How to initialize std::vector<std::vector<cv::Point> > contours to save data

C++
3 
string path2 = "woman.png";
   Mat img2 = imread(path2);
   Mat matrix2, imgWarp2;
   float w2 = 100, h2 = 60;


   Point2f src2[4] = { {1168.5, 147.5}, {1177.5, 147.5},  {1168.5, 160.5  }, {1177.5, 160.5} };

   Point2f dst2[4] = { {0.0f,0.0f},{w,0.0f},{0.0f,h},{w2,h2} };

   matrix2 = getPerspectiveTransform(src2, dst2);
   warpPerspective(img2, imgWarp2, matrix2, Point(w2, h2));