Page 94 - Socially Intelligent Agents Creating Relationships with Computers and Robots

Chapter 9

CREATING EMOTION RECOGNITION AGENTS
FOR SPEECH SIGNAL

Valery A. Petrushin
Accenture Technology Labs

Abstract This chapter presents agents for emotion recognition in speech and their appli-
cation to a real world problem. The agents can recognize five emotional states—
unemotional, happiness, anger, sadness, and fear—with good accuracy, and be
adapted to a particular environment depending on parameters of speech signal
and the number of target emotions. A practical application has been developed
using an agent that is able to analyze telephone quality speech signal and to dis-
tinguish between two emotional states—“agitation” and “calm”. This agent has
been used as a part of a decision support system for prioritizing voice messages
and assigning a proper human agent to respond the message at a call center.

1. Introduction

This study explores how well both people and computers can recognize
emotions in speech, and how to build and apply emotion recognition agents
for solving practical problems. The first monograph on expression of emotions
in animals and humans was written by Charles Darwin in the 19th century [4].
After this milestone work psychologists have gradually accumulated knowl-
edge in this field. A new wave of interest has recently risen attracting both psy-
chologists and artificial intelligence (AI) specialists. There are several reasons
for this renewed interest such as: technological progress in recording, storing,
and processing audio and visual information; the development of non-intrusive
sensors; the advent of wearable computers; the urge to enrich human-computer
interface from point-and-click to sense-and-feel; and the invasion on our com-
puters of life-like agents and in our homes of robotic animal-like devices like
Tiger’s Furbies and Sony’s Aibo, which are supposed to be able express, have
and understand emotions [6]. A new field of research in AI known as affective
computing has recently been identified [10]. As to research on recognizing
emotions in speech, on one hand, psychologists have done many experiments