Work with operations pixel by pixel and loops

edit

copy half an image :use a rect :

        Mat mat = (Mat_<uchar>(2, 4) << 5, 6, 0, 4, 0, 1, 9, 9);
        Mat mat2;
        cout << "mat =" << mat <<  endl;
        mat(Rect(0, 0, 4, 1)).copyTo(mat2);
        cout << "mat2 =" << mat2 << endl;

results :

mat =[  5,   6,   0,   4;
   0,   1,   9,   9]
mat2 =[  5,   6,   0,   4]

Many functions are optimized with a parallel loop or opencl but not all functions. Sometimes pixel loop are faster than opencv function. If you find this case write a post then somebody will make a Pull request to improve function or better do PR yourself you are welcome

Thanks for the reply. I will check the opencv function but for some proccess I like to use my own loops. Its more easy and faster for me than go to documentation and check the function parameters and Id like to perform pthreads by myselft. Thanks a lot.