• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1225-1235
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• 2016

This paper presents a method for computer-assisted slide presentation using vision-based gesture recognition. The proposed method consists of a sequence of steps, first detecting a hand in the scene of projector beam, then estimating the smooth trajectory of a hand or a pointing finger using Kalman Filter, and finally interfacing to an application system. Additional slide navigation control includes moving back and forth the pages of the presentation. The proposed method is to help speakers for an effective presentation with natural improved interaction with the computer. In particular, the proposed method of using finger pointing is believed to be more effective than using a laser pointer since the hand, the pointing or finger are more visible and thus can better grab the attention of the audience.

• Journal of Welding and Joining
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• 제30권4호
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• pp.38-43
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• 2012

Using a fiber laser heat source, an oil pressure sensor was fabricated to measure the pressure in commercial vehicles. A stepping motor was used for the rotational and translational motion in the diaphragms and hardware joining. Laser welding process algorism including shielding gas control and vision system was integrated by using LabVIEW software for the high quality welding and in-line monitoring purpose. For the maximum flexibility in pressure transmission to the pressure sensor, thin sheet metal diaphragm, $25{\sim}50{\mu}m$(SUS-316L), was used and the diaphragms were optimally designed with FEM analysis. The welded samples were cross-sectioned the observation showed that the maximum depth ratio was more than seven times of diaphragms. The maximum welding speed was measured to be as high as 50in/mm by the developed automation mechanism. The fabricated prototypes were tested for the proof pressure, spring constant and sealing. The FEM results of spring constant measurement was as accurate as up to 80% of the design value and the sensor was safely operated up to the nominal pressure of 10bars.

• Journal of Welding and Joining
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• 제34권2호
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• pp.59-66
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• 2016

The Gas Metal Arc(GMA) welding, called Metal Inert Gas(MIG) welding, has been an important component in manufacturing industries. A key technology for robotic welding processes is seam tracking system, which is critical to improve the welding quality and welding capacities. The objectives of this study were to develop the intelligent and cost-effective algorithms for image processing in GMA welding which based on the laser vision sensor. Welding images were captured from the CCD camera and then processed by the proposed algorithm to track the weld joint location. The proposed algorithms that commonly used at the present stage were verified and compared to obtain the optimal one for each step in image processing. Finally, validity of the proposed algorithms was examined by using weld seam images obtained with different welding environments for image processing. The results proved that the proposed algorithm was quite excellent in getting rid of the variable noises to extract the feature points and centerline for seam tracking in GMA welding and could be employed for general industrial application.

• Smart Structures and Systems
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• 제30권5호
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• pp.521-535
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• 2022

Efficient management of deteriorating civil infrastructure is one of the most important research topics in many developed countries. In particular, the remote displacement measurement of bridges using linear variable differential transformers, global positioning systems, laser Doppler vibrometers, and computer vision technologies has been attempted extensively. This paper proposes a remote displacement measurement system using closed-circuit televisions (CCTVs) and a computer-vision-based method for in-situ bridge bearings having relatively large displacement due to temperature change in long term. The hardware of the system is composed of a reference target for displacement measurement, a CCTV to capture target images, a gateway to transmit images via a mobile network, and a central server to store and process transmitted images. The usage of CCTV capable of night vision capture and wireless data communication enable long-term 24-hour monitoring on wide range of bridge area. The computer vision algorithm to estimate displacement from the images involves image preprocessing for enhancing the circular features of the target, circular Hough transformation for detecting circles on the target in the whole field-of-view (FOV), and homography transformation for converting the movement of the target in the images into an actual expansion displacement. The simple target design and robust circle detection algorithm help to measure displacement using target images where the targets are far apart from each other. The proposed system is installed at the Tancheon Overpass located in Seoul, and field experiments are performed to evaluate the accuracy of circle detection and displacement measurements. The circle detection accuracy is evaluated using 28,542 images captured from 71 CCTVs installed at the testbed, and only 48 images (0.168%) fail to detect the circles on the target because of subpar imaging conditions. The accuracy of displacement measurement is evaluated using images captured for 17 days from three CCTVs; the average and root-mean-square errors are 0.10 and 0.131 mm, respectively, compared with a similar displacement measurement. The long-term operation of the system, as evaluated using 8-month data, shows high accuracy and stability of the proposed system.

• 한국공작기계학회논문집
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• 제16권6호
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• pp.71-78
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• 2007

There have been continuous efforts to automate welding processes. This automation process could be said to fall into two categories, weld seam tracking and weld quality evaluation. Recently, the attempts to achieve these two functions simultaneously are on the increase. For the study presented in this paper, a vision sensor is made, and using this, the 3 dimensional geometry of the bead is measured in real time. For the application in welding, which is the characteristic of nonlinear process, a fuzzy controller is designed. And with this, an adaptive control system is proposed which acquires the bead height and the coordinates of the point on the bead along the horizontal fillet joint, performs seam tracking with those data, and also at the same time, controls the bead geometry to a uniform shape. A communication system, which enables the communication with the industrial robot, is designed to control the bead geometry and to track the weld seam. Experiments are made with varied offset angles from the pre-taught weld path, and they showed the adaptive system works favorable results.

