scholarly journals Solution of problem of returning to the starting point of autonomously flying UAV by visual navigation

Informatics ◽  
2020 ◽  
Vol 17 (2) ◽  
pp. 17-24
Author(s):  
R. S. Zhuk ◽  
B. A. Zalesky ◽  
Ph. S. Trotski
Keyword(s):  
Visual Odometry ◽  
Video Camera ◽  
Visual Navigation ◽  
Navigation Algorithm ◽  
Localization And Mapping ◽  
Starting Point ◽  
Navigation Algorithms ◽  
Aerial Vehicle ◽  
Navigation Signals ◽  
The Moment

An autonomous visual navigation algorithm is considered, designed for “home“ return of unmanned aerial vehicle (UAV) equipped with on-board video camera and on-board computer, out of GPS and GLONASS navigation signals. The proposed algorithm is similar to the well-known visual navigation algorithms such as V-SLAM (simultaneous localization and mapping) and visual odometry, however, it differs in separate implementation of mapping and localization processes. It calculates the geographical coordinates of the features on the frames taken by on-board video camera during the flight from the start point until the moment of GPS and GLONASS signals loss. After the loss of the signal the return mission is launched, which provides estimation of the position of UAV relatively the map created by previously found features. Proposed approach does not require such complex calculations as V-SLAM and does not accumulate errors over time, in contrast to visual odometry and traditional methods of inertial navigation. The algorithm was implemented and tested with use of DJI Phantom 3 Pro quadcopter.

scholarly journals Virtual testbed for monocular visual navigation of small unmanned aircraft systems

2020 ◽  
pp. 154851292095454
Author(s):  
Kyung Kim ◽  
Robert C Leishman ◽  
Scott L Nykl
Keyword(s):  
Real Time ◽  
Visual Odometry ◽  
Visual Navigation ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Military Operations ◽  
Flight Tests ◽  
Aircraft Systems ◽  
Navigation Algorithms ◽  
Virtual Testbed

Monocular visual navigation methods have seen significant advances in the last decade, recently producing several real-time solutions for autonomously navigating small unmanned aircraft systems without relying on the Global Positioning System (GPS). This is critical for military operations that may involve environments where GPS signals are degraded or denied. However, testing and comparing visual navigation algorithms remains a challenge since visual data is expensive to gather. Conducting flight tests in a virtual environment is an attractive solution prior to committing to outdoor testing. This work presents a virtual testbed for conducting simulated flight tests over real-world terrain and analyzing the real-time performance of visual navigation algorithms at 31 Hz. This tool was created to ultimately find a visual odometry algorithm appropriate for further GPS-denied navigation research on fixed-wing aircraft, even though all of the algorithms were designed for other modalities. This testbed was used to evaluate three current state-of-the-art, open-source monocular visual odometry algorithms on a fixed-wing platform: Direct Sparse Odometry, Semi-Direct Visual Odometry, and ORB-SLAM2 (with loop closures disabled).

scholarly journals Dynamical Analysis of a Navigation Algorithm

Mathematics ◽  
2021 ◽  
Vol 9 (23) ◽  
pp. 3139
Author(s):  
Mireya Cabezas-Olivenza ◽  
Ekaitz Zulueta ◽  
Ander Sánchez-Chica ◽  
Adrian Teso-Fz-Betoño ◽  
Unai Fernandez-Gamiz
Keyword(s):  
Lyapunov Method ◽  
Autonomous Vehicle ◽  
Artificial Vision ◽  
Dynamical Analysis ◽  
Longitudinal Control ◽  
Navigation Algorithm ◽  
Localization And Mapping ◽  
Navigation Algorithms ◽  
The Stability ◽  
Adequate Reliability

There is presently a need for more robust navigation algorithms for autonomous industrial vehicles. These have reasonably guaranteed the adequate reliability of the navigation. In the current work, the stability of a modified algorithm for collision-free guiding of this type of vehicle is ensured. A lateral control and a longitudinal control are implemented. To demonstrate their viability, a stability analysis employing the Lyapunov method is carried out. In addition, this mathematical analysis enables the constants of the designed algorithm to be determined. In conjunction with the navigation algorithm, the present work satisfactorily solves the localization problem, also known as simultaneous localization and mapping (SLAM). Simultaneously, a convolutional neural network is managed, which is used to calculate the trajectory to be followed by the AGV, by implementing the artificial vision. The use of neural networks for image processing is considered to constitute the most robust and flexible method for realising a navigation algorithm. In this way, the autonomous vehicle is provided with considerable autonomy. It can be regarded that the designed algorithm is adequate, being able to trace any type of path.

