• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.1174-1176
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• 2011

Unfortunately, the number of blind people increases every 5 seconds in our world. An extensive research was made on improving the conventional walking cane and developing a microcontroller based walking stick for the blind with sensors and a feedback in form of vibration. Two different kinds of sensors are used to detect obstacles, ultrasonic and infrared distance sensors. The signal from an ultrasonic sensor is fed to a microcontroller. With the help of the supporting software, the Pulse Width Modulation (PWM) principle is extensively used to form three zones and run the corresponding vibration motor at different spends according to how far the detected object is located. The other infrared distance sensors are connected to amplifiers and after that to their corresponding vibration motors through motor drivers. The vibration motors are to be located around the user's arm to notify the blind of the obstacles in the intended walking way. It can be very reliable and sufficient device guiding the blind other than the conventional walking cane which has many drawbacks which will be explained and discussed.

• Journal of Sensor Science and Technology
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• v.30 no.1
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• pp.36-41
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• 2021

The motivation of this paper is to easily analyze the properties of nondispersive infrared gas sensor that has more than two different optical path length and to suggest the criterion and definition of infrared light absorbance in order to minimize the measurement errors. With the output voltage ratios and the normalized derivatives of infrared ray (IR) absorbance, when the normalized derivatives of IR absorbance decreases from 0.28 to 0.10, the lower and higher limits of errors were decreased from -5.62% and 2.39% to -4.27% and 2.78%. When the normalized derivatives of IR absorbance were 0.10, the output voltage could be partitioned into two regions with one exponential equation and the temperature compensation error was less than 5%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.35-40
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• 2021

People counting data is crucial for most business owners, since they can derive meaningful information about customers movement within their businesses. For example, owners of the supermarkets can increase or decrease the number of checkouts counters depending on number of occupants. Also, it has many applications in smart buildings, too. Where it can be used as a smart controller to control heating and cooling systems depending on a number of occupants in each room. There are advanced technologies like camera-based people counting system, which can give more accurate counting result. But they are expensive, hard to deploy and privacy invasive. In this paper, we propose a method and a hardware sensor for counting people passing through a passage or an entrance using IR Infrared sensors. Proposed sensor operates at low voltage, so low power consumption ensure long duration on batteries. Moreover, we propose a new method that distinguishes human body and other objects. Proposed method is inexpensive, easy to install and most importantly, it is real-time. The evaluation of our proposed method showed that when counting people passing one by one without overlapping, recall was 96% and when people carrying handbag like objects, the precision was 88%. Our proposed method outperforms IR Infrared based people counting systems in term of counting accuracy.

• Journal of Sensor Science and Technology
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• v.26 no.3
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• pp.179-185
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• 2017

This article describes the characteristics of nondispersive infrared carbon dioxide gas sensor according to the temperatures and humidifies. In this researches, a thermopile sensor that included application-specific integrated circuit (ASIC) was used and the White-cell structure was implemented as an optical waveguide. The developed sensor modules were installed in gas chamber and then the temperature of gas chamber has been increased from 283 K to 313 K with 10K temperature step. In order to analyze the effects of humidity levels, the relative humidity levels were changed from 30 to 80%R.H. with small humidifier. Then, the characteristics of sensor modules were acquired with the increment of carbon dioxide concentrations from 0 to 2,000 ppm. When the initial voltages of sensors were compared before and after humidifying the chamber at constant temperature, the decrements of the output voltages of sensors are like these: 9mV (reference infrared sensor), 41 mV (carbon dioxide sensor), 2 mV (temperature sensor). With the increment of ambient temperature, the averaged output voltage of carbon dioxide sensor was increased 19 mV, however, when the humidity level was increased, it was decreased 14mV. Based upon the experimental results, the humidity effect could be alleviated by the increment of temperature, so the effects of humidity and temperature could be only compensated by the ambient temperature itself. The estimated carbon dioxide concentrations showed 10% large errors below 200 ppm, however, the errors of the estimations of carbon dioxide concentrations were less than ${\pm}5%$ from 400 to 2,000 ppm.

• Journal of Sensor Science and Technology
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• v.5 no.1
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• pp.1-8
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• 1996

High-sensitive pyroelectric infrared sensors have been fabricated with La-modified $PbTiO_{3}$(PLT) thin plates. The PLT thin plates have the composition of $(Pb_{0.9}La_{0.1}Ti_{0.75}O_{3})_{0.75}(PbO)_{0.25}$. Thickness of the thin plates is $100\;{\mu}m$. Top side electrodes exposed to IR are vacuum evaporated Ni-Cr, and bottom side electrodes are Ag. Each one takes the area of $1{\times}2\;mm^{2}$. The thin plates have a large resistivity of $6.41{\times}10^{10}{\Omega}{\cdot}cm$ and a relative dielectric constant of 341. They have a high figure of merit of $4.0{\times}10^{-11}\;Ccm/J$ due to its high pyroelectric coefficient of $4.45{\times}10^{-8}\;C/cm^{2}K$. The sensors show such a large voltage responsivity as 2501 V/W. That they can find practical applications like the pyroelectric infrared detectors.

