Close Message
None

Articles from Zhihua Ding

1-11 of 11
Categories:
Applications: Art, Bronchoscopy, Cardiology, Dentistry, Dermatology, Developmental Biology, Endoscopy, Glucose, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Urology
Business News: Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
Technology: Broadband Sources, Doppler, Probes, Tunable Sources
Miscellaneous: Jobs & Studentships, Student Theses, Textbooks

  1. Transit-time analysis based on delay-encoded beam shape for velocity vector quantification by spectral-domain Doppler optical coherence tomography

    Explore Article opticsinfobase.org (Jan 11 2010) Doppler

    Transit-time analysis based on delay-encoded beam shape for velocity vector quantification by spectral-domain Doppler optical coherence tomography We propose a transit-time based method to ascertain the azimuth angle of a velocity vector by spectral-domain Doppler optical coherence tomography (DOCT), so that three-dimensional (3-D) velocity vector can be quantified. A custom-designed slit plate with predetermined slit orientation is placed into the sample beam to create three delay-encoded sub-beams of different beam shape for sample probing. Based on the transit-time analysis for Doppler bandwidth, the azimuth angle within 90° range is evaluated by exploitation of the complex signals corresponding to three path length delays. 3-D velocity vector is quantified through further estimating of Doppler angle and flow velocity by ... (Read Full Article)

    Comment on Article

  2. Development of a high speed spectral domain optical coherence tomography system at 835 nm

    Explore Article SPIE Digital Library (Dec 1 2009) Developmental Biology , Doppler

    We develop a high speed multi-functional spectral domain (SD-OCT) system, using a broadband light source centered at 835nm and a custom-built spectrometer with a spectral resolution of 0.0674nm. After precise spectral calibration of the spectrometer, non-uniform discrete Fourier transform (NDFT) of the acquired spectral data is adopted for image reconstruction. In vivo imaging of human finger from volunteer at A-scan rate of 29 kHz with different reconstruction methods reveal that with the NDFT method, improved sensitivity fall-off especially at large depth is achieved in contrast to the conventional discrete Fourier transform (DFT) with interpolation method. And the phase information of ... (Read Full Article)

    Comment on Article Mentions:   Zhejiang University

  3. Transmissive RSOD for balance-detection-based OCT

    Explore Article SPIE Digital Library (Oct 28 2009)

    This paper presents a transmissive rapid scanning optical delay line (RSOD) for balance detection based optical coherence tomography (OCT). This transmissive RSOD, consisting of a reflective blazed grating, a Fourier lens, a fast-scanning galvo-mirror, a right-angle prism and a mirror, functions for phase modulation, axial scanning and dispersion compensation in OCT just as a reflective RSOD. The developed transmissive RSOD is implemented in OCT for balance detection. Comparison study indicates that improved quality of imaging is archived by the transmissive RSOD based OCT, in contrast to that by a conventional reflective RSOD based OCT. (Read Full Article)

    Comment on Article

  4. Sinusoidal B-M method based spectral domain optical coherence tomography for the elimination of complex-conjugate artifact

    Explore Article opticsinfobase.org (Sep 4 2009)

    Sinusoidal B-M method based spectral domain optical coherence tomography for the elimination of complex-conjugate artifact A high speed spectral domain optical coherence tomography based on the spatial sinusoidal phase modulation for the elimination of complex-conjugate artifact is presented, where sinusoidal phase modulation of reference arm (M scan) and transverse scanning of sample arm (B scan) are performed simultaneously (sinusoidal B-M method). Herein, the linear phase modulation of the reference arm in conventional linear B-M method is modified to sinusoidal phase modulation. The proposed sinusoidal B-M method relaxes the requirements on the phase-shifting mechanical system and avoids sensitivity fall-off along the transverse direction in contrast to the linear B-M method. A criterion for the relation between ... (Read Full Article)

    Comment on Article

  5. Two-dimensional scanning realized by an asymmetry fiber cantilever driven by single piezo bender actuator for optical coherence tomography

    Explore Article opticsinfobase.org (Jul 24 2009) Probes

    Two-dimensional scanning realized by an asymmetry fiber cantilever driven by single piezo bender actuator for optical coherence tomography We develop a fiber based probe that is capable of two-dimensional scanning applicable in optical coherence tomography (OCT). Based on the resonance of the fiber cantilever with asymmetry structure which has two distinguished resonant frequencies in orthogonal directions, Lissajous pattern is produced suitable for two-dimensional scanning upon a sample. Orthogonal resonances of the fiber cantilever are simultaneously excited by single piezo bender actuator with one driving signal consisting of two components corresponding to above-mentioned two resonant frequencies. By integrating a backward-placed two-dimensional position sensitive detector (PSD) into the probe, real-time lateral position of the scanning pattern is registered simultaneously for ... (Read Full Article)

