How to edit/read pixel values in OpenCv from Mat variable?

Question

I am looking for an efficient way for editing/reading pixels from Mat (or Mat3b) variable.

I have used :-

Image.at(i,j)

Answer 1

Here you can see some of the possibilities for fast element access.

But if you want to do it your way, you need to add a bracket. Otherwise you index computation is not correct:

for(int i=0; i

But the layout of the memory is not guaranteed to be contiguous due to padding. So according to this you should rather use a formula like this:

for(int i=0; i