Results 251 to 260 of about 536,964 (293)

Signal-to-noise ratio in coded aperture imaging

Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2012
Abstract We present a derivation of the signal-to-noise ratio (SNR) of a cyclic difference set (CDS) based coded mask which is simpler than that given in the literature, and which applies to any distribution of flux against the mask, not just Poisson statistics as is currently the case.
Alireza Talebitaher, Stuart V Springham
exaly   +2 more sources

Maximizing signal-to-noise and contrast-to-noise ratios in flash imaging

Magnetic Resonance Imaging, 1987
This paper presents an analysis of signal-to-noise and contrast-to-noise ratios from small tip angle, gradient reversal (FLASH) imaging. Analytic and numerical techniques are used to determine the delay times and tip angles that maximize signal-to-noise per unit time from a single tissue. Similar procedures are used to determine the delay times and tip
R E, Hendrick, J B, Kneeland, D D, Stark
exaly   +3 more sources

The intrinsic signal‐to‐noise ratio in NMR imaging

Magnetic Resonance in Medicine, 1986
AbstractThe fundamental limit for NMR imaging is set by an intrinsic signal‐to‐noise ratio (SNR) for a particular combination of rf antenna and imaging subjects. The intrinsic SNR is the signal from a small volume of material in the sample competing with electrical noise from thermally generated, random noise currents in the sample.
W A, Edelstein, G H, Glover, C J, Hardy, R W, Redington   +3 more
openaire   +2 more sources

Signal‐to‐noise ratio considerations in radiographic imaging

Medical Physics, 1983
The methodology employed to calculate radiographic signal‐to‐noise ratio (SNR) for the commonly used disk‐shaped test object is reviewed. Although the “matched” aperture yields the maximum SNR, its shape is difficult to achieve experimentally. On the other hand, a circular aperture having the same size as the object is much simpler to realize.
D P, Chakraborty, G T, Barnes
openaire   +2 more sources

Lesion detection and signal–to–noise ratio in CT images

Medical Physics, 1981
This study measured observers’ ability to detect and locate focal lesions on simulated CT images. The difficulty of the detection task was manipulated by changing the difference in attenuation between the lesion and its background (contrast), the random variation in the CT values (noise) or the lesion's size.
P F, Judy, R G, Swensson, M, Szulc
openaire   +2 more sources

Signal-to-noise ratio limitations for intensity correlation imaging

Journal of the Optical Society of America A, 2014
Intensity correlation imaging (ICI) is a concept which has been considered for the task of providing images of satellites in geosynchronous orbit using ground-based equipment. This concept is based on the intensity interferometer principle first developed by Hanbury Brown and Twiss.
Fried, David L., Riker, Jim, Agrawal, Brij   +2 more
openaire   +3 more sources

Signal-to-noise ratios for attenuation correction in PET imaging

IEEE Transactions on Medical Imaging, 1994
Attenuation correction is an important part of accurate image reconstruction in positron tomography. The usual correction method involves direct measurement of attenuation correction factors (ACFs). A reconstruct-reproject method, which has been suggested as providing superior noise properties, is sometimes employed; an attenuation image is first ...
B. T. A. McKee, L. G. Hiltz, P. J. Harvey   +2 more
openaire   +2 more sources

Contrast signal-to-noise ratio for image quality assessment

IEEE International Conference on Image Processing 2005, 2005
Peak signal-to-noise ratio (PSNR) is commonly used as an objective quality metric in signal processing. However, PSNR correlates poorly with the subjective quality rating. In this paper, we propose a new metric using contrast signal-to-noise ratio (CSNR), which measures the ratio of the contrast information level of distorted signal to the contrast ...
Susu Yao, Weisi Lin, Ee Ping Ong, Zhongkang Lu   +3 more
openaire   +1 more source

Single Image Signal-to-Noise Ratio Estimation for Magnetic Resonance Images

Journal of Medical Systems, 2009
A novel technique to quantify the signal-to-noise ratio (SNR) of magnetic resonance images is developed. The image SNR is quantified by estimating the amplitude of the signal spectrum using the autocorrelation function of just one single magnetic resonance image.
Kok Swee Sim, M. A. Lai, Chih Ping Tso, C. C. Teo   +3 more
openaire   +2 more sources