Patent ID: 7881424

Claim:
A method for reconstructing an image of an object under inspection, comprising: scanning the object under inspection with dual-energy rays emitted from a dual-energy ray generator to acquire dual-energy projection values for the object; using one or more processors of a computer to perform operations including: calculating projection values of base material coefficients corresponding to said dual-energy projection values based on a pre-created lookup table; reconstructing an image of base material coefficient distribution based on said projection values of base material coefficients; and calculating an atomic number image of said object based on said image of base material coefficient distribution to be displayed by a display; wherein said lookup table is created by selecting at least two different materials, detecting penetrative rays from dual-energy rays penetrating said at least two different materials under different combinations of thickness to acquire projection values, and creating a lookup table in a form of correspondence between said different combinations of thickness and said projection values.