This paper presents a focal spot qualification technique for industrial radioscopy equipment employing star pattern testing devices. The results indicate that star patterns are more reliable than alternative end-user methodologies for anisotropy evaluations, and that they have the same capacity to determine focal spot size as the technique described in ASTM E1165 (2012). The research is based on the edge detection technique, a well-known computational technique. This suggests an alternative way to calculate focal spots, which can be applied to other practices in nondestructive testing such as digital radiography and computed tomography. The proposed focal spot evaluation with star patterns employing the edge detection technique has proven to be in good agreement with the integrated line profile (IPL) technique, recommended in ASTM E1165. In this study, we have used a known-size tungsten ball (sphere) as a testing device. The star pattern test presented mean and standard deviation values below 5%, which indicates a strong compatibility with the technique described in ASTM E1165.
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