Mat drawing = Mat::zeros( canny_output.size(), CV_8UC3 ); this is a part of code what this really does is making a object in Mat structure called drawing i don't really understand what is with Mat::Zeros please help me i am new to open cv and c++..
It creates a Mat object filled with zeros (i.e a black image), that has the same size as canny_output, 8 bits depth and 3 channels.
For more information Mat::zeros