从Mat转换为Point2f或Point3f

Question

我有一个4 x 1或3 x 1 Mat变量，表示均匀或不均匀的点。我想将这个Mat变量转换为Point2f或Point3f类型，具体取决于它是均匀的还是不均匀的。

例如，如果

Mat point = (Mat_<float>(3, 1) << 6, 4, 2);

如果这是一个同质的表示，那么转换的点是Point2f类型，并且

Point2f pt;
pt.x = 6 / 2; pt.y = 4 / 2;

如果这不是齐次表示，则转换点的类型为Point3f和

Point3f pt;
pt.x = 6; pt.y = 4; pt.z = 2;

下面是我当前的代码，我对方法的调用是

Point3f pt_3d = mat2pt<Point3f>(point, 0);
Point2f pt_2d = mat2pt<Point2f>(point, 1);

错误是no viable conversion from Point3f to Point2f和no viable conversion from Point2f to Point3f

template<typename T>
T mat2pt(Mat mat, int t = 0)
{        
    if(t == 1) // homogeneous => inhomogeneous
    {
        if(mat.size() == Size(3, 1))
        {
            pt.x = mat.at<float>(0) / mat.at<float>(2);
            pt.y = mat.at<float>(1) / mat.at<float>(2);
            return pt;
        }
        else if(mat.size() == Size(4, 1))
        {
            Point3f pt;
            pt.x = mat.at<float>(0) / mat.at<float>(3);
            pt.y = mat.at<float>(1) / mat.at<float>(3);
            pt.z = mat.at<float>(2) / mat.at<float>(3);
            return pt;
        }
        else
        {
            cout << "incorrect Mat size" << endl;
            return;
        }
    }
    else if(t == 0)
    {
        if(mat.size() == Size(2, 1))
        {
            Point2f pt;
            pt.x = mat.at<float>(0);
            pt.y = mat.at<float>(1);
            return pt;
        }
        else if(mat.size() == Size(3, 1))
        {
            Point3f pt;
            pt.x = mat.at<float>(0);
            pt.y = mat.at<float>(1);
            pt.z = mat.at<float>(2);
        }
        else
        {
            cout << "incorrect Mat size" << endl;
            return;
        }
    }
    else
    {
        cout << "invalid value for parameter t" << endl;
    }
}