• 제목/요약/키워드: Laser structured light

검색결과 74건 처리시간 0.031초

Incremental displacement estimation of structures using paired structured light

  • Jeon, Haemin;Shin, Jae-Uk;Myung, Hyun
    • Smart Structures and Systems
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    • 제9권3호
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    • pp.273-286
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    • 2012
  • As civil structures are exposed to various external loads, it is essential to assess the structural condition, especially the structural displacement, in every moment. Therefore, a visually servoed paired structured light system was proposed in the previous study. The proposed system is composed of two screens facing with each other, each with a camera, a screen, and one or two lasers controlled by a 2-DOF manipulator. The 6-DOF displacement can be calculated from the positions of three projected laser beams and the rotation angles of the manipulators. In the estimation process, one of well-known iterative methods such as Newton-Raphson or extended Kalman filter (EKF) was used for each measurement. Although the proposed system with the aforementioned algorithms estimates the displacement with high accuracy, it takes relatively long computation time. Therefore, an incremental displacement estimation (IDE) algorithm which updates the previously estimated displacement based on the difference between the previous and the current observed data is newly proposed. To validate the performance of the proposed algorithm, simulations and experiments are performed. The results show that the proposed algorithm significantly reduces the computation time with the same level of accuracy compared to the EKF with multiple iterations.

구조물의 6자유도 변위 측정을 위한 비주얼 서보잉 기반 양립형 구조 광 로봇 시스템 (Visual Servoing-Based Paired Structured Light Robot System for Estimation of 6-DOF Structural Displacement)

  • 전해민;방유석;김한근;명현
    • 제어로봇시스템학회논문지
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    • 제17권10호
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    • pp.989-994
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    • 2011
  • This study aims to demonstrate the feasibility of a visual servoing-based paired structured light (SL) robot for estimating structural displacement under various external loads. The former paired SL robot, which was proposed in the previous study, was composed of two screens facing with each other, each with one or two lasers and a camera. It was found that the paired SL robot could estimate the translational and rotational displacement each in 3-DOF with high accuracy and low cost. However, the measurable range is fairly limited due to the limited screen size. In this paper, therefore, a visual servoing-based 2-DOF manipulator which controls the pose of lasers is introduced. By controlling the positions of the projected laser points to be on the screen, the proposed robot can estimate the displacement regardless of the screen size. We performed various simulations and experimental tests to verify the performance of the newly proposed robot. The results show that the proposed system overcomes the range limitation of the former system and it can be utilized to accurately estimate the structural displacement.

비전센서를 이용한 자동추적장치에 관한 연구 (A Study on Automatic Seam Tracking using Vision Sensor)

  • 전진환;조택동;양상민
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1995년도 추계학술대회 논문집
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    • pp.1105-1109
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    • 1995
  • A CCD-camera, which is structured with vision system, was used to realize automatic seam-tracking system and 3-D information which is needed to generate torch path, was obtained by using laser-slip beam. To extract laser strip and obtain welding-specific point, Adaptive Hough-transformation was used. Although the basic Hough transformation takes too much time to process image on line, it has a tendency to be robust to the noises as like spatter. For that reson, it was complemented with Adaptive Hough transformation to have an on-line processing ability for scanning a welding-specific point. the dead zone,where the sensing of weld line is impossible, is eliminated by rotating the camera with its rotating axis centered at welding torch. The camera angle is controlled so as to get the minimum image data for the sensing of weld line, hence the image processing time is reduced. The fuzzy controller is adapted to control the camera angle.

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입사빔의 파장에 따른 AsGeSes & Ag/AsGeSes 박막의 홀로그래픽 데이터 소거특성 (Holographic Data Grating Formation of AsGeSeS Single & Ag/AsGeSeS Double Layer Thin Films with the Incident Beam Wavelength)

  • 구용운;정홍배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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    • pp.1428-1429
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    • 2006
  • We investigated the diffraction efficiency, erasing property and rewriting property of diffraction grating with each wavelength of recording beam. A (P:P) polarized light was exposed on AsGeSeS and Ag/AsGeSeS thin film to form a diffraction grating by HeNe(635nm) laser and DPSS(532nm) laser. At the maximum efficiency condition, unpolarized HeNe laser beam was irradiated to erase 1ha generated diffraction grating. The HeNe laser showed more higher diffraction efficiency and the DPSS laser showed more faster diffraction grating time. At erasing and rewriting process, AsGeSeS(61%-85%)thin film showed better property than Ag doped Ag/AsGeSeS(53%-63%) double layer structured thin film.

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Efficient keV X-ray Generation from Irradiation of in-situ Produced Silver Clusters by Ti:sapphire Laser Pulses

  • Chakravarty, U.;Naik, P.A.;Kumbhare, S.R.;Gupta, P.D.
    • Journal of the Optical Society of Korea
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    • 제13권1호
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    • pp.80-85
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    • 2009
  • An experimental study of energy absorption and x-ray emission from ultrashort laser pulse irradiation of in-situ produced solid clusters has been performed. Silver clusters produced by a 30 mJ, 300 ps laser pulse were irradiated up to an intensity of $3{\times}10^{17}\;W/cm^2$ by a 70 mJ, 45 fs compressed laser pulse from the same Ti:sapphire laser. Absorption of the laser light exceeding 70% was observed, resulting in an x-ray yield (>1 keV) of ${\sim}60{\mu}J$ pulse. This may constitute a much simpler means of intense x-ray generation using ultrashort laser pulses as compared to the irradiation of structured / pre-deposited cluster targets, and it offers higher x-ray conversion efficiency than that from gas clusters and planar solid targets.

