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X-ray real-time imaging (radioscopy) for weld inspection 4th progress report
Non-Destructive Testing Centre at Harwell Laboratory of the Atomic Energy Authority is summarized in this article. Among the work included is the development of digital image processing and computer tomography. High definition radiography and advance in ultrasonic inspection of large sections of stainless steel are noted. Near-surface flaws in casting can be inspected and located using Pulse Video Thermography. 41962
Fletcher, M.J.; Speake, J.H.
Trends in automated non-destructive testing Welding and Metal Fabrication, Vol. 57, No. 6, pp. 239,240,242 (Jul. 1989) This article gives a brief overview of recent developments in automatic on-line nondestructive testing appropriate to the production of welded components. Real-time radiography in conjunction with digital image processing offers fast, high quality results. Surface particle inspection, used successfully in the automotive industry, offers good reliability especially when combined with liquid penetrant tests. Ultrasonic inspection is used to detect'internal defects where access is too difficult for radiography. Eddy current inspection is used successfully in examining offshore welded ferritic structures. 41819
Link, R.; Nuding, W.; Wiacker, H.; Busse, H.P.
Weld inspection using real-time radiography International A d v a n c e s in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp. 143-173, G o r d o n and Breach Science Publishers(1989) Real-time radiography has become a very useful technique for nondestructive inspection of welds. This paper describes the technique, discusses the features available with real-time systems, including image processing and automatic defect evaluation, and makes a comparison of this technique to standard film radiography. 41817
Anon
X-ray real-time imaging (radioecopy) for weld inspection 4th progress report Welding in the World, Vol. 27, Nos. 3/4, pp. 68,70,72,74,76 (1989) Four broad conclusions are reiterated for x-ray realtime imaging used for weld inspection, namely that IQ1 (image quality indicator) sensitivities are as good as those for film radiography. Only projective magnification and digital image processing together offer flaw sensitivity on a par with that attained on film. Digital image processing will consist of image flattening, contrast enhancement and frame integration. Finally image unsharpness measurements should be made separately from IQI sensitivity. The Working Group's experimental work is reviewed and applications of the technique are presented, such as airport baggage handling and the inspection of fusion butt joints in plastic pipes. A universal real-time radiographic system cannot be devised because pattern recognition is so complicated. Hardware and software design must be adapted to the specific inspection problem. 41813
Stupin, D.M.; Stokes, G.H.; Steven-Setchell, J.
Near-real-time radiography detects very small wires and thickness variations International A d v a n c e s in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp, 323-333, G o r d o n and Breach Science Publishers (1989) The author uses radiography with two simple image-processing techniques and 17 keV x-rays (45 kV pk) from a molybdenum anode to detect very small changes in a real density and very small-diameter wires. These image-processing techniques will improve the performance of any digital-imaging x-ray system and can be performed in about 30 s. Furthermore, the x-ray energy is nearly optimum for examining some plastic and ceramic parts. This technique can be modified for examining materials at other energies. 41711
Zahnow, H.J.
Line sensors in industrial image processing. (In German) Materialpruefung, Vol. 31, No. 4, p. 125 (Apr. 1989) The use of image processing systems by means of two-dimensional cameras for automatic sight control is mostly handicapped by two restrictions, problems due to sharpness of movement with moving objects, and the restricted geometrical resolution of two-dimensional cameras. Line cameras would be an important alternative for industrial practice. 41678
Rokhlin, S.1.; Cho, K.; Guu, A.C.
Closed-loop process control of weld penetration using real-time radiography Materials Evaluation, Vol. 47, No. 3, pp. 363-369 (Mar. 1989) In this study, real-time radiography is used for in-process control of arc welding. The advantages of this technique are on-line response to defect formation in the weld and the application of this information to welding process control. The experimental system developed includes the arc welding unit, the welding manipulator, the real-time x-ray imaging unit, and computerized image-processing and control units. In this system, welding current is automatically controlled as a function of defect-feature extraction from computer processing of weld images. The experimental results are demonstrated for the submerged arc welding process. In this process, the welding pool is covered by a thick layer of the welding flux and therefore is optically unobservable. The depth of the welding pool, which characterizes the weld penetration, is a very important characteristic of the weld quality. This characteristic is measured in real time and used for weld tracking and process control. Closed-loop intelligent process control has been demonstrated.
