• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.145-147
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• 2018

다수의 일반 카메라로 촬영한 영상들로 360도 영상을 제작하는 경우 다수의 영상 간 동일한 영역을 찾고 기하학 보정을 위한 영상 스티칭 기술이 필요하다. 영상 스티칭 기술은 여러 영상에서 추출한 특징점들의 유사도를 비교하여 영상들을 이어 붙여 큰 하나의 영상으로 만드는 것이다. 본 논문에서는 비콘이 부착된 공연장을 가정하여, 비콘을 통해서 촬영자의 위치를 대략적으로 파악하고, 사용자가 어플리케이션을 통하여 전송한 영상과 영상의 방위각, FOV(Field Of View)들을 이용하여 실내에서 촬영된 영상들을 스티칭 대상 영상들로 필터링하는 방법을 제안한다.

• The Journal of the Acoustical Society of Korea
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• v.27 no.7
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• pp.350-356
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• 2008

In this paper, we propose shading functions to the appropriate focused beamforming for near-field target estimation. This near field shading functions are based on Chebychev and Manning windows. In order to obtain the optimum sensor weighting values with the help of the proposed shading technique, we assume that the sensor positions associated to the non-uniformly distributed array are precisely known. We calculate a series of sensor weighting values from the FFT operation of given shading functions in time domain. By applying the shading weights on the sensor array, we can see that the level of sidelobe becomes diminished and the performance of estimating range and azimuth gets improved. In addition, we propose a non-uniform structure in terms of frequency bands, which may minimize the attenuation of incoming signals.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.479-486
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• 2015

A triplet line array has a capability for solving left/right ambiguity problem and high directivity of line array. For this, high computational powers and correlation between nearby sensors must be considered. Hardware powers are dramatically increased, so various adaptive beamforming techniques and signal processing techniques can be adopted for large triplet line array. To investigate the optimum signal processing method and improve the target detection capability, we need to analyze the noise correlation among the triplet line array sensors in real environment. In this paper we analyze the experimental data in the East Sea, investigate noise correlation between three hydrophones in triplet sensors, among the triplet sensors and time varying properties. Based on the acquired results, it is possible to verify some information for beamforming and signal processing methods with considering the properties of the triplet line array.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.6
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• pp.7-15
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• 2003

The purpose of this simulation study is to determine the window transmittance by RADIANCE lighting simulation tool where the horizontal blind is installed. Parameters such as sky types, seasonal changes, altitude, azimuth, and horizontal blind angle at a 0$^{\circ}$, 45$^{\circ}$, 90$^{\circ}$ were considered. The simulation results present that measured directional transmittances have different values according to each directional property of the horizontal blind. In addition, methodology was described to apply window transmittance data to DayDim program which is a lighting calculation and analysis tool especially for the performance of daylight responsive dimming systems.

• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.610-620
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• 2022

An acoustic vector sensor can simultaneously receive vector quantities, such as particle velocity and acceleration, as well as acoustic pressure at one location, and thus it can be used as a single input multiple output receiver in underwater acoustic communication systems. On the other hand, vector signals received by a single vector sensor have different channel characteristics due to the azimuth angle between the source and receiver and the difference in propagation angle of multipath in each component, producing different communication performances. In this paper, we propose a channel parameter-based weighting method to improve the performance of an acoustic communication system using a single vector sensor. To verify the proposed method, we used communication data collected from the experiment conducted during the KOREX-17 (Korea Reverberation Experiment). For communication demodulation, block-based time reversal technique which is robust against time-varying channels were utilized. Finally, the communication results showed that the effectiveness of the channel parameter-based weighting method for the underwater communication system using a single vector sensor was verified.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.103-109
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• 2012

Digital speedometer which is supposed to provide the basic data for analyzing human factors of drivers has a limitation for human behavior studies of drivers, because it records limited driving information including GPS velocities. Besides, Black Box, which is currently being actively commercialized in the market, records mostly vehicles' risky patterns rather than drivers' behaviors. As a result, it also shows a limit to analyze dangerous driving patterns. This study performed a risky driving study for human factor analysis. This study conducted before and after comparisons for real time warning study using a risky driving judgment device. The analysis was conducted based on Longitudinal acceleration, Lateral acceleration, and Yaw rate of vehicles.

• The Journal of the Acoustical Society of Korea
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• v.25 no.4
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• pp.184-190
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• 2006

Recently, Lee et al. have proposed an algorithm utilizing the signals from different paths by using bottom mounted simple linear array to estimate 3-D location of oceanic target. But this algorithm assumes that sound velocity is constant along depth of sea. Consequently, serious performance loss is appeared in real oceanic environment that sound speed is changed variously. In this paper, we present a 3-D near field localization algorithm for inhomogeneous sound speed. The proposed algorithm adopt localization function that utilize ray propagation model for multipath environment with linear sound speed profile(SSP), after that, the proposed algorithm searches for the instantaneous azimuth angle, range and depth from the localization cost function. Several simulations using linear SSP and non linear SSP similar to that of real oceans are used to demonstrate the performance of the proposed algorithm. The estimation error in range and depth is decreased by 100m and 50m respectively.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.2
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• pp.149-156
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• 2014

A magnetic compass module must be calibrated accurately before use. Moreover, the calibration process must be performed taking into account any magnetic dip if the magnetic compass module has tilt angles. For this, a calibration method for a magnetic compass module is explained. Tilt error of the magnetic compass module is compensated using a biaxial accelerometer generally. The accelerometer error causes a tilt angle calculation error that gives rise to an azimuth calculation error. For error property analysis, error equations are derived and simulations are performed. In the simulation results, the accuracy of derived error equations is verified. If a biaxial magnetic compass module is used instead of a triaxial one, the magnetic dip and z-axis magnetic compass data must be estimated for tilt compensation. Lastly, estimation equations for the magnetic dip and z-axis magnetic compass data are derived, and the performance of the equations is verified based on a simulation.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.65-72
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• 2017

We propose a method to generate the object-target identifier mapping information for system performance and effectiveness analysis of submarine engage system and verify the validity of the proposed method through experiments. In the submarine model of the engage simulator, the signal processing algorithm of the actual sonar system is installed. In the target information obtained through the sonar or signal processing process, the actual object information is not known, and the simulator does not provide such information. Therefore, in this study, we generated identifier mapping information for simulation post-analysis by using bearing, range, and speed of the target obtaind from sonar signal processing and the object collected.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1269-1274
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• 2018

In this paper, it covers technical aspect of drone by introducing the drone hovering. Arduino Uno and 3-axis attitude and azimuth sensor are the two main components of the drone. Arduino Uno is used as a main controller and 3-axis attitude and azimuth sensor are used to collect axial (X,Y,Z) data, which is massaged to determine the pitch (fore and aft tilt) and the bank (side to side tilt). Furthermore, drone stabilizes horizontal attitude by correcting these tilted angle through PID control.