c++ - 在没有循环的情况下在opencv::Mat中创建一个矩形零

Question

将 opencv::Mat 的特殊 block 设为零的有效方法是什么？ (没有循环)

Mat freq;

// Set some frequencies to 0
for (int y=0; y<freq.rows; y++)
{
    for (int x=Start; x<freq.cols; x++)
    {
        if (x>Start || y>Start)
            freq.at<double>(y,x) = 0.0;
    }
}
// Set some frequencies to 0
for (int y=Start; y<freq.rows; y++)
{
    for (int x=0; x<freq.cols; x++)
    {
        freq.at<double>(y,x) = 0.0;
    }
}

Answer 1

试试下面的代码

Mat src;
Mat roi  = src(Rect(x,y,width,height)); // Set Roi
roi.setTo(0); // Set all pixel to 0 on both src and roi