Real time detection of foreign objects in object to be tested - radiating body with radiation detected in pixels and absorption value determined based on multi-pixels in specified area and comparing this with preset threshold value.

: Scholz, O.; Kostka, G.; Hanke, R.; Bauer, N.

Abstract
The detection method is carried out in steps: (a) radiation of the object (104) under test with a radiation (106); (b) detecting the radiation in pixels, with the radiation penetrating the object under test; (c) determining an absorption value based on a multiple of pixels, lying in a predetermined surface area; (d) the absorption value is compared with a predetermined threshold value; (e) it is then determined, whether a foreign body is present in the object under test, based on the result of the comparison. The step (c) includes the adding up of the grey values of pixels (P(n)) of a line or a predetermined section to a line result (Z(m)) and further adding up the line results. USE - E.g. in foodstuffs industry to detect foreign bodies such as stones and metal splinters. ADVANTAGE - Facilitates variable position identification of foreign bodies in object under test with variable geometric dimensions, with high test throughput.