Ask Musikverket or Levande musikarv (or other music institutions) about which music sheets are preferably to work with, for example generate Midi-files or LilyPond. A test can be done if it also can be used as round tripping.
Work with structure, categories and do some test test of OMR for overview of the field.
Notes from discussion here: https://docs.google.com/document/d/1YjRhtE3CvX40KxHtKMOusd1HwnEZ6XfyCiLEwsQYHNM/edit#