The incident energy of the polychromatic beam is uncertain and the particles are made of mixtures with indeterminate proportions of materials. The model optimizes by minimizing the difference between the pixel predictions and the 2D labels in a batch. Therefore, as long as the assumption of the attenuation coefficients is within the acceptable range and the 2D predictions can reflect the main structure, the inaccurate assumption of the attenuation coefficient only has a limited effect on the 3D reconstruction results.