One of the major challenges that the human computer interface (HCI) faces nowadays is that of identifying a subject’s state, in a real world environment, characterized mainly by its being: open-recorded, event-elicited, and internal emotional state-driven (Picard, Vyzas, & Healey , 2001). The main requirement for such system regards the noninvasive character of their working principle. Subsequently, in order to improve communication in HCI systems or to asses the human state, the analysis of the body language could be a solution. Thus, a “sensitive computer” could use the body movements and the positions of the body in order to assess the state of a person (e.g., confusion, illness, nervousness, lack of attention, motor fatigue, agitation, etc.).
Key Terms in this Chapter
Fitness: A measure of the suitability of a potential solution for the given application. Each individual is an encoded representation of all the parameters that characterize the solution. It has an associated value (fitness) which is a measure of its performances.
Neural Network: A system of programs and data structures that approximates the operation of the human brain.
Human Computer Interface (HCI): The process by which users interact with computers; based on HCI, one designs and implements human-centric interactive computer systems.
Digital Signal Processor (DSP): A?specialized, programmable computer processing unit that is able to perform high-speed mathematical processing. DSP refers to manipulating analogue information that has been converted into a digital (numerical) form.
Genetic Algorithm (GA): An optimization and search technique based on the principles of Darwin’s theory of natural selection and Mendel’s work in genetics on inheritance: the stronger individuals are likely to survive in a competing environment. It allows a population composed of many individuals (possible solutions) to evolve under specified selection rules to a state that maximizes their suitability for the specific application.
Biosensor: A device incorporating a biological sensing element (the recognition element is biological in nature).
Sensor: A device that measures or detects a real-world condition, such as an acoustic (microphone, hydrophone), electromagnetic (radar), or optical (camera) signal.