1. Articles from r. myllylä

    1-11 of 11
    1. Characterization of ink-jet printed RGB color filters with spectral domain optical coherence tomography

      Characterization of ink-jet printed RGB color filters with spectral domain optical coherence tomography

      We present the use of sub-micron resolution optical coherence tomography (SMR SD-OCT) in volumetric characterization of ink- jet printed color filters, aimed for electronic paper display (EPD). The device used in the study is based on supercontinuum light source, Michelson interferometer centered at 600 nm and employs 400-800 nm spectral region. Spectra are acquired at a continuous rate of 140,000 per second. Color filter array of 143 μm x 141 μm sized and 6 rtm deep ink pools was studied. The volumetric OCT reconstruction was done using the experimental SMR SD-OCT device and a commercial SD-OCT imaging ...

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    2. Sub-micron resolution high-speed spectral domain optical coherence tomography in quality inspection for printed electronics.

      Sub-micron resolution high-speed spectral domain optical coherence tomography in quality inspection for printed electronics.

      We present the use of sub-micron resolution optical coherence tomography (OCT) in quality inspection for printed electronics. The device used in the study is based on a supercontinuum light source, Michelson interferometer and high-speed spectrometer. The spectrometer in the presented spectral-domain optical coherence tomography setup (SD-OCT) is centered at 600 nm and covers a 400 nm wide spectral region ranging from 400 nm to 800 nm. Spectra were acquired at a continuous rate of 140,000 per second. The full width at half maximum of the point spread function obtained from a Parylene C sample was 0:98 m. In ...

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    3. Ultra-high resolution optical coherence tomography for encapsulation quality inspection

      Ultra-high resolution optical coherence tomography for encapsulation quality inspection
      We present the application of ultra-high resolution optical coherence tomography (UHR-OCT) in evaluation of thin, protective films used in printed electronics. Two types of sample were investigated: microscopy glass and organic field effect transistor (OFET) structure. Samples were coated with thin (1–3 μm) layer of parylene C polymer. Measurements were done using experimental UHR-OCT device based on a Kerr-lens mode locked Ti:sapphire femtosecond laser, photonic crystal fibre and modified, free-space Michelson interferometer. Sub-micron resolution offered by the UHR-OCT system applied in the study enables registration of both interfaces of the thin encapsulation layer. Complete, volumetric characterisation of protective ...
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    4. Determination of suspension viscosity from the flow velocity profile measured by Doppler Optical Coherence Tomography

      Determination of suspension viscosity from the flow velocity profile measured by Doppler Optical Coherence Tomography
      In this paper we present, for the first time to our knowledge, the experimental results for determining suspension viscosity in a capillary type viscometer from flow velocity profiles measured by Doppler Optical Coherence Tomography. The suspension of 0.3?m polystyrene microspheres in a glycerol-water solution was used as a model fluid. The viscosity of the suspension was controlled by glycerol concentration. The shear rate and the shear stress at the capillary wall were measured at six flow rates. The corresponding viscosities were calculated. The comparison of the measured shear rates with the values calculated according to the flow rate ...
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    5. Experimental study of the multiple scattering effect on the flow velocity profiles measured in intralipid phantoms by DOCT

      Experimental study of the multiple scattering effect on the flow velocity profiles measured in intralipid phantoms by DOCT
      Abstract  Time domain Doppler Optical Coherence Tomography (DOCT) technique was applied to measure flow velocity profiles in highly scattering media. We analyzed the distortions of the measured velocity profiles of the 1% Intralipid solution flow embedded into the scattering medium at different embedding depths. For this purpose a tissue phantom consisting of a plain glass capillary (inner diameter 0.3 mm) embedded into a slab of Intralipid solution mimicking human skin was designed. The measured flow velocity profiles and behavior of distortions caused by multiple scattering are shown.
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    6. Effect of light scattering superficial layer on the accuracy of flow velocity profiles measurements by Doppler optical coherence tomography

      Effect of light scattering superficial layer on the accuracy of flow velocity profiles measurements by Doppler optical coherence tomography
      Doppler Optical Coherence Tomography (DOCT) is a modern technique used for accurate measurements of blood flow in the superficial layers of human skin, retina or other tissues and their phantoms. In this work, we considered the effect of both static and dynamic superficial layer of the scattering medium on the measured velocity of a flow located beneath this layer. In the case of static layer a tissue phantom consisting of a plain glass capillary (inner size 0.3 × 3 mm) embedded into a slab of Intralipid solution mimicking human skin was designed. Flow velocity profiles were measured at different embedding ...
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    7. Application of LabVIEW: Complex Software Controlling of System for Optical Coherence Tomography

