• Title/Summary/Keyword: Thick Plate Detection

Search Result 14, Processing Time 0.025 seconds

An Effective Method of Product Number Detection from Thick Plates (효과적인 후판의 제품번호 검출 방법)

  • Park, Sang-Hyun
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.10 no.1
    • /
    • pp.139-148
    • /
    • 2015
  • In this paper, a new algorithm is proposed for detecting the product number of each thick plate and extracting each character of the product number from a image which contains several thick plates. In general, a image of thick plates contains several steal plates. To obtain the product number from the image, we first need to separate each plate. To do so, we use the line edges of thick plates and a clustering algorithm. After separating each plate, background parts are eliminated from the image of each plate. Background parts of an individual thick plate image consist of the dark part of steel and the white part of paint which is used for printing the product number. We propose a two-tiered method where dark background parts are first eliminated and then white parts are eliminated. Finally, each character is extracted from the product number image using the characteristics of product number. The results of the experiments on the various steal plates images emphasize that the proposed algorithm detects each thick plate and extracts the product number from a image effectively.

Flaw Detection in a Conductor Using Sensor Head of Amorphous Wire (비정질 와이어를 센서헤드로 이용한 금속의 미세결함 검출)

  • Kim, Y.H.;Shin, K.H.
    • Journal of the Korean Magnetics Society
    • /
    • v.12 no.5
    • /
    • pp.174-178
    • /
    • 2002
  • Ac magnetic field was changed in the vicinity of a flaw because of the distribution of eddy current within a conductor, when the magnetic field was applied to a conductor having a flaw. The flaw detection was performed by using Co-based amorphous wire sensor head. The wire has almost 0 magneto-striction and high permeability. An comparative uniform magnetic field was applied to a 1㎜ thick copper plate and a 25㎛ thick aluminum sheet conductor using spiral typed coil. The size of the coil has 40㎜$\times$40㎜ outer width and 8㎜$\times$8㎜ inner width. The copper plate and the aluminum sheet has 0.5㎜ and 0.1㎜ wide gap, respectively. The frequency range of applied field was 100㎑∼600㎑. The induced voltage difference of 2.5㎷ was obtained in the maximum voltage and minimum one measured across the gap of the 1mm thick conductor. In the case of aluminum sheet, 0.4㎷ was obtained. From this results, the effectiveness of Co-based amorphous wire was confirmed in the ECT technique.

Detection of Deep Subsurface Cracks in Thick Stainless Steel Plate

  • Kishore, M.B.;Park, D.G.;Jeong, J.R.;Kim, J.Y.;Jacobs, L.J.;Lee, D.H.
    • Journal of Magnetics
    • /
    • v.20 no.3
    • /
    • pp.312-316
    • /
    • 2015
  • Unlike conventional Eddy Current Test (ECT), Pulsed Eddy Current (PEC) uses a multiple-frequency current pulse through the excitation coil. In the present study, the detection of subsurface cracks using a specially designed probe that allows the detection of a deeper crack with a relatively small current density has been attempted using the PEC technique. The tested sample is a piece of 304 stainless steel (SS304) with a thickness of 30mm. Small electrical discharge machining (EDM) notches were put in the test sample at different depths from the surface to simulate the subsurface cracks in a pipe. The designed PEC probe consists of an excitation coil and a Hall sensor and can detect a subsurface crack as narrow and shallow as 0.2 mm wide and 2 mm deep. The maximum distance between the probe and the defect is 28 mm. The peak amplitude of the detected pulse is used to evaluate the cracks under the sample surface. In time domain analysis, the greater the crack depth the greater the peak amplitude of the detected pulse. The experimental results indicated that the proposed system has the potential to detect the subsurface cracks in stainless steel plates.

