Browsing by Author "Fujiwara, M"

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    PublicationOpen Access
    Measurement of the mid-infrared Fourier spectroscopic imaging of whole human face by portable apparatus (size: 50* 50 mm, weight: 200 g)
    (International Society for Optics and Photonics, 2014-11-20) Qi, W; Suzuki, Y; Fujiwara, M; Saito, T; Suzuki, S; Abeygunawardhana, P. K. W; Wada, K; Nishiyama, A; Ishimaru, I
    In the daily living space, measurement of the biological-substance distributions such as sebum can be realized by the proposed method of imaging-type 2-dimensional Fourier spectroscopy. This method has the strong robustness for mechanical vibrations. So, the spectrometer (size: 50*50mm, weight: 200g) can be produced without anti-vibration mechanism. Moreover, the phase shifter is a core part of the spectrometer, and it is constructed by the low-price bimorph type actuator which is depending on the vibration control of the piezoceramic in proposed method. It is appropriate as the actuator of the phase shifter from the evaluation results of the actuator straightness and position accuracy in the midinfrared region. As we know, the Fourier spectroscopy has a high light utilization efficiency. Therefore, the low price microbolometer can be used as the imaging sensor. So, the low-price (10,000 U.S. dollars), compact and high portability spectrometer can be produced. Furthermore, the much higher position accuracy in the short wavelength region is requested as we know, the phase shift correction method has been proposed. In this paper, high performance evaluations of the portable spectroscopy apparatus have been discussed by using the CO2 laser spectroscopy results in the midinfrared region. Then, the phase shift correction method was explained. At the end, we demonstrated the feasibility of the mid-infrared imaging of whole human faces without active illuminations.
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    PublicationOpen Access
    Proposal of AAA-battery-size one-shot ATR Fourier spectroscopic imager for on-site analysis: Simultaneous measurement of multi-components with high accuracy
    (International Society for Optics and Photonics, 2015-03-12) Hosono, S; Qi, W; Sato, S; Suzuki, Y; Fujiwara, M; Hiramatsu, H; Suzuki, S; Abeygunawardhana, P. K. W; Wada, K; Nishiyama, A; Ishimaru, I
    For simultaneous measurement of multi-components on-site like factories, the ultra-compact (diameter: 9[mm], length: 45[mm], weight: 200[g]) one-shot ATR (Attenuated Total Reflection) Fourier spectroscopic imager was proposed. Because the proposed one-shot Fourier spectroscopic imaging is based on spatial-phase-shift interferometer, interferograms could be obtained with simple optical configurations. We introduced the transmission-type relativeinclined phase-shifter, that was constructed with a cuboid prism and a wedge prism, onto the optical Fourier transform plane of infinity corrected optical systems. And also, small light-sources and cameras in the mid-infrared light region, whose size are several millimeter on a side, are essential components for the ultra-compact spectroscopic configuration. We selected the Graphite light source (light source area: 1.7×1.7[mm], maker: Hawkeye technologies) whose radiation factor was high. Fortunately, in these days we could apply the cost-effective 2-dimensional light receiving device for smartphone (e.g. product name: LEPTON, maker: FLIR, price: around 400USD). In the case of alcoholic drinks factory, conventionally workers measure glucose and ethanol concentrations by bringing liquid solution back to laboratories every day. The high portable spectroscopy will make it possible to measure multi-components simultaneously on manufacturing scene. But we found experimentally that absorption spectrum of glucose and water and ethanol were overlapped each other in near infrared light region. But for mid-infrared light region, we could distinguish specific absorption peaks of glucose (@10.5[μm]) and ethanol (@11.5[μm]) independently from water absorption. We obtained standard curve between absorption (@9.6[μm]) and ethanol concentration with high correlation coefficient 0.98 successfully by ATR imaging-type 2-dimensional Fourier spectroscopy (wavelength resolution: 0.057[μm]) with the graphite light source (maker: Hawkeye technologies, type: IR-75).
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    PublicationEmbargo
    Signal conditioning for imaging type Fourier spectroscopy using Independent Component Analysis
    (IEEE, 2014-10-22) Abeygunawardhana, P. K. W; Fujiwara, M; Suzuki, S; Ishimaru, I
    Biomedical Signal Processing, in which Spectroscopic measurement plays a crucial role, has been the center of attraction by many researchers during the past few years. Two - dimensional imaging type Fourier spectroscopy is a technique which can limit the measuring depth into focal plane. Although the various substances including bio genic substances can be measured, measured results include two or more signals mixed together. In this paper, Independent Component Analysis known as ICA has been used to separate those mixed signals.
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    PublicationOpen Access
    Signal Improvement in Imaging Type Two-Dimensional Fourier Spectroscopy for Wild-Field Internal Non-Destructive Inspection
    (2015-01) Abeygunawardhana, P. K. W; Fujiwara, M; Suzuki, S; Ishimaru, I; Nishiyama, A
    —Imaging type two-dimensional Fourier spectroscopy is the wave front-division interferometer which limits the measurement depth into focal plane. This method has shown the potential in many areas such as measurement of biological substances and non-destructive inspections. Presence of noise in the signal may affect the end result of test. This paper proposes the algorithm for improving spectral data by finding low noisy point and filtering them. Cross correlation with median noisy signal is used to find the best signal to be considered. Experiment was conducted for testing fingerprint, alcohol measurement and measurement of ink. Proposed algorithm was conducted for the data obtained from ink measurement.
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    PublicationOpen Access
    Wide-field spectroscopic imaging of biological-substance distributions on entire faces by measuring middle infrared lights emitted from human bodies itself
    (SPIE, 2014-02-28) Suzuki, Y; Qi, W; Fujiwara, M; Hiramatsu, H; Suzuki, S; Abeygunawardhana, P. K. W; Wada, K; Nishiyama, A; Ishimaru, I
    We are aiming at the realization of the measurement technology for the biological-substance distributions, such as sebum, on entire faces at the daily-life environment. We proposed the imaging-type 2-dimensional Fourier spectroscopy [1] that is the palmtop-size portable measurement apparatus and has the strong robustness for mechanical vibrations. And the proposed method can measure the wide-field 2-dimensional middle-infrared spectroscopic-imaging of radiation lights emitted from human bodies itself without light sources. In the proposed method, we install the phase-shifter, that can give an arbitrary phase difference for the half-flux of objective beams, at the optical Fourier transform plane of the infinity corrected optical system. The near-common-path interferometer that is a phase-shift interferometer between objective beams can be realized. In this proposed method, the emitted rays from each single-bright-point on measurement surfaces can interfere with each other. Thus, even if the middle infrared-lights from human bodies are the spatially incoherent light, we can acquire the interferograms at each pixel on an imaging array-device in accordance with the amount of phase shift as the 2-dimensional image-intensity changes. We demonstrated the feasibility of the middle infrared spectroscopic imaging of whole human faces without active illuminations.