Non-intrusive detection of combustion intermediates by photoionization via Rydberg states and microwave backscattering

Non-intrusive liveness detection by face images

A technique evaluating liveness in face image sequences is presented. To ensure the actual presence of a live face in contrast to a photograph (playback attack), is a significant problem in face authentication to the extent that anti-spoofing measures are highly desirable. The purpose of the proposed system is to assist in a biometric authentication framework, by adding liveness awareness in a ...

Microwave saturation of the Rydberg States of electrons on helium.

We present measurements of the resonant microwave excitation of Rydberg energy levels for surface-state electrons on superfluid helium. The temperature-dependent contribution to the linewidth gamma(T) agrees with theoretical predictions and is very small below 700 mK, in the ripplon scattering regime. Absorption saturation and power broadening were observed as the fraction of electrons in the f...

Microwave spectroscopy of Al I Rydberg states: F terms

Energy level separations in high-lying Rydberg states of neutral aluminium have been measured by a two-photon millimetre-wave resonance method to obtain n 2F–(n + 1) 2F intervals for n = 29–37 with an accuracy ±1 MHz. An Al atomic beam was excited stepwise by pulsed lasers, and the Rydberg atoms were detected by state-selective field ionization. From these data and previous optical data for the...

Orbital evolution and promotion effects in the photoionization dynamics of 2Σ− Rydberg states of OH

extremal region detection guided by maxima of gradient magnitude

a problem of computer vision applications is to detect regions of interest under dif- ferent imaging conditions. the state-of-the-art maximally stable extremal regions (mser) detects affine covariant regions by applying all possible thresholds on the input image, and through three main steps including: 1) making a component tree of extremal regions’ evolution (enumeration), 2) obtaining region ...