【作者】 蔡军卫；

【导师】 刘莉；

【作者基本信息】 兰州大学 ， 计算机软件与理论， 2008， 硕士

【摘要】 近年来,随着网络多媒体数据和数据库应用的增加,如何对这些数据进行自动分类和检索已成为一个研究热点。尤其对音频而言,由于出现越来越多在线音乐存储和音乐检索,这就需要一种更加有效的机制去组织检索这些海量数据。基于文本的传统检索方式只能对有标注信息的音乐文件进行检索,基于内容的检索则不依靠标注信息,而是根据音乐中的旋律、节奏、音色等信息进行检索。本文旨在研究基于内容的音乐检索关键技术,主要涉及音乐旋律特征抽取、音乐旋律匹配、音乐数据库以及系统构建等方面。目前在国内外,这些技术在理论研究上已经取得很大进展,并且开发了很多相关的应用系统。然而,现有系统在应用的广泛性、自动化程度、可扩展性等方面仍存在很多问题。本文的研究工作主要以此展开,针对MIDI音乐格式对乐音库的自动构建、多音轨MIDI主旋律自动抽取以及系统实现等方面进行了深入研究。首先,本文通过改进一个网络爬虫程序Larbin,实现了乐音库的自动化构建,增强了整个系统的自动化程度和音乐库的可扩充性。其次,本文深入研究了音乐相似度计算理论,设计了一种新的相对音高旋律表示方式。在此基础上,提出并实现了一种基于旋律相似度计算的多音轨MIDI主旋律抽取算法,实验表明具有良好的召回率和精确度,证明了该算法的可行性和有效性。最后,利用这些相关工作,构建了一个基于哼唱的检索系统,实验结果证明了该系统的有效性。更多还原

【Abstract】 With the increasing applications of multimedia data on the Internet and multimedia databases, there are more and more researches on automatic classifying, indexing and retrieving multimedia data. This is particularly true for music files, since much more online music storing and searching applications are available and they need an efficient mechanism to organize these massive data. Text-based retrieval is only effective for music files with metadata. Content-based music information retrieval is to access the desired music files by melody, rhythm, timbre and other difficult-to-extract layers of significance.This thesis mainly focuses on the key technologies on content-based music retrieval, mainly involving musical melody feature extraction, musical melody matching, the structure of musical melody database, the whole retrieval system constructing and many other issues. Currently at home and abroad, researchers have made great progresses on these technologies in terms of theory, and developed many relate application systems. However, there are many problems with extensiveness, automation and scalability in these existing systems. Therefore the research work in this thesis is related to these problems. The studies are mainly on automatic construction of music database, melody automatic extraction method from polyphonic MIDI and system’s implementation for MIDI.First, through modifying an open source crawler (Larbin), I realize an offline system to automatically construct the music database. It enhances the whole system’s automation and the scalability of the music database.Second, the thesis explores the theory of melody similarity and designs a new representation method for melody. I propose and realize an algorithm for extracting the melody from polyphonic MIDI based on the melody similarity computation. Experiment results show that the recall and precision are better, and prove the effectiveness of the algorithm.Finally, the thesis constructs a musical retrieval system based on humming. Experiment results show the system is efficient.更多还原