Poppler annotates with empty annotations
Sometimes, when processing a document with poppler normaliser, the enriched WebLab document contains metadata like dc:title or dc:creator with empty values (or containing only spaces/newlines).
It would be better not to annotate instead of having such empty values.
The main trouble with empty title is that at the result portlet creates a link with an empty title inside, and as a result you cannot click on that document...
For instance the document at http://www.mitsubishielectric.com/news/2015/0528-b.pdf produces empty title and creator.