Identifying single electron charge sensor events using wavelet edge detection

The operation of solid-state qubits often relies on single-shot readout using a nanoelectronic charge sensor, and the detection of events in a noisy sensor signal is crucial for high fidelity readout of such qubits. The most common detection scheme, comparing the signal to a threshold value, is accurate at low noise levels but is not robust to low-frequency noise and signal drift. We describe an alternative method for identifying charge sensor events using wavelet edge detection. The technique is convenient to use and we show that, with realistic signals and a single tunable parameter, wavelet detection can outperform thresholding and is significantly more tolerant to 1/f and low-frequency noise.Comment: 11 pages, 4 figure

Quantum copying can increase the practically available information

While it is known that copying a quantum system does not increase the amount of information obtainable about the originals, it may increase the amount available in practice, when one is restricted to imperfect measurements. We present a detection scheme which using imperfect detectors, and possibly noisy quantum copying machines (that entangle the copies), allows one to extract more information from an incoming signal, than with the imperfect detectors alone. The case of single-photon detection with noisy, inefficient detectors and copiers (single controlled-NOT gates in this case) is investigated in detail. The improvement in distinguishability between a photon and vacuum is found to occur for a wide range of parameters, and to be quite robust to random noise. The properties that a quantum copying device must have to be useful in this scheme are investigated.Comment: 10 pages, 6 figures, accepted PR

A Multilevel Quantization Scheme for the Decentralized Detection of an Unknown Signal

Recently a quantization and fusion scheme was proposed and analyzed for the distributed detection of an unknown signal in noise. The scheme is a modified version of the counting rules and can either be thought of as a feedback of the fusion decision to the local sensors or in terms of multiple partitioning of the observation space. The proposed quantization and fusion scheme is more robust than the counting rules and performs reasonably well in most configurations of the alternative hypothesis. In this paper we consider the unknown signal detection problem as a hypothesis testing problem with unrestricted alternatives and compare the performance of the scheme with that of the Pearson\u27s Chi-square test

A Robust Image Watermarking Based on Image Restoration Using SIFT

This paper introduces a novel robust watermarking scheme for digital images, which is robust against common signal processing and geometric distortion attacks. In order to be resistant to geometric distortion attacks, the matched feature points determined by the scale-invariance feature transform (SIFT) are used for image restoration to reduce the synchronization errors caused by geometric distortion attacks. An adaptive embedding scheme is applied in discrete Fourier transform (DFT) domain of each subimage. The watermark detection decision is based on the number of matched bits between the retrieved and original watermark in the embedding image blocks. Experimental results show that the proposed watermarking is robust to common signal processing attacks and geometric distortion attacks, including rotation, scaling, cropping, shearing and some combined attacks

Encrypted Color Image Transmission in LDPC Encoded MIMO Wireless Communication System with implementation of MP-WFRFT based

This paper emphasizes on comprehensive study for the performance evaluation of LDPC encoded MIMO wireless communication system under implementation of MP-WFRFT based physical layer security scheme. The 4 5F4; multi antenna configured simulated system under investigation incorporates LDPC channel coding scheme and various types of modulation (QPSK, DQPSK, and 4-QAM) and signal detection (ZF, MMSE, ZF-SIC and MMSE-SIC) techniques. On considering transmission of encrypted color image in a hostile fading channel, it is noticeable from MATLAB based simulation study that the LDPC channel encoded system is very much robust and effective in retrieving color image under utilization of MMSE-SIC signal detection and 4-QAM digital modulation techniques