In medical x ray computed tomography (CT) imaging devices, the x ray tube usually emits a polychromatic spectrum of photons resulting in beam-hardening artifacts in the reconstructed images. The bone-correction method has been widely adopted to compensate for beam-hardening artifacts. However, its correction performance is highly dependent on the empirical determination of a scaling factor, which is used to adjust the ratio of the reconstructed value in the bone region to the actual mass density of bone-tissue. A significant problem with bone-correction is that a large number of physical experiments are routinely required to accurately calibrate the scaling factor. In this article, an improved bone-correction method is proposed, based on the projection data consistency condition, to automatically determine the scaling factor. Extensive numerical simulations have verified the existence of an optimal scaling factor …