scholarly journals Single-Camera Trilateration

2019 ◽  
Vol 9 (24) ◽  
pp. 5374
Author(s):  
Yu Zhou ◽  
Wenfei Liu ◽  
Xionghui Lu ◽  
Xu Zhong
Keyword(s):  
Performance Analysis ◽  
Mobile Robots ◽  
Pinhole Camera ◽  
Single Camera ◽  
Single Image ◽  
Camera Model ◽  
Perspective Geometry ◽  
Camera Position ◽  
Position And Orientation ◽  
Insight Into

This paper presents a single-camera trilateration scheme which estimates the instantaneous 3D pose of a regular forward-looking camera from a single image of landmarks at known positions. Derived on the basis of the classical pinhole camera model and principles of perspective geometry, the proposed algorithm estimates the camera position and orientation successively. It provides a convenient self-localization tool for mobile robots and vehicles equipped with onboard cameras. Performance analysis has been conducted through extensive simulations with representative examples, which provides an insight into how the input errors and the geometric arrangement of the camera and landmarks affect the performance of the proposed algorithm. The effectiveness of the proposed algorithm has been further verified through an experiment.

scholarly journals Fast 3D Rotation Estimation of Fruits Using Spheroid Models

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2232
Author(s):  
Antonio Albiol ◽  
Alberto Albiol ◽  
Carlos Sánchez de Merás
Keyword(s):  
Fruit Quality ◽  
3D Model ◽  
Geometric Model ◽  
Fruit Shape ◽  
Single Camera ◽  
Global Score ◽  
Topographic Map ◽  
Single Image ◽  
Large Effort ◽  
Fruit Surface

Automated fruit inspection using cameras involves the analysis of a collection of views of the same fruit obtained by rotating a fruit while it is transported. Conventionally, each view is analyzed independently. However, in order to get a global score of the fruit quality, it is necessary to match the defects between adjacent views to prevent counting them more than once and assert that the whole surface has been examined. To accomplish this goal, this paper estimates the 3D rotation undergone by the fruit using a single camera. A 3D model of the fruit geometry is needed to estimate the rotation. This paper proposes to model the fruit shape as a 3D spheroid. The spheroid size and pose in each view is estimated from the silhouettes of all views. Once the geometric model has been fitted, a single 3D rotation for each view transition is estimated. Once all rotations have been estimated, it is possible to use them to propagate defects to neighbor views or to even build a topographic map of the whole fruit surface, thus opening the possibility to analyze a single image (the map) instead of a collection of individual views. A large effort was made to make this method as fast as possible. Execution times are under 0.5 ms to estimate each 3D rotation on a standard I7 CPU using a single core.

scholarly journals Determining Shape and Size of Personal Space of a Human when Passed by a Robot

2021 ◽  
Author(s):  
Margot M. E. Neggers ◽  
Raymond H. Cuijpers ◽  
Peter A. M. Ruijten ◽  
Wijnand A. IJsselsteijn
Keyword(s):  
Mobile Robots ◽  
Humanoid Robot ◽  
Personal Space ◽  
Human Robot Interaction ◽  
Autonomous Mobile Robots ◽  
Robot Interaction ◽  
Human Comfort ◽  
Navigation Algorithms ◽  
Insight Into ◽  
Shape And Size

AbstractAutonomous mobile robots that operate in environments with people are expected to be able to deal with human proxemics and social distances. Previous research investigated how robots can approach persons or how to implement human-aware navigation algorithms. However, experimental research on how robots can avoid a person in a comfortable way is largely missing. The aim of the current work is to experimentally determine the shape and size of personal space of a human passed by a robot. In two studies, both a humanoid as well as a non-humanoid robot were used to pass a person at different sides and distances, after which they were asked to rate their perceived comfort. As expected, perceived comfort increases with distance. However, the shape was not circular: passing at the back of a person is more uncomfortable compared to passing at the front, especially in the case of the humanoid robot. These results give us more insight into the shape and size of personal space in human–robot interaction. Furthermore, they can serve as necessary input to human-aware navigation algorithms for autonomous mobile robots in which human comfort is traded off with efficiency goals.

scholarly journals Simultaneous convergence of position and orientation of wheeled mobile robots using trajectory planning and robust controllers

2018 ◽  
Vol 15 (1) ◽  
pp. 172988141875457 ◽  
Author(s):  
Héctor M Becerra ◽  
J Armando Colunga ◽  
Jose Guadalupe Romero
Keyword(s):  
Mobile Robots ◽  
Trajectory Planning ◽  
Sliding Mode ◽  
Orientation Angle ◽  
Robust Tracking ◽  
Robust Controllers ◽  
Wheeled Mobile Robots ◽  
Control Approach ◽  
Position And Orientation ◽  
Robot Position

This article is devoted to the design of robust position-tracking controllers for a perturbed wheeled mobile robot. We address the final objective of pose-regulation in a predefined time, which means that the robot position and orientation must reach desired final values simultaneously in a user-defined time. To do so, we propose the robust tracking of adequate trajectories for position coordinates, enforcing that the robot’s heading evolves tangent to the position trajectory and consequently the robot reaches a desired orientation. The robust tracking is achieved by a proportional–integral action or by a super-twisting sliding mode control. The main contribution of this article is a kinematic control approach for pose-regulation of wheeled mobile robots in which the orientation angle is not directly controlled in the closed-loop, which simplifies the structure of the control system with respect to existing approaches. An offline trajectory planning method based on parabolic and cubic curves is proposed and integrated with robust controllers to achieve good accuracy in the final values of position and orientation. The novelty in the trajectory planning is the generation of a set of candidate trajectories and the selection of one of them that favors the correction of the robot’s final orientation. Realistic simulations and experiments using a real robot show the good performance of the proposed scheme even in the presence of strong disturbances.

