• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.1
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• pp.55-69
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• 2017

Recently, the IoT (Internet of Things) environment is being developed rapidly through network which is linked to intellectual objects. Through the IoT, it is possible for human to intercommunicate with objects and objects to objects. Also, the IoT provides artificial intelligent service mixed with knowledge of situational awareness. One of the industries based on the IoT is a car industry. Nowadays, a self-driving vehicle which is not only fuel-efficient, smooth for traffic, but also puts top priority on eventual safety for humans became the most important conversation topic. Since several years ago, a research on the recognition of the surrounding environment for self-driving vehicles using sensors, lidar, camera, and radar techniques has been progressed actively. Currently, based on the WAVE (Wireless Access in Vehicular Environment), the research is being boosted by forming networking between vehicles, vehicle and infrastructures. In this paper, a research on the recognition of a traffic signs on highway was processed as a part of the awareness of the surrounding environment for self-driving vehicles. Through the traffic signs which have features of fixed standard and installation location, we provided a learning theory and a corresponding results of experiment about the way that a vehicle is aware of traffic signs and additional informations on it.

• International Journal of Highway Engineering
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• v.10 no.2
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• pp.159-166
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• 2008

Video image processing systems (VIPS) offer numerous benefits to transportation models and applications, due to their ability to monitor traffic in real time. VIPS based on a wide-area detection algorithm provide traffic parameters such as flow and velocity as well as occupancy and density. However, most current commercial VIPS utilize a tripwire detection algorithm that examines image intensity changes in the detection regions to indicate vehicle presence and passage, i.e., they do not identify individual vehicles as unique targets. If VIPS are developed to track individual vehicles and thus trace vehicle trajectories, many existing transportation models will benefit from more detailed information of individual vehicles. Furthermore, additional information obtained from the vehicle trajectories will improve incident detection by identifying lane change maneuvers and acceleration/deceleration patterns. However, unlike human vision, VIPS cameras have difficulty in recognizing vehicle movements over a detection zone longer than 100 meters. Over such a distance, the camera operators need to zoom in to recognize objects. As a result, vehicle tracking with a single camera is limited to detection zones under 100m. This paper develops a methodology capable of monitoring individual vehicle trajectories based on image processing. To improve traffic flow surveillance, a long distance tracking algorithm for use over 200m is developed with multi-closed circuit television (CCTV) cameras. The algorithm is capable of recognizing individual vehicle maneuvers and increasing the effectiveness of incident detection.

• Journal of Energy Engineering
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• v.8 no.2
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• pp.298-308
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• 1999

Experimental study on characteristics of direct contact condensation of steam discharged into a sub-cooled water pool has been performed using five different sizes of horizontal nozzle over a wide range of steam mass fluxes and pool temperatures. Steam condensation phenomena have been observed visually and by taking pictures of steam jets using a high speed video camera. Two different steam jet shapes such as ellipsoidal shape and conical shape were typically observed for a stable steam jet, depending on the steam mass flux and pool temperature. The steam jet expansion ratio and the steam jet length as well as the condensation heat transfer coefficients were determined. The effect of steam mass flux, pool temperature, and nozzle diameter on these parameters were also discussed. Empirical correlations for the steam jet lengths and the condensation heat transfer coefficients as a function of steam mass flux and condensation driving potential were established. The axial and radial temperature distributions in steam jet and in surrounding water were measured. The effect of steam mass flux, pool temperature, and nozzle diameter were also discussed. The condensation regime map, which consists of six regimes such as chugging, transient chugging, condensation oscillation, stable condensation, bubble condensation oscillation, and intermittent oscillation condensation, were established. In addition, the dynamic pressures at the pool wall were measured. The close relation of dynamic pressure and steam condensation mode, which is also dependent on steam mass flux and pool temperature, was found.

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.798-809
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• 2014

Video stabilization is performed to remove unexpected shaky and irregular motion from a video. It is often used as preprocessing for robust feature tracking and matching in video. Typical video stabilization algorithms are developed to compensate motion from surveillance video or outdoor recordings that are captured by a hand-help camera. However, since the vehicle video contains rapid change of motion and local features, typical video stabilization algorithms are hard to be applied as it is. In this paper, we propose a novel approach to compensate shaky and irregular motion in vehicle video using linear regression model and vertical projection histogram matching. Towards this goal, we perform vertical projection histogram matching at each sub region of an input frame, and then we generate linear regression model to extract vertical translation and rotation parameters with estimated regional vertical movement vector. Multiple binarization with sub-region analysis for generating the linear regression model is effective to typical recording environments where occur rapid change of motion and local features. We demonstrated the effectiveness of our approach on blackbox videos and showed that employing the linear regression model achieved robust estimation of motion parameters and generated stabilized video in full automatic manner.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.362-371
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• 1995

