• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1470-1471
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• 2008

We present a front-side micromachined thermopile with high sensitivity in the 3-5${\mu}m$ window, and discuss its application to a novel non-dispersive infrared (NDIR) $CO_2$ gas sensor with a light source emitting collimated light. The micromachined thermopile shows a measured sensitivity of 30 mV/W and a $D^*$ of $0.3{\times}10^8cm^{\surd}Hz/W$. Using this newly fabricated thermopile, we also have successfully developed a small, sensitive NDIR $CO_2$ detector module for accurate air quality monitoring systems in energy-saving building and automotive applications. The novel sample cavity comprising specular reflectors around the light bulb is configured to uniformly emit collimated light into the entrance aperture of the cavity in order to enhance the sensitivity of NDIR $CO_2$ detector.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.3
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• pp.337-344
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• 2017

In this paper, the optical axis alignment(OAA) of an infrared sensor(IRS) using a microwave sensor(MWS) was presented as a method of an axis alignment to minimize the problems that could be caused by the misalignment of the two sensors in the missile including the dual-mode sensor. The azimuth(AZ) and elevation(EL) angles of the two targets used for each sensor test were calculated by using the transformation equation and the test results of the MWS and IRS, and then the proposed OAA was verified by comparing the angles. Furthermore, the validity of the proposed OAA was demonstrated by confirming the abnormality of the OAA through the test results of the electro optical head(EOH) of the IRS which was equipped with a tilt on the missile fuselage.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.938-941
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• 2007

The most of humonoid robot which is utility for the existing industry use a magnetic sensor and infrared sensor and route in their courses consist of guidance or the optical tape. It is impossible to establish courses in the room that is the working environment of the humonoid robot. So It has need of the development of the flexible humonoid robot. In this paper, we describe the map building method combined with ultrasonic sensors and infrared sensor additionally.

• Journal of Sensor Science and Technology
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• v.25 no.5
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• pp.349-353
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• 2016

Recently, research on bolometer-type uncooled infrared image sensor which is made for industrial applications has been increasing. In general, it is difficult to calibrate fixed pattern noise (FPN) of bolometer array. In this paper, average-current calibration algorithm is presented for reducing bolometer resistance offset. A resistor which is produced by standard CMOS process, on the average, has a deviation. We compensate for deviation of each resistor using average-current calibration algorithm. The proposed algorithm has been implemented by a chip which is consisted of a bolometer pixel array, average current generators, current-to-voltage converters (IVCs), a digital-to-analog converter (DAC), and analog-to-digital converters (ADCs). These bolometer-resistor array and readout circuit were designed and manufactured by $0.35{\mu}m$ standard CMOS process.

• Journal of Sensor Science and Technology
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• v.26 no.5
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• pp.360-365
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• 2017

In this study, a heat treatment process was applied to ZnS nano-powder to improve the optical properties of ZnS ceramic, and the characteristics of heat treatment time were studied. The ZnS nano-powders were synthesized by hydrothermal synthesis. The heat treatment was carried out at $550^{\circ}C$ for 0.5, 1, 2, and 4 hours in a vacuum atmosphere ($10^{-2}torr$). X-ray diffraction and scanning electron microscope analyzes confirmed the change of crystal phase and grain size to confirm the structural change with heat treatment time. The heat treated ZnS nano-powder was sintered by hot pressing, and the change of optical properties of the ZnS ceramic was analyzed by infrared spectroscopy.

• Journal of the Korea Society of Computer and Information
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• v.17 no.3
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• pp.105-111
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• 2012

Photoplethysmogram is widely used to measure heart rate and arterial blood oxygen saturation in human. This paper describes implementation a photoplethysmography monitoring system that uses 780nm and 940nm length infrared light in radial artery. That system used combinations of 8 LEDs and 2 photoelectricities. When recorded on the skin over radial artery, the radial pulse wave was inverted. The mechanism of inverted pulse wave skin, which was reduced during systolic period and increase during diastolic period of the cardiac cycle. Through this system, we discovered optimal environments and combinations of sensors in both penetration type and reflection type. These results suggest that radial arterial wall way reflect infrared ray.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.1
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• pp.25-32
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• 2010

The paper proposes a hierarchical fault detection method for the high voltage equipment using a microphone array which detects the location of fault and the thermal imaging and CCD cameras which verifies the fault and stores the image, respectively. There are partial arc discharges on the faulty insulators, which generates a specific pattern of sound. Detecting the signal using the microphone array, the location of the faulty insulator can be estimated. The 6th band-pass filter was applied to remove noise signal from wind or external influence. When the mobile robot carries the thermal and CCD cameras to the possible place of the fault insulator, the fault insulators or power transmission wires can be detected by the thermal images, which are caused by the aging or natural erosion. Finally, the CCD camera captures the image of the fault insulator for the record. The detection scheme of fault location using the microphone array and the thermal images have been proved to be effective through the real experiments. As a result of this research, it becomes possible to use a mobile robot with the integrated sensors to detect the fault insulators instead of a human being.

• Journal of Sensor Science and Technology
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• v.28 no.5
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• pp.305-310
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• 2019

The purpose of this study is to classify the concentration of HbA1c (glycosylated hemoglobin), which is an indicator in the management of accurate blood glucose level in diabetic patients, using a non-invasive optical property measurement method. To measure the optical properties of HbA1c, the optical source uses LEDs and laser diodes of 400 nm in the visible region and 1450 nm in the nearinfrared region using thermopile to detect the Raman scattering intensity. An HbA1c control solution was used. As a result, the optical properties of 5% (normal) and 9% (abnormal) HbA1c control solutions showed specificity in which the output values were reversed at 850 nm and 950 nm, respectively. This property was applied to distinguish between normal and abnormal values in diabetes. In addition, considering tissue penetration depths for non-invasive measurements, two wavelengths were determined to be effective in distinguishing the concentrations of HbA1c control solutions at 5%, 7%, and 9%.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.9-20
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• 2005

In this paper, we propose ubiTrack, a system which tracks users' location in indoor environments by employing infrared-based proximity method. Most of recently developed systems have focussed on performance and accuracy. For this reason, they adopted the idea of centralized management, which gathers all information in a main system to monitor users' location. However, these systems raise privacy concerns in ubiquitous computing environments where tons of sensors are seamlessly embedded into environments. In addition, centralized systems also need high computational power to support multiple users. The proposed ubiTrack is designed as a passive mobile architecture to relax privacy problems. Moreover, ubiTrack utilizes appropriate area as a unit to efficiently track users. To achieve this, ubiTrack overlaps each sensing area by utilizing the TDM (Time-Division Multiplexing) method. Additionally, ubiTrack exploits various filtering methods at each receiver and utilization module. The filtering methods minimize unexpected noise effect caused by external shock or intensity weakness of ID signal at the boundary of sensing area. ubiTrack can be applied not only to location-based applications but also to context-aware applications because of its associated module. This module is a part of middleware to support communication between heterogeneous applications or sensors in ubiquitous computing environments.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.1
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• pp.145-155
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• 2010

This paper presents a new approach to obstacle avoidance for mobile robot in unknown or partially unknown environments. The method combines two navigation subsystems: low level and high level. The low level subsystem takes part in the control of linear, angular velocities using a multivariable PI controller, and the nonlinear position control. The high level subsystem uses ultrasonic and IR sensors to detect the unknown obstacle include static and dynamic obstacle. This approach provides both obstacle avoidance and target-following behaviors and uses only the local information for decision making for the next action. Also, we propose a new algorithm for the identification and solution of the local minima situation during the robot's traversal using the set of fuzzy rules. The system has been successfully demonstrated by simulations and experiments.