• Title/Summary/Keyword: Segment Splitting Method

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The Weld Defects Expression Method by the Concept of Segment Splitting Method and Mean Distance (분할법과 평균거리 개념에 의한 용접 결함 표현 방법)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.2
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    • pp.37-43
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    • 2007
  • In this paper, laser vision sensor is used to detect some defects any $co_{2}$ welded specimen in hardware. But, as the best expression of defects of welded specimen, the concept of segment splitting method and mean distance are introduced in software. The developed GUI software is used for deriding whether any welded specimen makes as proper shape or detects in real time. The criteria are based upon ISO 5817 as limits of imperfections in metallic fusion welds.

A Study of the Comparison for Performance Advancement of Seam Tracking in Gas Metal Arc Welding (가스 메탈 아크 용접에서 추적성능 향상을 위한 성능 비교 연구)

  • Lee, Jeong-Ick
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.1
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    • pp.9-18
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    • 2007
  • There have been continuous efforts for automation of joint tracking system. This automation process is mainly used to do in root pass of gas metal arc welding in the field of heavy industry and shipbuilding etc. For automation, it is important using of vision sensor. Welding robot with vision sensor is used for weld seam tracking on welding fabrication. Recently, it is used to on post-weld inspection for weld quality evaluation. For real time seam tracking, it is very important role in vision process technique. Vision process is included in filtering and thinning, segmentation processing, feature extraction and recognition. In this paper, it has shown performance comparison results of seam tracking for real time root pass on gas metal arc welding. It can be concluded better segment splitting method than iterative averaging technique in the performance results of seam tracking.

Numerical Fracture analysis of prestressed concrete beams

  • Rabczuk, Timon;Zi, Goangseup
    • International Journal of Concrete Structures and Materials
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    • v.2 no.2
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    • pp.153-160
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    • 2008
  • Fracture of prestressed concrete beams is studied with a novel and robust three-dimensional meshfree method. The meshfree method describes the crack as a set of cohesive crack segments and avoids the representation of the crack surface. It is ideally suited for a large number of cracks. The crack is modeled by splitting particles into two particles on opposite sides of the crack segment and the shape functions of neighboring particles are modified in a way the discontinuous displacement field is captured appropriately. A simple, robust and efficient way to determine, on which side adjacent particles of the corresponding crack segment lies, is proposed. We will show that the method does not show any "mesh" orientation bias and captures complicated failure patterns of experimental data well.

Experimental Analysis of Algorithms of Splitting and Connecting Snake for Extracting of the Boundary of Multiple Objects (복수객체의 윤곽추출을 위한 스네이크 분리 및 연결 알고리즘의 실험적 분석)

  • Cui, Guo;Hwang, Jae-Yong;Jang, Jong-Whan
    • The KIPS Transactions:PartB
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    • v.19B no.4
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    • pp.221-224
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    • 2012
  • The most famous algorithm of splitting and connecting Snake for extracting the boundary of multiple objects is the nearest method using the distance between snake points. It often can't split and connect Snake due to object topology. In this paper, its problem was discussed experimentally. The new algorithm using vector between Snake segment is proposed in order to split and connect Snake with complicated topology of objects. It is shown by experiment of two test images with 3 and 5 objects that the proposed one works better than the nearest one.

Application of Image Processing on the Laser Welded Defects Estimation (레이저 용접물 결함 평가에 대한 화상처리의 이용)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.4
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    • pp.22-28
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    • 2007
  • The welded defects are usually called user's unsatisfaction for appearance and functional usage. For checking these defects effectively without time loss, setup of weldability estimation system is an important for detecting whole specimen quality. In this study, after catching a rawdata on welded specimen profiles and treating vision processing with these data, the qualitative defects are estimated from getting these information by laser vision camera at first. At the same time, the weldability estimation for whole specimen is produced. For user friendly, the weldability estimation results are shown each profiles, final reports and visual graphics method. So, user can easily determined weldability. By applying these system to welding fabrication, these technologies are contribution to on-line setup of weldability estimation system.

A Study of Inspection of Weld Bead Defects using Laser Vision Sensor (레이저 비전 센서를 이용한 용접비드의 외부결함 검출에 관한 연구)

  • 이정익;이세헌
    • Journal of Welding and Joining
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    • v.17 no.2
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    • pp.53-60
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    • 1999
  • Conventionally, CCD camera and vision sensor using the projected pattern of light is generally used to inspect the weld bead defects. But with this method, a lot of time is needed for image preprocessing, stripe extraction and thinning, etc. In this study, laser vision sensor using the scanning beam of light is used to shorten the time required for image preprocessing. The software for deciding whether the weld bead is in proper shape or not in real time is developed. The criteria are based upon the classification of imperfections in metallic fusion welds(ISO 6520) and limits for imperfections(ISO 5817).

