The automated inspection of aluminium castings is usually performed by analysing stationary radioscopic images taken at programmed positions of the specimens. The advantage of these methods are as follows: a) a number of frames of the same scene can be averaged in order to reduce the inherent noise of the X-ray images; b) using prior knowledge of the expected regular structure in the view, a bank of filters can be designed to generate an error-free reference image from the taken image. Thus, the computed reference image is compared with the real radioscopic image, and flaws are detected at the pixels where the difference between them is considerable. However, the disadvantages are as follows: a) to get the programmed positions of the specimen, it must be moved and braked several times by the manipulator. Thus, the specimen may so slide, that it might not be exactly placed at the required position, the filter might not work correctly and the detection may fail; b) normally, the filters are configured and tuned manually for each casting and position. Configuration of filters and setting of best views involve a couple of workweeks. Additionally, this operation must be carefully optimised in order to minimise false detections while maximising detection probability.
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