In coronary angiography, coronaries are imaged filled by a contrast medium which is injected through a catheter. To increase vessel visibility relative to surrounding structures, a background-less, subtraction-like appearance of the angiograms may be desired. This paper describes algorithms to increase vessel contrast and to attenuate background. Due to the strong motion in coronary angiograms, direct subtraction of a mask image acquired initially without contrast agent cannot be applied. We therefore distinguish vessels from background by their contrast, their size and their motion. These criteria are evaluated on a multiscale structure. Enhancement is then applied at locations which are likely to contain vessels. To avoid unacceptable noise boosting, we integrate a multiscale noise reduction filter into this concept. Both performance and computational simplicity make our algorithms attractive.© (2002) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.