Morphological attribute lters operate on images based on properties or attributes of connected components. Until recently, attribute ltering was based on a single global threshold on a scalar property to remove or retain objects. A single threshold struggles in case no single property or attribute value has a suitable, usually multi-modal, distribution. Vector-attribute ltering allows better description of characteristic features for 2D images. In this paper, we apply vector-attribute ltering to 3D and incorporate unsupervised pattern recognition, where connected components are classi ed based on the similarity of feature vectors. Using a single attribute allows multi-thresholding for attribute lters where more than two classes of structures of interest can be selected. In vector-attribute lters automatic clustering avoids the need for either setting very many attribute thresholds, or nding suitable class prototypes in 3D and setting a dissimilarity threshold. Explorative visualization reduces to visualizing and selecting relevant clusters. We show that the performance of these new lters is better than those of regular attribute lters in enhancement of objects in medical images.