skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Systematic Approach for Validation of X-Ray Automatic Defect Recognition Systems

Abstract

With the advent of digital radiography, there has been a gradual shift from operators viewing images to find defects to totally automated defect recognition (ADR) systems. This has resulted in reduced operator subjectivity, reduced operator fatigue, and increased productivity. These automated defect recognition solutions are based on reference or non-reference based approaches or a combination of both. There exists some amount of uncertainty or reluctance to accept automated systems in view of no systematic quantified metrics available on performance of these ADR systems in comparison to human operators. This paper describes the metrics that one could follow to quantify the performance of ADR systems such as detectability for different defect types and sizes, accuracy, false call rate, robustness to various noise levels etc., As it might be difficult to have images with defects of various sizes, shapes, contrast and noise levels, a methodology to generate images with simulated defects with variability's in parameters such as size, shape, contrast to noise ratio etc., is demonstrated. This can be used to generate probability of detection estimates for different defect types and geometries. This will result in establishing confidence limits for ADR systems and can be used to judge if it would meetmore » specific customer requirement. This would facilitate increase in the acceptability of ADR systems over current manual defect recognition systems for applications in various industries such as Castings, Oil and Gas, Aviation etc.« less

Authors:
; ; ;  [1]
  1. John F. Welch Technology Centre, GE Global Research Centre, Bangalore (India)
Publication Date:
OSTI Identifier:
21054958
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 894; Journal Issue: 1; Conference: Conference on review of progress in quantitative nondestructive evaluation, Portland, OR (United States), 30 Jul - 4 Aug 2006; Other Information: DOI: 10.1063/1.2718188; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; ACCURACY; COMPARATIVE EVALUATIONS; DEFECTS; DETECTION; FATIGUE; IMAGES; NOISE; PERFORMANCE; PROBABILITY; VALIDATION; X RADIATION; X-RAY RADIOGRAPHY

