Building Computer Vision Projects with OpenCV 4 and C++

Looking inside the code

You may have noticed that the flow of the code looks similar to the face detection code that we discussed in the Overlaying a face mask in a live video section. We load a face detection cascade classifier as well as the eye detection cascade classifier. Now, why do we need to load the face cascade classifier when we are detecting eyes? Well, we don't really need to use the face detector, but it helps us in limiting our search for the eyes' location. We know that the eyes are always located on somebody's face, so we can limit eye detection to the face region. The first step would be to detect the face and then run our eye detector code on this region. Since we would be operating on a smaller region, it would be faster ...