A method for controlled diagnosis-oriented enhancement of selected regions of interest in intraoral radiographs is presented. Image enhancement is accomplished by adaptive non-linear grey scale transformation depending on the result of objective quality measurement. In order to assure reliable image duality measurement as well as controlled image enhancement, automatic image segmentation is applied to avoid the influence of disturbing factors (e.g. metallic restorations) on quality measurement and image enhancement. Based on existing a-priori knowledge about object structure and composition of the selected regions of interest in intraoral radiographs, different image segmentation algorithms and image enhancement procedures were developed for different types of diagnosis. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.