    Comment on Article

  6. Development of a non-uniform discrete Fourier transform based high speed spectral domain optical coherence tomography system

    Explore Article opticsinfobase.org (Jul 2 2009)

    Development of a non-uniform discrete Fourier transform based high speed spectral domain optical coherence tomography system We develop a high speed spectral domain optical coherence tomography (SD-OCT) system based on a custom-built spectrometer and non-uniform discrete Fourier transform (NDFT) to realize minimized depth dependent sensitivity fall-off. After precise spectral calibration of the spectrometer, NDFT of the acquired spectral data is adopted for image reconstruction. The spectrometer is able to measure a wavelength range of about 138nm with a spectral resolution of 0.0674nm at central wavelength of 835nm, corresponding to an axial imaging range of 2.56mm in air. Zemax simulations and sensitivity fall-off measurements under two alignment states of the spectrometer are given. Both theoretical simulations and ... (Read Full Article)

    Comment on Article

  7. Time-domain interpolation for Fourier-domain optical coherence tomography

    Explore Article opticsinfobase.org (Jun 8 2009)

    Time-domain interpolation for Fourier-domain optical coherence tomography The imaging speed and quality of a Fourier-domain optical-coherence-tomography (FD-OCT) technique is largely limited by the resampling process. A time-domain interpolation approach based on zero padding is proposed that gets a close fall-off but much-reduced imaging time in FD-OCT data processing as compared with the common zero-padding interpolation method. The experimental results obtained with an FD-OCT system using a 2048 pixel line scan camera showed that the fall-off was improved by 2 dB in deep z position and that the processing time was reduced to 468 ms per 400 axial scan lines with a Pentium Dual E2140 computer; that is, ... (Read Full Article)

    Comment on Article

  8. Wavelength encoded OCT imaging using swept-source

    Explore Article SPIE Digital Library (Jan 8 2008) Endoscopy , Tunable Sources

    Ling Wang, Zhihua Ding, Tong Wu et al. Wavelength-encoded imaging uses wavelength division multiplexing to produce cross-sectional images without mechanical scanning, and could be of a great interest in endoscope applications. In this paper, a scheme for wavelength-encoded imaging using time-encoded Frequency-domain optical coherence tom ... [Proc. SPIE Int. Soc. Opt. Eng. 6826, 68261V (2008)] published Tue Jan 8, 2008. (Read Full Article)

    Comment on Article

  9. Common path endoscopic optical coherence tomography with outside path length compensation

    Explore Article SPIE Digital Library (Jan 8 2008) Endoscopy

    Yaliang Yang, Zhihua Ding, Jie Meng et al. Endoscopic optical coherence tomography (OCT) allowing high-resolution imaging of internal tissue is attractive for medical imaging. Fibre, fibre bundle or GRIN lens rod acting as endoscopic probe is placed in the sample arm of a Michelson interferometer in current endoscopic OCT systems, this arran ... [Proc. SPIE Int. Soc. Opt. Eng. 6826, 68261S (2008)] published Tue Jan 8, 2008. (Read Full Article)

    Comment on Article

  10. High-speed spectral-domain optical coherence tomography at 830nm wavelength

    Explore Article SPIE Digital Library (Jan 8 2008)

    We present a high-speed spectral domain optical coherence tomography (SD-OCT) system at 830 nm wavelength which is consisted of a fiber based Michelson interferometer and a custom-built spectrometer. The designed resolution of the spectrometer is about 67.4pm which limits the maximum detection depth ... [Proc. SPIE Int. Soc. Opt. Eng. 6826, 68260A (2008)] published Tue Jan 8, 2008. (Read Full Article)

    Comment on Article

  11. High resolution optical coherence tomography with an improved depth range using an axicon lens

    Explore Article PatFT » Page 1 of 1 (Jul 4 2006) Patents

    In optical coherence tomography (OCT), Axial and lateral resolutions are determined by the source coherence length and numerical aperture of the sampling lens, respectively. While axial resolution can be improved using a broadband light source, there is a trade-off between lateral resolution and focusing depth when conventional optical elements are used. The incorporation of an axicon lens into the sample arm of the interferometer overcomes this limitation. Using an axicon lens with a top angle of 160 degrees, 10 .mu.m or better-lateral resolution is maintained over a focusing depth of at least 6 mm. In addition to high lateral resolution, ... (Read Full Article)

    Comment on Article Mentions:   Cambridge Technology   John S. Nelson   Zhongping Chen

1-11 of 11
HomeAll ArticlesProfilesQuotesComments Login Register Powered by HiveFire