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

6hair, skin and clothes. The proposed method and the suitability of these patch-based traits are thenvalidated both analytically and empirically.Deviating from security related themes, we focus on a completely different application: employingsoft biometrics in evaluation of female facial aesthetics. This approach is novel in that,in the context of female facial aesthetics, it combines soft biometrics with previous approaches onphoto quality and beauty assessment. This study helps us to understand the role of this specificset of features in affecting the way humans perceive facial images. Based on the above objectiveparameters, we further construct a simple linear metric that suggests modifiable parametersfor aesthetics enhancement, as well as tunes systems that would seek to predict the way humansperceive facial aesthetics. Moreover using the designed metric we evaluate beauty indices withrespect to aging, facial surgery and females famous for their beauty. We simulate an automatictool for beauty prediction with both realistic accuracy and performance.Remaining in the realm of human perception, we also provide a comparative study of differentaccess control systems based on fingerprint, PIN, soft biometrics and face recognition. Towardscomparing these systems, we design real–life access control interfaces, each based on the abovementioned methods, and then proceeded to empirically evaluate the degree of usability for each ofthese interfaces. Our study is based on the recorded assessments of a set of users who rated theirinteraction with each interface, in terms of privacy, ease of use, user-friendliness, comfort andinteraction time. The results reinforce, from a usability point of view, the employment of novelbiometric authentication methods as viable alternatives to the currently predominant PIN basedmethods for access control.Overall this dissertation has contributed the following:– identification and introduction of novel applications for soft biometrics, such as humanidentification (bag of soft biometrics), re–identification as well as aesthetics prediction– development of theoretical framework for SBSs in the applications: pruning the search andhuman identification– application of the developed theoretical framework on existing SBSs– construction of a novel image processing tool for classification of soft biometric traits andemploying such a tool in challenging scenarios– obtaining evidence for the high user friendliness of soft biometric based control accesssystems.This work was conducted in part within the European Project ACTIBIO [ACT11] and wassupported in part by the European Commission under contract FP7-215372.