About OpenCV coordinates

Question

I had a quick question about OpenCV and how it presents coordinates of a ROI when performing face tracking. I was able to print out (x,y) coordinates. But I'm trying to figure out a good way to plot these coordinates. Does anyone know what are the units? Are they in pixels? Can I plot them in terms of frames or something like that? Thanks, I'm still kind of a newbie with OpenCV libraries.

Answer 1

OpenCV represents the coordinates in pixels. Top-left corner is defined as (0,0). Direction to the right is x (columns), direction to bottom is y (rows).

Typically you draw points using circle(img,center,radius,...) and lines using line(img,point1,point2,...).