1. Articles from Kate Sugden

    1-7 of 7
    1. Non-planar calibration phantoms for optical coherence tomography

      Non-planar calibration phantoms for optical coherence tomography

      Optical coherence tomography (OCT) is increasingly used in areas such as ophthalmology and contact lens metrology. However, in such cases, image distortion can occur due to the non-planar nature of the measured sample. Postprocessing algorithms can be implemented to correct this distortion. Here we present an OCT phantom designed to confirm the validity of post-processing algorithms used for measuring curved surfaces. A multi-purpose OCT phantom has been created within a fused silica plano-convex lens using the direct femtosecond laser writing technique. This phantom can be used to calibrate and quantitatively assess the performance (e.g. resolution, sensitivity and distortion) of ...

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    2. Developments in contact lens measurement: A comparative study of industry standard geometric inspection and optical coherence tomography

      Developments in contact lens measurement: A comparative study of industry standard geometric inspection and optical coherence tomography

      Purpose The aim of this study was to compare a developmental optical coherence tomography (OCT) based contact lens inspection instrument to a widely used geometric inspection instrument (Optimec JCF), to establish the capability of a market focused OCT system. Methods Measurements of 27 soft spherical contact lenses were made using the Optimec JCF and a new OCT based instrument, the Optimec is830. Twelve of the lenses analysed were specially commissioned from a traditional hydrogel (Contamac GM Advance 49%) and 12 from a silicone hydrogel (Contamac Definitive 65), each set with a range of back optic zone radius (BOZR) and centre ...

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      Mentions: Kate Sugden
    3. Fabrication of high quality optical coherence tomography (OCT) calibration artefacts using femtosecond inscription

      Fabrication of high quality optical coherence tomography (OCT) calibration artefacts using femtosecond inscription

      Optical coherence tomography (OCT) is a non-invasive three-dimensional imaging system that is capable of producing high resolution in-vivo images. OCT is approved for use in clinical trials in Japan, USA and Europe. For OCT to be used effectively in a clinical diagnosis, a method of standardisation is required to assess the performance across different systems. This standardisation can be implemented using highly accurate and reproducible artefacts for calibration at both installation and throughout the lifetime of a system. Femtosecond lasers can write highly reproducible and highly localised micro-structured calibration artefacts within a transparent media. We report on the fabrication of ...

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    4. Three-dimensional calibration targets for optical coherence tomography

      Three-dimensional calibration targets for optical coherence tomography

      The recent expansion of clinical applications for optical coherence tomography (OCT) is driving the development of approaches for consistent image acquisition. There is a simultaneous need for time-stable, easy-to-use imaging targets for calibration and standardization of OCT devices. We present calibration targets consisting of three-dimensional structures etched into nanoparticle-embedded resin. Spherical iron oxide nanoparticles with a predominant particle diameter of 400 nm were homogeneously dispersed in a two part polyurethane resin and allowed to harden overnight. These samples were then etched using a precision micromachining femtosecond laser with a center wavelength of 1026 nm, 100kHz repetition rate and 450 fs ...

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    5. Feature Of The Week 1/8/12: Ultrafast Processing and Rendering of OCT Data using a GPU

      Feature Of The Week 1/8/12: Ultrafast Processing and Rendering of OCT Data using a GPU
      Processing of the large volumetric data is the bottleneck of the current FD-OCT systems. Solving this issue enables real time visualisation. Various groups have applied utilising the full power of GPU for OCT data processing allows to realise the full potential of OCT. GPU based data processing to OCT. Here we present a GPU-CPU based processing methodology as well evaluates the performance of various GPUs.In standard processing, interference data are copied to GPU and entire computation is carried out on GPU. Processed data are stored in GPU memory, which allows rendering and visualising the data.To benchmark the processing ...
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    6. Femtosecond laser micro-inscription of optical coherence tomography resolution test artifacts

      Femtosecond laser micro-inscription of optical coherence tomography resolution test artifacts
      Optical coherence tomography (OCT) systems are becoming more commonly used in biomedical imaging and, to enable continued uptake, a reliable method of characterizing their performance and validating their operation is required. This paper outlines the use of femtosecond laser subsurface micro-inscription techniques to fabricate an OCT test artifact for validating the resolution performance of a commercial OCT system. The key advantage of this approach is that by utilizing the nonlinear absorption a three dimensional grid of highly localized point and line defects can be written in clear fused silica substrates.
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    7. Processing and rendering of Fourier domain optical coherence tomography images at a line rate over 524 kHz using a graphics processing unit

      Processing and rendering of Fourier domain optical coherence tomography images at a line rate over 524 kHz using a graphics processing unit
      In Fourier domain optical coherence tomography (FD-OCT), a large amount of interference data needs to be resampled from the wavelength domain to the wavenumber domain prior to Fourier transformation. We present an approach to optimize this data processing, using a graphics processing unit (GPU) and parallel processing algorithms. We demonstrate an increased processing and rendering rate over that previously reported by using GPU paged memory to render data in the GPU rather than copying back to the CPU. This avoids unnecessary and slow data transfer, enabling a processing and display rate of well over 524,000 A-scan/s for a ...
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    1-7 of 7
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    1. (6 articles) Kate Sugden
    2. (5 articles) Janarthanan Rasakanthan
    3. (4 articles) Peter D. Woolliams
    4. (4 articles) Pete H. Tomlins
    5. (3 articles) UK National Physical Laboratory
    6. (2 articles) University of London
    7. (1 articles) Medical University of Vienna
    8. (1 articles) Wolfgang Drexler
    9. (1 articles) Boris Pova┼żay
    10. (1 articles) Michelson Diagnostics
    11. (1 articles) UCLA
    12. (1 articles) University of Wisconsin
    13. (1 articles) University of St. Andrews
    14. (1 articles) Duke University
    15. (1 articles) Kishan Dholakia
    16. (1 articles) Cynthia A. Toth
    17. (1 articles) Richard B. Rosen
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    Processing and rendering of Fourier domain optical coherence tomography images at a line rate over 524 kHz using a graphics processing unit Femtosecond laser micro-inscription of optical coherence tomography resolution test artifacts Feature Of The Week 1/8/12: Ultrafast Processing and Rendering of OCT Data using a GPU Three-dimensional calibration targets for optical coherence tomography Fabrication of high quality optical coherence tomography (OCT) calibration artefacts using femtosecond inscription Developments in contact lens measurement: A comparative study of industry standard geometric inspection and optical coherence tomography Non-planar calibration phantoms for optical coherence tomography Monitoring Response to Platelet-Rich Plasma in Patients with Alopecia Areata with Optical Coherence Tomography: A Case Series NONPERFUSION AREA QUANTIFICATION IN BRANCH RETINAL VEIN OCCLUSION: A WIDEFIELD OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY STUDY Nonperfusion Assessment in Retinal Vein Occlusion: Comparison between Ultra-Widefield Fluorescein Angiography and Widefield OCT-Angiography Anatomical Location of the Raphe and Extended Raphe in the Human Retina: Implications for Assessment of the Optic Nerve with OCT Assessing the Influence of OCT-A Device and Scan Size on Retinal Vascular Metrics