OpenCV C++ Mat == operator

Question

I'm using open CV in C++ , but i need some help at this example:

getContours((mask == 0), contours, hierarchy)

where this function just call findContours function from Open CV. I don't understand what really does mask == 0 as a parameter. mask is defined as a Mat data type. It`sa binary image black & white.

Answer 1

The == is a Matrix Expression that produces a binary matrix (of type CV_8UC1 ).

mask == 0 creates a binary mask where pixels are set to 255 if it was 0 in mask , or 0 otherwise.

If mask is binary, you're basically inverting it, same as ~mask .