在傳統的音樂曲式分析中，大多需要靠專家做人工的分析與判斷，非常的花費時間與人力，因此能自動化的分析樂曲的結構是相當重要的議題。在之前的音樂研究中較著重於尋找樂曲中不斷反覆出現的片段(repeating pattern)，但在找出這些片段後，並未能進一步分析其在音樂語意上的含意，因此對使用者來說，無法從中得到音樂相關的有用資訊，此外，因為沒有考慮到樂理，因此許多找出來的片段在實際的樂曲分析中是無用且多餘的資訊。
另一部份的研究則著重於如何把樂曲根據樂理或結構上的關係分成許多的樂句，在完成樂曲分段(segment)之後，因為欠缺更進一步的音樂資訊，因此無法根據結果告訴使用者樂句在音樂上的含意及樂句與樂句間的關連性。有鑑於之前的研究皆著重於結構上的分析而未能考慮到音樂上的含意，因此，我們建立一個音樂分析系統，提供自動化的結構分析，並根據結構分析的結果，告訴使用者此樂曲是屬於何種曲式。
在傳統的古典音樂當中，輪旋曲(Rondo)及賦格曲(Fugue)是經過嚴格定義及經常被使用的兩種曲式，輪旋曲的特點是一個主題不斷的出現，而且在一次主題出現結束後下一次主題出現前，會穿插進不同的片段，因此聽起來會有種轉圈圈的感覺；賦格曲則是一種多聲部的樂曲，在賦格曲中，會有一個主題穿插出現在樂曲中，同時在樂曲中使用大量的模仿與對位技巧，賦格曲可以說是一種最完整而濃縮的音樂形式。在我們的音樂分析系統中，是根據樂理上定義的輪旋曲與賦格曲特性來分析樂曲是否是屬於這兩種曲式，並標示出樂曲的主題出現的地方及使用的對位技巧。
我們利用傳統的找repeating pattern的方法並加上樂理的知識來找出主題；利用相似度的函數來計算每個插部間的相似度；對位的技巧則是由音型(contour)比對的方法加上音符長度的判斷與比較來達成，希望藉由結合傳統的音樂分析方法加上樂理的資訊，提供使用者較具有音樂語意的資訊，並進而取代專家做自動化的音樂分析。

Automatic music analysis is an increasingly active research area. In this area, two major purposes are to understand and to characterize musical forms because musical form is the organizing principle of music. Uncovering recurring structures and their organization in works offers a way to gain insights into the style or techniques of composers and improvisers.
In this paper, an automatic music analysis system based on musical forms is proposed to analyze the structure of music data. In our system, we focus on Rondo and Fugue, which are widely used and strictly structured musical forms. Our system consists of two main stages, i.e. feature extraction and musical form analysis. For feature extraction, we focus on monophonic features and represent music data as melody sequences. For musical form analysis, the compositional rules of Rondo and Fugue are adopted. The analysis results of our system show both the structure and the semantic meanings of the music. We make a series of experiments to show that our system has a high precision of detecting musical forms and analyzing the structure of the music.

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