구조화 레이저를 이용한 PC 기반 인-라인 검사 시스템 개발에 관한 연구 (A Study on Development of PC Based In-Line Inspection System with Structure Light Laser)

  • 신찬배;김진대;임학규;이재원
    • 한국정밀공학회지
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    • 제22권11호
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    • pp.82-90
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    • 2005
  • Recently, the in-line vision inspection has become the subject of growing research area in the visual control systems and robotic intelligent fields that are required exact three-dimensional pose. The objective of this article is to study the pc based in line visual inspection with the hand-eye structure. This paper suggests three dimensional structured light measuring principle and design method of laser sensor header. The hand-eye laser sensor have been studied for a long time. However, it is very difficult to perform kinematical analysis between laser sensor and robot because the complicated mathematical process are needed for the real environments. In this problem, this paper will propose auto-calibration concept. The detail process of this methodology will be described. A new thinning algorithm and constrained hough transform method is also explained in this paper. Consequently, the developed in-line inspection module demonstrate the successful operation with hole, gap, width or V edge.

자동 아크 용접공정의 용접개선변수 측정을 위한 시각 시스템 (Development of a vision sensor for measuring the weld groove parameters in arc welding process)

  • 김호학;부광석;조형석
    • Journal of Welding and Joining
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    • 제8권2호
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    • pp.58-69
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    • 1990
  • In conventional arc welding, position error of the weld torch with respect to the weld seam and variation of groove dimension are induced by inaccurate fitup and fixturing. In this study, a vision system has been developed to recognize and compensate the position error and dimensional inaccuracy. The system uses a structured laser light illuminated on the weld groove and perceived by a C.C.D camera. A new algorithm to detect the edge of the reflected laser light is introduced for real time processing. The developed system was applied to arbitarary weld paths with various types of joint in arc welding process. The experimental results show that the proposed system can detect the weld groove parameters within good accuracy and yield good tracking performance.

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비전센서와 구조화빔을 이용한 용접 형상 측정 시스템 (System for Measuring the Welding Profile Using Vision and Structured Light)

  • 김창현;최태용;이주장;서정;박경택;강희신
    • 한국레이저가공학회:학술대회논문집
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    • 한국레이저가공학회 2005년도 추계학술발표대회 논문집
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    • pp.50-56
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    • 2005
  • The robot systems are widely used in the many industrial field as well as welding manufacturing. The essential tasks to operate the welding robot are the acquisition of the position and/or shape of the parent metal. For the seam tracking or the robot tracking, many kinds of contact and non-contact sensors are used. Recently, the vision is most popular. In this paper, the development of the system which measures the shape of the welding part is described. This system uses the line-type structured laser diode and the vision sensor. It includes the correction of radial distortion which is often found in the image taken by the camera with short focal length. The Direct Linear Transformation (DLT) method is used for the camera calibration. The three dimensional shape of the parent metal is obtained after simple linear transformation. Some demos are shown to describe the performance of the developed system.

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높이 변화가 있는 막대기 용접선 추적용 시각센서 (Vision Sensor System for Weld Seam Tracking of I-Butt Joint with Height Variation)

  • 김무연;김재웅
    • Journal of Welding and Joining
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    • 제22권6호
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    • pp.43-49
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    • 2004
  • In this study, a visual sensor system which can detect I-butt weld joint with height variation and includes a seam tracking algorithm was investigated. Three-dimensional position of an object can be acquired by using the method of distance measurement, i.e., an optical trigonometry which results from the spatial relations between the camera, the object and the structured light by a visible laser. Effects of laser intensity and iris number for the image quality as well as object material were investigated for the optical system design. For the image processing, a region of interest is defined from the whole image and a line image of laser is drew by using the gray level difference in the image. From the drew laser line, the weld joint can be recognized in searching the biggest point position calculated from the central difference method. Through a series of welding experiments, a good tracking performance was confirmed under GMA welding.

레이저 변위 센서를 이용한 기상측정에 관한 연구 (A Study on the On-the-Machine Measuring using a laser displacement sensor)

  • 권세진;이정근;박정환;고태조;김선호
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2002년도 추계학술대회 논문집
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    • pp.371-374
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    • 2002
  • From reverse-engineering's point of view, the main step is the digitizing or gathering three-dimensional points on the target physical model. As well known, the touch or scanning probe gives higher accuracy, while the non-contact digitizing apparatus by use of laser or structured light can rapidly obtain digitized points of great bulk without contacting onto the part surface of the physical model. We propose a digitizing methodology by use of the LK-031 laser displacement sensor, which was tested with a physical model.

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