Convert point vector to Mat

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Hi, my objective is to obtain the right side of this image.

I thought I'd see the image as a polygon because I have the coordinates of the vertices, and then transform the vector that has the vertices in a matrix (cvMat).

My thought is correct or is there a simpler way to get this submatrix?

With the following code I can draw the polygon but I need to convert it to a matrix.

Point normImgTop, normImgEyebrowInner, normImgCNoseTip, normImgCNoseBase, normImgTipOfChin, normImgTopLip, normImgDownLip, normImgBottom, normImgTopRight, normImgBottomRight;

(...)

        std::vector<Point> contour;
        Mat roi(poseNormImg.rows, poseNormImg.cols, CV_8UC1);

        contour.push_back(normImgTop);
        contour.push_back(normImgEyebrowInner);
        contour.push_back(normImgCNoseTip);
        contour.push_back(normImgCNoseBase);
        contour.push_back(normImgTopLip);
        contour.push_back(normImgDownLip);
        contour.push_back(normImgTipOfChin);
        contour.push_back(normImgBottom);
        contour.push_back(normImgBottomRight);
        contour.push_back(normImgTopRight);

        const cv::Point *pts = (const cv::Point*) Mat(contour).data;
        int npts = Mat(contour).rows;
        std::cout << "Number of polygon vertices: " << npts << std::endl;

        // draw the polygon
        polylines(roi, &pts,&npts, 1,
                            true,           // draw closed contour (i.e. joint end to start)
                            Scalar(0,255,0),// colour RGB ordering (here = green)
                            3,              // line thickness
                            CV_AA, 0);

I'm using OpenCV 2.4.6.1 and C++.

Thank you