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When moment-preserving auto threshold algorithm is used to segment image whose histogram is unimodal or monotonic function, there is serious background interference, and the segmentation accuracy is greatly affected by the size variance of the object, so this paper puts forward an improved moment-preserving auto threshold algorithm. Aiming at the original(More)
Multi-frequency eddy current test (MFECT) is an important NDT technology, and it can be applied to realize multi-parameter detection and interference elimination effectively. Aiming at the problem that conventional single-frequency eddy current test can only identify defects but can't classify defects effectively, a new MFECT technology which adopts LFM(More)
Pulsed eddy current (PEC) thermography (a.k.a. induction thermography) has been successfully applied to detect defects (corrosion, cracks, impact, and delamination) in metal alloy and carbon fiber reinforced plastic. During these applications, the defect detection mechanism is mainly investigated based on the eddy current interaction with defect. In this(More)
The Pulsed Eddy Current (PEC) testing is an increasingly emerging nondestructive testing & evaluation (NDT&E) technique. The main purpose of this study is to improve the performance of defect edge identification of C-scan imaging technique utilizing the rectangular PEC sensor. When sensor scans along the defect, peak waves of response signals always present(More)
Multilayer structures are widely used in aircraft fuselage. Because of the interlayer air gap caused by deformation or disbonding, conventional single-frequency eddy current cannot discriminate between second-layer defect signals and gap signals. In this paper, several defects at varied locations (i.e., first-layer surface, first-layer subsurface,(More)
In this paper, based on ARM9 microcontroller S3C2440A and embedded operating system Windows CE, a new nondestructive system was established. The system uses borescope and eddy current testing dual techniques combined into a single probe, which takes advantage of borescope and eddy current testing. The system combines traditional nondestructive testing(More)
The estimation of fundamental matrix is a key problem in computer vision and also the basis of active vision. A new linear iterative algorithm for estimating the fundamental matrix has been presented. The algorithm is based on minimizing the actual distances between the projection points and their matched epipolar lines. The first two fundamental matrixes(More)
In this paper, two multi-frequency time-reversal (TR)-based imaging algorithms are explored for application to the nondestructive evaluation (NDE) imaging of defects in solids: time reversal with multiple signal classification (TRMUSIC) and a related phase-coherent form (PC-MUSIC). These algorithms are tested with simulated and experimental ultrasonic array(More)
It is different to detect defect in multilayer structure of an aging aircraft fuselage, pulsed eddy current (PEC) technique has been demonstrated to be capable of quantifying this defect. Based on theoretical analysis of PEC technique, the array probe is designed and the array PEC imaging technique has been supposed to detect corrosion in the multilayer(More)