scholarly journals High-precision Optical Position Measurement in Indoor Environments

2015 ◽  
Vol 10 (3) ◽  
pp. 24-27 ◽  
Author(s):  
Ralf Vandenhouten ◽  
Ole Wendlandt
Author(s):  
Hiroshi Nishizawa ◽  
Satoshi Fujita ◽  
Osamu Furuya

In order to clarify the destruction mechanism of large structures in large seismic movements, a non-contacting displacement measurement system with a three-dimensional dynamic position with high precision is required. We have developed a three-dimensional measuring system with image processing using optical motion capture technology. This system consists of light emitting markers installed on the object structure and plural high speed cameras which obtain images of markers’ movement simultaneously, to measure the dynamic position of the three dimensional spatial coordinates of the markers. In order to measure the dynamic position with high precision, we have ever developed sub-pixel processing method which is able to measure very small displacements of the markers by analyzing the luminance distribution. Moreover, we have developed a new marker of spherical surface emission type which formed the luminance profile to improve furthermore the accuracy in rotational movement. Shaking tests were carried out with this measuring system and the results indicated that this system using new markers had sufficient accuracy within errors of a few millimeters in the structure of a 4 meter cube. Consequently, we have acquired the potential to apply to the measurement to the 3-D Full Scale Earthquake Testing Facility (E-Defense).


Sensors ◽  
2019 ◽  
Vol 20 (1) ◽  
pp. 193 ◽  
Author(s):  
Haibin Tong ◽  
Ning Xin ◽  
Xianli Su ◽  
Tengfeng Chen ◽  
Jingjing Wu

Wireless sensor networks (WSNs) and the Internet of Things (IoT) have been widely used in industrial, construction, and other fields. In recent years, demands for pedestrian localization have been increasing rapidly. In most cases, these applications work in harsh indoor environments, which have posed many challenges in achieving high-precision localization. Ultra-wide band (UWB)-based localization systems and pedestrian dead reckoning (PDR) algorithms are popular. However, both have their own advantages and disadvantages, and both exhibit a poor performance in harsh environments. UWB-based localization algorithms can be seriously interfered by non-line-of-sight (NLoS) propagation, and PDR algorithms display a cumulative error. For ensuring the accuracy of indoor localization in harsh environments, a hybrid localization approach is proposed in this paper. Firstly, UWB signals cannot penetrate obstacles in most cases, and traditional algorithms for improving the accuracy by NLoS identification and mitigation cannot work in this situation. Therefore, in this study, we focus on integrating a PDR and UWB-based localization algorithm according to the UWB communication status. Secondly, we propose an adaptive PDR algorithm. UWB technology can provide high-precision location results in line-of-sight (LoS) propagation. Based on these, we can train the parameters of the PDR algorithm for every pedestrian, to improve the accuracy. Finally, we implement this hybrid localization approach in a hardware platform and experiment with it in an environment similar to industry or construction. The experimental results show a better accuracy than traditional UWB and PDR approaches in harsh environments.


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