• 한국터널지하공간학회 논문집
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• 제25권3호
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• pp.245-259
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• 2023

본 논문의 목적은 국내외 터널 스캐닝 시스템들을 분석하여 비접촉 이동식 상태점검 장비 개발에 대한 시사점을 도출하기 위한 것이다. 국내외 터널 스캐닝 시스템은 레이저 스캔과 이미지 스캔의 두 가지 기술로 개발되고 있다. 레이저 스캐닝 장비는 포인트 클라우드로부터 터널 라이닝의 기하하적 특성을 재현하는데 장점이 있다. 이미지 스캐닝 장비는 컴퓨터 비전을 활용하여 터널 라이닝 표면의 미세한 균열, 누수 등 손상 검출이 용이하다. 터널 라이닝의 손상 검출을 위해서는 이미지 스캐닝 장비가 더 적합할 것으로 분석되었다. 향후 개발 예정인 카메라 기반의 터널 스캐닝 시스템은 조명, 저장장치, 전원 공급 장치 및 차량 주행 속도 동기화 제어 장치로 구성되어야 할 것이다.

• 대한기계학회논문집A
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• 제35권7호
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• pp.737-743
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• 2011

서비스 로봇은 비전 카메라, 초음파 센서, 레이저 스캐너, 마이크로폰 등과 같은 다양한 센서를 장착하고 있다. 이들 센서들은 이들 각각의 고유한 기능을 가지고 있기도 하지만, 몇몇을 조합하여 사용함으로써 더욱 복잡한 기능을 수행할 수 있다. 음성영상 융합은 서로가 서로를 상호보완 해주는 대표적이면서도 강력한 조합이다. 사람의 경우에 있어서도, 일상생활에 있어 주로 시각과 청각 정보에 의존한다. 본 발표에서는, 음성영상 융합에 관한 두 가지 연구를 소개한다. 하나는 음원 방향 검지 성능의 향상에 관한 것이고, 나머지 하나는 음원 방향 검지와 얼굴 검출을 이용한 로봇 어텐션에 관한 것이다.

• 전기학회논문지
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• 제62권2호
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• pp.257-263
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• 2013

In case of image observation equipments, CCTV for short distance visual field is usually installed and operated mostly as the means of crime-prevention. However, the extensive demand for monitoring problems in case of the increase in intelligent crimes and disasters has led to the necessity of the development of long-distance observation equipments embedded with Night View functions. In case of the Night View equipments, the relevant market is set up to be focused mostly on Thermal Observation Device(hereinafter, TOD), but some shortcomings such as the limitation of image visibility and excessive maintenance cost, etc. have actually caused the necessity of new long distance Night View equipment. Moreover there might follow lots of difficulties in long-distance visualization in the event that irregular reflection is generated by minute particles in the atmosphere such as fog, smog, and dust, etc. These factors are motivate the work presented in this study. Our study is aimed at the realization of Pulsed Laser Illuminator and newly proposed Range-Gated image acquisition technology. And also the implementation of Tracker for continuous trace of the objects of interest from the obtained sequence images.

• Journal of Platform Technology
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• 제9권4호
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• pp.60-70
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• 2021

본 논문은 2채널 이상의 다중 카메라를 사용하는 곡면 스크린 사격 시스템에서 패턴 레이저 영상의 좌표를 안정적으로 추적할 수 있는 방법을 제안하였다. 이 방법은 HMD 사격 방식을 대체할 수 있는 다중 스크린 사격 방식에 적용시 매우 효과적으로 타겟점을 추적 및 획득할 수 있다. 개별 카메라로부터 획득한 변형이 심한 곡면 스크린의 영상을 영상 정규화, 영상 이진화 및 노이즈 제거를 통해 보정한다. 이 보정된 영상을 매칭점을 기준으로 사격의 탄착점 추적에 용의한 유클리드 공간 맵으로 생성하여 적용한다. 실험한 결과, 곡면 스크린 사격 시스템에서 패턴 레이저의 영상 좌표를 안정적으로 추출하였고, 실세계 좌표 위치와 광대역 유클리드 맵의 타켓점 위치 오차를 최소화하였다. 실험을 통해 제안한 방법의 신뢰성을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권5호
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• pp.641-647
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• 2003

The use of infrared range-finder sensor as the environment recognition system for mobile robot have the advantage of low sensing cost compared with the use of other vision sensor such as laser finder CCD camera. However, it is not easy to find the previous works on the use of infrared range-finder sensor for a mobile robot because of the non-linear characteristic of that. This paper describes the error due to non-linearity of a sensor and the correction of it using neural network. The neural network consists of multi-layer perception and Levenberg-Marquardt algorithm is applied to learning it. The effectiveness of the proposed algorithm is verified from experiment.