From eaa88e7bc7200a2b9b89b16a52c86eb9df5ad898 Mon Sep 17 00:00:00 2001
From: Alex <alexander.panov@xperience.ai>
Date: Mon, 25 Mar 2024 14:07:03 +0300
Subject: [PATCH] fix detect rotated grid, added test

---
 modules/calib3d/src/circlesgrid.cpp        | 48 ++++++++++++++++------
 modules/calib3d/src/circlesgrid.hpp        |  1 +
 modules/calib3d/test/test_chesscorners.cpp | 37 +++++++++++++++++
 3 files changed, 74 insertions(+), 12 deletions(-)

diff --git a/modules/calib3d/src/circlesgrid.cpp b/modules/calib3d/src/circlesgrid.cpp
index df9534f755..d32913f9ef 100644
--- a/modules/calib3d/src/circlesgrid.cpp
+++ b/modules/calib3d/src/circlesgrid.cpp
@@ -701,22 +701,26 @@ bool CirclesGridFinder::isDetectionCorrect()
   {
     case CirclesGridFinderParameters::SYMMETRIC_GRID:
     {
-      if (holes.size() != patternSize.height)
+      rotatedGrid = holes.size() != patternSize.height && holes.size() == patternSize.width;
+      if (holes.size() != patternSize.height && holes.size() != patternSize.width)
         return false;
 
-      std::set<size_t> vertices;
+      size_t num_vertices = 0ull;
       for (size_t i = 0; i < holes.size(); i++)
       {
-        if (holes[i].size() != patternSize.width)
+        if (holes[i].size() != patternSize.width && rotatedGrid == false)
+        {
           return false;
-
-        for (size_t j = 0; j < holes[i].size(); j++)
+        }
+        else if (holes[i].size() != patternSize.height && rotatedGrid == true)
         {
-          vertices.insert(holes[i][j]);
+          rotatedGrid = false;
+          return false;
         }
-      }
 
-      return vertices.size() == patternSize.area();
+        num_vertices += holes[i].size();
+      }
+      return num_vertices == patternSize.area();
     }
 
     case CirclesGridFinderParameters::ASYMMETRIC_GRID:
@@ -1431,12 +1435,32 @@ Size CirclesGridFinder::getDetectedGridSize() const
 void CirclesGridFinder::getHoles(std::vector<Point2f> &outHoles) const
 {
   outHoles.clear();
-
-  for (size_t i = 0; i < holes.size(); i++)
+  if (rotatedGrid == false)
   {
-    for (size_t j = 0; j < holes[i].size(); j++)
+    for (size_t i = 0ull; i < holes.size(); i++)
     {
-      outHoles.push_back(keypoints[holes[i][j]]);
+      for (size_t j = 0ull; j < holes[i].size(); j++)
+      {
+        outHoles.push_back(keypoints[holes[i][j]]);
+      }
+    }
+  }
+  else
+  {
+    bool visit_all = false;
+    size_t j = 0ull;
+    while (visit_all != true)
+    {
+      visit_all = true;
+      for (size_t i = 0ull; i < holes.size(); i++)
+      {
+        if (j < holes[i].size())
+        {
+          outHoles.push_back(keypoints[holes[i][j]]);
+          visit_all = false;
+        }
+      }
+      j++;
     }
   }
 }
diff --git a/modules/calib3d/src/circlesgrid.hpp b/modules/calib3d/src/circlesgrid.hpp
index f058af7a43..8fba89fd11 100644
--- a/modules/calib3d/src/circlesgrid.hpp
+++ b/modules/calib3d/src/circlesgrid.hpp
@@ -186,6 +186,7 @@ private:
 
   const cv::Size_<size_t> patternSize;
   cv::CirclesGridFinderParameters parameters;
+  bool rotatedGrid = false;
 
   CirclesGridFinder& operator=(const CirclesGridFinder&);
   CirclesGridFinder(const CirclesGridFinder&);
diff --git a/modules/calib3d/test/test_chesscorners.cpp b/modules/calib3d/test/test_chesscorners.cpp
index 56cb81e4ab..a63d5b3e83 100644
--- a/modules/calib3d/test/test_chesscorners.cpp
+++ b/modules/calib3d/test/test_chesscorners.cpp
@@ -792,5 +792,42 @@ TEST(Calib3d_AsymmetricCirclesPatternDetector, regression_19498)
     EXPECT_FALSE(res);
 }
 
+TEST(Calib3d_RotatedCirclesPatternDetector, issue_24964)
+{
+    string path = cvtest::findDataFile("cv/cameracalibration/circles/circles_24964.png");
+    Mat image = cv::imread(path);
+    ASSERT_FALSE(image.empty()) << "Can't read image: " << path;
+
+    vector<Point2f> centers;
+    Size parrernSize(7, 6);
+    Mat goldCenters(parrernSize.height, parrernSize.width, CV_32FC2);
+    Point2f firstGoldCenter(380.f, 430.f);
+    for (int i = 0; i < parrernSize.height; i++)
+    {
+        for (int j = 0; j < parrernSize.width; j++)
+        {
+            goldCenters.at<Point2f>(i, j) = Point2f(firstGoldCenter.x + j * 100.f, firstGoldCenter.y + i * 100.f);
+        }
+    }
+
+    bool found = false;
+    found = findCirclesGrid(image, parrernSize, centers, CALIB_CB_SYMMETRIC_GRID);
+
+    EXPECT_TRUE(found);
+    ASSERT_EQ(centers.size(), (size_t)parrernSize.area());
+    double error = calcError(centers, goldCenters);
+    EXPECT_LE(error, precise_success_error_level);
+
+    // "rotate" the circle grid by 90 degrees
+    swap(parrernSize.height, parrernSize.width);
+
+    found = findCirclesGrid(image, parrernSize, centers, CALIB_CB_SYMMETRIC_GRID);
+    error = calcError(centers, goldCenters.t());
+
+    EXPECT_TRUE(found);
+    ASSERT_EQ(centers.size(), (size_t)parrernSize.area());
+    EXPECT_LE(error, precise_success_error_level);
+}
+
 }} // namespace
 /* End of file. */