This study describes with the sinking behaviour for the purse seine. The experiment was carried out using three model purse seines of knotless netting. The nettings were woven in same leg length(10.5mm) of polypropylene 170 denier, polyamide 210 denier and polyester 250 denier two thread ply twine, each of the seines were named PP seine, PA seine and PES seine. Dimension of Purse seine models were 420cm for corkline and 85cm for seine depth, each models rigged 65.8g, 50.6g and 35.8g(weight in water) of lead for a leadline, seine models will have the same weight in water. Experiments carried out in the observation channel in a flume tank under still water conditions. Sinking motion was recorded by the one set of TV-camera for VTR, and reading coordinate carried out by the video digitization system. The results obtained were as follows: 1) Netting bundle for PP seine was existence on the surface of the water, spread out a netting by sinking force of sinkers. 2) Netting bundle for PES seine was existence in the middle of corkline and leadline. 3) Average sinking speed of seine margin was fastest for 10.7cm/s of PP seine, followed by 9.7cm/s of PA and 9.2cm/s of PES seines. 4) In all seines, the force of horizontal movement for the seine setting was values of ranged in disregard.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.31 no.4
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• pp.372-378
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• 1995

This study describes an analysis on the sinking characteristics in purse seine. The experiment was carried out using three simplified model seines in a flume tank under still water condition. The densities($\rho$) of netting materials were 0.91g/$cm^3$ for PP seine, 1.14g/$cm^3$ for PA seine and 1.38g/$cm^3$ for PES seine. Differential equations were derived from the conservation of momenta of the model seines and used to determine the sinking speeds of the depths of leadline and the other portions of seines. An analysis carried out by simultaneous differential equations for numerical method by subroutine Runge-Kutta-Gill. The results obtained were as follows: 1) Sinking speed of net margin was fastest for PP seine, followed by PA and PES seines. 2) The coefficient of resistance for netting of seine was estimated to be $K_D=0.061({\frac{\rho}{{\rho}_w}})^4$. 3) The coefficient of resistance for netting bundle of seine was estimated to be $C_R=0.91({\frac{\rho}{{\rho}_w}}$. 4) In all seines, the calculated depths of leadline closely agreed with the measured ones(meas.=0.99cal.).

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.33-49
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• 2002

This study was intended to provide basic materials for golf coaching by somatotype by analyzing and comparing the kinematic factors found in each somatotype at the time of golf swing. For this purpose, the somatotype was divided into endomorph, mesomorph and ectomorph in reference to the weight, height and upper arm circumference of each of nine professional golfers. Each of their swing motions was videotaped with the camcorder and their swing motion was analyzed by dividing it into 8 sections. The time required for the swing motion, the displacement of the center of the human body and the rotation angle of the upper body were calculated through the three-dimensional image analysis based on the DLT(Direct Linear Transformation). Based on the findings of this study, the following conclusion was drawn: The endomorphic golfers showed the longest required golf swing time, followed by the mesomorphic golfer and then the endomorphic golfer. The displacement of left-to-right movement was largest in the mesomorphic golfers, followed by the endomorphic golfers the up-to-down displacement was upward at the time of impact and that the endomorphic and mesomorphic golfers raised the sense of stability by maintaining an almost uniform height at the time of impact. As for the rotational angle of the upper body and the rotational angle of the thigh, the upper body and the thigh took a form of rotating earlier in the ectomorphic golfers at the time of impact, who showed a somewhat different characteristics compared to the endomorphic and mesomorphic golfers. It is necessary to investigate the movement of more fundamental forces in presenting the theory related to the kinematic characteristics of this swing by somatotype. Accordingly, it is thought that it is necessary to analyze the center of pressure(COP) using the ground counterforce in the future study.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1812-1816
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• 2009

