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Sensors 2017, 17(8), 1790;

A Visual-Based Approach for Indoor Radio Map Construction Using Smartphones

1,2,* , 1,2,3
Shenzhen Key Laboratory of Spatial Smart Sensing and Services, Shenzhen University, Shenzhen 518060, China
Key Laboratory for Geo-Environment Monitoring of Coastal Zone of the National Administration of Surveying, Mapping and Geoinformation, Shenzhen University, Shenzhen 518060, China
State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China
Author to whom correspondence should be addressed.
Received: 1 June 2017 / Revised: 27 July 2017 / Accepted: 2 August 2017 / Published: 4 August 2017
(This article belongs to the Special Issue Indoor LiDAR/Vision Systems)
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Localization of users in indoor spaces is a common issue in many applications. Among various technologies, a Wi-Fi fingerprinting based localization solution has attracted much attention, since it can be easily deployed using the existing off-the-shelf mobile devices and wireless networks. However, the collection of the Wi-Fi radio map is quite labor-intensive, which limits its potential for large-scale application. In this paper, a visual-based approach is proposed for the construction of a radio map in anonymous indoor environments. This approach collects multi-sensor data, e.g., Wi-Fi signals, video frames, inertial readings, when people are walking in indoor environments with smartphones in their hands. Then, it spatially recovers the trajectories of people by using both visual and inertial information. Finally, it estimates the location of fingerprints from the trajectories and constructs a Wi-Fi radio map. Experiment results show that the average location error of the fingerprints is about 0.53 m. A weighted k-nearest neighbor method is also used to evaluate the constructed radio map. The average localization error is about 3.2 m, indicating that the quality of the constructed radio map is at the same level as those constructed by site surveying. However, this approach can greatly reduce the human labor cost, which increases the potential for applying it to large indoor environments. View Full-Text
Keywords: indoor localization; radio map; smartphone; structure from motion; fingerprint indoor localization; radio map; smartphone; structure from motion; fingerprint

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Liu, T.; Zhang, X.; Li, Q.; Fang, Z. A Visual-Based Approach for Indoor Radio Map Construction Using Smartphones. Sensors 2017, 17, 1790.

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