Abstract

This chapter describes the work on human-computer interaction being carried out in our laboratory at the University of Osaka. Recognition of human expressions is necessary for human-computer interactive applications. A vision system is suitable for recognition of human expression since this involves passive sensing and the human gestures of hand, body and face that can be recognized without any discomfort for the user. The computer should not restrict the movements of the human to the front of the computer. Therefore, we study methods of looking at people using a network of active cameras.

Introduction

Sensing of human expressions is very important for human-computer interactive applications such as virtual reality, gesture recognition, and communication. A vision system is suitable for human-computer interaction since this involves passive sensing and the human gestures of the hand, body, and face that can be recognized without any discomfort for the user. We therefore use cameras for the sensors in our research to estimate human motion and gestures.

Facial expression is a natural human expression and is necessary to communicate such emotions as happiness, surprise, and sadness to others. A large number of studies have been made on machine recognition of human facial expression. Many of them are based on multi-resolution monochrome images and template pattern matching techniques [62, 293, 324]. This kind of approach needs some average operation on the face model or blurring of the input image to cope with the different appearance of faces in the images.