Using OpenCV to perform face detection

Unlike what you may think from the outset, performing face detection on a still image or a video feed is an extremely similar operation. The latter is just the sequential version of the former: face detection on videos is simply face detection applied to each frame read into the program from the camera. Naturally, a whole host of concepts are applied to video face detection such as tracking, which does not apply to still images, but it's always good to know that the underlying theory is the same.

So let's go ahead and detect some faces.

Performing face detection on a still image

The first and most basic way to perform face detection is to load an image and detect faces in it. To make the result visually meaningful, we will draw rectangles around faces on the original image.

Now that you have haarcascades included in your project, let's go ahead and create a basic script to perform face detection.

import cv2

filename = '/path/to/my/pic.jpg'

def detect(filename...