• Title/Summary/Keyword: inspection.calibration

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Effective Application of Close-Range Photogrammetry with Digital Images in Industrial Precise Measurement (산업정밀측정에서 수치영상을 이용한 근접사진측량의 효율적 응용)

  • 이진덕
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.14 no.1
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    • pp.17-25
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    • 1996
  • The development of still video CCD cameras has simplified dramatically the digital imaging process. Still video cameras have flexibility that allows digital image acquisition and on-board image storage without being connected to a computer. The objective of this paper is to evaluate the performance of digital close-range photogrammetric system using the still video camera for dimensional inspection and structural monitoring being required in various industries. Some sub-pixel measurement techniques, which is indispensable for digital image measurement, were suggested. The author carried out the self-calibration of a high resolution DCS420 still video camera and then test application of a structure. The self-calibrating bundle adjustments resulted in object space accuracies which exceed 1 :46,000. It is ascertained that this digital close-range photogrammetric system has high accuracy potential and task effectiveness for industrial applications.

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Quantitative nondestructive evaluation of thin plate structures using the complete frequency information from impact testing

  • Lee, Sang-Youl;Rus, Guillermo;Park, Tae-Hyo
    • Structural Engineering and Mechanics
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    • v.28 no.5
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    • pp.525-548
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    • 2008
  • This article deals the theory for solving an inverse problem of plate structures using the frequency-domain information instead of classical time-domain delays or free vibration eigenmodes or eigenvalues. A reduced set of output parameters characterizing the defect is used as a regularization technique to drastically overcome noise problems that appear in imaging techniques. A deconvolution scheme from an undamaged specimen overrides uncertainties about the input signal and other coherent noises. This approach provides the advantage that it is not necessary to visually identify the portion of the signal that contains the information about the defect. The theoretical model for Quantitative nondestructive evaluation, the relationship between the real and ideal models, the finite element method (FEM) for the forward problem, and inverse procedure for detecting the defects are developed. The theoretical formulation is experimentally verified using dynamic responses of a steel plate under impact loading at several points. The signal synthesized by FEM, the residual, and its components are analyzed for different choices of time window. The noise effects are taken into account in the inversion strategy by designing a filter for the cost functional to be minimized. The technique is focused toward a exible and rapid inspection of large areas, by recovering the position of the defect by means of a single accelerometer, overriding experimental calibration, and using a reduced number of impact events.

Design Conformance Verification of Military FM Radio Set Automatic Test Equipment (군용 FM 무전기 세트 자동시험장비(ATE) 설계 적합성 검증)

  • Kim, Byung-Jun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.15 no.3
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    • pp.389-396
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    • 2020
  • In order to obtain a good quality product, a proper verification of production/test facilities must be preceded before the quality conformity inspection of the product. Among the various production/test facilities, ATE is widely used in the civilian industry such as the automotive industry, aerospace industry, semiconductor industry today. In addition, ATE is actively used in the defense industry production and performance tests. This paper is the result of systematically verifying the Design Conformance of ATS which is ATE of military FM radio set using various methods. And It is expected to be a good reference at the present time when the design conformity verification procedure for ATE for military supplies is not documented.

Development and Evaluation of the Usefulness for Hoffman Brain Phantom Based on 3D Printing Technique (3D 프린팅 기법 기반의 Hoffman Brain 팬텀 개발 및 유용성 평가)

  • Park, Hoon-Hee;Lee, Joo-Young
    • Journal of radiological science and technology
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    • v.42 no.6
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    • pp.441-446
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    • 2019
  • The purpose of this paper is to recognize the usefulness of the Phantom produced with 3D printing technology by reproducing the original phantom with 3D printing technology. Using CT, we obtained information from the original phantom. The acquired file was printed by the SLA method of ABS materials. For inspection, SPECT/CT was used to obtain images. We filled the both Phantom with a solution mixed with 99mTcO4 1 mCi in 1 liter of water and acq uired images in accordance with the standard protocol. Using Image J, the SNR for each slice of the image was obtained. As a reference images, AC images were used. For the analysis of acquired images, ROI was set in the White mater and Gray mater sections of each image, and the average Intensity Value within the ROI were compared. According to the results of this study, 3D printed phantom's SNR is about 0.1 higher than the conventional phantom. And the ratio of Intensity Value was shown in the original 1 : 3.4, and the printed phantom was shown to be 1 : 3.2. Therefore, if Calibration Value is applied, It is assumed that it can be used as an alternative to the original.

A Study on the Mutual Recognition Agreements of Standards, Test and Certification of Smart City

  • Kim, Yong-Jae
    • Asian Journal of Business Environment
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    • v.6 no.2
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    • pp.27-32
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    • 2016
  • Purpose - This paper aims to analyze and investigate to find out the appropriate ways to make an easy TBT of smart city. It is an important issue between Korea and China because TBT of smart city has lots of advantages in IT, S/W, IOT, and Home network. Research design, data and methodology - First, the paper made use of reviewing2nd data analysis and focused on group interview, and then compared with analysis on the international rule and system such as smart city system, technical regulation, and standard through test certification procedure and inspection. Second, this paper reviewed electric/electronic test, certification, and calibration. Third, through analyzing MRA between Korea and china, the paper focused on SDoC, Mutual Acceptance of International certification, and IECCB scheme. Results - Through the comparison and analysis, this paper found that it is important to promote multi-track agreements with the countries that need short-term promotion. Moreover, it is necessary to conclude an agreement with the leading countries in Middle East and Central America. Conclusions - Through the above the reviews and analysis, we can see the importance of promotion in FTA and MRA with the efforts to remove the obstacles and promote to make an easy TBT by MRA between Korea and China.

