OCR based post processing of OMR for the recovery of transposing instruments in complex orchestral scores

Given a scanned score page, Optical Music Recognition (OMR) attempts to reconstruct all contained music information. However, the available OMR systems lack the ability to recognize transposition information contained in complex orchestral scores. 1 An additional unsolved OMR problem is the handling of orchestral scores using compressed notation. 2 Here, the information of which instrument has to play which staff is crucial for a correct interpretation of the score. But this mapping is lost along the pages of the score during the OMR process. In this paper, we present a method for retrieving the instrumentation and transposition information of orchestral scores. In our approach, we combine the results of Optical Character Recognition (OCR) and OMR to regain the information available through text annotations of the score. In addition, a method to reconstruct the instrument and transposition information for staves where text annotations were omitted or not recognized is presented. In an evaluation we analyze the impact of transposition information on the quality of score-audio synchronizations of orchestral music. The results show that the knowledge of transposing instruments improves the synchronization accuracy and that our method helps in regaining this knowledge.