Filters








3,386 Hits in 4.3 sec

Automatic online spectral calibration of Fourier-domain OCT for robotic surgery

Xuan Liu, Marcin Balicki, Russell H. Taylor, Jin U. Kang, Anita Mahadevan-Jansen, Tuan Vo-Dinh, Warren S. Grundfest
2011 Advanced Biomedical and Clinical Diagnostic Systems IX  
We present a new automatic spectral calibration (ASC) method for spectral Domain optical coherence tomography (SD-OCT).  ...  Our ASC method calibrates the spectral mapping of the spectrometer in SD-OCT, and does not require external calibrating light source or a commercial spectral analyzer.  ...  (a) M-scan obtained when we imaged a mirror in air using sinusoidal modulated robot motion; (b) time varying peak position of OCT A-scans; (c) result of Fourier analysis of Fig. 3(b); (d) commanded robot  ... 
doi:10.1117/12.875210 pmid:22611481 pmcid:PMC3354775 fatcat:ga2e32a4nnf6rixifxn7o6ekva

The correlation between optical coherence tomography retinal shape irregularity and axial length

Stewart Lake, Murk Bottema, Keryn Williams, Karen Reynolds, Steffen Hamann
2019 PLoS ONE  
The shape of this contour was described by the best-fit curvature (K), and Fourier analysis of the difference between K and the RPE.  ...  To describe the retinal contour in optical coherence tomography (OCT) images, and report the relationship between retinal contour and axial length.  ...  Awareness of its reliability and usefulness, combined with the volume of information within OCT images has led to the development of multiple tools for quantitative analysis of retinal OCT scans to guide  ... 
doi:10.1371/journal.pone.0227207 pmid:31887186 pmcid:PMC6936846 fatcat:pyuxgbtxavhetagraz5mekup4q

COMPARISON OF SPECTRAL/FOURIER DOMAIN OPTICAL COHERENCE TOMOGRAPHY INSTRUMENTS FOR ASSESSMENT OF NORMAL MACULAR THICKNESS

ALAN C. SULL, LAUREL N. VUONG, LORI LYN PRICE, VIVEK J. SRINIVASAN, IWONA GORCZYNSKA, JAMES G. FUJIMOTO, JOEL S. SCHUMAN, JAY S. DUKER
2010 Retina  
PURPOSE-To report normal macular thickness measurements and assess reproducibility of retinal thickness measurements acquired by a time domain optical coherence tomography (OCT)  ...  The linear regression analysis shown in Figure 4 shows Although an attempt was made to generate an equation to convert spectral / Fourier domain OCT and Stratus OCT measurements interchangeably (Figure  ...  All scans acquired had a signal strength of at least 7 (range, 7-10). Spectral / Fourier domain OCT imaging was performed using 3 commercially-available instruments.  ... 
doi:10.1097/iae.0b013e3181bd2c3b pmid:19952997 pmcid:PMC2819609 fatcat:3sgpoo5gobhkpdayiygty5fgnm

Three-dimensional and high-speed swept-source optical coherence tomography for in vivo investigation of human anterior eye segments

Yoshiaki Yasuno, Violeta Dimitrova Madjarova, Shuichi Makita, Masahiro Akiba, Atsushi Morosawa, Changho Chong, Toru Sakai, Kin-Pui Chan, Masahide Itoh, Toyohiko Yatagai
2005 Optics Express  
This paper presents a simple calibration method using a fringe analysis technique for spectral rescaling.  ...  A two-and three-dimensional swept source optical coherence tomography (SS-OCT) system, which uses a ready-to-ship scanning light source, is demonstrated.  ...  interference signal by using a spectrometer consisting of a diffraction grating, Fourier transform lens, and a detector array or a line-scan camera.  ... 
doi:10.1364/opex.13.010652 pmid:19503280 fatcat:6mbzbe23kbduhdrchzukg5xldu

Comparison of Clinically Relevant Findings from High-Speed Fourier-Domain and Conventional Time-Domain Optical Coherence Tomography