이미지 해석에 의한 유속장 측정방법은 유체역학분야에서 지난 30 여년 동안 많이 활용되어온 속도측정 기법으로 오늘날에는 이를 수공학 분야에서 이를 유량측정 등 수리현상 해석에 활용하려는 시도가 다각적으로 이루어지고 있다. 이에 본 연구에서는 이미지 해석에 의한 유속장 측정방법을 용담댐 시험유역에 적용하여 그의 자연하천에서의 적용성을 검토하고자 한다. 이미지 해석에 의한 유속장 측정방법은 PIV(Particle Image Velocimetry)로 통칭되고 있으며, PIV는 seeding, illumination, recording, 및 image processing의 네 가지 요소로 구성된다. seeding을 위해서 유체를 따라 흐를수 있는 작은 입자를 유체에 첨가한다. 유체를 따라 흐르는 입자들의 선명한 이미지를 얻기 위해서illumination이 필요하다. PIV를 이용하여 흐름을 해석하기 위한 illumination은 일반적으로 이중펄스 레이저가 이용된다. 이렇게 유속장 해석을 하려는 유체에 대하여 seeding 및 illumination이 준비되면 단일노출- 다중 프레임법, 혹은 다중노출-단일 프레임법으로 흐름을 recording을 한다. image processing은 이미지를 다운로드하고, 디지타이징 및 화질향상을 하는 전처리(pre-processing), 상관계수의 산정에 의한 유속 벡터의 결정 및 에러 벡터를 제거하고 유속장을 그래프화하는 후처리(post-processing) 과정으로 구성된다. LSPIV(Large Scale PIV)는 PIV의 기본원리를 근거로 하여 기존의 PIV에 비하여 실험실 내에서의 수리모형실험이나 일반 하천에서의 유속측정과 같은 큰 규모$(4m^2\sim45,000m^2$)의 흐름해석을 할 수 있도록 Fujita et al.(1994)와 Aya et al.(1995)이 확장시킨 것이다. PIV와 비교시 LSPIV의 다른 점은 넓은 흐름 표면적을 포함하기 위하여 촬영시에 카메라의 광축과 흐름 사이의 각도가 PIV에서 이용하는 수직이 아닌 경사각을 이용하였고 이에 따라 발생하는 이미지의 왜곡을 제거하기 위하여 이미지 변환기법을 적용하여 왜곡이 없는 정사촬영 이미지로 변환시킨다. 이후부터는 PIV의 이미지 처리 방법이 적용되어 표면유속을 산정한다. 다만 이미지 변환을 PIV 이미지 처리 전에 하느냐 후에 하느냐에 따라 유속장 해석결과에 차이가 있다. PIV의 네가지 단계를 포함하여 LSPIV의 각 단계를 구분하면, seeding, illumination, recording, image transformation,image processing 및 post-processing의 여섯 단계로 나뉘어진다 (Li, 2002). LSPIV를 적용시 물표면 입자의 Tracing을 위하여 자연하천에서 사용하기에 적합한 환경친화적인 seeding 재료인 Wood Mulch를 사용하여 유속을 측정하였다. 적용지점은 용담댐 상류의 동향수위관측소 지점으로 이 지점은 한국수자원공사의 수자원시험유역이 위치하고 있다. 이미지의 촬영은 가정용 비디오 캠코더 (Sony DCR-PC 350)을 이용하여 두 줄기의 흐름에 대하여 각각 약 5분 동안의 영상을 촬영한후 이중에서 seeding의 분포가 잘 이루어진 약 1분간을 추출한후 이를 이용하여 PIV 분석에 이용하였다. 대체적으로 유속장의 계산이 무난하게 이루어지었으나 비교적 수질 상태가 양호하고, 수심이 낮고, 하상재료가 자갈로 이루어져 있어 비슷한 색상의 seeding 재료를 추적하기 어려운 구간이 발생한 부분에서는 유속의 계산이 정확히 이루어지지 않았다.

• The Korean Journal of Rheology
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• v.10 no.4
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• pp.185-194
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• 1998

Flow-induced voids during resin impregnation and poor fiber wetting give serious effects on the mechanical properties of composites in resin transfer molding process. In order to better understand the characteristics of resin flow and to investigate the mechanism of void formation, flow visualization experiment for the resin impregnation was carried out on plain weaving glass fiber mats using silicon oils with various viscosity values. The permeability and the capillary pressure for the fiber mats of different porosities were obtained by measuring the penetration length of the resin with time and with various injection pressure. At low porosity and low operating pressure, the capillary pressure played a significant role in impregnation process. Video-assisted microscopy was used in taking the magnified photograph of the flow front of the resin to investigate the effect of the capillary pressure on the void formation. The results showed that the voids were formed easily when the capillary pressure was relatively high. No voids were detected above the critical capillary number of 2.75$\times$$10^{-3}, and below the critical number the void content increased exponentially with decrease of the capillary number. The content of void formed was independent of the viscosity of the resin. For a given capillary number, the void content reduced with the lower porosity of the fiber mat.

• The Journal of Information Technology
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• v.7 no.2
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• pp.93-104
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• 2004

Sports scene is characterized by large amount of global motion due to pan and zoom of camera motion, and includes many small objects moving independently. Some short period of sports games is thrilling to televiewers, and important to producers. At the same time that kinds of scenes exhibit exceptionally dynamic motions and it is very difficult to analyze the motions with conventional algorithms. In this thesis, several algorithms are proposed for global motion analysis on these dynamic scenes. It is shown that proposed algorithms worked well for motion compensation and panorama synthesis. When cascading the inter frame motions, accumulated errors are unavoidable. In order to minimize these errors, interpolation method of motion vectors is introduced. Affined transform or perspective projection transform is regarded as a square matrix, which can be factorized into small amount of motion vectors. To solve factorization problem, we preposed the adaptation of Newton Raphson method into vector and matrix form, which is also computationally efficient. Combining multi frame motion estimation and the corresponding interpolation in hierarchical manner enhancement algorithm of motion parameters is proposed, which is suitable for motion compensation and panorama synthesis. The proposed algorithms are suitable for special effect rendering for broadcast system, video indexing, tracking in complex scenes, and other fields requiring global motion estimation.