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Defect detection and restoration of degraded videos is an important topic in media content management systems. Frame pixel-shift is a common form of severe defect in videos caused by loss of consecutive pixels by the video transmission system. Pixel-shift refers to the large amount of pixel shifts one by one due to a small quantity of image data loss. The damaged region in the affected frame is usually quite large, causing serious degradation of visual quality. This paper addresses the issue of how to automatically detect and restore frame pixel-shift in videos. Pixel-shift frame detection relies on spatio-temporal information and motion estimation. Accurate measurement of pixels shift is achieved based on the analysis of temporal frequency information and restoration is accomplished by reversing the pixels shift and spatio-temporal interpolation. Performance evaluation using real video sequences demonstrate the good performance of our algorithm. [ABSTRACT FROM AUTHOR]

Quantum Fisher information matrix (QFIM) is a core concept in theoretical quantum metrology due to the significant importance of quantum Cramér–Rao bound in quantum parameter estimation. However, studies in recent years have revealed wide connections between QFIM and other aspects of quantum mechanics, including quantum thermodynamics, quantum phase transition, entanglement witness, quantum speed limit and non-Markovianity. These connections indicate that QFIM is more than a concept in quantum metrology, but rather a fundamental quantity in quantum mechanics. In this paper, we summarize the properties and existing calculation techniques of QFIM for various cases, and review the development of QFIM in some aspects of quantum mechanics apart from quantum metrology. On the other hand, as the main application of QFIM, the second part of this paper reviews the quantum multiparameter Cramér–Rao bound, its attainability condition and the associated optimal measurements. Moreover, recent developments in a few typical scenarios of quantum multiparameter estimation and the quantum advantages are also thoroughly discussed in this part. [ABSTRACT FROM AUTHOR]

The widely used quantum Cramér–Rao bound (QCRB) sets a lower bound for the mean square error of unbiased estimators in quantum parameter estimation, however, in general QCRB is only tight in the asymptotical limit. With a limited number of measurements biased estimators can have a far better performance for which QCRB cannot calibrate. Here we introduce a valid lower bound for all estimators, either biased or unbiased, which can serve as standard of merit for all quantum parameter estimations. [ABSTRACT FROM AUTHOR]

Quantum correlation provides a promising measure beyond entanglement. Here, we propose a necessary and sufficient condition for nonzero quantum correlation in continuous variable systems, which is simple and easy to perform in terms of a marker Qr. In order to get this condition, we introduce continuous-variable local orthogonal bases of the operator space, which are generalized from the orthogonal basis sets in local operator space for discrete variables. Based on this, we obtain the marker Qr for all bipartite continuous variable states, and provide several examples including two-mode Gaussian and non-Gaussian states. Our result may provide a candidate for quantum correlation measures, and can be measured by designed quantum circuits. [ABSTRACT FROM AUTHOR]

Decoupling is an important tool used to prolong the coherence time of quantum systems. However, most decoupling schemes have assumed selective controls on the system, and it is believed that with global pulses one can only decouple systems with certain coupling terms like secular dipole-dipole coupling. In this article, we show that with global pulses it is possible to reduce the coupling strength of other types of coupling, which we demonstrate with Ising coupling. The complexity of such pulses is independent of the size of the system. [ABSTRACT FROM AUTHOR]