FACIAL SOFT BIOMETRICS - Library of Ph.D. Theses | EURASIP

17ric. In Section 6.6 we employ the developed metric to conduct experiments and answer questionsregarding the beauty index in three cases: for famous attractive females, for aging females and incase of facial surgery. Finally we proceed to simulate in Section 6.7 based on both, the presentedmetric, as well as state of the art algorithmic accuracies an automatic tool for beauty prediction.Chapter 7 - Practical implementation of soft biometrics classification algorithmsTowards practical implementation of the related concepts and ideas, in Chapter 7 we developa tool (concatenation of classification algorithms) for classification of facial soft biometric traits,where we specifically emphasize on the most obvious facial identifiers, primarily mentioned byhumans, when portraying an unknown individual. The constructed tool is streamlined to achievereliability of identification at reduced complexity, and hence focuses on simple yet robust softbiometrictraits, including hair color, eye color and skin color, as well as the existence of beard,moustache and glasses. We then specifically focus on extraction and categorization of eye color,and present an additional study where we illustrate the influence of surrounding factors like illumination,eye glasses and sensors on the appearance of eye color.In Section 7.1 a bag of six facial soft biometrics is elaborated, for which estimation algorithmsare featured, along with the related experimental results, see Section 7.1.2. We then proceedto focus on eye color as a soft biometric trait in Section 7.2 and examine an automatic eye colorclassifier in challenging conditions, such as changing illumination, presence of glasses and camerasensors, see Section 7.4.Chapter 8 - User acceptance study relating to soft biometricsFinally we conclude with a usability study that verifies the user acceptance of SBSs, specificallywhen compared to existing PIN or fingerprint access control systems.The pervasiveness of biometric systems, and the corresponding growth of the biometric marketsee [usa11a], has successfully capitalized on the strength of biometric-based methods in accuratelyand effectively identifying individuals. As a result, modern state-of-the-art intrusion detection andsecurity systems include by default at least one biometric trait. It is the case though that little emphasishas been given to better understanding user-acceptance and user-preference regarding suchsystems. Existing usability related works, such as in [CAJ03] and [LBCK03], focus on establishingfunctional issues in existing ATM machines, or on studying the influence of user interactionon the performance of fingerprint based systems (see [KED11]) and interfaces (see [RJMAS09]).Other interesting works (see [usa11b], [CG05], [CJMR09]), analyze possible methods that improveinterface design. Our emphasis here is on providing insight on the attitudes and experiencesof users towards novel and emerging biometric verification methods, and to explore whether suchnovel biometric technologies can be, in terms of user acceptance, valid alternatives to existingprevalent PIN based systems. Our focus, in addition to considering the traditional PIN-basedmethod, is to explore the usability aspects of systems based on classical biometrics such as fingerprintand face recognition, and to then proceed to study the usability of systems based on theemerging class of soft-biometric methods. Our evaluation is based on having the users rate andrank their experiences with different access methods.In Section 8.2 we briefly describe the user test setting, as well as the conditions and the performedtest procedures. We then proceed to elaborate on the chosen verification methods and onthe designed interfaces. In Section 8.2 we present the results obtained from the user study, in termsof evaluation and quantification of the different usability measurement characteristics. In the samesection we provide the user test outcomes of direct comparisons between the four presented meth-