ChunkSim

2010 ◽  
pp. 131-149
Author(s):  
Pedro Furtado
Keyword(s):  
Performance Analysis ◽  
Simulation Analysis ◽  
System Size ◽  
Analysis Tool ◽  
Data Allocation ◽  
Data Warehouses ◽  
Availability Analysis ◽  
On Demand ◽  
Self Tuning ◽  
Insight Into

Self-tuning physical database organization involves tools that determine automatically the best solution concerning partitioning, placement, creation and tuning of auxiliary structures (e.g. indexes), based on the workload. To the best of our knowledge, no tool has focused on a relevant issue in parallel databases and in particular data warehouses running on common off-the-shelf hardware in a sharednothing configuration: determining the adequate tradeoff for balancing load and availability with costs (storage and loading costs). In previous work, we argued that effective load and availability balancing over partitioned datasets can be obtained through chunk-wise placement and replication, together with on-demand processing. In this work, we propose ChunkSim, a simulator for system size planning, performance analysis against replication degree and availability analysis. We apply the tool to illustrate the kind of results that can be obtained by it. The whole discussion in the chapter provides very important insight into data allocation and query processing over shared-nothing data warehouses and how a good simulation analysis tool can be built to predict and analyze actual systems and intended deployments.

Platforms and Tools Within the HyperLedger Framework

2021 ◽  
pp. 23-44
Author(s):  
lamia Chaari Fourati ◽  
Taher Layeb ◽  
Achraf Haddaji ◽  
Samiha Ayed ◽  
Wiem Bekri
Keyword(s):  
Performance Analysis ◽  
Research Community ◽  
Use Cases ◽  
Suitable Tool ◽  
New Generation ◽  
Insight Into

During this last decade, the blockchain (BC) paradigm is being required in several use cases and scenarios in particular for security, privacy, and trust provisioning. Accordingly, the research community and developers developed several emulation tools and frameworks for BC-based systems performance analysis. Making an adequate decision regarding the choice of the most suitable tool that can be used to develop and validate the performances of a specific BC-based system or application still requires more investigation. In this context, this chapter describes and highlights the most features and characteristics of the BC platforms and tools within the Hyperledger framework. The goal is to illustrate the advantages and the limitations of several BC tools and development environments within Hyperledger. In addition, this chapter provides an insight into BC 3.0 as the new generation of BC that meets the requirements of the smart application.

scholarly journals Camera Calibration for Coastal Monitoring Using Available Snapshot Images

2020 ◽  
Vol 12 (11) ◽  
pp. 1840 ◽  
Author(s):  
Gonzalo Simarro ◽  
Daniel Calvete ◽  
Paola Souto ◽  
Jorge Guillén
Keyword(s):  
Laboratory Data ◽  
Ground Control ◽  
Control Points ◽  
Coastal Monitoring ◽  
Ground Control Points ◽  
Camera Position ◽  
Overall Performance ◽  
Position And Orientation ◽  
Monitoring Practice

Joint intrinsic and extrinsic calibration from a single snapshot is a common requirement in coastal monitoring practice. This work analyzes the influence of different aspects, such as the distribution of Ground Control Points (GCPs) or the image obliquity, on the quality of the calibration for two different mathematical models (one being a simplification of the other). The performance of the two models is assessed using extensive laboratory data (i.e., snapshots of a grid). While both models are able to properly adjust the GCPs, the simpler model gives a better overall performance when the GCPs are not well distributed over the image. Furthermore, the simpler model allows for better recovery of the camera position and orientation.

Placing Three-Dimensional Models in an Uncalibrated Single Image of an Architectural Scene

2004 ◽  
Vol 13 (6) ◽  
pp. 692-707 ◽  
Author(s):  
Sara Keren ◽  
Ilan Shimshoni ◽  
Ayellet Tal
Keyword(s):  
Augmented Reality ◽  
Three Dimensional ◽  
3D Models ◽  
Automatic Extraction ◽  
Single Image ◽  
Vanishing Points ◽  
Correct Position ◽  
3D Objects ◽  
Position And Orientation ◽  
Three Dimensional Models

This paper discusses the problem of inserting 3D models into a single image. The main focus of the paper is on the accurate recovery of the camera's parameters, so that 3D models can be inserted in the “correct” position and orientation. The paper addresses two issues. The first is an automatic extraction of the principal vanishing points from an image. The second is a theoretical and an experimental analysis of the errors. To test the concept, a system that “plants” virtual 3D objects in the image was implemented. It was tested on many indoor augmented-reality scenes. Our analysis and experiments have shown that errors in the placement of the objects are unnoticeable.

Sign in / Sign up

Export Citation Format

Share Document