Merge pull request #25045 from AleksandrPanov:aruco_fix_unnecessary_copying

fix unnecessary copying in ArucoDetector

modules/objdetect/src/aruco/aruco_detector.cpp

@@ -145,10 +145,8 @@ static void _findMarkerContours(const Mat &in, vector<vector<Point2f> > &candida
         minPerimeterPixels = 4*minSize;
     }
 
-    Mat contoursImg;
-    in.copyTo(contoursImg);
     vector<vector<Point> > contours;
-    findContours(contoursImg, contours, RETR_LIST, CHAIN_APPROX_NONE);
+    findContours(in, contours, RETR_LIST, CHAIN_APPROX_NONE);
     // now filter list of contours
     for(unsigned int i = 0; i < contours.size(); i++) {
         // check perimeter
@@ -161,8 +159,7 @@ static void _findMarkerContours(const Mat &in, vector<vector<Point2f> > &candida
         if(approxCurve.size() != 4 || !isContourConvex(approxCurve)) continue;
 
         // check min distance between corners
-        double minDistSq =
-            max(contoursImg.cols, contoursImg.rows) * max(contoursImg.cols, contoursImg.rows);
+        double minDistSq = max(in.cols, in.rows) * max(in.cols, in.rows);
         for(int j = 0; j < 4; j++) {
             double d = (double)(approxCurve[j].x - approxCurve[(j + 1) % 4].x) *
                            (double)(approxCurve[j].x - approxCurve[(j + 1) % 4].x) +
@@ -177,9 +174,9 @@ static void _findMarkerContours(const Mat &in, vector<vector<Point2f> > &candida
         bool tooNearBorder = false;
         for(int j = 0; j < 4; j++) {
             if(approxCurve[j].x < minDistanceToBorder || approxCurve[j].y < minDistanceToBorder ||
-               approxCurve[j].x > contoursImg.cols - 1 - minDistanceToBorder ||
-               approxCurve[j].y > contoursImg.rows - 1 - minDistanceToBorder)
-                tooNearBorder = true;
+               approxCurve[j].x > in.cols - 1 - minDistanceToBorder ||
+               approxCurve[j].y > in.rows - 1 - minDistanceToBorder)
+               tooNearBorder = true;
         }
         if(tooNearBorder) continue;
 
@@ -883,7 +880,7 @@ void ArucoDetector::detectMarkers(InputArray _image, OutputArrayOfArrays _corner
                 detectorParams.minMarkerLengthRatioOriginalImg == 0.0));
 
     Mat grey;
-    _convertToGrey(_image.getMat(), grey);
+    _convertToGrey(_image, grey);
 
     // Aruco3 functionality is the extension of Aruco.
     // The description can be found in:

modules/objdetect/src/aruco/aruco_utils.cpp

@@ -38,12 +38,12 @@ void _copyVector2Output(vector<vector<Point2f> > &vec, OutputArrayOfArrays out,
     }
 }
 
-void _convertToGrey(InputArray _in, OutputArray _out) {
-    CV_Assert(_in.type() == CV_8UC1 || _in.type() == CV_8UC3);
-    if(_in.type() == CV_8UC3)
+void _convertToGrey(InputArray _in, Mat& _out) {
+    CV_Assert(_in.type() == CV_8UC1 || _in.type() == CV_8UC3 || _in.type() == CV_8UC4);
+    if(_in.type() != CV_8UC1)
         cvtColor(_in, _out, COLOR_BGR2GRAY);
     else
-        _in.copyTo(_out);
+        _out = _in.getMat();
 }
 
 }

modules/objdetect/src/aruco/aruco_utils.hpp

@@ -16,9 +16,9 @@ namespace aruco {
 void _copyVector2Output(std::vector<std::vector<Point2f> > &vec, OutputArrayOfArrays out, const float scale = 1.f);
 
 /**
-  * @brief Convert input image to gray if it is a 3-channels image
+  * @brief Convert input image to gray if it is a BGR or BGRA image
   */
-void _convertToGrey(InputArray _in, OutputArray _out);
+void _convertToGrey(InputArray _in, Mat& _out);
 
 template<typename T>
 inline bool readParameter(const std::string& name, T& parameter, const FileNode& node)