Rail defect diagnosis using wavelet packet decomposition

Automated fabric defect detection—A review

“…Its typical example is plain and twill fabric. Apart from those that can be defined by wallpaper groups, there are other textures that consist of random, non-directional components or a mixture of patterned and non-patterned materials namely printed circuit boards (PCBs) [21,[23][24][25], wood [26][27][28][29][30][31][32], wafer [33], pearl [34], and rail [35].…”

A new cracks detection device for magnetic steels

“…Despite the fact that improved safety standards are constantly being introduced, the forces acting on a rail track -due to wheel-rail contact stresses (WRCS) -are quite large and frequently repeated and -combined with the high speeds of modern trainscan result in the quick evolution of small defects and cracks (which constitute Rolling Contact Fatigue or RCF) into partial or complete rail track failure, which can cause catastrophic accidents such as train derailments [1,2]. Therefore, it is essential to be able to detect RCF in its early stages and observe the time evolution of it (before the cracks increase in number and/or grow in size and the rail track breaks), in order to apply the correct maintenance/replacement strategy [1,3].…”

“…Similarly, ultrasonic wave * e-mail: manios@ims.demokritos.gr (corresponding author) techniques [4,6] have been extensively used for the detection of internal defects/cracks. Other, more recent NDE methods, are electromagnetic acoustic transducers [4], laser ultrasonics [4], ultrasonic guided waves [3,4,7], wavelet packet decomposition [2], and alternating current field measurement (ACFM) probes [4].…”

A study of general orthogonal four-element wavelet packet bases

“…Wavelet packets, owing to their good properties, have attracted considerable attention. They can be widely applied in science and engineering [4,5]. Coifman R. R. and Meyer Y. firstly introduced the notion for orthogonal wavelet packets.…”