Abstract : Many methods based on the morphological notion of shapes (i.e., connected components of level sets) have been proved to be very efficient in shape recognition and shape analysis. The inclusion relationship of the level lines (bound-aries of level sets) forms the tree of shapes, a tree-based image representation with a high potential. Numerous applications using this tree representation have been proposed. In this article, we propose an efficient algorithm that extracts a set of disjoint level lines in the image. These selected level lines yield a simplified image with clean contours, which provides an intuitive idea about the main structure of the tree of shapes. Besides, we obtain a saliency map without transition prob-lems around the contours by weighting level lines with their significance. Experimental results demonstrate the efficiency and usefulness of our method.