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CU Depth Decision Based on FAST Corner Detection for HEVC Intra Prediction (HEVC 화면 내 예측을 위한 FAST 에지 검출 기반의 CU 분할 방법)

  • Jeon, Seungsu;kim, Namuk;Jeon, Byeungwoo
    • Journal of Broadcast Engineering
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    • v.21 no.4
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    • pp.484-492
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    • 2016
  • The High efficiency video coding (HEVC) is the newest video coding standard that achieves coding efficiency higher than previous video coding standards such as H.264/AVC. In intra prediction, the prediction units (PUs) are derived from a large coding unit (LCU) which is partitioned into smaller coding units (CUs) sizing from 8x8 to 64x64 in a quad-tree structure. As they are divided until having the minimum depth, Optimum CU splitting is selected in RDO (Rate Distortion Optimization) process. In this process, HEVC demands high computational complexity. In this paper, to reduce the complexity of HEVC, we propose a fast CU mode decision (FCDD) for intra prediction by using FAST (Features from Accelerated Segment Test) corner detection. The proposed method reduces computational complexity with 53.73% of the computational time for the intra prediction while coding performance degradation with 0.7% BDBR is small compared to conventional HEVC.

SURGICAL TREATMENT OF LARGE CYST ON THE MANDIBLE BY USING SAGGITAL SPLIT RAMUS OSTEOTOMY (하악골에 발생한 거대 낭종에서 하악지 시상분할골절단술을 이용한 외과적 치료)

  • Park, Hong-Ju;Ryu, Jae-Young;Kook, Min-Suk;Oh, Hee-Kyun
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.30 no.1
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    • pp.100-107
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    • 2008
  • First of all a good surgical access is considered among various approach methods to the cystic lesion. A poor surgical access can lead to a failure of the whole treatment. A sagittal split ramus osteotomy (SSRO) on the large cyst occurring in the mandibular ramus lets us not only reduce operation time, but can additionally contribute to a good visual field. In addition, a merit exists that it lets this operating method provide soft tissue adhesion for proximal and distal segment and decrease post operative necrosis. We experienced three cases of a large cyst on the mandibular angle and ramus. By employing a sagittal splitting of the mandible, it provided good surgical access and operation results without recurrence during a follow-up period. The surgical technique described may be helpful in treating similar large cysts.

An Weldability Estimation of Laser Welded Specimens (레이저 용접물의 용접성 평가)

  • Lee, Jeong-Ick
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.1
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    • pp.60-68
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    • 2007
  • It has been conducted by laser vision sensor for weldability estimation of front-bead after doing high speed butt laser welding of any condition. It has been developed a real time GUI(Graphic User Interface) system for weldability application in the basis of texts and field qualify levels. In the reference of bead imperfections, defects absolute position and defects intensity index of front-bead in the basis of formability reference, it has been produced a weldability estimation and defects intensity index of back-bead by back propagation neural network. In the result of by comparing measuring data by laser vision sensor of back-bead and data by back propagation neural network of one, it has been shown the similar results. Finally, under knowledge of welding condition in production line, it has been conducted a weldability estimation of back-bead only in knowledge of informations of front-bead data without using laser vision sensor or welding inspection experts and furthermore it can be used data for final inspection results of back-bead.

Back-bead Prediction and Weldability Estimation Using An Artificial Neural Network (인공신경망을 이용한 이면비드 예측 및 용접성 평가)

  • Lee, Jeong-Ick;Koh, Byung-Kab
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.4
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    • pp.79-86
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    • 2007
  • The shape of excessive penetration mainly depends on welding conditions(welding current and welding voltage), and welding process(groove gap and welding speed). These conditions are the major affecting factors to width and height of back bead. In this paper, back-bead prediction and weldability estimation using artificial neural network were investigated. Results are as follows. 1) If groove gap, welding current, welding voltage and welding speed will be previously determined as a welding condition, width and height of back bead can be predicted by artificial neural network system without experimental measurement. 2) From the result applied to three weld quality levels(ISO 5817), both experimented measurement using vision sensor and predicted mean values by artificial neural network showed good agreement. 3) The width and height of back bead are proportional to groove gap, welding current and welding voltage, but welding speed. is not.