Given a music score, would you be able to identify the melody line.
For example, the following is Schubert Impromptu Op 90 No 3:
https://www.dropbox.com/s/gvqpwk2cuj78q9j/IMSLP00364-Franz_Schubert_Impromptus_Op_90_No3.pdf?dl=0
Where is the melody line in this music score?
You can validate your answer by listening to the following recording, where the melody line becomes obvious.
https://www.youtube.com/watch?v=w_z9oSn-eIM

However, in classical music, the melody line is often not the highest notes. The melody line is often in the middle. That makes identifying the melody line in the music score slightly more challenging. The following is Franz Liszt-Schumann Widmung
https://www.dropbox.com/s/8f0prwnpu9f0854/IMSLP04377-Liszt_Schumann_Widmung.pdf?dl=0
You can hear the following recording, and compare with the music score above:
https://www.youtube.com/watch?v=wPtk09KQ35o

Identifying the melody line of a string quartet is even more challenging, as the melody is often played interchangeably by violin, viola, and cello. The following is Haydn String Quartet Op 76 No 3, 2nd movement. 
https://www.dropbox.com/s/3o5awq6lbdt9sm5/IMSLP454963-PMLP57211-op76_no3_2nd_mov.pdf?dl=0
The recording is here:
https://www.youtube.com/watch?v=C0DZARmcRso

The project aims to develop algorithms to identify the melody line from the given music scores. This work is limited by the availability of music scores in a form of MusicXML (or MIDI).

Identifying the melody line from an orchestral music score is the most challenging, and is out of scope of this project.