NDT International June 1990
41670
Amin, K.E,; Leo, T.P.
Radiographic detectability limits for seeded defects in both green and densifled silicon nitride Nondestructive Testing of High-Performance Ceramics, Conference Proceedings, Boston, Massachusetts, (United States), 25-27 Aug. 1987, pp. 211-232. Edited by A. Vary and J. Snyder. T h e A m e r i c a n Ceramic Society (1987) Both conventional and microfocus x-ray radiographic techniques were utilized to investigate the detectability limits for a wide variety of seeded inclusions (foreign phases) in both molded and hot isostatically pressed Sisub(3)Nsub(4) base ceramics. Various digital image processing techniques were effectively utilized to enhance the sensitivity of detection of defects. 41570
Baldevraj, C.B.
Status paper on image processing techniques for non-destructive testing in India Indian Non-Destructive Inspection Journal, Vol. 7, No. 6, pp, 17-29 (Mar. 1989) This paper presents an overview of image processing techniques used in India for non-destructive testing (NDT). A wide range of NDT techniques are used including radiography ultrasonics and thermal imaging. A brief description of the equipment used is presented with each item.
Elad, D.; Sahar, M.; Einav, S.; Avidor, J.M.; Zeltser, R.; Rosenberg, N. 41484
A novel non-contact technique for measuring complex surface shapes under dynamic conditions Journal of Physics E. Scientific Instruments, Vol. 22, No. 5, pp. 279282 (May. 1989) This work presents a novel non-contact technique for dynamic visoalisation and measurement of three-dimensional surfaces of moving boundaries, and the topography of irregular shaped surfaces. The system is based on the principles of rastersterography, and involves advanced methods of image processing for the reconstruction of the real geometry. 41453
Todd-Pokropek, A.; Gagnon, D.
Scatter correction in tomography Proceedings of a one-day Meeting of the Materials and Testing G r o u p of the Institute of Physics, 13 D e c e m b e r 1988, L o n d o n . Eds. N. MacCuaig and R. Holt. pp. 41-52 (1989) Scatter correction, for both planar images and, in particular, in Single Photon Emission Computerized Tomography (SPECT), is of considerable importance not just for the purposes of improving image quality. Scatter is significant not only in reducing contrast, but also in limiting quantitative accuracy for example by rendering the attenuation correction in SPECT to become ill-behaved. A number of recent developments have occurred in nuclear medicine image processing where attempts are made to incorporate the extra information from the scattered signal in order to improve the overall performance of such imaging systems. 41436
Tait, W.H.; Hanson, M.E.
Microcomputer processing of film radiographs British Journal of Radiology, Vol. 62, No. 739, pp. 613-619 (Jul. 1989) An inexpensive image processing system, assembled from commercially available components and driven by "in-house" software, was tested as a means of processing radiographs obtained in a radiology department. In this preliminary study, the main interest was to investigate, through subjective appraisal, the ability of the system to recover the image quality of poorly exposed radiographs. Subsidiary objectives were to obtain some information regarding the specification limits of the system and its components, as well as some quantitative estimate of its advantages for clinical diagnosis. The system was used to process a set of film radiographs of an anthropomorphic chest phantom, produced under conditions that were designed to provide a wide range of image qualities. 41427
Corneloup, G.
Numeric ultrasonic image processing method: application to nondestructive testing of stainless austenitic steel welds. (In French) C E A Centre d ' E t u d e s Nucleaires de Cadarache, CEA-R-5472, 243 pp. (Sep. 1988) Bibliographic research on the means used to improve ultrasonic inspection of heterogeneous materials has shown, a signal assembly in the form of an image (space, time) which carries an original solution to fault detection in highly noisy environments. A numeric grey-level ultrasonic image processing detection method is proposed in the way which the ultrasonic image evolves in space and time in the presence of a defect: the first criterion studies the horizontal stability of the gradients in the image and the second takes into account the timetransient nature of the defect echo. A very important rise in the signal-to-noise ratio obtained in welding inspections evidencing defects (real and artificial) is shown with the help of a computerized ultrasonic image processing/management system, developed for this application. 41356
Lawrence, P.F.