• Journal of Sensor Science and Technology
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• v.20 no.2
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• pp.114-117
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• 2011

A thick 25 ${\mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated and then thin 1.6 ${\mu}m$ thickness P(VDF/TrFE) film pyroelectric infrared ray sensor has been fabricated also. These thick and thin P(VDF/TrFE) film pyroelectric infrared ray sensor was mounted in TO-5 housing to detect infrared light of 5.5 ~ 14 ${\mu}m$ wavelength for human body detecting with each other. The noise output voltage of the thick P(VDF/TrFE) film pyroelectric infrared ray sensor were 380 mV and NEP(noise equivalent power) is $3.95{\times}10^{-7}$ W which is the similar value with the commercial pyroelectric infrared ray sensor using ceramic materials as a sensing material. The NEP and specific detectivity $D^*$ of the thin P(VDF/TrFE) film pyroelectric infrared ray sensor were $2.13{\times}10^{-8}$ W and $9.37{\times}106$ cm/W under emission energy of 13 ${\mu}W/cm^2$ respectively. These result caused by lower thermal diffusion coefficient of a thin 1.6 ${\mu}m$ thickness PVDF/TrFE film than the thick 25 ${\mu}m$ thickness poled P(VDF/TrFE) film pyroelectric infrared ray sensor.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.88-93
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• 1993

This paper introduces an ARV(Autonomous Road Vehicle) system which can run on orads without help of a driver by detecting road boundaries through computer vision. This vehicle can also detect obstacles in front through sonar sensors and infrared sensors. This system largely consists of a handle steering module and a braking module. From road boundaries, the steering module determines handle turn angle. The braking module stops or decelerates to avoid collision depending on the relative speeds and distance to the obstacles detected by different sensors. This ARV system has been implemented in a small jeep and can run 30-40 km/h city traffic. In this paper, we illustrate the structure of the ARV systems and its operation principle.

• Journal of Cadastre & Land InformatiX
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• v.48 no.1
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• pp.71-91
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• 2018

In recent years, application of UAV(Unmanned Aerial Vehicle) to seed sowing and pest control has been actively carried out in the field of agriculture. In this study, UAS(Unmanned Aerial System) is constructed by combining image sensor of various wavelength band and SfM((Structure from Motion) based image analysis technique in UAV. Utilization of UAS based vegetation survey was investigated and the applicability of precision farming was examined. For this purposes, a UAS consisting of a combination of a VIS_RGB(Visible Red, Green, and Blue) image sensor, a modified BG_NIR(Blue Green_Near Infrared Red) image sensor, and a TIR(Thermal Infrared Red) sensor with a wide bandwidth of $7.5{\mu}m$ to $13.5{\mu}m$ was constructed for a low cost UAV. In addition, a total of ten vegetation indices were selected to investigate the chlorophyll, nitrogen and water contents of plants with visible, near infrared, and infrared wavelength's image sensors. The images of each wavelength band for the test area were analyzed and the correlation between the distribution of vegetation index and the vegetation index were compared with status of the previously surveyed vegetation and ground cover. The ability to perform vegetation state detection using images obtained by mounting multiple image sensors on low cost UAV was investigated. As the utility of UAS equipped with VIS_RGB, BG_NIR and TIR image sensors on the low cost UAV has proven to be more economical and efficient than previous vegetation survey methods that depend on satellites and aerial images, is expected to be used in areas such as precision agriculture, water and forest research.

• The Journal of Korea Robotics Society
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• v.6 no.1
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• pp.42-48
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• 2011

It is very important for a mobile robot to recognize and model its environments for navigation. However, the grid map constructed by sonar sensors cannot accurately represent the environment, especially the narrow environment, due to the angular uncertainty of sonar data. Therefore, we propose a map building scheme which combines sonar sensors and IR sensors. The maps built by sonar sensors and IR sensors are combined with different weights which are determined by the degree of translational and rotational motion of a robot. To increase the effectiveness of sensor fusion, we also propose optimal sensor arrangement through various experiments. The experimental results show that the proposed method can represent the environment such as narrow corridor and open door more accurately than conventional sonar sensor-based map building methods.

• Journal of Advanced Navigation Technology
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• v.9 no.1
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• pp.28-33
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• 2005

In this paper, we developed the algorithm to control longitudinal and lateral motion of UAV(Unmanned Aerial Vehicle) with Infrared heat sensors and GPS(Global Positioning System) receiver. UAV was controlled to be flown horizontally and also turned coordinately maintaining the constant altitude. Accomplishing the flight test of UAV sevral times, we were able to develope low price controller to control bank angle for lateral motion, and also pitch angle and altitude for longitudinal motion simultaneously.