An Automatic Weight Measurement of Rope Using Computer Vision

  • Joo, Ki-See
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.2 no.1
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    • pp.141-146
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    • 1998
  • Recently, the computer vision such as part measurement, and product inspection is very popular to achieve the factory automation since the labor cost is dramatically increasing. In this paper, the diameter and the length of rope are measured by CCD camera which is orthogonally mounted on the ceiling. Two parameters which are the diameter and the length of rope are used to measure the weight of rope. If the weight of rope is reached to predetermined weight, the information is transmitted to PLC(programmable logic control) to cut the rope on the wheel. The cutting machine cuts the rope according to the information obtained from the CCD camera. To measure the diameter and length of rope on real time, the searching space for image segmentation is restricted the predetermined area according to the camera calibration position. Finally, to estimate the weight of rope, the knowledge base system which depends on the diameter, the length of rope, and weight relation between these information are constructed according to diameters of rope. This method contributes to achieve the factory automation, and reduce the production cost since the operators are unnecessary to measure the weight of rope by try-and-error method.

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A Study on Improvement of Image Processing for Precision Inner Diameter Measurement of Circular Hole (원형구멍 정밀 내경측정을 위한 영상처리 개선에 관한 연구)

  • Park, ChangYong;Kweon, HyunKyu;Li, JingHua;Zhang, Hua Xin
    • Journal of the Semiconductor & Display Technology
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    • v.16 no.3
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    • pp.8-13
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    • 2017
  • In this paper, the measurement of the inner diameter dimension of the circular hole by using a machine vision system was studied. This paper was focused on the theory and key technologies of machine vision inspection technology for the improvement of measurement accuracy and speed of the micro circular holes. A new method was proposed and was verified through the experiments on Gray conversion, binarization, edge extraction and Hough transform in machine vision system processes. Firstly, the Hough transform was proposed in order to improve the speed increase and implementation ease, it demonstrated the superiority of Hough transform and improvement through a comparative experiment. Secondly, we propose a calibration method of the system in order to obtain exactly the inner diameter of the circular hole. Finally, we demonstrate the reliability of the entire system as a MATLAB-based implementation of the GUI program, measuring the inner diameter of the circular hole through the circular holes of different dimensions measuring experiment.

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Development of Self-Driven Pneumatic Robot for Boresonic Examination of Turbine Rotor (터빈로터 중심공 검사용 자기주행 공압형 로봇 개발)

  • Kang, Baejun;An, Myungjae;Lee, Chul-Hee
    • Journal of Drive and Control
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    • v.18 no.1
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    • pp.31-38
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    • 2021
  • This study presents a new principle for driving the robot aimed at reducing the position error for the boresonic examination of turbine rotor. The conventional method of inspection is performed by installing manipulator onto the flange of the turbine rotor and connecting a pipe, which is then being pushed into the bore. The longer the pipe gets, the greater sagging and distortion appear, making it difficult for the ultrasonic sensor to contact with the internal surface of the bore. A pneumatic pressure will ensure the front or rear feet of the robot in close contact with the inner wall to prevent slipping, while the ball screw on the body of the robot will rotate to drive it in the axial direction. The compression force required for tight contact was calculated in the form of a three-point support, and a static structural simulation analysis was performed by designing and modeling the robot mechanism. The driving performance and ultrasonic detection ability have been tested by fabricating the robot, the test piece for ultrasonic calibration and the transparent mock-up for robot demonstration. The tests have confirmed that no slipping occurs at a certain pneumatic pressure or over.

A Feasibility Analysis of Rapid Acquisition Test for Cement Fineness using Hydrometer (시멘트 인수검사 시 액체밀도계법에 의한 분말도 품질 신속평가 가능성 분석)

  • Han, Cheon-Goo;Kim, Young-Tae
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.6
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    • pp.29-34
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    • 2018
  • In this research, regarding the cement supplied to ready mixed concrete plant, the feasibility of rapid acquisition test for cement fineness using hydrometer which used for early strength evaluation of concrete was analyzed. Additionally, regarding the rapid test with hydrometer control factors were provided. As a result of analysis, quality control using hydrometer was possible with the regressive equation obtained in five minute between density of suspension and fineness of cement powder. As the control factors, dispersing admixture, replacing kerosene as a medium, and temperature of cement and water were evaluated. According to the control factor evaluation, the tap water was optimum as a medium and calibration of keeping the temperature of water to $20^{\circ}C$ or correction factor was needed for density results. Finally, it is considered that the suggested rapid quality evaluation method using hydrometer is cheaper and easier method than currently used Blaine test.

Vignetting Dimensional Geometric Models and a Downhill Simplex Search

  • Kim, Hyung Tae;Lee, Duk Yeon;Choi, Dongwoon;Kang, Jaehyeon;Lee, Dong-Wook
    • Current Optics and Photonics
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    • v.6 no.2
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    • pp.161-170
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    • 2022
  • Three-dimensional (3D) geometric models are introduced to correct vignetting, and a downhill simplex search is applied to determine the coefficients of a 3D model used in digital microscopy. Vignetting is nonuniform illuminance with a geometric regularity on a two-dimensional (2D) image plane, which allows the illuminance distribution to be estimated using 3D models. The 3D models are defined using generalized polynomials and arbitrary coefficients. Because the 3D models are nonlinear, their coefficients are determined using a simplex search. The cost function of the simplex search is defined to minimize the error between the 3D model and the reference image of a standard white board. The conventional and proposed methods for correcting the vignetting are used in experiments on four inspection systems based on machine vision and microscopy. The methods are investigated using various performance indices, including the coefficient of determination, the mean absolute error, and the uniformity after correction. The proposed method is intuitive and shows performance similar to the conventional approach, using a smaller number of coefficients.