Question

Mat img=imread("image_location");

I studied that ‘img’ variable is like an object reference variable in java which refers the original object(an image in this case).
Out of curiosity i thought to find out what the ‘img’ variable holds.If it refers to the actual object,it should hold an address and return the address when i use

cout<<img;

But,Shock,it is returning the actual image(pixel values) to the output.
I think there is something wrong with my understanding.
Plz help,I’m a noob programmer who’s trying to make my brain understand these concepts.

Answer 1

cv::Mat holds the data representing the image in an array, plus other data specific to the cv::Mat instance. The data array itself depends on the image’s format. You can have different numbers of channels and channel depth, and when you use imread you can pass a second parameter that gives you some control over this. So cv::Mat does not have a pointer to the original object, it has a pointer to an array containing data representing that object.

On top of that, in newer versions of OpenCV, the ostream& operator<< is overloaded for cv::Mat, and that tries to produce a nice printout of the array values in matrix format. This is what you see when you std::cout << someMat;