• Journal of the Optical Society of Korea
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• v.17 no.2
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• pp.142-147
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• 2013

In order to deduce the difficulty of fixing the Ritchey-Chretien (R-C) dual reflective optical system and enhance the stability of the secondary mirror, a compact integral structure is presented here composed of two transmitting and two reflective aspheric surfaces. The four surfaces were manufactured from a single germanium lens and integrated together. The two reflective surfaces formed by coating the inner reflecting films were assembled in one lens. It makes the installation of the two mirrors easier and the structure of the secondary mirror more stable. A design of mid-wave infrared (MWIR) compact imaging system is presented with a spectral range chosen as $3.7-4.8{\mu}m$. The effective focal length is f=90 mm. The field of view (FOV) for the lens is $4.88^{\circ}$. It has good imaging capability with Modulation Transfer Function (MTF) of all field of view more than 0.55 close to the diffraction limitation. Outdoor experiments were carried out and it is shown that the integral catadioptric optical system performs well on imaging.

• Journal of the Korean Magnetics Society
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• v.21 no.5
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• pp.180-184
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• 2011

The changes in the blood flow in the peripheral vascular system under strong pulsed magnetic fields (pMF) were studied by digital infrared thermal imaging (DITI). After pMF stimulus temperatures in stimulated area were commonly increased in both groups of age and gender. In order to reduce heat generated from coil in pMF stimulus system plastic moldings were fabricated, so that certain distance was kept between stimulus system and the skin and to prevent direct contact to the skin. It is believed that skin temperature is increased by internal electromagnetic energy stimulated the peripheral vascular system by non-contact method.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.301-310
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• 1998

Infrared thermographic imaging visualizes noninvasively various abnormal condition by detecting the skin temperature. As the imaging represents the objective condition by the changes in blood flow under the control of autonomic nervous system, it is used to diagnosis and monitor the lumboscral radiculopathy. And asymmetry is important in the diagnosis of disc herniation. The most common type of disc herniation occurs psoterolaterally. This frequently causes nerve root compression leading to a radiculopathy in the distribution of the involved nerve root, most of which also provoke the asymmetric changes in thermography. Central disc herniation, which accounts for 5% to 35% of disc herniation, is typically associated with low back pain. But radiculopathy is usually abscent unless central disc heriniaton is large enough to cause compression of the cauda equina. To evalute the diagnostic value of the thermographic imaging in the diagnosis of central disc herniation, the imaging of 15 normal subjects and 48 patients with central disc herniation documented by CT scan were analyzed. The patients had either bilateral radiculophathy or no radiculopathy. The imaging of patient group with non rediculopathy did not show any significant thermal difference to control. While bilateral radiculopathy group reveled hypothermic pattern compared twith control. Thermal difference between left and right side did not present any significance in non radiculopathy group but hypothermia in bilateral radiculopathy group. Large herniation group demonstrated hyperthemic pattern while the others showed no significant change. Cranial caudal thermal difference did not show any difference between experiment groups. These results shows that infrared thermographic imaging can be used central disc herniation with bilateral radiculopathy, while it seems to little useful on the diagnosis of non radiculopathic disc herniation.

• Journal of Biomedical Engineering Research
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• v.44 no.6
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• pp.450-464
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• 2023

Pulse oximetry, a non-invasive technique for evaluating blood oxygen saturation, conventionally depends on isolated measurements, rendering it vulnerable to factors like illumination profile, spatial blood flow fluctuations, and skin pigmentation. Previous efforts to address these issues through imaging systems often employed red and near-infrared illuminations with distinct profiles, leading to inconsistent ratios of transmitted light and the potential for errors in calculating spatial oxygen saturation distributions. While an integrating sphere was recently utilized as an illumination source to achieve uniform red and near-infrared illumination profiles on the sample surface, its bulkiness presented practical challenges. In this work, we have enhanced the pulse oximetry imaging system by transitioning illumination from an integrating sphere to a multi-wavelength LED configuration. This adjustment ensures simultaneous emission of red and near-infrared light from the same position, creating a homogeneous illumination profile on the sample surface. This approach guarantees consistent patterns of red and near-infrared illuminations that are spatially uniform. The sustained ratio between transmitted red and near-infrared light across space enables precise calculation of the spatial distribution of oxygen saturation, making our pulse oximetry imaging system more compact and portable without compromising accuracy. Our work significantly contributes to obtaining spatial information on blood oxygen saturation, providing valuable insights into tissue oxygenation in peripheral regions.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1993.10a
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• pp.1354-1363
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• 1993

