Merge pull request #27877 from MaximSmolskiy:fix_QRCodeDetector_detectAndDecode_crash

Fix QRCodeDetector::detectAndDecode crash #27877

### Pull Request Readiness Checklist

Fix #27807 

The problem is that when we find closest points from hull, we can get same closest point for several different points

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [ ] The feature is well documented and sample code can be built with the project CMake

modules/objdetect/src/qrcode.cpp

@@ -772,21 +772,27 @@ vector<Point2f> QRDetect::getQuadrilateral(vector<Point2f> angle_list)
     const double experimental_area = fabs(contourArea(hull));
 
     vector<Point2f> result_hull_point(angle_size);
+    vector<bool> used_hull_point(hull_size, false);
     double min_norm;
     for (size_t i = 0; i < angle_size; i++)
     {
         min_norm = std::numeric_limits<double>::max();
-        Point closest_pnt;
+        int closest_pnt_idx = -1;
         for (int j = 0; j < hull_size; j++)
         {
+            if (used_hull_point[j])
+            {
+                continue;
+            }
             double temp_norm = norm(hull[j] - angle_list[i]);
             if (min_norm > temp_norm)
             {
                 min_norm = temp_norm;
-                closest_pnt = hull[j];
+                closest_pnt_idx = j;
             }
         }
-        result_hull_point[i] = closest_pnt;
+        result_hull_point[i] = hull[closest_pnt_idx];
+        used_hull_point[closest_pnt_idx] = true;
     }
 
     int start_line[2] = { 0, 0 }, finish_line[2] = { 0, 0 }, unstable_pnt = 0;
@@ -2958,12 +2964,7 @@ std::string ImplContour::decode(InputArray in, InputArray points, OutputArray st
     vector<Point2f> src_points;
     points.copyTo(src_points);
     CV_Assert(src_points.size() == 4);
-    if (contourArea(src_points) <= 0.0)
-    {
-        if (straight_qrcode.needed())
-            straight_qrcode.release();
-        return std::string();
-    }
+    CV_CheckGT(contourArea(src_points), 0.0, "Invalid QR code source points");
 
     QRDecode qrdec(useAlignmentMarkers);
     qrdec.init(inarr, src_points);