MatOfPoint作为minAreaRect的参数总是报错"throw new IllegalArgumentException("Incomatible Mat");

MatOfPoint matPt = contours.get(i)
       minRect.set(i, Imgproc.fitEllipse( new  MatOfPoint2f(matPt) ));
       ——  MatOfPoint作为minAreaRect的参数总是报错"throw new IllegalArgumentException("Incomatible Mat");
  "     ref: http://codego.net/475157/，不能直接把 MatOfPoint作为MatOfPoint2f的构造函数的参数
          解决方法为MatOfPoint率MatOfPoint2f 改为 
          MatOfPoint matPt = contours.get(i);
          MatOfPoint2f NewMtx = new MatOfPoint2f( matPt.toArray() );
             minRect.add(Imgproc.minAreaRect(NewMtx));