Browsing by Author "Tatam, Ralph P."

Browsing by Author "Tatam, Ralph P."

Sort by: Order: Results:

  • Fibre segment interferometry using code-division multiplexed optical signal processing for strain sensing applications 
    Kissinger, Thomas; Charrett, Thomas O. H.; Tatam, Ralph P. (Iop Publishing Ltd, 2013-09-30)
    A novel optical signal processing scheme for multiplexing fibre segment interferometers is proposed. The continuous-wave, homodyne technique combines code-division multiplexing with single-sideband modulation. It uses only ...
  • Fibre-coupled, multiplexed methane detection using range-resolved interferometry 
    Bremner, James; Kissinger, Thomas; Hodgkinson, Jane; Tatam, Ralph P. (Institute of Physics, 2021-02-08)
    We describe the first use of range-resolved interferometric signal processing for measurement of spectral transmission. This was applied to gas sensing using tunable diode laser spectroscopy, allowing the simultaneous and ...
  • Fibre-optic long period gratings for sensing applications 
    Khaliq, Sarfraz (Cranfield University, 2003-03)
    Long period gratings (LPGs) are formed by inducing a permanent periodic modulation of the refractive index (RI) of the core of an optical fibre. The transmission spectrum of the LPG contains a series of attenuation bands ...
  • Fibre-optic measurement of strain and shape on a helicopter rotor blade during a ground run: 2. Measurement of shape 
    Kissinger, Thomas; James, Stephen W.; Weber, Simone; Mullaney, Kevin; Chehura, Edmond; Pekmezci, Huseyin H.; Barrington, James; Staines, Stephen E.; Charrett, Thomas O. H.; Lawson, Nicholas J.; Lone, Mudassir; Atack, Richard; Tatam, Ralph P. (IOP Publishing, 2022-06-08)
    Optical fibre strain and shape measurement sensors were deployed on a rotor blade during a full-speed helicopter ground run, with real-time data wirelessly streamed from rotor hub-mounted sensor interrogators. In part 2 ...
  • Fibre-optic sensors with molecular coatings 
    Partridge, Matthew (Cranfield University, 2012-12)
    The intrinsic stability of fibre optic based sensing systems offer a platform that is suited to hazardous waste detection in a wide range of environments. Over the last few years Cranfield University has been working on ...
  • Finding minimum spanning trees more efficiently for tile-based phase unwrapping. 
    Al-Sawaf, Firas; Tatam, Ralph P. (Iop Publishing Ltd, 2006-06-06)
    The tile-based phase unwrapping method employs an algorithm for finding the minimum spanning tree (MST) in each tile. We first examine the properties of a tile's representation from a graph theory viewpoint, observing that ...
  • Formaldehyde sensor using non-dispersive UV spectroscopy at 340nm 
    Davenport, John; Hodgkinson, Jane; Saffell, John R.; Tatam, Ralph P. (International Society for Optical Engineering; 1999, 2014-05-22)
    Formaldehyde is a volatile organic compound that exists as a gas at room temperature. It is hazardous to human health causing irritation of the eyes, nose and throat, headaches, limited pulmonary function and is a potential ...
  • Frequency division multiplexing for interferometric planar Doppler velocimetry 
    Charrett, Thomas O. H.; Bledowski, Ian A.; James, Stephen W.; Tatam, Ralph P. (Optical Society of America, 2014-05-30)
    A new method of acquiring simultaneously the signal and reference channels used for interferometric planar Doppler velocimetry is proposed and demonstrated. The technique uses frequency division multiplexing (FDM) to ...
  • Frequency-division multiplexing for multicomponent shearography 
    Bledowski, Ian A.; Charrett, Thomas O. H.; Francis, Daniel; James, Stephen W.; Tatam, Ralph P. (Osa Optical Society of America, 2013-01-20)
    A new method of multiplexing the speckle patterns needed in multicomponent digital shearography systems is presented. Frequency-division multiplexing (FDM) of the measurement channels is achieved by recording speckle ...
  • Frequency-division-multiplexing technique for imaging metrology 
    Bledowski, Ian A. (Cranfield University, 2014)
    An algorithm to multiplex multiple image captures simultaneously onto a single image sensor at full frame resolution was developed for imaging metrology. Parseval’s theorem was used to obtain the image intensity from image ...
