敲鍵式音樂資料檢索系統-觀音

Abstract

在查詢音樂形式資料時，大部分的檢索系統需透過與該音樂相關之文字詮釋資料進行關鍵字檢索，如歌曲名稱、作曲家、演奏者等，但是在使用者只知道音樂片段旋律的情況下，傳統檢索方式將無法直接檢索這種非文字型態的音樂資料。敲鍵式音樂檢索系統為一種內容式音樂檢索系統（Content-Based Music Retrieval, CBMR），它提供了一個全新的查詢方式，系統預先擷取每一首歌曲的關鍵旋律，並將其節奏中相鄰音符間隔之時間差存放在資料庫，藉由使用者在查詢時持續敲擊鍵盤產生的時間間隔長短不一之節奏，透過適當之近似比對（Similarity Matching）技術，能得到節奏相近的音樂原件。這篇論文將展示如何建構一個敲鍵式音樂檢索系統，系統以〝觀音〞為名，旨在希望將人們腦海中的音樂聲音，透過很直覺之方式將其轉換成節奏，以敲擊鍵盤輸入查詢，系統依相似程度排序回應音樂之曲名、作曲者、聲音等查詢結果，讓眼睛能直接觀看到這段心裡的聲音。

在查詢音樂資料時，敲鍵式系統紀錄每一次按鍵到下一次按鍵的時間差表示音樂旋律中每個音符長短不一之節奏，不同於一般以輸入音高變化為主的內容式音樂查詢系統，它更適合用於沒有經過嚴格音感訓練的愛樂者，即使欠缺準確辨別音高的能力，也能藉由每一段音樂都擁有的另一項音樂特徵即〝節奏〞，利用敲鍵的律動而檢索出對應的音樂資料。

When we have requirement for music data retrieval by an OPAC (Online public access catalog) system, in most systems the user needs to fill out some text-based metadata, like title, composer, and so on , in the query process. Sometimes the user can only remember fragments of music content. So the traditional text-based OPAC system can not satisfy this kind of content-based requirement. A query by tapping mechanism is designed for content-based music retrieval (CBMR). The system extracts key melodies and saves to the themes database with beat information (durations of note) in advance. Then the system takes the user tapping on the keyboard information as query string vector. Apply appropriate similarity matching algorithm to get the intended song in database. This paper presents a query by tapping CBMR system called KUAN YIN. The main purpose is to provide an intuitive way for the user to organize query string via tapping keyboard and get the result by similarity ranked list. All text-based metadata that associates with the intended song will be displayed on the monitor. So KUAN YIN can make visible for the melody linger in mind.

The system records time interval between two consecutive key pressed as the music feature rhythm. It is different from other popular CBMR systems which extract the music feature pitches. Since there is no pitch information in the retrieval process, the system is more suitable for an amateur user. Pitch profile is difficult for people without formal music training to perceive correctly. KUAN YIN takes music rhythm information for comparison with every key pressed tempo which user tapping.