Research Papers - Dept of Computer Systems Engineering

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Author: search.filters.author.Nishiyama, ASubject: search.filters.subject.spectroscopic tomography

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Now showing 1 - 4 of 4
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    Compact optical system for imaging type two-dimensional spectroscopic tomography
    (IEEE, 2013-12-17) Abeygunawardhana, P. K. W; Nakada, S; Suzuki, S; Nishiyama, A; Ishimaru, I
    Spectroscopic measurement is being widely used for non-invasive blood sugar measurement in recent past. Imaging type two-dimensional spectroscopic tomography has been designed using wave front division interferometer. Variable phase filter, which has fixed mirror and movable mirror, has been used to introduce the phase shift between rays. Capability of measuring biogenic substances using this method has been proved. For the quantitative analysis with high accuracy, the correction of the background such as the light-source fluctuation and the phase-shift uncertainty is inevitable issue. Background noises and vibrations in test bed are part of the causes that could results such errors. This paper proposes a new closed optical system to improve the system performance. One-shot type spectroscopic tomography and Smooth Impact Drive Mechanism are used here.
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    PublicationEmbargo
    Quantitative spectroscopic tomography for the non-invasive measurement of the biogenic-substances
    (IEEE, 2012-11-21) Qi, W; Kojima, D; Sato, S; Suzuki, S; Abeygunawardhana, P. K. W; Nishiyama, A; Ishimaru, I
    The non-invasive blood sugar sensor by using imaging-type 2-dimensional Fourier spectroscopy is to be realized in this work. The spectroscopic imaging, that observes the biological tissue by the dark-field image, can measure the biogenic substance quantitatively such as the glucose concentration. For the quantitative analysis with high accuracy, the correction of the background such as the light-source fluctuation and the phase-shift uncertainty is inevitable issue. Thus, the quantitative bandpass plate on which the grating is locally formed has been proposed in this paper. Here, the diffractive light, whose diffraction angle depends on the wavelength, has been used as the reference light Object lens is used to narrow down the reference light and narrowed band pass diffraction light is obtained. The changes of imaging intensities with interference phenomenon on whole area of the observation image can be confirmed using the quantitative band pass filter. Thus, the light-source fluctuation from the amplitude of the reference light intensity and the phase-shift uncertainly from the interference-phase can be corrected respectively. In this paper, the theoretical accuracy of Fourier spectroscopy calculated with the numerical simulation and the background correction method of the spectral-absorption-index image by the diffraction grating type quantitative bandpass plate are presented.
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    PublicationOpen Access
    Novel algorithm for background correction of the quantitative spectroscopic tomography of the biogenic-substances
    (International Society for Optics and Photonics, 2013-02-25) Abeygunawardhana, P. K. W; Qi, W; Kojima, D; Suzuki, S; Nishiyama, A; Ishimaru, I
    The non-invasive blood sugar sensor by using imaging-type 2-dimensional Fourier spectroscopy is to be realized in this work. The spectroscopic imaging, that observes the biological tissue by the dark-field image, can measure the biogenic substance quantitatively such as the glucose concentration. For the quantitative analysis with high accuracy, the correction of the background such as the light-source fluctuation and the phase-shift uncertainty is inevitable issue. Thus, the quantitative band-pass plate on which the grating is locally formed has been already proposed by [1]. In that paper, the diffractive light, whose diffraction angle depends on the wavelength, has been used as the reference light. Object lens is used to narrow down the reference light and narrowed band pass diffraction light is obtained. The changes of imaging intensities with interference phenomenon on whole area of the observation image can be confirmed using the quantitative band pass filter. This paper proposed background correction method of the interferogram in spectroscopic tomography. Correction algorithm mainly contained two parts as light source fluctuation error correction and phase shift error correction.
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    PublicationOpen Access
    Quantitative measurement of biological substances in daily-life environment with the little-finger-size one-shot spectroscopic tomography
    (International Society for Optics and Photonics, 2014-02-28) Ishida, A; Sato, S; Nakada, S; Suzuki, S; Abeygunawardhana, P. K. W; Wada, K; Nishiyama, A; Ishimaru, I
    In daily-life environment, the quantitative measurement of biological substances, such as the blood glucose level in the human skin, is strongly required to realize the non-invasive healthcare apparatus. Fourier-spectroscopic-tomography of the little-finger-size with high time-resolution and with the strong robustness for mechanical vibrations is proposed. The proposed method is a kind of near-common-path interferometer with spatial phase-shift method. We install the transmission-type relative-inclined phase-shifter on the optical Fourier transform plane of the infinity corrected optical system. The phase shifter is constructed with the cuboid and wedge prisms to give the relative phase-shift spatially between each half-flux of the objective beams. The interferograms from each single-bright-point on an objective surface in a line are formed as fringe patterns on 2-dimensional imaging array devices. And because the proposed method is based on the imaging optics, only emitted rays from a focal plane can contribute forming of interferograms. Thus, the measurement plane can be limited onto the focal plane only. From the spectroscopic tomography, only at a localized vessel area in human skins, we can get the pinpointed near-infrared spectroscopic data. And we can expect the improvement of the determination precision, because a Fourier spectroscopic-character is acquired from multiple intensity data in accordance with amount of phase-shift. From the statistical point of view, the gradation of detector is improved with the square root of sample number, based on t-distribution. We constructed the statistical model to assure the determination accuracy, and demonstrated the feasibility of the glucose sensor using liquid cells.