(37, 170));
+    convex2.push_back(cv::Point(0,210));
+    convex2.push_back(cv::Point(0, 300));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(0, 300));
+    expected_intersection.push_back(cv::Point(0, 210));
+    expected_intersection.push_back(cv::Point(37, 170));
+    expected_intersection.push_back(cv::Point(30, 210));
+
+    EXPECT_EQ(intersection, expected_intersection);
+    EXPECT_NEAR(area, 1950, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_1)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(20,210));
+    convex2.push_back(cv::Point(30, 210));
+    convex2.push_back(cv::Point(37, 170));
+    convex2.push_back(cv::Point(7, 172));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(7, 172));
+    expected_intersection.push_back(cv::Point(37, 170));
+    expected_intersection.push_back(cv::Point(30, 210));
+    expected_intersection.push_back(cv::Point(20, 210));
+
+    EXPECT_EQ(intersection, expected_intersection);
+    EXPECT_NEAR(area, 783, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_2)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(0,0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(0, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(-2,210));
+    convex2.push_back(cv::Point(-5, 300));
+    convex2.push_back(cv::Point(37, 150));
+    convex2.push_back(cv::Point(7, 172));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(0, 202));
+    expected_intersection.push_back(cv::Point(7, 172));
+    expected_intersection.push_back(cv::Point(37, 150));
+    expected_intersection.push_back(cv::Point(0, 282));
+
+    EXPECT_EQ(intersection, expected_intersection);
+    EXPECT_NEAR(area, 1857.19836425781, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_3)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(15, 0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(15, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(0,210));
+    convex2.push_back(cv::Point(30, 210));
+    convex2.push_back(cv::Point(37, 170));
+    convex2.push_back(cv::Point(7, 172));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(15, 171));
+    expected_intersection.push_back(cv::Point(37, 170));
+    expected_intersection.push_back(cv::Point(30, 210));
+    expected_intersection.push_back(cv::Point(15, 210));
+
+    EXPECT_EQ(intersection, expected_intersection);
+
+    EXPECT_NEAR(area, 723.866760253906, std::numeric_limits<float>::epsilon());
+}
+
+
+TEST(Imgproc_IntersectConvexConvex, intersection_4)
+{
+    std::vector<cv::Point> convex1;
+    convex1.push_back(cv::Point(15, 0));
+    convex1.push_back(cv::Point(740, 0));
+    convex1.push_back(cv::Point(740, 540));
+    convex1.push_back(cv::Point(15, 540));
+
+    std::vector<cv::Point> convex2;
+    convex2.push_back(cv::Point(15, 0));
+    convex2.push_back(cv::Point(740, 0));
+    convex2.push_back(cv::Point(740, 540));
+    convex2.push_back(cv::Point(15, 540));
+
+    std::vector<cv::Point> intersection;
+    float area = cv::intersectConvexConvex(convex1, convex2, intersection);
+
+    std::vector<cv::Point> expected_intersection;
+    expected_intersection.push_back(cv::Point(15, 0));
+    expected_intersection.push_back(cv::Point(740, 0));
+    expected_intersection.push_back(cv::Point(740, 540));
+    expected_intersection.push_back(cv::Point(15, 540));
+
+    EXPECT_EQ(intersection, expected_intersection);
+    EXPECT_NEAR(area, 391500, std::numeric_limits<float>::epsilon());
+}
+
+
+} // namespace
+} // opencv_test