Patent ID: 8442186

Claim:
A method for characterizing regions within an inspected object wherein at least one of a lower-Z scattering material and a higher-Z scattering material lies along a single line of sight, the method comprising: a. scanning the inspected object with penetrating radiation emitted by a source characterized by an energy distribution; b. detecting penetrating radiation scattered by the inspected object in a manner generating a first detector signal that distinguishes between materials of higher and lower effective atomic number under a first set of conditions with respect to the energy distribution of the penetrating radiation; c. detecting penetrating radiation scattered by the inspected object in a manner generating a second detector signal that distinguishes between materials of higher and lower effective atomic number under a second set of conditions with respect to the energy distribution of the penetrating radiation; d. generating a differential image based on a function of the first and the second detector signals; and e. determining placement of materials of lower Z and higher Z within a single line of sight relative to the source, based at least on the differential image.