Optical methods were developed to examine their feasibility for quality evaluation of peanut with pod. Surface color and internal quality of peanut were measured without contact. The surface color of peanut was measured by light reflectance at a region of visible wavelengths. Its characteristic was high correlated with a visual grading of peanut. A trial machine for the color grading of peanut was developed using an optical sensor and it was considered to compare with the visual grading. The spectral reflectance at a region of near infrared wavelengths from 1,200 to 2,500nm was measured , and the chemical components of peanut were related to spectral reflectance at special wavelengths. The protein, fat and moisture contents of peanut were estimated by the near infrared methods. An infrared imaging method was developed to evaluate the internal quality of peanut with pod. As thermal characteristic of peanut with pod was deeply related to internal quality , the quality of peanut can be evaluated by temperature changes on the surface of peanut. Measurement of surface color, near infrared reflectance and thermal imaging were shown to be very effective in grading of peanut with pod.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1251-1260
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• 2008

Diffuse wireless optical communication offers more robust optical links in terms of coverage and shadowing than line-of-sight links. However, traditional diffuse wireless infrared (IR) transceiver systems are more susceptible to multi-path distortion and great power decrease, which results in limiting high-speed performance. Multi-beam is an effective technique to compensate for multi-path distortion in a wireless infrared environment. The goal of this paper is to analyze the transmission characteristics by replacing traditional diffuse system (TDS) which contains single wide angle transmitter and single element receiver by system consisting of three-beam transmitter and non-imaging receiver (TNS) attached with compound parabolic concentrator (CPC). In the simulation, we use the recursive model developed by Barry and Kahn and build the scenario based on 10 different cases which have been listed in Table 1. Moreover, we also check the reliability of the TNS diffuse link channel by BER test on the basis of different receiver positions and room sizes. The simulation results not only show the basic transmission characteristics of TNS diffuse link, but also are references to design more efficient and reliable indoor infrared transmission systems.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.282-282
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• 2010

LED Device was designed of electronic circuits of electrical power part for used Pspice student version and used Infrared LED lamps of load part. LED was used Computerized Electronic Medical Infrared Thermographic Imaging System for body surface Investigation of variable Body thermal asymmetry. It was knowledge body thermal Asymmetry of body surface and quantity body surface of electromagnetic wave to inflow electrical power part.

• Journal of the Korean Society of Industry Convergence
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• v.24 no.6_2
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• pp.927-935
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• 2021

This study conducted a study to improve the problems of the existing fire sensor system. In the case of the existing system, it took more than 3 minutes to detect a fire even at a short distance, making it difficult to extinguish the initial fire. In order to improve these problems, in this study, a fire detection system using an infrared thermal imaging camera was studied. The infrared image-based fire detection system is relatively wide and can detect fire over a long distance, so it has the advantage of being applicable to many fire detection systems. As a result of conducting a field test using the fire detection system, a fire that occurred about 2 km ahead was detected within about 10 seconds. Since the fire detection function of this system can detect within 10 seconds from a distance of about 2 km, it was applicable to forest fires that occur frequently in spring and autumn.

• Korean Journal of Optics and Photonics
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• v.18 no.2
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• pp.135-141
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• 2007

This paper describes the design technology for a third generation thermal imaging system, which is more compact than before, using a $320\times240$ mid-IR focal plane detector. The third generation non-scanning thermal imaging system was constructed as a compact thermal imaging module as a reconnaissance, surveillance and navigation sensor for helicopter and infantry vehicles in the $1980's\sim1990's$ and now, we designed a new compact infrared camera and studied a new type of non-uniformity correction lens fer this camera.

• Current Optics and Photonics
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• v.1 no.5
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• pp.500-504
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• 2017

In this paper, we developed a temperature measurement system based on an infrared temperature imaging module for thermal safety verification of a plasma skin treatment device (PSTD). We tested a pilot product of the low-temperature PSTD using the system, and the temperature increase of each plasma torch was well-monitored in real-time. Additionally, through the approximation of the temperature increase of the plasma torches, a certain limitation of the plasma treatment time on skin was established with the International Electrotechnical Commission (IEC) guideline. We determined an appropriate plasma treatment time ($T_{Safe}$ < 24 minutes) using the configured temperature measurement system. We believe that the temperature measurement system has a potential to be employed for testing thermal safety and suitability of various medical devices and industrial instruments.