Developments in inspection techniques Foundry Trade Journal, Vol. 163, No. 3393, P. 487 (23 Jun. 1989) This article describes work at the National NDT Centre at Harwell Laboratory and is relevant to the castings industry. Five major techniques, radiography, magnetic particle inspection, the use of penetrants, as well as
167
Fletcher, M.J.; Speake, J.H.
Trends in automated non-destructive testing Welding and Metal Fabrication, Vol. 57, No. 6, pp. 239,240,242 (Jul. 1989) This article gives a brief overview of recent developments in automatic on-line nondestructive testing appropriate to the production of welded components. Real-time radiography in conjunction with digital image processing offers fast, high quality results. Surface particle inspection, used successfully in the automotive industry, offers good reliability especially when combined with liquid penetrant tests. Ultrasonic inspection is used to detect'internal defects where access is too difficult for radiography. Eddy current inspection is used successfully in examining offshore welded ferritic structures. 41819
Link, R.; Nuding, W.; Wiacker, H.; Busse, H.P.
Weld inspection using real-time radiography International A d v a n c e s in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp. 143-173, G o r d o n and Breach Science Publishers(1989) Real-time radiography has become a very useful technique for nondestructive inspection of welds. This paper describes the technique, discusses the features available with real-time systems, including image processing and automatic defect evaluation, and makes a comparison of this technique to standard film radiography. 41817
Anon
X-ray real-time imaging (radioecopy) for weld inspection 4th progress report Welding in the World, Vol. 27, Nos. 3/4, pp. 68,70,72,74,76 (1989) Four broad conclusions are reiterated for x-ray realtime imaging used for weld inspection, namely that IQ1 (image quality indicator) sensitivities are as good as those for film radiography. Only projective magnification and digital image processing together offer flaw sensitivity on a par with that attained on film. Digital image processing will consist of image flattening, contrast enhancement and frame integration. Finally image unsharpness measurements should be made separately from IQI sensitivity. The Working Group's experimental work is reviewed and applications of the technique are presented, such as airport baggage handling and the inspection of fusion butt joints in plastic pipes. A universal real-time radiographic system cannot be devised because pattern recognition is so complicated. Hardware and software design must be adapted to the specific inspection problem. 41813
Stupin, D.M.; Stokes, G.H.; Steven-Setchell, J.
Near-real-time radiography detects very small wires and thickness variations International A d v a n c e s in Nondestructive Testing. Edited by Warren J. McGonnagle. Vol. 14, pp, 323-333, G o r d o n and Breach Science Publishers (1989) The author uses radiography with two simple image-processing techniques and 17 keV x-rays (45 kV pk) from a molybdenum anode to detect very small changes in a real density and very small-diameter wires. These image-processing techniques will improve the performance of any digital-imaging x-ray system and can be performed in about 30 s. Furthermore, the x-ray energy is nearly optimum for examining some plastic and ceramic parts. This technique can be modified for examining materials at other energies. 41711
Zahnow, H.J.
Line sensors in industrial image processing. (In German) Materialpruefung, Vol. 31, No. 4, p. 125 (Apr. 1989) The use of image processing systems by means of two-dimensional cameras for automatic sight control is mostly handicapped by two restrictions, problems due to sharpness of movement with moving objects, and the restricted geometrical resolution of two-dimensional cameras. Line cameras would be an important alternative for industrial practice. 41678
Rokhlin, S.1.; Cho, K.; Guu, A.C.
Closed-loop process control of weld penetration using real-time radiography Materials Evaluation, Vol. 47, No. 3, pp. 363-369 (Mar. 1989) In this study, real-time radiography is used for in-process control of arc welding. The advantages of this technique are on-line response to defect formation in the weld and the application of this information to welding process control. The experimental system developed includes the arc welding unit, the welding manipulator, the real-time x-ray imaging unit, and computerized image-processing and control units. In this system, welding current is automatically controlled as a function of defect-feature extraction from computer processing of weld images. The experimental results are demonstrated for the submerged arc welding process. In this process, the welding pool is covered by a thick layer of the welding flux and therefore is optically unobservable. The depth of the welding pool, which characterizes the weld penetration, is a very important characteristic of the weld quality. This characteristic is measured in real time and used for weld tracking and process control. Closed-loop intelligent process control has been demonstrated.
NDT International June 1990
41670
Amin, K.E,; Leo, T.P.