L’absence chez Michel Butor. L’Emploi du temps et Degrés

2012 ◽  
pp. 66-80
Author(s):  
Michał Mrozowicki
Keyword(s):  
Human Memory ◽  
Point Of View ◽  
Narrative Discourse ◽  
The Novel ◽  
Michel Butor ◽  
Starting Point ◽  
One Year ◽  
The Moment ◽  
Narrative Mode ◽  
The City

Michel Butor, born in 1926, one of the leaders of the French New Novel movement, has written only four novels between 1954 and 1960. The most famous of them is La Modification (Second thoughts), published in 1957. The author of the paper analyzes two other Butor’s novels: L’Emploi du temps (Passing time) – 1956, and Degrés (Degrees) – 1960. The theme of absence is crucial in both of them. In the former, the novel, presented as the diary of Jacques Revel, a young Frenchman spending a year in Bleston (a fictitious English city vaguely similar to Manchester), describes the narrator’s struggle to survive in a double – spatial and temporal – labyrinth. The first of them, formed by Bleston’s streets, squares and parks, is symbolized by the City plan. During his one year sojourn in the city, using its plan, Revel learns patiently how to move in its different districts, and in its strange labyrinth – strange because devoid any centre – that at the end stops annoying him. The other, the temporal one, symbolized by the diary itself, the labyrinth of the human memory, discovered by the narrator rather lately, somewhere in the middle of the year passed in Bleston, becomes, by contrast, more and more dense and complex, which is reflected by an increasinly complex narration used to describe the past. However, at the moment Revel is leaving the city, he is still unable to recall and to describe the events of the 29th of February 1952. This gap, this absence, symbolizes his defeat as the narrator, and, in the same time, the human memory’s limits. In Degrees temporal and spatial structures are also very important. This time round, however, the problems of the narration itself, become predominant. Considered from this point of view, the novel announces Gerard Genette’s work Narrative Discourse and his theoretical discussion of two narratological categories: narrative voice and narrative mode. Having transgressed his narrative competences, Pierre Vernier, the narrator of the first and the second parts of the novel, who, taking as a starting point, a complete account of one hour at school, tries to describe the whole world and various aspects of the human civilization for the benefit of his nephew, Pierre Eller, must fail and disappear, as the narrator, from the third part, which is narrated by another narrator, less audacious and more credible.

Smartphone-Based Indoor Visual Navigation with Leader-Follower Mode

2021 ◽  
Vol 17 (2) ◽  
pp. 1-22
Author(s):  
Jingao Xu ◽  
Erqun Dong ◽  
Qiang Ma ◽  
Chenshu Wu ◽  
Zheng Yang
Keyword(s):  
Real Time ◽  
Environmental Changes ◽  
State Of The Art ◽  
Visual Navigation ◽  
Indoor Navigation ◽  
Location Services ◽  
Localization And Mapping ◽  
Leaders And Followers ◽  
Indoor Navigation System ◽  
Free Pair

Existing indoor navigation solutions usually require pre-deployed comprehensive location services with precise indoor maps and, more importantly, all rely on dedicatedly installed or existing infrastructure. In this article, we present Pair-Navi, an infrastructure-free indoor navigation system that circumvents all these requirements by reusing a previous traveler’s (i.e., leader) trace experience to navigate future users (i.e., followers) in a Peer-to-Peer mode. Our system leverages the advances of visual simultaneous localization and mapping ( SLAM ) on commercial smartphones. Visual SLAM systems, however, are vulnerable to environmental dynamics in the precision and robustness and involve intensive computation that prohibits real-time applications. To combat environmental changes, we propose to cull non-rigid contexts and keep only the static and rigid contents in use. To enable real-time navigation on mobiles, we decouple and reorganize the highly coupled SLAM modules for leaders and followers. We implement Pair-Navi on commodity smartphones and validate its performance in three diverse buildings and two standard datasets (TUM and KITTI). Our results show that Pair-Navi achieves an immediate navigation success rate of 98.6%, which maintains as 83.4% even after 2 weeks since the leaders’ traces were collected, outperforming the state-of-the-art solutions by >50%. Being truly infrastructure-free, Pair-Navi sheds lights on practical indoor navigations for mobile users.

scholarly journals Autonomous visual navigation in an unmanned aerial vehicle onboard system

