I am aware of that darknet/yolov3 outputs relative coordinates, would the coordinate (0,0) be at the bottom left, or at the top left?

I am confused as opencv2 seems to have the y=0 at the top of the image as is usual when working with matrices. Yet mathematicaly and intuitively (for me at least) the coordinate (0,0) should be at the bottom left.


1 Answer 1


(0, 0) is top left.

Here an a helpful blog that goes through all the features in the output vector.

This is common in image processing. There are a few reasons that this is the convention in computer vision. Check here for a list, the accepted answer states:

This is caused in the history. Early computers had Cathode Ray Tubes (CRTs) which "draw" the image with a cathode ray from the upper left corner to the lower right.


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