In a second concept some extensions are made to the first one reported in the previous
section in order to decrease the false-positive-rate of the mouth and nose region.
Therefor a validation was implemented which checks the regions with a set of rules.
The detected regions are related to each other and the face area. Primary point of
reference is the region of the eyes which has a very good detection rate. The violation of a rule excludes the region from the list of potential candidates. The rules were set
up under the condition that they are not too detailed and not too general to avoid
excluding too many right or too little wrong detected regions.