An apparent increase in the detectability of certain flaws results when the ultrasonic inspection beam was oriented off the longitudinal axis of railroad rail. Here, artificial reflectors were used to better define the extent of material "seen" by inspection beams, and determine how surface curvature might affect the inspection. Presumably, such information could be useful for suggesting optimu...

Visual inspection, although labor-intensive, costly, and inaccurate, is a common practice used in the condition assessment of underground tunnels to ensure safety and serviceability. This paper presents a system thatcan construct a mosaic image of a tunnel surface with little distortion, allowing a large area of tunnels to be visualized, and enabling tunnel inspection to be carried out off-line...

NDE in an in-service situation is used as a basis for integrity management as well as planning of future and maintenance actions. In such an environment it is of paramount importance that the performance level of the NDT method(s) used in terms of Probability Of Detection (POD) is known. It is widely acknowledged that there is no such thing as ‘THE POD’ of an NDE method or technique. This is be...

In the majority of semiconductor manufacturing, the visual inspection process of the wafer surface depends on human experts. However, the inefficiencies of human visual inspection has led to the development of image process to perform inspection tasks. The occurrence of different type of defect arises from the manufacturing processed variations, like miss-out calibration or poor maintenance of ...

Pipe line inspection is an important task where robotics could be applied extensively. Robotic pipeline inspection devices reported in literature are primarily of internal type, requiring special preparation of pipelines for their deployment and retrieval. In this context, robotic systems which can traverse along the external surface of the pipeline structure have the advantage of being able to...

Automated visual inspection, a crucial manufacturing step, has been replacing the more time-consuming and less accurate human inspection. This research explores automated visual inspection of surface defects in a light-emitting diode (LED) chip. Commonly found on chip surface are water-spot blemishes which impair the appearance and functionality of LEDs. Automated inspection of water-spot defec...

Consider a search game with an immobile hider in a graph. A Chinese postman tour is a closed trajectory which visits all the points of the graph and has minimal length. We show that encircling the Chinese postman tour in a random direction is an optimal search strategy if and only if the graph is weakly Eulerian (i.e it consists of several Eulerian curves connected in a tree-like structure).