聲學場景改變之偵測技術

Acoustic Scene Change Detection Approach

林昶宏(Chang-Hong Lin) ； 張振魁(Chen-Kuei Chang) ； 陳明彥(Ming-Yen Chen)

《電腦與通訊》 164期 (2015/12) Pp. 55-61

摘要

本研究提出在室內空間之中，利用脈衝音（Impulse Sound）自喇叭陣列週期性地發出脈衝音，透過聲波的反射與室內的物體、地面、牆面與屋頂等作用產生對應的殘響（Reverberation）， 此殘響之特徵即可反應出室內空間的特性，我們稱為聲學場景（acoustic scene）。當室內空間中的狀態產生變化，如家具擺設位置改變、門窗開啟或關閉、人員數量的增減時，再次於此空間透過脈衝音反射取得的聲學場景即會顯現出差異，此時即可評估室內空間是否發生擾動。本技術透過擷取室內殘響的頻譜，計算頻譜與初始空間的頻譜的頻譜差量，再轉換為時域上的差值向量以表示聲學場景與初始聲學場景在各個時間點的差異。當差異的總和超過訓練時得到的門檻值時，則代表聲學場景改變。

關鍵字

聲學場景轉換偵測 ； 聲學場景建模 ； 房間脈衝響應 ； 喇叭陣列

並列摘要

This work proposes an acoustic scene change detection approach in the indoor space by reverberation. Speakers emit impulse signals periodicity. Sound waves are then influenced with objects, the floor, walls, and roofs, and generate corresponding reverberation. This reverberation can represent the characteristic of the indoor space, which is called acoustic scene. When the state of the indoor space changes, such as furniture changes positions, windows are open or closed, and the number of people in the room increases or decreases, the acoustic scene would differ from the one before. In this way, we can evaluate whether the indoor scene changes or not. This work presents the difference between the current acoustic scene and the initial acoustic scene by calculating the difference between the current spectrogram and the initial spectrogram of the reverberation. When the sum of acoustic scene differences is greater than the threshold decided in the training stage, we say that acoustic scene change occurs.

並列關鍵字

Acoustic Scene Change Detection ； ASCD ； Acoustic Scene Modelling ； ASM ； Room Impulse Response ； RIR ； Speaker Array ； SA