Scanning of paper scores

Audiveris doesn’t support direct scanning because there is still no open-source solution for cross-platform access to scanning devices from Java projects. We will need to use an external scanning utility. Fortunately, all major scanner manufacturers offer such a utility. There is also a variety of freely available scanning software for all common operating systems.

When scanning for music recognition, we should pay attention to the following advices:

  • Prefer grayscale images to black-and-white or color images. This will help avoid unwanted symbols distortion in the scanning software. Audiveris will binarize the image by itself using a specific adaptive algorithm.

  • Choose an optimal image resolution according to the following criteria:
    • Too low resolution (below 200 DPI) may hide key details while too high (more than 500 DPI) quickly turns into a significant waste of CPU and memory resources without any advantage for the recognition.
    • As a rule of thumb, 300 DPI is generally a good resolution for a paper of standard A4 or US Letter size. For scores that exhibit small symbols, we’ll need to increase the image resolution to 400 DPI.
    • An even better rule is to scan the image so that the resulting vertical distance between two staff lines is about 20 pixels.

  • Paper placement should be made carefully to avoid image rotation, warping, shadows and dark vertical stripes. Audiveris usually detects any rotation and/or warping but, to keep image quality intact, it never attempts to graphically correct them. Instead, the distorted staff lines are kept as they are, and are used as local references for any symbol processing.

  • Any post-processing of scanned images in the scanning software should be turned off. Special settings like “Line Art”, “Text”, “Dithering” or “Halftone” should be disabled because they often lead to unwanted image distortions.
    We should prefer a dedicated image processing software in order to carefully enhance low-quality images when needed. See the Improve Input section.