This paper presents a new assessment of four approaches to acoustic echo cancellation in the presence of non-linear echo. The comparison is performed with algorithms that are configured to give equivalent performance under linear-only echo conditions, thereby giving a more meaningful assessment. We also compare the effect of non-linear echo to that of noise and show that, whilst performance dif...

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...

The purpose of this study was to analyze the background parenchymal echotexture (BP echo) on breast ultrasound in detail and to evaluate the relation BP echo with menopausal status. In addition, we correlated BP echo with mammographic breast density (MGD) and background parenchymal enhancement (BPE) on magnetic resonance imaging (MRI).The institutional review board of our hospital approved this...

BACKGROUND AND PURPOSE In multiple sclerosis, gadolinium enhancement is used to classify lesions as active. Regarding the need for a standardized and accurate method for detection of multiple sclerosis activity, we compared 2D-spin-echo with 3D-gradient-echo T1WI for the detection of gadolinium-enhancing MS lesions. MATERIALS AND METHODS Fifty-eight patients with MS were prospectively imaged ...

Introduction: Two techniques have been presented in the last year to acquire both angiographic and venographic information in a single acquisition (MRAV) using susceptibility weighted imaging (SWI). One uses a double echo approach with the shorter echo used for the angiography and the longer echo used for the venography (1). The other uses a single echo that is a compromise between the two with...