2017 ◽  
Author(s):  
А.О. Комаров ◽  
◽  
М.А. Скворцова ◽  
О.В. Орешкова ◽  
◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Visual Navigation ◽  
Aerial Vehicle ◽  
Onboard System

scholarly journals Se, tale, høre – oplevelsens kunst

1970 ◽  
pp. 31
Author(s):  
Bruno Ingemann
Keyword(s):  
Cultural History ◽  
Art History ◽  
Fine Arts ◽  
Video Camera ◽  
History Museum ◽  
Starting Point ◽  
Functional Context

See, talk, listen – the art of experience This article presents the manner in which two informants experience an exhibition of the works of a well known Danish painter, Ole Sporring. One of the informants, Jakob (27), wears a small video camera on his head which records his walk through the exhibition, looking at the paintings and talking with his companion, Gunnar (55). Ingemann states that he has used this method in video-walks previously in the context of a cultural history museum (Ingemann 1999). A painting can be seen as an object taken from one functional context – the painter’s studio – and contextualised in an exhibition with others of his paintings, drawings, photographs and objects (Braxendale 1991). Csikszentmihalyi & Robinson have found four factors that are important when one encounters an art-work: the perceptual, the emotional, the intellectual and the communication dimensions. In their project 57 informants educated in the field of fine arts themselves chose the artworks they related to as prototypical examples. In my project I focused on informants who had no formal art history training and I myself selected the exhibition they would visit. My theoretical starting point differs from that of Csikszentmihalyi & Robin- son in that they focus on the art whereas I focus on the informants and their experience (Dewey 1934). 

scholarly journals Authoring Bioconductor workflows with BiocWorkflowTools

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 431
Author(s):  
Mike L. Smith ◽  
Andrzej K. Oleś ◽  
Wolfgang Huber
Keyword(s):  
Data Analysis ◽  
The Other ◽  
Technical Solution ◽  
Single Source ◽  
Journal Publication ◽  
Source Document ◽  
Manual Intervention ◽  
Starting Point ◽  
The Moment ◽  
High Degree

The Bioconductor Gateway on the F1000Research platform is a channel for peer-reviewed and citable publication of end-to-end data analysis workflows rooted in the Bioconductor ecosystem. In addition to the largely static journal publication, it is hoped that authors will also deposit their workflows as executable documents on Bioconductor, where the benefits of regular code testing and easy updating can be realized. Ideally these two endpoints would be met from a single source document. However, so far this has not been easy, due to lack of a technical solution that meets both the requirements of the F1000Research article submission format and the executable documents on Bioconductor. Submission to the platform requires a LaTeX file, which many authors traditionally have produced by writing an Rnw document for Sweave or knitr. On the other hand, to produce the HTML rendering of the document hosted by Bioconductor, the most straightforward starting point is the R Markdown format. Tools such as pandoc enable conversion between many formats, but typically a high degree of manual intervention used to be required to satisfactorily handle aspects such as floating figures, cross-references, literature references, and author affiliations. The BiocWorkflowTools package aims to solve this problem by enabling authors to work with R Markdown right up until the moment they wish to submit to the platform.

scholarly journals A method of iterative image normalization for tasks of visual navigation of UAVs

2019 ◽  
pp. 144-152
Author(s):  
M O Elantcev ◽  
I O Arkhipov ◽  
R M Gafarov
Keyword(s):  
Satellite Image ◽  
Visual Navigation ◽  
Transformation Matrix ◽  
Current Frame ◽  
Scale Parameters ◽  
Perspective Distortion ◽  
Shift Rotation ◽  
Previous Frame ◽  
Aerial Vehicle ◽  
Camera Position

The work deals with a method of eliminating the perspective distortion of an image acquired from an unmanned aerial vehicle (UAV) camera in order to transform it to match the parameters of the satellite image. The normalization is performed in one of the two ways. The first variant consists in the calculation of an image transformation matrix based on the camera position and orientation. The second variant is based on matching the current frame with the previous one. The matching results in the shift, rotation, and scale parameters that are used to obtain an initial set of pairs of corresponding keypoints. From this set four pairs are selected to calculate the perspective transformation matrix. This matrix is in turn used to obtain a new set of pairs of corresponding keypoints. The process is repeated while the number of the pairs in the new set exceeds the number in the current one. The accumulated transformation matrix is then multiplied by the transformation matrix obtained during the normalization of the previous frame. The final part presents the results of the method that show that the proposed method can improve the accuracy of the visual navigation system at low computational costs.

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