Chapter 3. Recognizing Facial Expressions with Machine Learning

Automatic facial expression recognition has attracted much attention since the early nineties, especially in human-computer interaction. As computers start becoming a part of our life, they need to become more and more intelligent. Expression recognition systems will enhance this intelligent interaction between the human and the computer.

Although humans can recognize facial expressions easily, a reliable expression recognition system is still a challenge. In this chapter, we will introduce a basic implementation of facial expression using various algorithms from the OpenCV library, including feature extraction and classification using the ml module.

In this chapter, we will be going through the following topics in brief:

• A simple architecture to recognize human facial expressions

• Feature extraction algorithms in the OpenCV library

• The learning and testing stage, with various machine learning algorithms