Below is my code, and am I right using like this?
vector<double> filter1; //row vector
sepFilter2D(src, convolvedImg, CV_64FC3, filter1, filter1, Point(-1, -1), 0.0, BORDER_DEFAULT);
//filter1 = [0.00443305 0.0540056 0.242036 0.39905 0.242036 0.0540056 0.00443305]