      This article briefly describes the system for optical coherence tomography (OCT), an interferometric imaging technique and focuses on software controlling of this complex apparatus and data acquisition (DAQ) by means of LabVIEW. It states advanced LabVIEW techniques for parallel DAQ, multi-instrument communication, and postprocessing needed to assure OCT measurements being carried out at the University of Oulu.
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    8. Optical and terahertz measurement techniques for flat-faced pharmaceutical tablets: a case study of gloss, surface roughness and bulk properties of starch acetate tablets

      Abstract. Surface and bulk properties of flat-faced starch acetate tablets were studied. For surface quality inspection optical coherence tomography and recently developed diffractive glossmeter were utilized. Both these optical devices together provide local information on surface roughness and gloss of a tablet over a measured area. The concepts of mean topography and mean gloss profile for surface quality of a tablet are introduced. It was observed that the surface quality of the tablet varies, and compression at high pressure may not guarantee a good surface quality of the tablet. Using novel statistical parameters for gloss and relevant surface roughness parameter ...
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    9. Role of multiple scattering in formation of OCT skin images

      Optical coherence tomography (OCT) images of model human skin samples are obtained by using Monte Carlo simulations. The contributions of least and multiple scattering, diffusion and nondiffusion components and of separate scattering orders are studied by using a multilayer skin model based on experimental images. The model images are obtained by neglecting speckles or taking them into account. It is shown that least scattering forms the image of the upper skin layers, while the contribution of multiple scattering can be characterised as a blurred full image with a lower contrast. Repeated scattering mainly contributes to the OCT image at depths ...
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    10. Detecting glucose-induced changes in in vitro and in vivo experiments with optical coherence tomography.

      Related Articles Detecting glucose-induced changes in in vitro and in vivo experiments with optical coherence tomography. J Biomed Opt. 2008 Mar-Apr;13(2):021111 Authors: Kinnunen M, Myllylä R, Vainio S Optical clearing is a well-known phenomenon. It is based on the matching of refractive indices of a bulk material and scattering particles. The same principle is also used in scattering-based optical measurements of different constituents, such as glucose. By registering changes in scattering, it is possible to evaluate changes in the concentration of a solvent. This work describes the use of optical coherence tomography (OCT) to monitor glucose-induced changes ...
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    11. Optical coherence tomography of paper: Monte Carlo simulation for multilayer mode

      In present work the capabilities of an optical coherence tomography (OCT) setup to visualize paper structure are analyzed by means of Monte Carlo-simulation of the OCT images. The OCT setup at 910 nm was considered. Efficiency of several different optical clearing agents (OCA) for increasing the quality of the obtained images was studied. A multilayer non-planar edged paper model was developed for the characterization of a paper sample and simple recovery of its parameters. The effect of the setup parameters on the obtained OCT-images was studied. It was shown by comparison with the experimental data that the developed model provides ...
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    1-11 of 11
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  2. Topics in the News

    1. (11 articles) University of Oulu
    2. (11 articles) Risto A. Myllylä
    3. (5 articles) Janne Lauri
    4. (4 articles) Moscow State University
    5. (4 articles) Alexander V. Priezzhev
    6. (3 articles) Jakub Czajkowski
    7. (3 articles) Tapio E. J. Fabritius
    8. (3 articles) Alexander V. Bykov
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    10. (2 articles) Mikhail Y. Kirillin
    11. (1 articles) Tufts University
    12. (1 articles) Sungkyunkwan University
    13. (1 articles) University College London
    14. (1 articles) Massachusetts Institute of Technology
    15. (1 articles) Jay S. Duker
    16. (1 articles) Colin Hopper
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    Effect of light scattering superficial layer on the accuracy of flow velocity profiles measurements by Doppler optical coherence tomography Experimental study of the multiple scattering effect on the flow velocity profiles measured in intralipid phantoms by DOCT Determination of suspension viscosity from the flow velocity profile measured by Doppler Optical Coherence Tomography Ultra-high resolution optical coherence tomography for encapsulation quality inspection Sub-micron resolution high-speed spectral domain optical coherence tomography in quality inspection for printed electronics. Characterization of ink-jet printed RGB color filters with spectral domain optical coherence tomography Remote scanning for ultra-large field of view in wide-field microscopy and full-field OCT Inadequate Intimal Angiogenesis as a Source of Coronary Plaque Instability Comparison of optical coherence tomography angiography results of adult patients with Familial Mediterranean fever and healthy individuals Intravascular ultrasound or optical coherence tomography-defined anatomic severity and hemodynamic severity assessed by coronary physiologic indices Optical coherence tomography in the assessment of cutaneous cancer margins of the face: an immediate ex vivo study Global Analysis of Macular Choriocapillaris Perfusion in Dry Age-Related Macular Degeneration using Swept-Source Optical Coherence Tomography Angiography