1. A method for identifying defects in radiographic image data corresponding to a scanned object, the method comprising: acquiring radiographic image data corresponding to a scanned object, wherein the radiographic image data comprises at least one of an inspection test image and a reference image corresponding to the scanned object; identifying one or more regions of interest in the reference image; aligning the inspection test image with the one or more regions of interest identified in the reference image, to obtain a residual image; identifying one or more defects in the inspection test image based upon at least one of the residual image and one or more defect probability values computed for one or more pixels in the residual image, wherein the step of identifying the one or more defects in the inspection test image based upon the one or more defect probability values further comprises computing one or more cumulative distribution function (CDF) values for one or more pixels in the reference image and the residual image; and computing a probability density function (PDF) for each pixel in the reference image and the residual image based upon the CDF values computed for the one or more pixels in the reference image, wherein the PDF for each pixel is computed as a function of a defect probability of a pixel at a particular pixel location and a defect prior term.