Results 191 to 200 of about 230,662 (251)

An improvement of signal-to- noise ratio for phase image

2017
Aims and objectives: Transverse relaxation time ( T 2 ) is a time constant which includes only nuclear-nuclear interactions. T 2 * is a time constant including nuclear-nuclear interactions and static magnetic field ( B 0 ) inhomogeneity, which is affected by...
Mitsuharu Miyoshi, Natsuki Ikemitsu, Hiroaki Hayashi, Yuki Matsumoto, Toshiaki Sasaki, Yuki Kanazawa, Masafumi Harada, Takatoshi Usuda   +7 more
openaire   +2 more sources

Theoretical investigation of the signal-to-noise ratio in fluorescence lifetime imaging.

Journal of The Optical Society of America A-optics Image Science and Vision, 2003
We deduce the signal-to-noise ratio for fluorescence lifetime imaging when using frequency-domain methods. We assume mono-exponential decay and quantum-noise-limited performance.
J. Philip, K. Carlsson
semanticscholar   +1 more source

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 ...
P.J. Harvey, B.T.A. McKee, L. G. Hiltz
openaire   +3 more sources

Improving Image Formation by Pushing the Signal-to-Noise Ratio

2010
Two-photon and confocal laser scanning microscopes represent fundamental optical techniques for biological investigations, thanks to their optical sectioning capability. However, in several experimental situations, low-intensity signals are detected, and the imaging quality can be remarkably limited by noise contribution.
Alberto Diaspro, Alberto Diaspro, Giuseppe Vicidomini, Giuseppe Vicidomini, Emiliano Ronzitti, Emiliano Ronzitti, Francesca Cella Zanacchi, Francesca Cella Zanacchi   +7 more
openaire   +3 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.
David L. Fried, Brij N. Agrawal, Jim F. Riker   +2 more
openaire   +3 more sources

Signal-to-noise ratios in acousto-photonic imaging

SPIE Proceedings, 2006
The concept of tagging photons with ultrasound for medical imaging has been under development by several groups since the early 1990's. All the early attempts were plagued by low signals. The problem is very fundamental because the goal of good spatial resolution requires sampling only that light which has gone through a very small volume.
openaire   +2 more sources

Signal-to-noise ratios of coherent imaging ladar

SPIE Proceedings, 2007
We analyze the signal and noise in coherent active laser imaging systems (LADARs). The principle LADAR noise sources are shot noise in the detection process and target fluctuations in the reflected signal including speckle. The statistical relationships between signal and noise are similar for RADAR and LADAR.
openaire   +2 more sources

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, C. C. Teo, C. P. Tso, M.A. Lai   +3 more
openaire   +3 more sources

Accurate histopathology from low signal-to-noise ratio spectroscopic imaging data.

In Analysis, 2010
Fourier Transform Infrared (FT-IR) spectroscopic imaging is emerging as an automated alternative to human examination in studying development and disease in tissue. The technology's speed and accuracy, however, are limited by the trade-off with signal-to-
R. Reddy, R. Bhargava
semanticscholar   +1 more source

Signal-to-Noise Ratio of Image Devices

1960
Publisher Summary This chapter discusses the signal-to-noise ratio of image devices. In an X-ray image intensifier, the X-rays are absorbed in a fluorescent screen that converts the X-rays into light. The light quanta excite the photocathode, which is deposited upon the fluorescent material. In such cases, therefore, an image represented by X-rays is
openaire   +2 more sources