Strata: Fine-Grained Acoustic-based Device-Free Tracking
Strata: Fine-Grained Acoustic-based Device-Free Tracking
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DOI：
10.1145/3081333.3081356
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发表时间：
2017-06
期刊：
影响因子：
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通讯作者：
Sangki Yun;Yi-Chao Chen;Huihuang Zheng;L. Qiu;Wenguang Mao
中科院分区：
文献类型：
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作者：
Sangki Yun;Yi-Chao Chen;Huihuang Zheng;L. Qiu;Wenguang Mao
下一代设备，如虚拟现实（VR），增强现实（AR）和智能家电，需要一种简单直观的方式供用户与它们进行交互。为了满足这些需求，我们开发了一种新的基于声学的无设备跟踪系统，称为Strata，使用户能够通过简单地移动手指与附近的设备进行交互。在Strata中，移动的（例如，智能电话）以听不见的频率发送已知的音频信号，并分析由移动手指反射的接收信号以跟踪手指位置。为了明确地考虑多径传播，移动的估计信道脉冲响应（CIR），其表征具有不同延迟的信号遍历路径。每个信道抽头对应于一定延迟范围内的多径效应。移动的选择与手指移动相对应的信道抽头，并提取所选抽头的相位变化，以精确地估计手指的距离变化。此外，它估计的手指的绝对距离的基础上的CIR的变化，使用一种新的优化框架。然后，我们结合联合收割机的绝对和相对距离估计，以准确地跟踪移动目标。我们在三星Galaxy S4移动的手机上实施了跟踪系统。通过微基准测试和用户研究，我们表明，我们的系统实现了高跟踪精度和低延迟，而无需额外的硬件。
Next generation devices, such as virtual reality (VR), augmented reality (AR), and smart appliances, demand a simple and intuitive way for users to interact with them. To address such needs, we develop a novel acoustic based device-free tracking system, called Strata, to enable a user to interact with a nearby device by simply moving his finger. In Strata, a mobile (e.g., smartphone) transmits known audio signals at inaudible frequency, and analyzes the received signal reflected by the moving finger to track the finger location. To explicitly take into account multipath propagation, the mobile estimates the channel impulse response (CIR), which characterizes signal traversal paths with different delays. Each channel tap corresponds to the multipath effects within a certain delay range. The mobile selects the channel tap corresponding to the finger movement and extracts the phase change of the selected tap to accurately estimate the distance change of a finger. Moreover, it estimates the absolute distance of the finger based on the change in CIR using a novel optimization framework. We then combine the absolute and relative distance estimates to accurately track the moving target. We implement our tracking system on Samsung Galaxy S4 mobile phone. Through micro-benchmarks and user studies, we show that our system achieves high tracking accuracy and low latency without extra hardware.