Building Computer Vision Projects with OpenCV 4 and C++

Implementing face detection using the OpenCV deep learning module

From OpenCV 3.4, the deep learning module was available as a contrib source (https://github.com/opencv/opencv_contrib), but from version 4.0, deep learning is part of OpenCV core. This means that OpenCV deep learning is stable and in good maintenance.

We can use a pretrained Caffe model based on the SSD deep learning algorithm for faces. This algorithm allows us to detect multiple objects in an image in a single deep learning network, returning a class and bounding box per object detected. 

To load the pretrained Caffe, model we need to load two files:

• Proto file or configuration model; in our case, the file is saved in data/deploy.prototxt
• Binary trained model, which has ...