1. An x-ray examination apparatus comprising an x-ray source for irradiating an object under examination, means for detecting x-ray radiation exiting from said object and for forming therefrom pixel-values comprised by an image of said object, and means for compensating for any vignetting effect in said image, said compensating means comprising pixel-value amplification means for amplifying pixel-values of the image in relation to a decrease in brightness due to an image perturbation.