نتایج جستجو برای: subtraction technique
تعداد نتایج: 620977 فیلتر نتایج به سال:
CT Angiography (CTA) is an established technique for the minimally invasive imaging of arteries. The technique of maximum intensity projection (MIP) is often used to get a comprehensive overview of the vascular anatomy. On a MIP, however, arterial wall calcifications may hinder the visualization of the arterial lumen. These calcifications are in direct contact with the contrast-enhanced blood, ...
Underwater acoustic tank evaluation of acoustic properties of samples using spectrally dense signals
This papa deals with exploring the availability and reliability of subtraction techniques, based on spectrally dense signals such as Maximan Length Sequences, in evaluating the echo reduction losses of samples of interest in undawater acoustics. These techniques, first employed in air acoustics, were adapted to the undawater environment. Experimental results how how a measurement can be accompl...
PURPOSE We retrospectively explored the use of the delayed mask technique for intraarterial digital subtraction angiography (IADSA) to demonstrate the anatomy of aneurysm necks. METHODS The delayed mask technique was utilized in 22 patients who had craniotomies for aneurysms demonstrated at angiography. The operative notes were compared to the angiographic findings of both the traditionally m...
This article describes a modified technique for enhancing noisy speech to improve automatic speech recognition (ASR) performance. The proposed approach improves the widely used spectral subtraction which inherently suffers from the associated musical noise effects. Through a psychoacoustic masking and critical band variance normalization technique, the artifacts produced by spectral subtraction...
A method of liver scanning based on a subtraction technique with simultaneous use of two tracers, 67Ga-citrate and 99mTc-sulfur colloid, is described. The subtraction technique isolates radiogallium uptake by the space-occupying hepatic lesions by subtracting interference due to tracer uptake by healthy hepatic tissue. In 82 patients, the method yielded a correct result in 94.7% of the positive...
The basic problem suffered by a communication system is in the removal of additive background noise. Spectral Subtraction method (SSM) has been successfully implemented to suppress the background noise. This paper proposed a novel hybrid system for enhancing noise-corrupted speech which involves a parallel combination of Spectral Subtraction and soft thresholding method in wavelet domain for sp...
With dual-radiopharmaceutical (DR) parathyroid scintigraphy, imaging with 99mTcO4-or 123I-NaI is combined with 99mTc-sestamibi scintigraphy for localization of parathyroid adenomas. The set images are then either visually compared or digitally subtracted to aid in interpretation. While both EANM and SNMMI guidelines recommend use of digital subtraction over visual interpretation alone, to date,...
A well known technique for speech enhancement is spectral subtraction. This technique is attractive due to its simplicity and its low computational cost. However, spectral subtraction has the drawback of generating residual noise with a musical character, the so-called musical noise. In this paper, we propose a simple modi cation of the lter coe cient calculation in form of a recursion of the p...
We develop a new method for estimating and removing the spectrum of the sky from deep spectroscopic observations. Our method does not rely on simultaneous measurement of the sky spectrum with the object spectrum. The technique is based on the iterative subtraction of continuum estimates and eigenvector sky models derived from singular value decompositions of sky spectra and sky spectra residual...
We present simultaneous spectroscopic observations taken during four observing runs (1996 to 1999) of Hα, Hβ, Hǫ, Ca ii H & K, and Ca ii IRT lines of the chromospherically active binary BF Lyn. Both components have strong emission in the Hǫ, Ca ii H & K and Ca ii IRT lines and a strong filling-in of the Hα and Hβ lines have been observed after the application of the spectral subtraction techniq...
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