Pearse A. Keane, Rizwan A. Bhatti, Jacob W. Brubaker, Sandra Liakopoulos, Srinivas R. Sadda, Alexander C. Walsh
2009 American Journal of Ophthalmology  
Methods-FDOCT scans (128 B-scans × 512 A-scans) were obtained using a prototype instrument (3D-OCT, Topcon, Japan) in 50 eyes of 28 consecutive patients undergoing conventional high resolution (6 B-scans  ...  × 512 A-scans) TDOCT imaging (StratusOCT, Carl Zeiss Meditec, USA).  ...  Acknowledgments Institutional Review Board: Approval for data collection and analysis was obtained from the institutional review board of the University of Southern California.  ... 
doi:10.1016/j.ajo.2009.03.004 pmid:19427620 pmcid:PMC2729434 fatcat:wimbf7mmnvcq3kcjwtlvxacpey

AUTOMATED THREE-DIMENSIONAL SEGMENTATION OF RETINAL OCT IMAGES

Narendra Kumar Patel .
2015 International Journal of Research in Engineering and Technology  
Fourier Domain -Optical Coherence Tomography (FD-OCT) is a well-established imaging technique in ophthalmology.  ...  The algorithm is tested upon the images of healthy volunteers obtained from Cirrus HD-OCT system.  ...  MACULAR ANALYSIS Fovea At fovea, the A-scans have less total intensity i.e. addition of all pixels of A-scan. The normalized A-scan sum matrix is converted to binary form with threshold 0.5.  ... 
doi:10.15623/ijret.2015.0424010 fatcat:ox3xt7ot3zdh5nbol5lc5sehv4

Computational methods for analysis of human breast tumor tissue in optical coherence tomography images

Adam M. Zysk, Stephen A. Boppart
2006 Journal of Biomedical Optics  
Fig. 6 OCT image of a horizontal tumor margin ͑logarithmic re-sponse͒ assessed using the combined detection technique at three representative scan lines ͑arrows indicate columns 40, 115, and 190͒.  ...  We present methods for the assessment of human breast tissue based on spatial and Fourier-domain analysis.  ...  Fig. 2 2 Fourier-domain data from OCT axial scans showing the unique signature from each tissue type.  ... 
doi:10.1117/1.2358964 pmid:17092164 fatcat:fs2layeigrb2de7gkswyjj4r7q

Optical computing for optical coherence tomography

Xiao Zhang, Tiancheng Huo, Chengming Wang, Wenchao Liao, Tianyuan Chen, Shengnan Ai, Wenxin Zhang, Jui-Cheng Hsieh, Ping Xue
2016 Scientific Reports  
A processing rate of 10 mega-A-scans/second was experimentally achieved, which is, to our knowledge, the highest speed for OCT imaging.  ...  In the so-called optical computing OCT, fast Fourier transformation (FFT) of A-scan signal is optically processed in real time before being detected by photoelectric detector.  ...  Instead of software algorithm and GPUs computing, we employed an all-optical real-time Fourier transformation system to process the A-scan data before the OCT light signal is converted to electrical signal  ... 
doi:10.1038/srep37286 pmid:27869131 pmcid:PMC5116674 fatcat:yyl4sh334ffxdkrywawmzp4nby

Swept source optical coherence tomography using an all-fiber 1300-nm ring laser source

Michael A. Choma, Kevin Hsu, Joseph A. Izatt
2005 Journal of Biomedical Optics  
Lastly, the effects of analog-todigital converter aliasing on image quality in swept source OCT are discussed.  ...  A differential swept source OCT system is presented, and images of in vivo human cornea and skin are presented.  ...  k domain before Fourier transformation into an A scan.  ... 
doi:10.1117/1.1961474 pmid:16178643 fatcat:5u4epl4ndzaplbd2pfoahkehbi

Acceleration of OCT Signal Processing with Lookup Table Method for Logarithmic Transformation

Xinyu Li, Shanshan Liang, Jun Zhang
2019 Applied Sciences  
Real-time Fourier domain optical coherence tomography (FDOCT) has been widely used in clinical applications.  ...  In order to accelerate the imaging processing and display of FDOCT, an alternative lookup table-based strategy for logarithmic transformation was presented.  ...  It has been reported that a multi-MHz scan rate can be achieved in a swept source OCT (SSOCT) system by using an ultra-high-speed Fourier domain mode-locked laser [2] .  ... 
doi:10.3390/app9071278 fatcat:qvpeoueifvdmlkwp43kiyfaghe

