نتایج جستجو برای: frequency domain fd

تعداد نتایج: 863757  

Journal: :Circulation journal : official journal of the Japanese Circulation Society 2012
Yuichi Ozaki Hironori Kitabata Hiroto Tsujioka Seiki Hosokawa Manabu Kashiwagi Kohei Ishibashi Kenichi Komukai Takashi Tanimoto Yasushi Ino Shigeho Takarada Takashi Kubo Keizo Kimura Atsushi Tanaka Kumiko Hirata Masato Mizukoshi Toshio Imanishi Takashi Akasaka

BACKGROUND Although an intracoronary frequency-domain optical coherence tomography (FD-OCT) system overcomes several limitations of the time-domain OCT (TD-OCT) system, the former requires injection of contrast media for image acquisition. The increased total amount of contrast media for FD-OCT image acquisition may lead to the impairment of renal function. The safety and usefulness of the non-...

2018
Lei Zhang Guoxing Zhang Zhizheng Liang Ekene Frank Ozioko

The traditional taxi prediction methods model the taxi trajectory as a sequence of spatial points. It cannot represent two-dimensional spatial relationships between trajectory points. Therefore, many methods transform the taxi GPS trajectory into a two-dimensional image, and express the spatial correlations by trajectory image. However, the trajectory image may have noise and sparsity according...

Journal: :JACC. Cardiovascular interventions 2013
Hiram G Bezerra Guilherme F Attizzani Vasile Sirbu Giuseppe Musumeci Nikoloz Lortkipanidze Yusuke Fujino Wei Wang Sunao Nakamura Andrej Erglis Giulio Guagliumi Marco A Costa

OBJECTIVES We compared intravascular ultrasound (IVUS) and 2 different generations of optical coherence tomography (OCT)-time-domain OCT (TD-OCT) and frequency-domain OCT (FD-OCT)-for the assessment of coronary disease and percutaneous coronary intervention (PCI) using stents. BACKGROUND OCT is a promising light-based intravascular imaging modality with higher resolution than IVUS. However, t...

2010
H.-W. Chang S.-Y. Mu

The frequency-domain finite-difference (FD-FD) methods have been successfully used to obtain numerical solutions of the twodimensional (2-D) Helmholtz equation. The standard second-order accurate FD-FD scheme is known to produce unwanted numerical spatial and temporal dispersions when the sampling is inadequate. Recently compact higher-order accurate FD-FD methods have been proposed to reduce t...

Journal: :IEEE Signal Processing Letters 2021

As the digital version of a continuous-time delay, concept fractional delay (FD) is exploited to approximate desired that not multiple sampling interval. However, in FD filters, there always severe distortion at beginning delayed signals, referred as head distortion. This letter identifies cause and proposes solution this problem for reducing overall filters. For purpose performance evaluation,...

Journal: :EURASIP J. Adv. Sig. Proc. 2014
Andrea M. Tonello Mauro Girotto

A filter bank modulation transceiver is presented. The idea is to obtain good sub-channel frequency confinement as it is done by the family of exponentially modulated filter banks that is typically referred to as filtered multitone (FMT) modulation. However, differently from conventional FMT, the linear convolutions are replaced with circular convolutions. Since transmission occurs in blocks, t...

2010
Li Huo Jiefeng Xi Yicong Wu Xingde Li

A forward-viewing resonant fiber-optic endoscope of a scanning speed appropriate for a high-speed Fourier-domain optical coherence tomography (FD-OCT) system was developed to enable real-time, three-dimensional endoscopic OCT imaging. A new method was explored to conveniently tune the scanning frequency of a resonant fiber-optic scanner, by properly selecting the fiber-optic cantilever length, ...

Journal: :Vision Research 2004
P. T. Quaid T. Simpson J. G. Flanagan

The purpose of this paper was to investigate the effects of both monocular and dichoptic masking on the frequency doubling (FD) illusion, using both temporal and spatial masks. Monocular spatial tuning effects occurred around the fundamental FD spatial frequency of 0.25 cycles per degree (c/deg), whereas dichoptic spatial frequency tuning effects occurred at the doubled spatial frequency of 0.5...

Journal: :IEEE Transactions on Wireless Communications 2021

A well-known drawback of orthogonal frequency-division multiplexing (OFDM) is its signal with high peak-to-average power ratio (PAPR). Among a number PAPR reduction techniques, clipping and filtering (CAF) the simplest approach, which effectively reduces band-limited OFDM signals at cost increasing in-band distortion. In order to mitigate performance degradation caused by distortion, several it...

2007
Maria G. Jafari Mark D. Plumbley

In this paper, we investigate the importance of the high frequencies in the problem of convolutive blind source separation (BSS) of speech signals. In particular, we focus on frequency domain blind source separation (FD-BSS), and show that when separation is performed in the low frequency bins only, the recovered signals are similar in quality to those extracted when all frequencies are taken i...

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