1. Articles from Ramona Cernat

    1-7 of 7
    1. Down-conversion en-face optical coherence tomography

      Down-conversion en-face optical coherence tomography

      We present an optical coherence tomography (OCT) method that can deliver an en-face OCT image from a sample in real-time, irrespective of the tuning speed of the swept source. The method, based on the master slave interferometry technique, implements a coherence gate principle by requiring that the optical path difference (OPD) between the arms of an imaging interferometer is the same with the OPD in an interrogating interferometer. In this way, a real-time en-face OCT image can originate from a depth in the sample placed in the imaging interferometer, selected by actuating on the OPD in the interrogating interferometer, while ...

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    2. Gabor fusion master slave optical coherence tomography

      Gabor fusion master slave optical coherence tomography

      This paper describes the application of the Gabor filtering protocol to a Master/Slave (MS) swept source optical coherence tomography (SS)-OCT system at 1300 nm. The MS-OCT system delivers information from selected depths, a property that allows operation similar to that of a time domain OCT system, where dynamic focusing is possible. The Gabor filtering processing following collection of multiple data from different focus positions is different from that utilized by a conventional swept source OCT system using a Fast Fourier transform (FFT) to produce an A-scan. Instead of selecting the bright parts of A-scans for each focus position ...

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    3. Design and testing of prototype handheld scanning probes for optical coherence tomography

      Design and testing of prototype handheld scanning probes for optical coherence tomography

      Three simple and low-cost configurations of handheld scanning probes for optical coherence tomography have been developed. Their design and testing for dentistry applications are presented. The first two configurations were built exclusively from available off-the-shelf optomechanical components, which, to the best of our knowledge, are the first designs of this type. The third configuration includes these components in an optimized and ergonomic probe. All the designs are presented in detail to allow for their duplication in any laboratory with a minimum effort, for applications that range from educational to high-end clinical investigations. Requirements that have to be fulfilled to achieve ...

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    4. Spatial Compounding Algorithm for Speckle Reduction of Dynamic Focus OCT Images

      Spatial Compounding Algorithm for Speckle Reduction of Dynamic Focus OCT Images

      Optical coherence tomography is capable of imaging the microstructures within tissues. To preserve the transverse resolution at all imaging depths, we implement a dynamic focusing scheme. To improve the quality of images further, a simple speckle reduction scheme is employed which uses the vibration introduced by the translation stage used for axial scanning. A spatial compounding technique is developed based on co-registration followed by an averaging algorithm. We conclude that the degree of speckle reduction achieved is worth the expense of more complicated processing required.

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    5. Dual instrument for in vivo and ex vivo OCT imaging in an ENT department

      Dual instrument for in vivo and ex vivo OCT imaging in an ENT department

      A dual instrument is assembled to investigate the usefulness of optical coherence tomography (OCT) imaging in an ear, nose and throat (ENT) department. Instrument 1 is dedicated to in vivo laryngeal investigation, based on an endoscope probe head assembled by compounding a miniature transversal flying spot scanning probe with a commercial fiber bundle endoscope. This dual probe head is used to implement a dual channel nasolaryngeal endoscopy-OCT system. The two probe heads are used to provide simultaneously OCT cross section images and en face fiber bundle endoscopic images. Instrument 2 is dedicated to either in vivo imaging of accessible surface ...

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    6. Evaluation of effective noise bandwidth for broadband optical coherence tomography operation

      Key noise parameters in optical coherence tomography (OCT) systems employing splitters with a nonflat spectral response are evaluated using a supercontinuum fiber laser source with a spectrum of 450 nm-1700 nm and a time domain OCT architecture based on 1300 nm fiber splitters. The spectral behavior of the splitter leading to balanced detection is measured over a range of 300 nm. Because of spectrally different signals at the balanced detector input a residual excess photon noise term results. A rigorous treatment of this noise term [Appl. Opt.43, 4802 (2004)] introduced two new quantities that take into account the spectral ...

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    7. Multi-channel time domain spectroscopic optical coherence tomography system

      A detection method based on 7 spectral windows at the photodetection stage in an optical coherence tomography system was tested. We investigated its utility in two directions: spectroscopic optical coherence tomography and signal to noise ratio improvement. A diffraction grating was used in the photodetection unit to diffract light over a 16 photodetector array. Currently, this array has been configured to deliver 7 channels only by binning two adjacent photodetectors. The improvement of the signal to noise ratio has been investigated. Preliminary results of spectroscopy analysis which will be shown are B-scan OCT imaging of paint layers. The ultimate aim ...

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    1-7 of 7
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  2. Topics in the News

    1. (7 articles) Ramona Cernat
    2. (6 articles) University of Kent
    3. (6 articles) Adrian G. Podoleanu
    4. (5 articles) Adrian Bradu
    5. (3 articles) George M. Dobre
    6. (1 articles) Nizhny Novgorod State Medical Academy
    7. (1 articles) New York Eye and Ear Infirmary
    8. (1 articles) Grigory V. Gelikonov
    9. (1 articles) Richard B. Rosen
    10. (1 articles) Pearse A. Keane
    11. (1 articles) Joost Daemen
    12. (1 articles) Notal Vision
    13. (1 articles) Thorlabs
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    Dual instrument for in vivo and ex vivo OCT imaging in an ENT department Spatial Compounding Algorithm for Speckle Reduction of Dynamic Focus OCT Images Design and testing of prototype handheld scanning probes for optical coherence tomography Gabor fusion master slave optical coherence tomography Down-conversion en-face optical coherence tomography Fantom Encore Sirolimus-eluting Bioresorbable Scaffold for Treatment of De-novo CAD: the ENCORE-I Study Assessment of Microcirculatory Dysfunction in Septic Shock Patients by OCTA OCT system used at home demonstrates potential for daily monitoring of AMD Optical Coherence Tomography Biomarkers of the Outer Blood—Retina Barrier in Patients with Diabetic Macular Oedema Retinal Boundary Segmentation in Stargardt Disease Optical Coherence Tomography Images Using Automated Multi-channel swept source optical coherence tomography concept based on photonic integrated circuits Assessment of Retinal Vessel Density in Adult-Onset Foveomacular Vitelliform Dystrophy by Optical Coherence Tomography Angiography