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The loop closure detection (LCD) methods in Unmanned Aerial Vehicle (UAV) Visual Inertial Navigation System (VINS) are often affected by issues such as insufficient image texture information and limited observational perspectives, resulting in constrained UAV positioning accuracy and reduced capability to perform complex tasks. This study proposes a Bag-of-Words (BoW) LCD method based on Neural Radiance Field (NeRF), which estimates camera poses from existing images and achieves rapid scene reconstruction through NeRF. A method is designed to select virtual viewpoints and render images along the flight trajectory using a specific sampling approach to expand the limited observational angles, mitigating the impact of image blur and insufficient texture information at specific viewpoints while enlarging the loop closure candidate frames to improve the accuracy and success rate of LCD. Additionally, a BoW vector construction method that incorporates the importance of similar visual words and an adapted virtual image filtering and comprehensive scoring calculation method are designed to determine loop closures. Applied to VINS-Mono and ORB-SLAM3, and compared with the advanced BoW model LCDs of the two systems, results indicate that the NeRF-based BoW LCD method can detect more than 48% additional accurate loop closures, while the system's navigation positioning error mean is reduced by over 46%, validating the effectiveness and superiority of the proposed method and demonstrating its significant importance for improving the navigation accuracy of VINS. [ABSTRACT FROM AUTHOR]

Wang, L.; Yi, T., and Ren, Y., 2018. Quantitative analysis of the impact of information loss rate on internet word-of-mouth transmission. In: Liu, Z. L. and Mi, C. (eds.), Advances in Sustainable Port and Ocean Engineering. Journal of Coastal Research, Special Issue No. 83, pp. 729–734. Coconut Creek (Florida), ISSN 0749-0208. With the rapid development of Internet application, Internet word-of-mouth has become an important propagation mode. According to social physics methods, we analyze the running mechanism of the Internet word-of-mouth. And then we build a spread model of Internet word of mouth combining with the neighbor effect, carrying on the simulation model with MATLAB. Finally, We analyze how the information loss rate effects on the word-of-mouth quantitatively resulting from the simulation. [ABSTRACT FROM AUTHOR]