Canny Edge Detector thresh2 > thresh1
Question:
I am currently writing a program in python using OpenCV and its function canny(). To find two good threshold values, I am using this code
http://mathalope.co.uk/2015/06/03/canny-edge-detection-app-with-opencv-python/
My question is: How exactly does the program "decide" which pixel is an edge pixel if the lower threshold is bigger than the upper one? I know how it works for upper>lower, but can’t grasp the process if it’s the other way round.
Thanks!
Answers:
The two thresholds are swapped if the low threshold is higher.
OpenCV is open source, so you can look at the source code:
if (low_thresh > high_thresh)
std::swap(low_thresh, high_thresh);
I am currently writing a program in python using OpenCV and its function canny(). To find two good threshold values, I am using this code
http://mathalope.co.uk/2015/06/03/canny-edge-detection-app-with-opencv-python/
My question is: How exactly does the program "decide" which pixel is an edge pixel if the lower threshold is bigger than the upper one? I know how it works for upper>lower, but can’t grasp the process if it’s the other way round.
Thanks!
The two thresholds are swapped if the low threshold is higher.
OpenCV is open source, so you can look at the source code:
if (low_thresh > high_thresh)
std::swap(low_thresh, high_thresh);