(I was attending a CS conference in California this week so my post is late.) I have read some papers related to my 3 topics. I gained a clear understanding of the technologies I need for my three topics. I also explored the new ideas from Xunfei’s feedback. There are already available APPs that can scan printed music sheet and play the music. Most of them are not free. I only found two free APPs called PlayScore2 and iSeeNotes. PlayScore2 works much better than iSeeNotes. I tested the APP with my printed music sheet, and the result was not as good as I thought. It couldn’t read all the music notes. If I am going on this topic, my goal will be enhancing the accuracy. But scanning and reading hand written music sheet would be very challenging. Even I cannot read those old music sheets very well.