1. A medical imaging system comprising: an x-ray source for generating x-rays; calibration markers positioned in a path of the x-rays; an x-ray receiving device for receiving the generated x-rays and deriving a digital image representing objects through which the generated x-rays have passed, the digital image including representations of the calibration markers; and a processor coupled to the x-ray receiving device for performing image processing operations on the digital image, the image processing operations de-emphasizing the visual presence of the representations of the calibration markers.