OpenCV 3.0 Computer Vision with Java

Integral images

Some face recognition algorithms, such as OpenCV's face detection algorithm make heavy use of features like the ones shown in the following image:

These are the so-called Haar-like features and they are calculated as the sum of pixels in the white area minus the sum of pixels in the black area. You might find this type of a feature kind of odd, but when training it for face detection, it can be built to be an extremely powerful classifier using only two of these features, as depicted in the following image:

In fact, a classifier that ...