| Haptics is the discipline that deals with the study of the complex sense of touch as an interface between human beings and machines. Consequently, haptic technology facilitates the exploration of and the interaction with the virtual world through touch. This can be done by utilizing special electro-mechanical interface devices equipped with specialized sensors. Haptic technology is being applied in many fields, such as scientific visualization, surgical procedures, education and arts.;This research investigates the issues related to the usage of haptics as a mechanism to extract behavioral features that characterize a biometric identifier system. In order to test this possibility, we designed a haptic-biometric system in which, position, velocity, force, angular orientation of the end-effector and torque data, among other attributes extracted from given haptic interfaces, are continuously measured and stored as users perform a specific task. We first proved the applicability of the haptic technology to analyze the characteristics of human hand movement patterns while users are interacting with a particular haptic device. Then, we analyzed the information content of the haptic data generated directly from the haptic interface in order to select those of the greatest user-classificatory worth. For example, the physical attributes, such as force, angular orientation of the end-effector as well as torque are presumed to provide valuable information content pertaining to a user's unique behavior when he/she interacts with haptics in a Virtual Environment (VE). To analyze the information content, a new concept called entropic signature has been introduced, which characterizes both the way in which an individual is unique, and the magnitude of that uniqueness when using haptics in VE. Consequently, through a series of experimental works, which were based on the entropic signature approach, it was shown the suitability of haptics for authentication based on behavioral haptic biometrics.;Moreover, we provided evidence that our proposed haptic-based biometric system is best suited in biometrics' verification mode rather than in biometric identification. In addition, we conducted further testing in order to discover individual's abilities and to evaluate their psychomotor patterns through selected tasks under different conditions such as stress, repeatability and concentration. Finally, an important and novel advantage of this research versus current authentication modes (biometrics and non- biometrics) is the fact that the authentication mode can be carried out at any given moment during the multimodal human-computer interaction process. |
