Embodiments of methods and/or apparatus for 3-D volume image reconstruction of a subject, executed at least in part on a computer for use with a digital radiographic apparatus can obtain image data for 2-D projection images over a range of scan angles. For each of the plurality of projection images, an enhanced projection image can be generated. In embodiments of imaging apparatus, CBCT systems, and methods for operating the same can, through a de-noising application based on a different corresponding object, maintain image reconstruction characteristics (e.g., for a prescribed CBCT examination) while reducing exposure dose, reducing noise or increase a SNR while an exposure setting is unchanged.