The invention relates to peripheral equalization during a mammography X-ray examination. High contrast tissue pixel values are removed from the background estimate by finding the minimum intensity values of the pixel located in the neighborhood, which have approximately the same distance to the skin line. Thus, high attenuating pixel values may be removed from the estimate and replaced by lower attenuating tissue pixel values. After a minimum filtration, a conventional peripheral equalization is performed. This may result in less overshoots and intensity values for higher attenuating structures in the peripheral region may become more consistent with intensity values for higher attenuating structures in the fully compressed region.