Building Computer Vision Projects with OpenCV 4 and C++

Face detection

Until the year 2000, there were many different techniques used for finding faces, but all of them were either very slow, very unreliable, or both. A major change came in 2001 when Viola and Jones invented the Haar-based cascade classifier for object detection, and in 2002 when it was improved by Lienhart and Maydt. The result is an object detector that is both fast (it can detect faces in real time on a typical desktop with a VGA webcam) and reliable (it detects approximately 95 percent of frontal faces correctly). This object detector revolutionized the field of face recognition (as well as that of robotics and computer vision in general), as it finally allowed real-time face detection and face recognition, especially as Lienhart ...