Polychromatic quantitative absorption tomography for multi-component samples with cross-contamination artifact...

Beam-hardening and material cross-contamination remain significant challenges in quantitative computed tomography of multi-component samples acquired using polychromatic x-ray sources. In this work, a polychromatic quantitative absorption tomography (QAT) technique is extended to reconstruct component-specific density distribution maps in a two-component sample. The technique decomposes projection sinograms acquired under two distinct incident x-ray spectra into component-specific column density sinograms using a spectral forward model. Residual cross-contamination artifacts are addressed using a quantitative correction procedure based on spatial reference masks obtained by segmenting conventional linear attenuation reconstructions. Contaminated regions are identified from these masks and reinterpreted in the sinogram domain using the same polychromatic forward model prior to back-projection. Experimental validation was performed on an intertwined Al-Cu wire sample. The proposed correction improves material separation, reduces streak artifacts, and brings reconstructed densities within one standard deviation of independently measured average densities of the components. Together, the extended QAT technique and quantitative correction procedure provide a physically consistent methodology for improved quantitative densitometry in multi-component samples, with extensibility to samples containingcomponents.