使用偏光陣列之可見光定位

Abstract

隨著固態照明技術的快速發展，使用LED 作為照明的燈源越來越 普遍，這也因而成為了發展“可見光” 應用的重要跳板。在本論文中， 我們提出了一個創新的室內可見光定位系統叫做LiBeamScanner，只需 使用單一一個客製化的LED 燈泡並配合使用感光元件作為接收端，便 能達到非常高精準度的室內定位，使用單一顆燈泡也就意味著我們的 系統即使在燈分佈稀疏的地方也能進行定位，另外，選擇使用感光元 件而不考慮相機也就表示我們未來能將系統的接收端設計在對於耗能 限制較高的穿戴式設備上。 在實際的設計上，我們提出了一個新穎的方法，透過將訊息調變並 隱藏在一個個非常細微的光束(narrow light beams) 裡，然後將之同時投影在平面上各個相應的位置，換句話說不同的位置收到的訊息會不 一樣，也由於這些光束彼此間幾乎不會互相干擾，即具有高解析度， 因而能提供高精準度的定位。最後的定位結果顯示我們的系統大部分 的定位誤差小於3 公分，而平均誤差則不超過5 公分。

With the rapid development of the solid state lighting technologies, using LED as the lighting source is increasingly common. This becomes an important springboard for the development of “visible light” applications. In this thesis, we proposes LiBeamScanner, a novel indoor visible light positioning system that utilizes only a single custom LED light bulb and a light sensor to achieve extremely high positioning accuracy. Single light bulb means that a dense deployment of illuminaries is unnecessary, and the use of a light sensor, instead of a camera, implies that even systems with strict energy constraints, such as wearable devices, can make use of our system. At the physical layer, we propose a novel transmitter design that allows information to be modulated onto very narrow light beams, projected to a large number of fine-grained locations simultaneously. More importantly, these light beams generate negligible interference to each other, as a result providing a high resolution for enabling accurate positioning. Evaluation results of our prototype show that most of the errors are less than 3cm and the average error does not exceed 5cm.