| author = Hendriks, CL Luengo and van Vliet, Lucas J
| booktitle = International Conference on Computer Analysis of Images and Patterns
| pages = 722-729
,| year = 2003 ,
| organization = Springer
}}</ref>). For example, applying a median filter or a morphological opening with horizontal direction results in the enhancement of horizontal parts of bright structures. Similarly, using a vertical structuring element results in the enhancement of the vertical portions of the structures.