• Title, Summary, Keyword: Ultrasonic image construction

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APPLICATION OF DIGITAL ULTRASONIC IMAGE CONSTRUCTION SYSTEM FOR THE DETECTION OF CRACKS IN WATER DISTRIBUTION SYSTEM

  • Lee, Hyun-Dong;Kwak, Phill-Jae;Shin, Hyeon-Jae;Jang, You-Hyun
    • Environmental Engineering Research
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    • v.11 no.2
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    • pp.99-105
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    • 2006
  • A digital ultrasonic image construction system was developed for the nondestructive detection of cracks in water distribution pipes. The system consists of PC based ultrasonic testing system and a scanning device. The PC based ultrasonic system has an ultrasonic pulse/receive board for the generation and reception of ultrasonic signals, an analogue to digital conversion board for the digitization of the received ultrasonic signals, and transducers for the ultrasonic sensors. Using this system, the digitized ultrasonic signals were properly constructed in accordance with the position information obtained by scanning device that moves an ultrasonic transducer along the outer surface of pipes. In the construction of the ultrasonic signals, signal processing concepts, such as spatial average and array concept, were considered to enhance the resolution of ultrasonic images of pipe wall. Using the developed system, crack detection experiments were performed in both laboratory and field, which shows promise for crack detection in the water distribution system.

The Construction of Ultrasonic Hologram and the Image Reconstruction Using Computer (초음파 홀로그램의 구성과 컴퓨터 영상재현)

  • Jang, Seong-Hwan;Go, Dae-Sik;Jeon, Gye-Seok
    • The Journal of the Acoustical Society of Korea
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    • v.8 no.4
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    • pp.23-28
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    • 1989
  • In this paper, the construction of ultrasonic hologram and the image reconstruction using computer have been studied, and it has been compared with optical reconstruction. The ultrasonic hologram has been constructed using c-scanning method$(128\times128 step)$and the image of the object has been reconstructed by computer using Rayleigh -Sommerfeld formula and DFT algorithm. In this experiment, the holography system has been builted with the transducer of 5MHz center frequency and 5cm focal length, and the mechanical c-scanning system. It has been shown that the reconstructed image using computer for aluminum plane with the 'S' shaped defect has been displayed image of high quality.

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Non-destructive Inspection of Top-Down Construction Joints of Column in SRC Structure using Ultrasonic Method (초음파법을 이용한 콘크리트 역타시공 이음부 공극의 화상검출특성)

  • Park, Seok-Kyun;Baek, Un-Chan;Lee, Han-Bum;Kim, Myoung-Mo
    • Journal of the Korean Society for Nondestructive Testing
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    • v.20 no.4
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    • pp.290-295
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    • 2000
  • The joint treatment of concrete is one of the technical problems in top down construction method. Joints created with the top down construction result in serious weakness from the aspects of both structural and water-barrier function. Ultrasonic method was used for the inspection of top down construction joints of a various column in SRC structure in this study. The advantages and limitations of this method for non-destructive inspection in top down construction joints are investigated. As a result, it has been verified that the semi-direct measurement method is more effective than the other methods for detecting the voids of construction joints using ultrasonic method.

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Detecting Pattern of Voids in Concrete Using Ultrasonic Image Processing Technique (초음파 화상처리기법을 이용한 콘크리트 내부공동의 형상검출에 관한 연구)

  • 박석균;이한범;오윤식
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.783-788
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    • 2001
  • Voids created with concrete construction or deterioration result in serious weakness from the aspects of both structural and durable function. Ultrasonic method using image processing technique was used for detecting pattern of voids in concrete in this study Experimental investigation was carried out for three types(patterns) of void in concrete. The effect of curing period of concrete and ultrasonic measurement method was also investigated. As a result it has been verified that the semi-direct measurement method is more effective than the other methods for detecting pattern of voids in concrete in ultrasonic method using image processing technique. The longer the curing period of concrete is, the better the detection accuracy of void pattern can be obtained.

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A Study about the Construction of Intelligence Data Base for Micro Defect Evaluation (미소 결함 평가를 위한 지능형 데이터베이스 구축에 관한 연구)

  • 김재열
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.585-590
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    • 2000
  • Recently, It is gradually raised necessity that thickness of thin film is measured accuracy and managed in industrial circles and medical world. Ultrasonic Signal processing method is likely to become a very powerful method for NDE method of detection of microdefects and thickness measurement of thin film below the limit of Ultrasonic distance resolution in the opaque materials, provides useful information that cannot be obtained by a conventional measuring system. In the present research, considering a thin film below the limit of ultrasonic distance resolution sandwiched between three substances as acoustical analysis model, demonstrated the usefulness of ultrasonic Signal processing technique using information of ultrasonic frequency for NDE of measurements of thin film thickness, sound velocity, and step height, regardless of interference phenomenon. Numeral information was deduced and quantified effective information from the image. Also, pattern recognition of a defected input image was performed by neural network algorithm. Input pattern of various numeral was composed combinationally, and then, it was studied by neural network. Furthermore, possibility of pattern recognition was confirmed on artifical defected input data formed by simulation. Finally, application on unknown input pattern was also examined.

