Browsing by Author "Qi, W"

Now showing 1 - 5 of 5

Open 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.
Open 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.
Open 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).
Embargo
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.
Open 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.