Radiographic detectability limits for seeded defects in both green and densifled silicon nitride Nondestructive Testing of High-Performance Ceramics, Conference Proceedings, Boston, Massachusetts, (United States), 25-27 Aug. 1987, pp. 211-232. Edited by A. Vary and J. Snyder. T h e A m e r i c a n Ceramic Society (1987) Both conventional and microfocus x-ray radiographic techniques were utilized to investigate the detectability limits for a wide variety of seeded inclusions (foreign phases) in both molded and hot isostatically pressed Sisub(3)Nsub(4) base ceramics. Various digital image processing techniques were effectively utilized to enhance the sensitivity of detection of defects. 41570
Baldevraj, C.B.
Status paper on image processing techniques for non-destructive testing in India Indian Non-Destructive Inspection Journal, Vol. 7, No. 6, pp, 17-29 (Mar. 1989) This paper presents an overview of image processing techniques used in India for non-destructive testing (NDT). A wide range of NDT techniques are used including radiography ultrasonics and thermal imaging. A brief description of the equipment used is presented with each item.
Elad, D.; Sahar, M.; Einav, S.; Avidor, J.M.; Zeltser, R.; Rosenberg, N. 41484
A novel non-contact technique for measuring complex surface shapes under dynamic conditions Journal of Physics E. Scientific Instruments, Vol. 22, No. 5, pp. 279282 (May. 1989) This work presents a novel non-contact technique for dynamic visoalisation and measurement of three-dimensional surfaces of moving boundaries, and the topography of irregular shaped surfaces. The system is based on the principles of rastersterography, and involves advanced methods of image processing for the reconstruction of the real geometry. 41453
Todd-Pokropek, A.; Gagnon, D.
Scatter correction in tomography Proceedings of a one-day Meeting of the Materials and Testing G r o u p of the Institute of Physics, 13 D e c e m b e r 1988, L o n d o n . Eds. N. MacCuaig and R. Holt. pp. 41-52 (1989) Scatter correction, for both planar images and, in particular, in Single Photon Emission Computerized Tomography (SPECT), is of considerable importance not just for the purposes of improving image quality. Scatter is significant not only in reducing contrast, but also in limiting quantitative accuracy for example by rendering the attenuation correction in SPECT to become ill-behaved. A number of recent developments have occurred in nuclear medicine image processing where attempts are made to incorporate the extra information from the scattered signal in order to improve the overall performance of such imaging systems. 41436
Tait, W.H.; Hanson, M.E.
Microcomputer processing of film radiographs British Journal of Radiology, Vol. 62, No. 739, pp. 613-619 (Jul. 1989) An inexpensive image processing system, assembled from commercially available components and driven by "in-house" software, was tested as a means of processing radiographs obtained in a radiology department. In this preliminary study, the main interest was to investigate, through subjective appraisal, the ability of the system to recover the image quality of poorly exposed radiographs. Subsidiary objectives were to obtain some information regarding the specification limits of the system and its components, as well as some quantitative estimate of its advantages for clinical diagnosis. The system was used to process a set of film radiographs of an anthropomorphic chest phantom, produced under conditions that were designed to provide a wide range of image qualities. 41427
Corneloup, G.
Numeric ultrasonic image processing method: application to nondestructive testing of stainless austenitic steel welds. (In French) C E A Centre d ' E t u d e s Nucleaires de Cadarache, CEA-R-5472, 243 pp. (Sep. 1988) Bibliographic research on the means used to improve ultrasonic inspection of heterogeneous materials has shown, a signal assembly in the form of an image (space, time) which carries an original solution to fault detection in highly noisy environments. A numeric grey-level ultrasonic image processing detection method is proposed in the way which the ultrasonic image evolves in space and time in the presence of a defect: the first criterion studies the horizontal stability of the gradients in the image and the second takes into account the timetransient nature of the defect echo. A very important rise in the signal-to-noise ratio obtained in welding inspections evidencing defects (real and artificial) is shown with the help of a computerized ultrasonic image processing/management system, developed for this application. 41356
Lawrence, P.F.
Developments in inspection techniques Foundry Trade Journal, Vol. 163, No. 3393, P. 487 (23 Jun. 1989) This article describes work at the National NDT Centre at Harwell Laboratory and is relevant to the castings industry. Five major techniques, radiography, magnetic particle inspection, the use of penetrants, as well as
167