Patent ID: 6788761
Filing Date: 2004-09-07
Classification: G01N,G01V

Abstract:
A method of screening items to detect target objects therein, comprising:a) passing X-rays through an item from a plurality of different angles and with a plurality of energy levels; b) detecting X-rays that have been attenuated by passing through the item to produce detected values representative of the attenuation of the X-rays by the item; c) analyzing the detected values to produce a first representation of objects within the item, the objects in the first representation being based at least in part on a ratio of attenuation of x-rays having different energies; d) performing a computed tomographic reconstruction of at least a portion of the detected values to produce a second representation of one or more objects within the item; e) forming a third representation of objects in the item by combining the first and second representations, and f) wherein forming the third representation includes altering the first representation by changing the estimate of the atomic number of an object based on the second representation of objects.