• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.11
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• pp.7-13
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• 2002

BSCT 320${\times}$240 IRFPA detector module is implemented, which is a key component in uncooled thermal imaging systems. The detector module consists of two parts, infrared sensitive pixel array and read-out integrated circuit(ROIC). The BSCT 320${\times}$240 pixels are made by laser scribe process and 10-${\mu}m$ micro-bump to satisfy 50-${\mu}m$ pitch and 95-% fill-factor. The ROIC has been designed to electrically address the pixels sequentailly and to improve signal-to-noise ratio with single transistor amplifier, HPF, tunable LPF and clamp circuit. The fabricated hybrid chip of detector and ROIC has been mounted on the TEC built-in ceramic package for more stable operation and tested for lots of electrical and optical properties. The IRFA sample has shown successful properties and met with good results of fill-factor, detectivity and responsivity.

• Journal of the Korean Society for Nondestructive Testing
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• v.37 no.2
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• pp.91-98
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• 2017

Recently, composite materials have been mainly used in the main wings, ailerons, and fuselages of aircraft and rotor blades of helicopters. Composite materials used in rapid moving structures are subject to impact by hail, lightning, and bird strike. Such an impact can destroy fiber tissues in the composite materials as well as deform the composite materials, resulting in various problems such as weakened rigidity of the composite structure and penetration of water into tiny cracks. In this study, experiments were conducted using a 2 kW halogen lamp which is most frequently used as a light source, a 2 kW near-infrared lamp, which is used for heating to a high temperature, and a 6 kW xenon flash lamp which emits a large amount of energy for a moment. CFRP composite sandwich panels using Nomex honeycomb core were used as the specimens. Experiments were carried out under impact damages of 1, 4 and 8 J. It was found that the detection of defects was fast when the xenon flash lamp was used. The detection of damaged regions was excellent when the halogen lamp was used. Furthermore, the near-infrared lamp is an effective technology for showing the surface of a test object.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.47.1-47.1
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• 2018

The NISS (Near-infrared Imaging Spectrometer for Star formation history) onboard NEXTSat-1 have successfully developed by KASI. The capability of both imaging and spectroscopy is a unique function of the NISS. At first, it have realized the low-resolution spectroscopy (R~20) with a wide field of view of $2{\times}2deg$. in a wide near-infrared range from 0.95 to $2.5{\mu}m$. The major scientific mission is to study the cosmic star formation history in local and distant universe. It will also demonstrate the space technologies related to the infrared spectro-photometry in space. Now, the NISS is ready to launch in late 2018. After the launch, the NISS will be operated during 2 years. As an extension of the NISS, the SPEHREx (Spectro-Photometer for the History of the Universe Epoch of Reionization, and Ices Explorer) is the NASA MIDEX (Medium-class Explorer) mission proposed together with KASI (PI Institute: Caltech). It will perform the first all-sky infrared spectro-photometric survey to probe the origin of our Universe, to explore the origin and evolution of galaxies, and to explore whether planets around other stars could harbor life. Compared to the NISS, the SPHEREx is designed to have much more wide FoV of $3.5{\times}11.3deg$. as well as wide spectral range from 0.75 to $5.0{\mu}m$. After passing the first selection process, the SPHEREx is under the Phase-A study. The final selection will be made in the end of 2018. Here, we report the status of the NISS and SPHEREx missions.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.6
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• pp.619-627
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• 2016

Cells of a PV (photovoltaic) module can suffer defects due to various causes resulting in a loss of power output. As a malfunctioning cell has a higher temperature than adjacent normal cells, it can be easily detected with a thermal infrared sensor. A conventional method of PV cell inspection is to use a hand-held infrared sensor for visual inspection. The main disadvantages of this method, when applied to a large-scale PV power plant, are that it is time-consuming and costly. This paper presents an algorithm for automatically detecting defective PV panels using images captured with a thermal imaging camera from an UAV (unmanned aerial vehicle). The proposed algorithm uses statistical analysis of thermal intensity (surface temperature) characteristics of each PV module to verify the mean intensity and standard deviation of each panel as parameters for fault diagnosis. One of the characteristics of thermal infrared imaging is that the larger the distance between sensor and target, the lower the measured temperature of the object. Consequently, a global detection rule using the mean intensity of all panels in the fault detection algorithm is not applicable. Therefore, a local detection rule was applied to automatically detect defective panels using the mean intensity and standard deviation range of each panel by array. The performance of the proposed algorithm was tested on three sample images; this verified a detection accuracy of defective panels of 97% or higher. In addition, as the proposed algorithm can adjust the range of threshold values for judging malfunction at the array level, the local detection rule is considered better suited for highly sensitive fault detection compared to a global detection rule. In this study, we used a panel area extraction method that we previously developed; fault detection accuracy would be improved if panel area extraction from images was more precise. Furthermore, the proposed algorithm contributes to the development of a maintenance and repair system for large-scale PV power plants, in combination with a geo-referencing algorithm for accurate determination of panel locations using sensor-based orientation parameters and photogrammetry from ground control points.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.22-27
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• 2017