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Spatial Compounding of Ultrasonic Diagnostic Images for Rotating Linear Probe with Geometric Parameter Error Compensation

  • Choi, Myoung Hwan;Bae, Moo Ho
    • Journal of Electrical Engineering and Technology
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    • v.9 no.4
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    • pp.1418-1425
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    • 2014
  • In ultrasonic medical imaging, spatial compounding of images is a technique where ultrasonic beam is steered to examine patient tissues in multiple angles. In the conventional ultrasonic diagnostic imaging, the steering of the ultrasonic beam is achieved electronically using the phased array transducer elements. In this paper, a spatial compounding approach is presented where the ultrasonic probe element is rotated mechanically and the beam steering is achieved mechanically. In the spatial compounding, target position is computed using the value of the rotation axis and the transducer array angular position. However, in the process of the rotation mechanism construction and the control system there arises the inevitable uncertainties in these values. These geometric parameter errors result in the target position error, and the consequence is a blurry compounded image. In order to reduce these target position errors, we present a spatial compounding scheme where error correcting transformation matrices are computed and applied to the raw images before spatial compounding to reduce the blurriness in the compounded image. The proposed scheme is illustrated using phantom and live scan images of human knee, and it is shown that the blurriness is effectively reduced.

Air-coupled ultrasonic tomography of solids: 1 Fundamental development

  • Hall, Kerry S.;Popovics, John S.
    • Smart Structures and Systems
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    • v.17 no.1
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    • pp.17-29
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    • 2016
  • Ultrasonic tomography is a powerful tool for identifying defects within an object or structure. But practical application of ultrasonic tomography to solids is often limited by time consuming transducer coupling. Air-coupled ultrasonic measurements may eliminate the coupling problem and allow for more rapid data collection and tomographic image construction. This research aims to integrate recent developments in air-coupled ultrasonic measurements with current tomography reconstruction routines to improve testing capability. The goal is to identify low velocity inclusions (air-filled voids and notches) within solids using constructed velocity images. Finite element analysis is used to simulate the experiment in order to determine efficient data collection schemes. Comparable air-coupled ultrasonic signals are then collected through homogeneous and isotropic solid (PVC polymer) samples. Volumetric (void) and planar (notch) inclusions within the samples are identified in the constructed velocity tomograms for a variety of transducer configurations. Although there is some distortion of the inclusions, the experimentally obtained tomograms accurately indicate their size and location. Reconstruction error values, defined as misidentification of the inclusion size and position, were in the range of 1.5-1.7%. Part 2 of this paper set will describe the application of this imaging technique to concrete that contains inclusions.

Geophysical Techniques for Underwater Landslide Monitoring (수중 산사태 모니터링을 위한 지반물리탐사기술)

  • Truong, Q. Hung;Lee, Chang-Ho;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.23 no.7
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    • pp.5-16
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    • 2007
  • The monitoring and investigation of underwater landslide help to understand its mechanism, increase the usefuless of design and construction and reduce the losses. This paper presents three high resolution geophysical techniques electrical resisitance, ultrasonic wave reflection imaging, and shear wave tomography conducted to determine the lab-scaled submerged landslide. Electrical resistance profiles of a soil mass obtained by an electrical resistance probe provide detailed information to assess the spatial distribution of the soil mass with milimetric resolution. An ultrasonic wave image obtained by recording the reflections from interfaces of different impedance materials permits detecting layers and landslide with submilimetric resolution. The pixel based image of immersed landslides is created by the inversion of the boundary information achieved from the traveling time of shear waves. The experimental results show that the ultrasonic wave imaging and the electrical resistance can provide complementary information; and their association with S-wave tomography image can produce a 3-D view of the underwater landslide. This study suggests that geophysical techniques may be effective tools for the detection of the underwater landslides and spatial distribution offshore.

A Study on Construction of Automatic Inspection System for Welding Flaws (용접결함 검사 자동화 시스템 구축에 관한 연구)

  • Kim, Chang-Hyun;Yu, Hong-Yeon;Hong, Sung-Hoon;Kim, Jae-Yeol
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.37-42
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    • 2007
  • The purpose of this research is stability estimation of plant structure through classification and recognition about welding flaw in SWP(Spiral Welding Pipe). And, In this research, we used nondestructive test based on ultrasonic test as inspection method, and made up 2-axes inspection robot in order to control of ultrasonic probe on the SWP surface, and programmed to image processing and probabilistic neural network(PNN) classifying code by MATLAB programming. Through this process, we proved efficiency on the system of SWP stability Estimation.

The image construction of the surface and subsurface defects using complex amplitude of the reflected ultrasonic signals from the solid (초음파 반사신호의 복소 진폭을 이용한 교체 내부 결함의 영상 구조)

  • Kim, Hyun;Lim, Ho;Kim, Ki-Yeoul;Koo, Kil-Mo
    • The Journal of Information Technology
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    • v.4 no.2
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    • pp.129-136
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    • 2001
  • Most of the acoustic microscopes have been constructed acoustic image by simply measuring the amplitude of the reflected signal from the specimen. This method fails to produce images of good quality because the change in amplitude is not sensitive enough to specimen with fine variation. In this paper, we have been constructed the acoustic microscope system which has been able to measure simultaneously the amplitude and phase of the reflected ultrasonic signal. And also we have been constructed the amplitude and phase images for the 500 won coin as a sample and the alumium spacimen with internal round defect, and compared and analyzed these images. In expermental result, the phase image have shown better sensitive than the amplitude image and given better contrast for the micro height variation of specimen. It will be expected that the phase image can be used as an additional bit of information to improve ambiguituities in amplitude image on nondestructive testing for specimen with fine variation.

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