Advances in fingerprint authentication technology have led to it being used in a growing range of personal devices such as PCs and smartphones. However, they have also made it possible to capture fingerprints remotely with a digital camera, putting the target person at risk of illegal log-ins and identity theft. This article shows how fingerprint captured in this manner can be authenticated and how people can protect their fingerprints against surreptitious photography. First we show that photographed fingerprints have enough information to spoof fingerprint authentication systems by demonstrating with “fake fingers” made from such photographs. Then we present a method that defeats the use of surreptitious photography without preventing the use of legitimate fingerprint authentication devices. Finally, we demonstrate that an implementation of the proposed method called “BiometricJammer,” a wearable device put on a fingertip, can effectively prevent the illegal acquisition of fingerprints by surreptitious photography while still enabling contact-based fingerprint sensors to respond normally.

The new frequency bands that will be allocated to W-CDMA cellular networks might open the possibility to use higher bandwidths than the 5 MHz specified in 3GPP. In this paper the temporal channel properties, i.e., power delay profile, in terms of number of Rake receiver fingers and their characteristics, are analyzed for 5, 10, 20, and 30 MHz bandwidths. The lower bandwidth impulse responses are obtained by filtering measurement results obtained with a channel sounder having a bandwidth of 30 MHz.

We have proposed a new string-based haptic interface device in this paper. It is a kind of device that allows a user to use both hands and multi-fingers to direct manipulate the virtual objects in the computer simulated virtual environment. One of the advantages of the device is to allow the user to use both hands to perform the cooperative works of hands, such as holding a large object that cannot be grasped or held by single hand. In addition, the haptic feedback sensation provided by the device at the fingertips makes possible for the user to perform dexterous manipulation, such as manipulating small size of objects. We have discussed about the design of the proposed device and have elaborated the methods of fingertip positions measurement and force feedback generation. The experiments had been carried out to verify the capabilities of the proposed device.

This paper is concerned with analysis of nonlinear dynamics under geometric constraints that express pinching motions of a pair of multi-degrees of freedom fingers with soft tips. The dynamics of such a pair of soft fingers can be expressed by a set of complicated nonlinear differential equations with algebraic constraints, even if the motion is constrained in a plane. However, it is shown from the passivity analysis that dynamic stable grasping (pinching) can be realized by means of a feedforward input of desired internal force with coefficients composed of elements of Jacobian matrices plus a feedback of the difference between moments of rotation exerted at both sides of the object. It is shown in the case of a pair of 2 d.o.f. and 3 d.o.f. fingers (corresponding to a pair of thumb and index fingers) that a principle of linear superposition is applicable to design of additional feedback signals for controlling simultaneously the posture (rotational angle) and position of the mass center of the object, though the dynamics are nonlinear. A sufficient condition for applicability of the principle of superposition is discussed and given as a condition for unique stationary resolution of the overall motion to elementary motions (stable grasping, rotation control, x and y coordinates control). The principle implies that a skilled motion can be resolved into some of elementary motions which human can learn separately and independently.