In this paper the application of multirate acoustic echo canceller derived from cochlea model and psychoacustically motivated noise and residual echo attenuation system operating on the signal decomposed in cochlear spaced subbands are described. Polyphase realisation of the FIR filter bank with non-uniform frequency resolution achieved by the frequency transformation of filter characteristic u...

The amplitude of low-field nuclear magnetic resonance (NMR) is weak, and the echo is buried in the noise. The reduction of noise is critical to accurately extract echo amplitude. Phase correction-adaptive line enhancement (PC-ALE) is proposed to noise suppression based on the principle of ALE and NMR spin-echo characteristics. The echo amplitude is calculated after two-stage processes; phase sh...

High-resolution MR imaging of the inner ear with a heavily T2-weighted 3D fast spin-echo sequence has been performed successfully at 1.5 T. However, at 3 T, the longer T1 time of CSF necessitates a longer TR, resulting in significantly prolonged imaging times. In this study, the fast recovery 3D fast spin-echo sequence, which permits the TR to be reduced while maintaining T2 contrast, was optim...

Patients had the 3Tesla MRI scan after 4.5 days from the index event. The structural MRI protocol, including standard MR sequences (DWI axial image, 3D T1 MP RAGE, 3D FLAIR, GRE) was applied to identify MR visible abnormalities. Axial diffusion-weighted images were acquired by using a spin-echo echo-planar imaging sequence (repetition time (TR)/echo time (TE), 2800/77 ms; field of view (FOV), 2...

We report a measurement of the spin-echo decay of a single electron spin confined in a semiconductor quantum dot. When we tip the spin in the transverse plane via a magnetic field burst, it dephases in 37 ns due to the Larmor precession around a random effective field from the nuclear spins in the host material. We reverse this dephasing to a large extent via a spin-echo pulse, and find a spin-...

BACKGROUND AND PURPOSE MR imaging techniques have proved their efficacy in imaging the head and neck region. In this study, we compared T1-weighted, dual T2-weighted, and fat-suppressed MR imaging and unenhanced and contrast-enhanced 3D time-of-flight MR angiography sequences for detection of head and neck paragangliomas. METHODS Thirty-one patients with 70 paragangliomas were examined. Four ...

In this paper, we propose improved versions of normalized least mean square (NLMS) algorithm: single and multiple -variable step size normalized least mean square (VSSNLMS) algorithms for echo cancellation. The presented algorithms exhibit faster convergence rate in comparison to NLMS algorithm. Simulation results employing standard figure of merits show how the algorithms perform better than N...

In this paper we describe a system that suppresses the acoustic interference due to the coupling between the microphone and the loudspeakers of a hands-free multi-channel desktop audio system. The proposed system operates in the Short-Time Fourier Transform domain and uses spectral subtraction to suppress the unwanted interference, which consists of the local audio and the remote speech signal ...

Echolocating horseshoe bats respond to flight-speed induced shifts in echo frequency by adjusting the frequency of subsequent calls. Under natural conditions, Doppler effects may force the frequency of a returning echo several kilohertz above the original emission frequency. By lowering subsequent call frequencies, the bat can return echo frequencies to within a narrow spectral bandwidth to whi...

PURPOSE To compare T2-weighted fat-suppressed fast spin-echo imaging with fat-suppressed conventional spin-echo imaging in the detection of normal intraorbital and pericavernous anatomy and orbital disease, and to determine the efficacy of fat saturation with T2-weighted fast spin-echo imaging of the cavernous sinus. METHODS Contrast-to-noise ratios of normal intraorbital anatomy were calcula...