Image Enhancement of Simplified Ultrasonic CT Using Frequency Analysis Method

• Published in: Journal of mechanical science and technology Vol. 16; no. 12; pp. 1627 - 1632
• Main Authors: KIM, Kyung-Cho, FUKUHARA, Hiroaki, YAMAWAKI, Hisashi
• Format: Journal Article
• Language: English
• Published: Seoul 대한기계학회 01.12.2002; Korean Society of Mechanical Engineers; Springer Nature B.V
• Subjects: Acoustical measurements and instrumentation; Acoustics; Analysing. Testing. Standards; Applied sciences; Arc welding; Computed tomography; Computer aided tomography; Crack propagation; Cross-disciplinary physics: materials science; rheology; Electron beam welding; Exact sciences and technology; Fatigue failure; Frequency analysis; Frequency response; Fundamental areas of phenomenology (including applications); High strength steels; Image enhancement; Inspection; Materials science; Materials testing; Metallurgy; Metals. Metallurgy; Nondestructive testing; Nondestructive testing: ultrasonic testing, photoacoustic testing; Physics; R&D; Research & development; Testing for defects; Ultrasonic testing; Waveforms; Welded joints; Welding; Acoustic measurement; Image processing; High strength steel; Frequency domain method; Mechanical joint; Experimental study; Arc welding; Computerized tomography; Fatigue crack; Electron beam welding; Welded joint; Ultrasonic control; C scan; Acoustic image; Non destructive test
• ISSN: 1738-494X; 1226-4865; 1976-3824
• DOI: 10.1007/BF03021664

In this paper, a simplified ultrasonic CT system, which uses the information in three directions, that is, 90°, +45° and --45° about the inspection plane, is applied to the high strength steel, and the frequency analysis method for enhancing the C scan or CT image is developed. This frequency analysis method is based on the frequency response property of the material. By comparing the magnitudes in the frequency domain, the special frequency which shows a significant difference between the welded joint and base material was found and used to obtain a C scan or CT image. Experimental results for several kinds of specimens, having a welded joint by electron beam welding, a weld joint by arc welding, on a fatigue crack, showed that the obtained C scan or CT image has better resolution than the results of previous experiments using the maximum value of the received waveform.[PUBLICATION ABSTRACT]