於本論文中, 我們研製了建構在無線網路的環境下之無線語音定位系統,利用無線語音定位系統偵測聲音訊號, 進而得知聲音源所在位置之資訊, 應用於室內環境之中。

本文無線網路建構於ZigBee無線傳輸技術之下,透過Chipcon所研發的的CC2430 ZigBee無線傳輸開發模組作為平臺。首先,我們先將利用RSS(Received Signal Strength) 定位法則, 進行實際量測, 建構強度分佈, 所分佈情形作為距離的界定, 透過分析比對來估算每個節點強度與距離的相對位置。接下來利用海龍(Heron) 公式與三角定理, 再搭配最小均方法(Minimum Mean Square Error,MMSE) 演算法, 作為本文之定位演算法, 進而訂定出發聲源所在之位置。

在量測中, 我們得知, 當感測之偵測範圍逐漸擴大時, 訊號的不穩定性越顯著, 使得誤差距離隨著偵測範圍增加而逐漸增加, 同時也觀察到, 當感測器佈建增加時, 可以使精準度提高、誤差距離降低, 甚至在小範圍的時候, 可達到準確的定位能力。

最後, 我們運用此系統實際進行聲音源之估測距離、定位, 並將估測結果分析, 而實驗的結果也驗証了本文所提的無線語音定位系統, 確實能提供利用聲音訊號之定位能力。

In this thesis, we develop a voice localization system in wireless network by
detecting the position of a sound signal through a set of microphones, transmitting the received data through wireless channel, and evaluating its position by properly devised algorithm. Be more specific, the received data, under the ZigBee wireless transmission technology, are transmitted to a PC using the CC2430 sensor module, devised by Chipcon Science and Technology. Thereafter, using the established RSS intensity distribution, we translate the RSS into the information of the distance between the position of the voice signal and that of the sensor. We then adopt the Heron theorem and some triangular equalities to estimate the position of the
sound signal via the minimum mean square error (MMSE) criterion.

Some experiments are conducted for locating a sound signal in an indoor environment to assess the developed system as well as the location algorithm. Experimental results show that in general there is a close match between the true position and the estimated one. Also, we observe that the estimation errors increase as the detection area gets larger and decrease as more sensors are employed.

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