PERFORMANCE DEFINITION AND STANDARDIZATION OF ELECTRONIC NOSES

The performance of any electronic nose is ultimately determined by the properties of its constituent parts (e.g., the sensors, signal proces sing and pattern-recognition engine). Electronic noses currently explo it the technologies of several classes of sensor material (e.g. semico nducting oxide, conducting polymer, phthalocyanines and lipid coatings ) as well as a variety of pattern-recognition paradigms (e.g. back-pro pagation, self-organizing map and discriminant function analysis). Con sequently, there is a need to compare objectively the performance of t he increasing number of both research and commercial electronic noses. This paper addresses this problem and suggests the need for odour sta ndards to quantify both the ability of an electronic nose to discrimin ate between similar odours (i.e. its 'resolving power') and a number o f dissimilar odours (i.e. its 'range'). We present a generic model fro m which we can define these two fundamental parameters, and hence deve lop a benchmark for the performance of these different electronic nose s against two proposed odour standards. This model can be employed not only as a design tool to predict the performance of an electronic nos e against an odour standard, but also as a diagnostic tool that can de termine, for example, the effect of random errors in the sampling meth od, sensor characteristics or the effect of systematic errors associat ed with sensor drift or changes in ambient temperature. We believe tha t our definition of odour standards and performance parameters for ele ctronic noses could be used to create a European standard, which is no w required in this rapidly expanding field and marketplace.