• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.4
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• pp.400-403
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• 2008

In this work, an individual trespassing detector using a PIR sensor to detect infrared rays only between the range of $9.4{\sim}10.4{\mu}m$ radiated from the body is proposed. This detector using FIR sensor detects not insect or object but human body, It doesn't restrict the inhabitant's behavior because the filter of pm sensor is designed to have face angle and the detector only detects the window area. The existing wide angle filter, RIR sensor, detects $30^{\circ}$ angle while the face angle filter sensor on this paper detects $11^{\circ}$ angle with 3cm of face angle filter from 2m of detecting distance. In case of interruption of electric power, 250mAh of lithium-ion battery has worked for 10 hours consuming 22mA in normal state. Meanwhile, in case of interruption of electric power, 250mAh of battery has worked for 4 hours consuming 60mA in trespassing detecting state. Projector, receptor, controller and alarm are put on one PCB in order to make it convenient to install without any special installation skill.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.8
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• pp.1840-1846
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• 2014

An experimental outdoor optical wireless data communication system with an optical filter in the presence of sunlight or artificial light is presented. For the efficient blocking of light noise outdoors, we employ an optical filter made of microlouver film on the top of the photo diode. This filter is designed to block any light noise incident from an angle higher than $30^{\circ}$ on the assumption that light noise does not face the photo diode horizontally. Outdoor experiments daytime with the optical filtering have been conducted. The experimental results demonstrate that the optical filter effectively blocks nearly all light noise incident from the specified angle or higher and more than 90% of the transmitted data packets are successfully received. The proposed outdoor visible light data communication can thus facilitate a practical free space outdoor optical wireless data transmission.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.257-264
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• 2015

For the tracking of the way-points of hovering AUV (HAUV), we suggest a simple PID controller. The way-points are designed to approach to a virtual underwater structure and the heading angles at each way-point are set to look at the structure in the face. The proposed controller consists of a vertical controller to maintain the depth and pitch angle, and a horizontal controller to move to the desired position as well as to adjust the heading angle of the HAUV. In the simulation using Matlab/Simulink, the HAUV with the proposed PID controller is shown to track all the way-points within 1 m range while maintaining proper heading angle at each way-point.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.7
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• pp.1383-1390
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• 2012

In this paper, we propose a robust pupil detection method using rank order filter and pixel value difference in facial image. We have detected the potential pupil candidates using rank order filter. Many false pupil candidates found at eyebrow are removed using the fact that the pixel difference is much at the boundary between pupil and sclera. The rest pupil candidates are grouped into pairs. Each pair is verified according to geometric constraints such as the angle and the distance between two candidates. A fitness function is obtained for each pair using the pixel values of two pupil regions, we select a pair with the smallest fitness value as a final pupil. The experiments have been performed for 400 images of the BioID face database. The results show that it achieves more than 90% accuracy, and especially the proposed method improves the detection rate and high accuracy for face with spectacle.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.282-288
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• 2022

Facial masks have become indispensable in daily life to prevent infection and spread through respiratory droplets in the era of the corona pandemic. To understand how effective two different types of masks (i.e., KF-94 mask and dental mask) are in blocking respiratory droplets, i) we preferentially analyze wettability characteristics (e.g., contact angle and contact angle hysteresis) of filters consisting of each mask, and ii) subsequently observe the dynamic behaviors of microdroplets impacting at high velocities on the filter surfaces. Different wetting properties (i.e., hydrophobicity and hydrophilicity) are found to exhibit depending on the constituent materials and pore sizes of each filter. In addition, the pneumatic conditions for stably and uniformly dispensing microdroplets with a certain volume and impacting behaviors associated with the impacting velocity and filter type change are systematically explored. Three distinctive dynamics (i.e., no penetration, capture, and penetration) after droplet impacting are observed depending on the type of filter constituting the masks and droplet impact velocity. The present experimental results not only provide very useful information in designing of face masks for prevention of transmission of infectious respiratory diseases, but also are helpful for academic researches on droplet impacts on various porous surfaces.

• Journal of KIISE:Software and Applications
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• v.35 no.10
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• pp.600-607
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• 2008

This paper proposes a robust human detection method irrespective of their pose variation using the multiple oriented 2D elliptical filters (MO2DEFs). The MO2DEFs can detect the humans regardless of their poses unlike existing object oriented scale adaptive filter (OOSAF). To overcome OOSAF's limitation, we introduce the MO2DEFs whose shapes look like the oriented ellipses. We perform human detection by applying four different 2D elliptical filters with specific orientations to the 2D spatial-depth histogram and then by taking the thresholds over the filtered histograms. In addition, we determine the human pose by using convolution results which are computed by using the MO2DEFs. We verify the human candidates by either detecting the face or matching head-shoulder shapes over the estimated rotation. The experimental results showed that the accuracy of pose angle estimation was about 88%, the human detection using the MO2DEFs outperformed that of using the OOSAF by $15{\sim}20%$ especially in case of the posed human.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.656-663
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• 2001

This paper presents a sensor fusion method to recognize a cylindrical object a CCD camera, a laser slit beam and ultrasonic sensors on a pan/tilt device. For object recognition with a vision sensor, an active light source projects a stripe pattern of light on the object surface. The 2D image data are transformed into 3D data using the geometry between the camera and the laser slit beam. The ultrasonic sensor uses an ultrasonic transducer array mounted in horizontal direction on the pan/tilt device. The time of flight is estimated by finding the maximum correlation between the received ultrasonic pulse and a set of stored templates - also called a matched filter. The distance of flight is calculated by simply multiplying the time of flight by the speed of sound and the maximum amplitude of the filtered signal is used to determine the face angle to the object. To determine the position and the radius of cylindrical objects, we use a statistical sensor fusion. Experimental results show that the fused data increase the reliability for the object recognition.