A Study on Development of Arc Sensor System for Automatic Multi-pass Welding of Thick Plate (후판의 자동 다층용접을 위한 아크센서 시스템 개발에 관한 연구)

  • 문현준;김종희;최주호;김형식
    • Journal of Welding and Joining
    • /
    • v.13 no.4
    • /
    • pp.122-131
    • /
    • 1995
  • An automatic welding equipment for thick plates requires the capability of the seam tracking of the weld line which often includes misalignment of the workpiece and variation of groove width. In this study, an automatic welding equipment and control algorithms based on the arc sensor were proposed for the GMA welding of thick plates which had misalignment and gap variation. The developed system being constituted with 5 axis can be automatically controlled by computer and also automnatically set the welding conditions such as welding current, and voltage. The proposed algorithms for the seam tracking in multi-pass welding of the thick plates were constituted as follows : the detection of weaving-end point for findng the variation of groove width, the control of welding velocity for acquiring a constant thickness deposition of weld metal, and the calculation of groove width and height of an arbitrary pass in the multi-pass weld. As results of the application of the system, it was revealed that the system had a good capability in seam tracking and made an excellent weld quality in V groove butt joint.

  • PDF

A Study on the Size Evaluation of Disc and Band Type Flaw by Ultrasonic Tandem Testing (초음파(超音波)TANDEM사각법(斜角法)에 의한 원형(圓形) 및 띠형결함(形缺陷)의 크기 평가(評價)에 관한 연구(硏究))

  • Han, E.K.;Eom, H.S.;Kim, J.J.
    • Journal of the Korean Society for Nondestructive Testing
    • /
    • v.5 no.2
    • /
    • pp.12-21
    • /
    • 1986
  • Generally, butt welds with plate thickness $30{\sim}40mm$ are welded with groove angle $40^{\circ},\;60^{\circ},\;70^{\circ}$, etc. In the detection of internal weld defects, oblique testing with single probe has been mainly used. But, recently, in acccordance with enlargement of welded structure, thick plate with 100-200mm are frequently required. Thus I-groove welding method was lately developed and often used. In this case, most frequently generated defects are the lack of weld penetration and incomplete fusion between base metal and welding material. If we would detect by oblique testing with single probe, detecting flaw is occassionally impossible or very underestimated. In this study, the limit for applying tandem method was studied in dise and band type flaws. The estimation of flaw size could be within 10% error compared to real flaws.

  • PDF

RADIATION SAFETY STUDIES AT TOHOKU UNIVERSITY CYRIC

  • Yamadera M. Baba A.;Miura T.;Aoki T.;Hagiwara M.;Kawata N.
    • Journal of Radiation Protection and Research
    • /
    • v.26 no.3
    • /
    • pp.231-236
    • /
    • 2001
  • A brief introduction is presented on the radiation safety studies at Tohoku University Cyclotron & Radioisotope Center. Studies on two subject are described; (1) measurement of the thick target neutron yield and radioisotope production / activation cross section for ten's of MeV neutrons and ions using K=110 Tohoku University cyclotron to provide basicdata for accelerator shielding, and (2) development of techniques for high sensitive radiation detection and profile measurement using an Imaging Plate which is a high sensitive two-dimensional radiation sensor. Application of the Imaging Plate techniques to localization of very weak radioactivity and to neutron profile measurement is described.

  • PDF

A Study on Characteristics of Plasma Emission Signals with Welding Conditions in CO2 Laser (CO2 레이저용접시 용접조건에 따른 플라즈마 방사신호의 특성연구)

  • Kim, Jong-Do;Lee, Chang-Je
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.33 no.11
    • /
    • pp.1256-1261
    • /
    • 2009
  • Today, implementation of the defect detection in laser welding has been researched for a long time, but most studies have been made around thin plate within $1{\sim}3mm^t$. Therefore, this study was measured and analyzed light emission signals of the induced plasma in $CO_2$ laser lap welding of $6mm^t$ Zn primer-coated steel, and based on this analysis, research made an investigation into possibility of monitoring in thick plate welding. It was been analyzing the measured signals by RMS and FFT processing, as a results, we were able to confirm definite difference of two signals between humping bead and sound bead. Thus, possibility of real time monitoring in $CO_2$ laser lap welding verified experimentally.

