A theoretically based transformation, which reorders SPECT sinograms degraded by the Poisson noise according to their signal-to-noise ratio (SNR), has been proposed. The transformation is equivalent to the maximum noise fraction (MNF) approach developed for Gaussian noise treatment. It is a two-stage transformation. The first stage is the Anscombe transformation, which converts Poisson distribu...

To alleviate excessive smoothing of high signal-to-noise ratio (SNR) regions which are correspond to the structural features of MR images by using classical anisotropic diffusion (AD) filter. A novel AD filter called SNR controlled anisotropic diffusion is proposed. In this filter, an adaptive diffusivity function which is based on the correction factor of MR images was constructed. This adapti...

Optomechanical systems are often used for the measurement of weak forces. Feedback loops can be used in these systems for achieving noise reduction. Here we show that even though feedback is not able to improve the signal to noise ratio of the device in stationary conditions, it is possible to design a nonstationary strategy able to improve the sensitivity.

It is well known that magnetic resonance magnitude image data obey a Rician distribution. Unlike additive Gaussian noise, Rician "noise" is signal-dependent, and separating signal from noise is a difficult task. Rician noise is especially problematic in low signal-to-noise ratio (SNR) regimes where it not only causes random fluctuations, but also introduces a signal-dependent bias to the data t...

Recently, a novel resource-efficient technique for the reporting channel transmissions in cooperative spectrum sensing was proposed. In this technique, secondary users are allowed to simultaneously send their local decisions to the fusion center, saving time and frequency resources. Expressions for the probabilities of detection and false alarm for the unitary-gain AWGN reporting channels were ...

This article focuses on techniques for acoustic noise reduction, signal filters and source reconstruction. For noise reduction, bandpass filters and cross correlations are found to be efficient and fast ways to improve the signal to noise ratio and identify a possible neutrino-induced acoustic signal. The reconstruction of the position of an acoustic point source in the sea is performed by usin...

The VisuShrink is one of the important image denoising methods. It however does not provide good quality of image due to removing too many coefficients especially using soft-thresholding technique. This paper proposes a new image denoising scheme using wavelet transformation. In this paper, we modify the coefficients using soft-thresholding method to enhance the visual quality of noisy image. T...

A low-complexity SNR estimation algorithm for OFDM systems in frequency-selective fading channels is proposed. The estimator is based on a conventional preamble having two identical parts. It uses the correlation of the received signal samples to estimate signal power while noise power is estimated using the difference between received samples. Simulation results show that the proposed estimato...