Audiveris

Audiveris allows you to load the music sheets from image files, in several formats, such as PNG, BMP, JPG, TIFF, PDF and many others. The application supports colored as well as black and white pictures. It is recommendable that you use high-resolution images, in order to obtain a quicker and more reliable result.
After loading the scanned music sheet that you want to work with, the next move is to transcribe the scanned file, either from the toolbar or the 'Score' menu. This in turn will cause Audiveris to automatically analyze the file and extract the music notes.
You can choose the preferred visualization mode, as 'Logical', 'Physical' or 'Combined, whichever you feel is best suited for your needs. From the context menu, you can 'Dump' voices or chords from the output file.
The consequent step is to select the output format of the resulted music score. You can print the result to PDF format, but you can also export it to a MusicXML file.
An important feature of Audiveris is the fact that it can be run from command-line, but at the moment, it only accepts a limited number of arguments.
Audiveris is a reliable tool that you can successfully use to perform OCR operations on scanned music files, allowing you to obtain good quality results than can then be exported to formats that function with other music programs. Thanks to the numerous features and options, Audiveris proves a useful tool for anyone passionate in the field, and while the user interface could use a makeover, it is approachable even by the less experienced.