Effective Line Detection of Steel Plates Using Eigenvalue Analysis (고유값 분석을 이용한 효과적인 후판의 직선 검출)

  • Park, Sang-Hyun;Kim, Jong-Ho;Kang, Eui-Sung
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.15 no.7
    • /
    • pp.1479-1486
    • /
    • 2011
  • In this paper, a simple and robust algorithm is proposed for detecting straight line segments in a steel plate image. Line detection from a steel plate image is a fundamental task for analyzing and understanding of the image. The proposed algorithm is based on small eigenvalue analysis. The proposed approach scans an input edge image from the top left comer to the bottom right comer with a moving mask. A covariance matrix of a set of edge pixels over a connected region within the mask is determined and then the statistical and geometrical properties of the small eigenvalue of the matrix are explored for the purpose of straight line detection. Before calculating the eigenvalue, each line segment is separated from the edge image where several line segments are overlapped to increase the accuracy of the line detection. Additionally, unnecessary line segments are eliminated by the number of pixels and the directional information of the detected line edges. The respects of the experiments emphasize that the proposed algorithm outperforms the existing algorithm which uses small eigenvalue analysis.

Fabrication and Characterization of Multi-Channel Electrode Array (MEA) (다중 채널 전극의 제작 및 특성 평가)

  • Seong, Rak-Seon;Gwon, Gwang-Min;Park, Jeong-Ho
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.51 no.9
    • /
    • pp.423-430
    • /
    • 2002
  • The fabrication and experimentation of multi-channel electrodes which enable detecting and recording of multi-site neuronal signals have been investigated. A multi-channel electrode array was fabricated by depositing 2000${\AA}$ thick Au layer on the 1000${\AA}$ thick Ti adhesion layer on a glass wafer. The metal paths were patterned by wet etching and passivated by depositing a PECVD silicon nitride insulation layer to prevent signals from intermixing or cross-talking. After placing a thin slice of rat cerebellar granule cell in the culture ring located in central portion of the multi-channel electrode plate, a neuronal signal from an electrode which is in contact with the cerebellar granule cell has been detected. It was found that the electrode impedance ranges 200㏀∼1㏁ and the impedance is not changed by cleaning with nitric acid. Also, the impedance is inversely proportion to the exposed electrode area and the cross-talk is negligible when the electrode spacing is bigger than 600$\mu\textrm{m}$. The amplitude and frequency of the measured action potential were 38㎷ and 2㎑, which are typical values. From the experimental results, the fabricated multi-channel electrode array proved to be suitable for multi-site neuronal signal detection for the analysis of a complicated cell network.

Predictive model of fatigue crack detection in thick bridge steel structures with piezoelectric wafer active sensors

  • Gresil, M.;Yu, L.;Shen, Y.;Giurgiutiu, V.
    • Smart Structures and Systems
    • /
    • v.12 no.2
    • /
    • pp.97-119
    • /
    • 2013
  • This paper presents numerical and experimental results on the use of guided waves for structural health monitoring (SHM) of crack growth during a fatigue test in a thick steel plate used for civil engineering application. Numerical simulation, analytical modeling, and experimental tests are used to prove that piezoelectric wafer active sensor (PWAS) can perform active SHM using guided wave pitch-catch method and passive SHM using acoustic emission (AE). AE simulation was performed with the multi-physic FEM (MP-FEM) approach. The MP-FEM approach permits that the output variables to be expressed directly in electric terms while the two-ways electromechanical conversion is done internally in the MP-FEM formulation. The AE event was simulated as a pulse of defined duration and amplitude. The electrical signal measured at a PWAS receiver was simulated. Experimental tests were performed with PWAS transducers acting as passive receivers of AE signals. An AE source was simulated using 0.5-mm pencil lead breaks. The PWAS transducers were able to pick up AE signal with good strength. Subsequently, PWAS transducers and traditional AE transducer were applied to a 12.7-mm CT specimen subjected to accelerated fatigue testing. Active sensing in pitch catch mode on the CT specimen was applied between the PWAS transducers pairs. Damage indexes were calculated and correlated with actual crack growth. The paper finishes with conclusions and suggestions for further work.