1. Peter D. Woolliams

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    1. Mentioned In 19 Articles

    2. Methods to assess sensitivity of optical coherence tomography systems

      Methods to assess sensitivity of optical coherence tomography systems
      Measuring the sensitivity of an optical coherence tomography (OCT) system determines the minimum sample reflectivity it can detect and provides a figure of merit for system optimization and comparison. The published literature lacks a detailed description of OCT sensitivity measurement procedures. Here we describe a commonly-used measurement method and introduce two new phantom-based methods, which also offer a means to directly visualize low reflectivity conditions relevant to biological tissue. We ...
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    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 ...
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    4. 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 ...
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    5. Estimating the resolution of a commercial optical coherence tomography system with limited spatial sampling

      Estimating the resolution of a commercial optical coherence tomography system with limited spatial sampling
      Optical coherence tomography (OCT) is becoming increasingly widespread as an experimental tool for clinical investigation, facilitated by the development of commercial instruments. In situ performance evaluation of such 'black box' systems presents a challenge, where the instrument hardware and software can limit access to important configuration parameters and raw data. Two key performance metrics for imaging systems are the point-spread function (PSF) and the associated modulation transfer function (MTF). However ...
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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 ...
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    7. The modulation transfer function of an optical coherence tomography imaging system in turbid media

      The modulation transfer function of an optical coherence tomography imaging system in turbid media
      In this paper we describe measurements of the contrast transfer function, modulation transfer function and point-spread function of an optical coherence tomography (OCT) imaging system through scattering layers having a dimension-less scattering depth over the range 0.2–6.9. The results were found to be insensitive to scattering density, indicating that these measurement parameters alone do not well characterize the practical imaging ability of an OCT instrument. Attenuation and ...
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    8. Elastographic contrast generation in optical coherence tomography from a localized shear stress

      Elastographic contrast generation in optical coherence tomography from a localized shear stress
      A technique for generating contrast in two-dimensional shear strain elastograms from a localized stress is presented. The technique involves generating a non-uniform, localized stress via a magnetically actuated implant. Its effectiveness is demonstrated using finite-element simulations and a phantom study provides experimental verification of this. The method is applied to a superficial cancerous lesion model represented as a stiff inclusion in normal tissue. The lesion was best distinguished from its ...
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    9. Feature Of The Week 11/22/09: Development of Optical Coherence Tomography Point-Spread Function Test Artifacts

      Feature Of The Week 11/22/09: Development of Optical Coherence Tomography Point-Spread Function Test Artifacts
      Feature Of The Week 11/22/09: The Biophotonics group of the UK National Physical Laboratory is working on methods and phantoms to help with the uptake of OCT technology in to the medical and other industrial sectors. They are looking at the requirements for consistent and robust characterization methods to determine the fundamental system performance of OCT systems. An important baseline metric in this respect is the system 3D ...
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    10. Report on Optical Tissue Phantoms from National Physical Laboratory in UK

      Report on Optical Tissue Phantoms from National Physical Laboratory in UK
      The key figures of merit for Optical Coherence Tomography (OCT) systems are sensitivity and resolution. These parameters can be used to determine the suitability of instruments for purpose and to gauge the practical improvements to instruments afforded by modifications to the design. Therefore, NPL is developing reproducible and stable phantoms for depth resolved sensitivity and three-dimensional resolution or point-spread-function (PSF
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    11. Point-spread function phantoms for optical coherence tomography

      Point-spread function phantoms for optical coherence tomography
      Recently scientists at the Uk's National Physical Laboratory completed an initial study into the development of robust point-spread function (PSF) phantoms, that are potentially suitable as OCT calibration standards. The findings have been published in a publicly available NPL report, available freely from the NPL website or upon request to Pete Tomlins (pete.tomlins@npl.co.uk).
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  2. About Peter D. Woolliams

    Peter Woolliams of the National Physical Laboratory in the U.K.