Scanning method

摘要

Scanning apparatus comprises a source of gamma radiation and an array of radiation detectors fixed in relationship to the source and rotating around an object. Normalized count data are collated in a matrix with rows corresponding to individual detectors and columns corresponding to scan position or angle. Patterns of counts higher or lower than a mean value, represented in colour, are detected and a change of density in the object is inferred. A pattern recognition algorithm may be used. A tomographic image may be formed of the object. Thsi may be used to find defects in undersea pipelines.