Time-encoded near-infrared spectroscopy (NIRS) system is proposed, based on a near-infrared (NIR) swept laser source, for comparison to the conventional NIRS method using a detector-type spectrometer. The cavity of the NIR swept laser source consists of a semiconductor optical amplifier (SOA) with a gain region around 800 nm, and several fiber-optic components. To change the output wavelength in time using an applied electric radio-frequency signal, an acousto-optic tunable filter (AOTF) is introduced in the fiber ring cavity configuration. To demonstrate the feasibility of an NIR swept laser source for NIRS imaging, the spectroscopic comparison of two kinds of absorbance-measuring systems a detector-type spectrometer using a white light source, and a source-type spectrometer using an NIR swept laser is successfully performed with an NIR-absorbing dye.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1334-1339
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• 2018

Spherical nickel ferrite nanoparticles were synthesized using the thermal decomposition method and coated with cetyl trimethyl ammonium bromide (CTAB) after the synthesis. Transmission electron microscopy images showed that the average diameter of the particles was 9.40 nm. The status of the CTAB-coating on the surface of the particles was checked using Fourier-transform infrared spectroscopy. Their hysteresis curve showed that the particles exhibited a superparamagnetic behavior. The $T_1$ and the $T_2$ relaxations of the nuclear spins were observed in aqueous solutions of the particles with different particles concentrations by using a magnetic resonance imaging (MRI) scanner, which showed that the $T_1$ and the $T_2$ relaxivities of the particles in water were $0.57mM^{-1}{\cdot}s^{-1}$ and $10.42mM^{-1}{\cdot}s^{-1}$, respectively. In addition, using an induction heating system, we evaluated their potentials for magnetic hyperthermia applications. The aqueous solution of the particles with a moderate concentration (smaller than 6.5 mg/mL) showed a saturation temperature larger than the hyperthermia target temperature of $42^{\circ}C$. These findings show that the CTAB-coated nickel ferrite particles are suitable for applications as $T_2$ contrast agents in MRI and heat generators in magnetic hyperthermia.

• Korean Journal of Optics and Photonics
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• v.14 no.4
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• pp.369-376
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• 2003

We analyzed the aspheric and/or diffractive surface effects to the performance in the long wavelength infrared (8-12 $\mu$m). Also we investigated the dependence of the NA values for the fixed effective focal length 100 mm when the field angle was varied from 5 degrees to 30 degrees stepped by 5 degrees. We chose the merit function as a criteria to compare the performance of the different lenses. Based on the analysis of the aspheric and/or diffractive surface effects, we designed the optical system of F/l.0 for the uncooled thermal imaging system. As for detector the pixel size was 45 $\mu$m square and the number of pixels were a 320${\times}$240 pixels.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.5
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• pp.371-379
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• 2018

Unlike general VHR (Very-High-Resolution) satellite sensors that are mainly for panchromatic and MS (Multispectral) imaging, Worldview-3 sensor additionally provides eight SWIR (Short Wavelength Infrared) bands in wavelength range from 1198 nm to 2365 nm. This study investigates the effect of informative Worldview-3 SWIR bands for wetland classification performance. Worldview-3 imagery acquired over Sunchon Bay, which is a coastal wetland located in South Korea, is used to implement the classification. Land-cover classes for the scene are determined by referring to national land-cover maps, which are provided by the Ministry of Environment, overlapped with the scene. After that, training data for each determined class are collected. In order to analyze the effect of SWIR bands, classifications with and without SWIR bands are carried out and the results are then compared. In this regard, a SVM (Support Vector Machine) is utilized as their classifier. As a result of the accuracy assessments performed by test data that are independently extracted from training data, it was confirmed that classification performance was improved when the SWIR bands are included as input features for SVM-based classification.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.3
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• pp.236-246
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• 2010

Background & Objective : Microneedle therapy system(MTS) is popular these days. However, there are few reports about it in oriental medicine academia. This study is performed to evaluate the effect of MTS on acne patients. Methods : This study was conducted to evaluate the effect of MTS. Seven patients were treated for 7 weeks. Follow-up was performed after the treatment with Janus facial analysis system, skindex-29 and Digital Infrared Thermographic Imaging machine. Satisfaction degree and inconvenience were asked from the patients. Results and Conclusions : Microneedle therapy system(MTS) was good for acne like pore, wrinkle, spot(polarised), sebum, porphyrin and skin tone. Especially it had excellent effects on sebum and porphyrin.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1250-1254
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• 1992

This paper describes the designed and fabricated thermal imaging system with the SPRITE(Signal PRocessing in The Element) detector, operating in the 3-12 micron band. This system consists of an afocal telescope, a scan unit containing the SPRITE detector, an electronic processor unit and a cooler. The optical scan system utilizing rotating polygon and oscillating mirror, is 2-dimensional serial/parallel scan type using five elements of the detector. And the electronic processor unit performs digital scan conversion to reform the parallel data stream into serial analog data compatable with conventional RS-170 video. The scan field of view is 40 ${\times}$ 26.7 and the MRTD(Minium Resolvable Temperature Difference) is 0.6 K at 7.5 cycles/mm. The acquired thermal image indicates that this system has a satisfactory performance.