Generalized Image Reconstruction in Optical Coherence Tomography Using Redundant and Non-Uniformly-Spaced Samples

Karim Nagib, Biniyam Mezgebo, Namal Fernando, Behzad Kordi, Sherif S. Sherif
2021 Sensors  
We also correct an important theoretical error in the previously reported results related to OCT image reconstruction using the Non-uniform Discrete Fourier Transform (NDFT).  ...  ., a scaled NDFT, using the Fast Fourier Transform (FFT).  ...  Image reconstruction in Fourier domain OCT typically involves an inverse Fourier transform step applied to its A-scan data.  ... 
doi:10.3390/s21217057 pmid:34770364 pmcid:PMC8587445 fatcat:6ki3pjpr4jc2lhqa4ix4ysoefy

Fourier domain mode locking at 1050 nm for ultra-high-speed optical coherence tomography of the human retina at 236,000 axial scans per second

R. Huber, D. C. Adler, V. J. Srinivasan, J. G. Fujimoto
2007 Optics Letters  
A Fourier domain mode-locked (FDML) laser at 1050 nm for ultra-high-speed optical coherence tomography (OCT) imaging of the human retina is demonstrated.  ...  Ultra-high-speed retinal imaging is demonstrated at 236,000 axial scans per second.  ...  For ophthalmic applications, high-speed OCT systems typically use a broadband light source in combination with a spectrometer [3, 4] (spectral-Fourier domain OCT), which can achieve axial scan rates  ... 
doi:10.1364/ol.32.002049 pmid:17632639 fatcat:ojsd2pjlwzattnhxigxwd27pim

Towards automatic calibration of Fourier-Domain OCT for robot-assisted vitreoretinal surgery

Xuan Liu, Marcin Balicki, Russell H. Taylor, Jin U. Kang
2010 Optics Express  
We present a new real-time automatic spectral calibration (ASC) method for Fourier domain optical coherence tomography (FD OCT) that can be automatically performed by the system.  ...  The ASC method proposed can be performed during OCT scanning operation and does not require an external calibrating light source or a commercial optical spectrum analyzer.  ...  Fourier Domain OCT (FD OCT), which offers significantly improved sensitivity and imaging speed compared to time-domain OCT (TD-OCT) [6] [7] [8] [9] [10] [11] , has been incorporated with robotic surgical  ... 
doi:10.1364/oe.18.024331 pmid:21164780 pmcid:PMC3003938 fatcat:ub77dgrtkjdvxgzw3twqf3rfde

Real-time phase-resolved functional optical coherence tomography by use of optical Hilbert transformation

Yonghua Zhao, Zhongping Chen, Zhihua Ding, Hongwu Ren, J. Stuart Nelson
2002 Optics Letters  
The most straightforward method is spectral analysis using a fast Fourier transformation algorithm. 2 -4 However, this method depends on the fast Fourier transformation window time, which limits axial  ...  OCT is analogous to ultrasound imaging. However, OCT uses near-infrared optical waves instead of sound waves.  ... 
doi:10.1364/ol.27.000098 pmid:18007724 fatcat:i6wzy7x3vvbjbowtkaqmcfcpfm

Small Animal Retinal Imaging [chapter]

WooJhon Choi, Wolfgang Drexler, James G. Fujimoto
2015 Optical Coherence Tomography  
Swept source/Fourier domain OCT uses a wavelength swept laser source with photodiodes and a high speed A/D converter [23, 36] .  ...  Swept Source / Fourier Domain OCT Imaging using Swept Lasers Swept source / Fourier domain OCT is a complementary approach to spectral / Fourier domain OCT.  ... 
doi:10.1007/978-3-319-06419-2_65 fatcat:ler7orvavnaslkbfp2gewwk5um
« Previous Showing results 1 — 15 out of 3,386 results