Directional processing of line-drawing images based on adaptive morphological operations

Directional information has a strong meaning in line-drawing images. Therefore, the proposed approach for line-drawing images processing is based on a directional decomposition of the input image into a set of images each containing line segments in a respective range of directions. The directional information is then processed by using newly defined directional morphological operators, called tube-directional, that have accurate selectivity and controllable strictness. When using morphological operators, adaptation to a specific task is achieved only globally by setting the structure of the morphological kernel. The concept of one global adjustment for many local operations is somehow conflicting. In the proposed approach the parameters of the tube-directional morphological operators are determined locally for each element of the processed image.