Citation Formats

Navalgund, Megha, Venkatachalam, Rajashekar, Asati, Mahesh, and Venugopal, Manoharan. Systematic Approach for Validation of X-Ray Automatic Defect Recognition Systems. United States: N. p., 2007. Web. doi:10.1063/1.2718188.
Navalgund, Megha, Venkatachalam, Rajashekar, Asati, Mahesh, & Venugopal, Manoharan. Systematic Approach for Validation of X-Ray Automatic Defect Recognition Systems. United States. doi:10.1063/1.2718188.
Navalgund, Megha, Venkatachalam, Rajashekar, Asati, Mahesh, and Venugopal, Manoharan. Wed . "Systematic Approach for Validation of X-Ray Automatic Defect Recognition Systems". United States. doi:10.1063/1.2718188.
@article{osti_21054958,
title = {Systematic Approach for Validation of X-Ray Automatic Defect Recognition Systems},
author = {Navalgund, Megha and Venkatachalam, Rajashekar and Asati, Mahesh and Venugopal, Manoharan},
abstractNote = {With the advent of digital radiography, there has been a gradual shift from operators viewing images to find defects to totally automated defect recognition (ADR) systems. This has resulted in reduced operator subjectivity, reduced operator fatigue, and increased productivity. These automated defect recognition solutions are based on reference or non-reference based approaches or a combination of both. There exists some amount of uncertainty or reluctance to accept automated systems in view of no systematic quantified metrics available on performance of these ADR systems in comparison to human operators. This paper describes the metrics that one could follow to quantify the performance of ADR systems such as detectability for different defect types and sizes, accuracy, false call rate, robustness to various noise levels etc., As it might be difficult to have images with defects of various sizes, shapes, contrast and noise levels, a methodology to generate images with simulated defects with variability's in parameters such as size, shape, contrast to noise ratio etc., is demonstrated. This can be used to generate probability of detection estimates for different defect types and geometries. This will result in establishing confidence limits for ADR systems and can be used to judge if it would meet specific customer requirement. This would facilitate increase in the acceptability of ADR systems over current manual defect recognition systems for applications in various industries such as Castings, Oil and Gas, Aviation etc.},
doi = {10.1063/1.2718188},
journal = {AIP Conference Proceedings},
number = 1,
volume = 894,
place = {United States},
year = {Wed Mar 21 00:00:00 EDT 2007},
month = {Wed Mar 21 00:00:00 EDT 2007}
}
  • A combined x-ray photoemission and diamagnetic-susceptibility study of YBa/sub 2/Cu/sub 3/O/sub x/ with xapprox. =6 and 7 has been performed, with emphasis on the oxygen defect and the effect of heating in vacuum. By comparing spectra taken at these two oxygen contents, the core levels observed in the O 1s and Ba 4d spectral range are identified. Peak-intensity analysis indicates (1) that the oxygen released during the in situ heating is derived from or near the Cu-O-Cu-O chains of YBa/sub 2/Cu/sub 3/O/sub 7/ and (2) that there is a random distribution of oxygen defects in or near these chains leadingmore » to two chemically dissimilar barium atoms even in single-orthorhombic-phase samples« less
  • Optimal cooling of aluminum alloys following the high-temperature extrusion process suppresses precipitation of intermetallic compounds and results in a part capable of possessing maximum strength and hardness after the subsequent age-hardening process. Rapid quenching suppresses precipitation but can lad to large spatial temperature gradients in complex-shaped parts, causing distortion, cracking, high residual stress, and/or nonuniform mechanical properties. Conversely, slow cooling significantly reduces or eliminates these undesirable conditions but allows considerable precipitation, resulting in low strength, soft spots, and/or low corrosion resistance. This study presents a systematic method of locating and operating multiple spray nozzles for any shaped extrusion such thatmore » uniform, rapid cooling and superior mechanical and metallurgical properties are achieved. New correlations, offering increased accuracy and less computational time, were formulated for the high-temperature boiling regimes which have a critical influence on final mechanical properties. The quench factor technique related predicted thermal history to metallurgical transformations occurring within the extrusion to predict hardness distribution. The validity of this unique approach was demonstrated by comparing model predictions to the temperature response (and hardness after artificial aging) of an L-shaped Al2024-T6 extrusion to quenches with multiple, overlapping water sprays. The validation study reported herein concludes by exploring the possibility of applying quenching technology to improving the properties of extruded metal-matrix composites such as SiC{sub p}/Al6061 and cast alloys.« less
  • This symposium will explore simulation methods for the preclinical evaluation of novel 3D and 4D x-ray breast imaging systems – the subject of AAPM taskgroup TG234. Given the complex design of modern imaging systems, simulations offer significant advantages over long and costly clinical studies in terms of reproducibility, reduced radiation exposures, a known reference standard, and the capability for studying patient and disease subpopulations through appropriate choice of simulation parameters. Our focus will be on testing the realism of software anthropomorphic phantoms and virtual clinical trials tools developed for the optimization and validation of breast imaging systems. The symposium willmore » review the stateof- the-science, as well as the advantages and limitations of various approaches to testing realism of phantoms and simulated breast images. Approaches based upon the visual assessment of synthetic breast images by expert observers will be contrasted with approaches based upon comparing statistical properties between synthetic and clinical images. The role of observer models in the assessment of realism will be considered. Finally, an industry perspective will be presented, summarizing the role and importance of virtual tools and simulation methods in product development. The challenges and conditions that must be satisfied in order for computational modeling and simulation to play a significantly increased role in the design and evaluation of novel breast imaging systems will be addressed. Learning Objectives: Review the state-of-the science in testing realism of software anthropomorphic phantoms and virtual clinical trials tools; Compare approaches based upon the visual assessment by expert observers vs. the analysis of statistical properties of synthetic images; Discuss the role of observer models in the assessment of realism; Summarize the industry perspective to virtual methods for breast imaging.« less