X-Ray Multispectrum CT Imaging by Projection Sequences Blind Separation Based on Basis-Effect Decomposition

Multispectral CT is a promising method in material characterization, nondestructive evaluation, and other applications. For multispectral CT, the method of projection domain separation can make multispectral CT reconstruction less complex and easier to implement. But X-ray spectrum should be known. By blind separation of projection sequences with different X-ray energy, the ray spectrum is not known in advance, and narrow-spectrum projections can be captured too. However, the proposed blind separation is a signal processing method, without energy constraint. The energy directivity and component characterization accuracy are weaker. To address this problem, this article uses X-ray basis-effect decomposition to propose a new separation model. Both simulation and actual samples are tested to verify and evaluate the proposed method. The experimental results show that the proposed separation model has stronger energy spectrum directivity. The reconstructed attenuation coefficient has smaller error and superior narrow-spectrum characteristics.