We present, in this chapter, an overview of techniques for the performance evaluation of behavioral biometric systems. The BioAPI standard that defines the architecture of a biometric system is presented in the first part of the chapter. The general methodology for the evaluation of biometric systems is given including statistical metrics, definition of benchmark databases, and subjective evaluation. These considerations rely with the ISO/IEC19795-1 standard describing the biometric performance testing and reporting. The specificity of behavioral biometric systems is detailed in the second part of the chapter in order to define some additional constraints for their evaluation. This chapter is dedicated to researchers and engineers who need to quantify the performance of such biometric systems.
TopIntroduction
Biometrics is now a technology that is present in our daily life. It is used as for example in airports (passport verification), offices (access control, biometric USB key...) and even in some places in the world for banking operations... Different biometric modalities can be used for the identification / verification of an individual (face recognition, keystroke dynamics recognition, DNA analysis...) (Mahier et al., 2008).
The characterization of an human by considering its behavior in its daily life operations (gait, signature dynamics, voice...) (Han et al. 2006; Muramatsu & Matsumoto, 2007; Petrovska-Delacretaz et al., 2007) or through its interactions with a computer (mouse dynamics, keystroke dynamics...) represents an interesting and open area in research (Hwang et al., 2006; Orozco et al., 2006).
The performance evaluation of such biometric systems is very important for many reasons:
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To be used in a real (that is to say in an industrial) context, the quality of a biometric system must be precisely quantified. The context of use, the efficiency, the robustness of the algorithm must be defined to determine if it fulfills the requirements of a particular industrial application (logical access, physical access, e-commerce...) ;
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The comparison of different biometric modalities is essential to qualify their relative advantages and drawbacks ;
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The performance evaluation is also necessary in order to facilitate the research in this field (Hemery et al., 2006). We need a reliable evaluation method in order to put into obviousness the benefit of a new biometric system.
The objective of this chapter is to make an overview on evaluation techniques that are used in the state of the art to quantify the performance of behavioral biometric systems. An engineer or a researcher will find in the proposed chapter, the different criteria or methods he can use to validate a biometric system he intends to use in a real context. A behavioral biometric system can be evaluated by considering the general approach to evaluate a biometric system while taking into account the specificity of this type of modality.
The plan of the chapter is given below. In the section 1, we present the general approaches for the evaluation of a biometric system. It necessitates generally to use a benchmark database (Hemery et al., 2007) and a set of criteria (computation time, FAR...). The benchmark database can be composed of real biometric templates or synthetic ones. We present different solutions from the state of the art. Section 3 focuses on specificities of behavioral biometric systems. We present their specificities that must be taken into account for their evaluation. Section 4 concerns the future trends that must be achieved in order to facilitate research progress in this domain. We conclude this chapter in section 5.