In this paper, we investigate the performance of the Viterbi decoding algorithm with/without automatic repeat request (ARQ) over a Rician flat fading channel with unlimited interleaving. We show that the decay rate of the average bit error probability with respect to the bit energy to noise ratio is of order between df and df + 1 at high bit energy to noise ratio for both cases (with ARQ and wi...

In a number of applications, for example biomechanical imaging of tissue and geophysics, the goal is to recover wave speed from arrival times, the times when a wave front, initiated at a source, arrives at certain points in space. The mathematical model that relates the arrival times to the wave speed is assumed to be the Eikonal equation. Typically the measured arrival time data is noisy so th...

It is well-known that data from diffusion weighted imaging (DWI) follow the Rician distribution. The Rician distribution is also relevant for functional magnetic resonance imaging (fMRI) data obtained at high temporal or spatial resolution. We propose a general regression model for non-central χ (NC-χ) distributed data, with the heteroscedastic Rician regression model as a prominent special cas...

Introduction: Diffusion tensor imaging (DTI) is widely used to characterize white matter in health and disease. Previous approaches to the estimation of diffusion tensors have either been statistically suboptimal or have used Gaussian approximations of the underlying noise structure, which is Rician in reality. The most prevalent tensor estimation method, the log-linear minimum mean squared err...

PURPOSE Previous work has evaluated the quality of different analytic methods for extracting relaxation times from magnitude imaging data exhibiting Rician noise. However, biexponential analysis of relaxation in tissue, including cartilage, and materials is of increasing interest. We, therefore, analyzed biexponential transverse relaxation decay in the presence of Rician noise and assessed the ...

MRI is one of the most powerful techniques to study the internal structure of the body. MRI image quality is affected by various noises. Noises in MRI are usually thermal and mainly due to the motion of charged particles in the coil. Noise in MRI images also cause a limitation in the study of visual images as well as computer analysis of the images. In this paper, first, it is proved that proba...

The Rician distribution of noise in magnitude magnetic resonance (MR) images is particularly problematic in low signal-to-noise ratio (SNR) regions. The Rician noise distribution causes a nonzero minimum signal in the image, which is often referred to as the rectified noise floor. True low signal is likely to be concealed in the noise, and quantification is severely hampered in low-SNR regions....

Authors Jayabal Papitha, Bakthavachalam Sharmila, Damodaran Nedumaran Central Instrumentation and Service Laboratory, University of Madras, Guindy Campus, Chennai 600 0025, Tamil Nadu, INDIA Corresponding Author Damodaran Nedumaran Emails: [email protected] Abstract This paper presents a combined Fast Gradient Projection Method with Gabor filter technique for removing the Rician noise present i...

Developments in Medical imaging systems which are providing the anatomical and physiological details of the patients made the diagnosis simple day by day. But every medical imaging modality suffers from some sort of noise. Noise in medical images will decrease the contrast in the image, due to this effect low contrast lesions may not be detected in the diagnostic phase. So the removal of noise ...