I am trying to visualize the output of `calcOpticalFlowPyrLK()`. The problem is, I can't get to the output as in the examples. Every 10 frames I renew the points for the calculation of the flow. When drawing them I use simple code:
for (size_t i = 0; i < CornersCentroidNow.size(); i++){
if (feat_errors[i] > MAX_ERR || feat_found[i] == 0) continue;
Point p0(ceil(mc[i].x), ceil(mc[i].y)); // are the points of interest (centroids of contours)
Point p1(ceil(CornersCentroidNow[i].x), ceil(CornersCentroidNow[i].y));
arrowedLine(empty, p0, p1, Scalar(0, 0, 255), 2, 8, 0, 0.2);
}
after this block of code. When I draw them every frame I get this output:
If I update the previous frame used for `calcOpticalFlowPyrLK()` function
CentroidFrOld = CentroidFrNow.clone();
I get this output (the line is short and it is moving foward every 10 frames - as set to get new points)
If I swap the prew points and next points as well
CentroidFrOld = CentroidFrNow.clone();
mc = CornersCentroidNow;
I get this output (the line is short, but it is moving along with the object)
What I aim to get is a long straight arrow aiming in the right direction, but I am not able to achieve something similar as in the [flow tutorial](http://docs.opencv.org/master/d7/d8b/tutorial_py_lucas_kanade.html#gsc.tab=0). The only thing that author doesn't do is to find new points every few frames. Something like this
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