1. A method for correcting image artifacts due to detector overexposure in computed tomography, comprising the steps of: in each of a plurality of computed tomography 2D projection images subject to clipping due to overexposure of a radiation detector used to produce the 2D projection images, automatically electronically determining a maximum grayscale value as a function of an x-ray tube voltage, an x-ray tube current and a pulse width used to generate the 2D projection image; selecting a vertical image line in each of said 2D projection images and automatically electronically determining whether clipping is present in that 2D projection image at either a left side of said image line or a right side of said image line; for either side of said image line at which clipping is present, determining a horizontal coordinate, referenced to said image line, at which the clipping ends; for each of said sides in each of said 2D projection images in which clipping is present, automatically electronically extrapolating grayscale values between said horizontal coordinate at which clipping ends, and an edge of that 2D projection image closest to said coordinate at which clipping ends according to an extrapolation formula dependent on said maximum intensity and a size of the object in that 2D projection image, to obtain a corrected 2D projection image wherein the clipping is substantially compensated; and reconstructing a 3D image of the object from the plurality of corrected 2D projection images, said 3D image being substantially free of capping artifacts due to said overexposure.