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

98 8. USER ACCEPTANCE STUDY RELATING TO SOFT BIOMETRICSFigure 8.6. The majority of users, although not strongly familiar with biometrics, emphasized thatthe ranking as it is, holds only in the case of equal access verification accuracies for all methods.Figure 8.6: Overall user preference of access methods. Small bars represent high rankings.However, to verify the ranked preference users were also given the final task to freely chooseone of the four systems with the goal of reading a file. Figure 8.7 illustrates the ranking orderedby number of selections. The Soft biometrics module was most often chosen and thus the favorite,followed by PIN and fingerprint and finally face based verification (due to similarity with softbiometrics, but longer acquisition due to the blue mark).Figure 8.7: Freely selected access methods for performing a task.To recapitulate the testing, generally users were eager to explore both the known and newaccess methods. The primary concern of all users was related to reliability and accuracy of thepresented methods. Furthermore about half of the users asked about spoofing methods (e.g. holdinga photo in front of the camera) and related countermeasures. These reactions are evidence thatusers are aware of novel techniques and have a need to be illuminated on system characteristic inorder to gain the trust of the users for the access methods.8.3 Comparison of access control systemsUsing the above usability study we proceed to perform a broader comparison by includingcharacteristics pertinent to access control systems, such as cost efficiency, accuracy, processingspeed and maximum amount of enrolled users. We identified existing commercially available accesscontrol systems based on fingerprint, face and PIN based methods, see Table 8.2. We selectedcost efficient appliances representing each method and set price and related specifications in comparison.We note that the PIN based system is the most widely available access control system,followed by fingerprint based systems, and only few face recognition based systems. There are nocommercially available soft biometrics access control systems yet.