  • Full surface strain measurement using shearography 
    Groves, Roger M.; James, Stephen W.; Tatam, Ralph P. (International Society for Optical Engineering; 1999, 2001-12-31)
    Shearography is a full-field optical technique usually used for the determination of surface strain. Correlation of interferometric speckle patterns recorded before and after the object deformation yields fringes sensitive ...
  • Full-field interferometry using infinity corrected optics 
    Charrett, Thomas O. H.; Tatam, Ralph P. (IOP Publishing, 2015-12-01)
    In this paper the construction of full-field (imaging) interferometers using infinity corrected optics commonly used in microscopy is discussed, with an emphasis on self-mixing interferometry configurations where the ...
  • Full-field optical coherence tomography 
    Ford, Helen D.; Tatam, Ralph P. (International Society for Optical Engineering; 1999, 2005-12-31)
    To eliminate mechanical scanning in the probe head of an endoscopic OCT system, we propose the use of an imaging fibre bundle for probe beam delivery. Each fibre in the bundle addresses a Fizeau interferometer formed ...
  • Full-field optical coherence tomography using a fibre imaging bundle 
    Ford, Helen D.; Tatam, Ralph P. (2006-12-31)
    An imaging fibre bundle is demonstrated for spatially-multiplexed probe beam delivery in OCT, with the aim of eliminating the mechanical scanning currently required at the probe tip in endoscopic systems. Each fibre in ...
  • Gas cells for tunable diode laser absorption spectroscopy employing optical diffusers. Part 1: single and dual pass cells 
    Hodgkinson, Jane; Masiyano, Dackson; Tatam, Ralph P. (Springer Science Business Media, 2010-08-31)
    New designs for gas cells are presented that incorporate transmissive or reflective optical diffusers. These components offer simple alignment and can disrupt the formation of optical etalons. We analyse the performanc ...
  • Gas cells for tunable diode laser absorption spectroscopy employing optical diffusers. Part 2: Integrating spheres 
    Masiyano, Dackson; Hodgkinson, Jane; Tatam, Ralph P. (Springer Science Business Media, 2010-08-31)
    We have studied the effects of random laser speckle and self-mixing interference on TDLS based gas measurements made using integrating spheres. Details of the theory and TDLS apparatus are given in Part 1 of this paper ...
  • High sensitivity pressure measurement using optical fibre sensors mounted on a composite diaphragm 
    Aime, Laura F. J.; Kissinger, Thomas; James, Stephen W.; Chehura, Edmon; Verzeletti, Alberto; Tatam, Ralph P. (Optical Society of America, 2021-01-25)
    A pressure sensor specified for aerodynamic applications and based on optical fibre strain sensors mounted on a circular glass fibre reinforced polymer membrane is presented. The use of two fibre optic strain sensing ...
  • Highly linear, compact and cost-effective sensor probes for displacement measurements using range-resolved interferometry 
    Kissinger, Thomas; Wiseman, Kieran B.; Tatam, Ralph P. (EUSPEN, 2021-06-10)
    We demonstrate a novel approach for interferometric displacement and vibration sensing using range-resolved interferometry (RRI). The concept exploits the ability of RRI to reject the signal contributions due to multiple ...
  • Highly sensitive optical fibre long period grating biosensor anchored with silica core gold shell nanoparticles 
    Marques, L.; Hernandez, F. U.; James, Stephen W.; Morgan, S. P.; Clark, M.; Tatam, Ralph P.; Korposh, Sergiy (Elsevier, 2015-08-22)
    An optical fibre long period grating (LPG), modified with a coating of silica core gold shell (SiO2:Au) nanoparticles (NPs) deposited using the layer-by-layer method, was employed for the development of a biosensor. The ...
  • Imaging fibre bundles for Fizeau-based optical coherence tomography 
    Sarantavgas, G. F.; Ford, Helen D.; Tatam, Ralph P. (2008-03-05)
    An OCT system incorporating a coherent fibre imaging bundle is described. Fibres are accessed sequentially by a beam focused onto the input face of the bundle, allowing 2D or 3D images to be acquired using point detection. ...