221 research outputs found
Retaining Image Feature Matching Performance Under Low Light Conditions
Poor image quality in low light images may result in a reduced number of
feature matching between images. In this paper, we investigate the performance
of feature extraction algorithms in low light environments. To find an optimal
setting to retain feature matching performance in low light images, we look
into the effect of changing feature acceptance threshold for feature detector
and adding pre-processing in the form of Low Light Image Enhancement (LLIE)
prior to feature detection. We observe that even in low light images, feature
matching using traditional hand-crafted feature detectors still performs
reasonably well by lowering the threshold parameter. We also show that applying
Low Light Image Enhancement (LLIE) algorithms can improve feature matching even
more when paired with the right feature extraction algorithm.Comment: Accepted in ICCAS 2020 - 20th International Conference on Control,
Robotics, and System
ORB-SLAM: A Versatile and Accurate Monocular SLAM System
This paper presents ORB-SLAM, a feature-based monocular simultaneous localization and mapping (SLAM) system that operates in real time, in small and large indoor and outdoor environments. The system is robust to severe motion clutter, allows wide baseline loop closing and relocalization, and includes full automatic initialization. Building on excellent algorithms of recent years, we designed from scratch a novel system that uses the same features for all SLAM tasks: tracking, mapping, relocalization, and loop closing. A survival of the fittest strategy that selects the points and keyframes of the reconstruction leads to excellent robustness and generates a compact and trackable map that only grows if the scene content changes, allowing lifelong operation. We present an exhaustive evaluation in 27 sequences from the most popular datasets. ORB-SLAM achieves unprecedented performance with respect to other state-of-the-art monocular SLAM approaches. For the benefit of the community, we make the source code public
Real-Time Accurate Visual SLAM with Place Recognition
El problema de localización y construcción simultánea de mapas (del inglés Simultaneous Localization and Mapping, abreviado SLAM) consiste en localizar un sensor en un mapa que se construye en línea. La tecnología de SLAM hace posible la localización de un robot en un entorno desconocido para él, procesando la información de sus sensores de a bordo y por tanto sin depender de infraestructuras externas. Un mapa permite localizarse en todo momento sin acumular deriva, a diferencia de una odometría donde se integran movimientos incrementales. Este tipo de tecnología es crítica para la navegación de robots de servicio y vehículos autónomos, o para la localización del usuario en aplicaciones de realidad aumentada o virtual. La principal contribución de esta tesis es ORB-SLAM, un sistema de SLAM monocular basado en características que trabaja en tiempo real en ambientes pequeños y grandes, de interior y exterior. El sistema es robusto a elementos dinámicos en la escena, permite cerrar bucles y relocalizar la cámara incluso si el punto de vista ha cambiado significativamente, e incluye un método de inicialización completamente automático. ORB-SLAM es actualmente la solución más completa, precisa y fiable de SLAM monocular empleando una cámara como único sensor. El sistema, estando basado en características y ajuste de haces, ha demostrado una precisión y robustez sin precedentes en secuencias públicas estándar.Adicionalmente se ha extendido ORB-SLAM para reconstruir el entorno de forma semi-densa. Nuestra solución desacopla la reconstrucción semi-densa de la estimación de la trayectoria de la cámara, lo que resulta en un sistema que combina la precisión y robustez del SLAM basado en características con las reconstrucciones más completas de los métodos directos. Además se ha extendido la solución monocular para aprovechar la información de cámaras estéreo, RGB-D y sensores inerciales, obteniendo precisiones superiores a otras soluciones del estado del arte. Con el fin de contribuir a la comunidad científica, hemos hecho libre el código de una implementación de nuestra solución de SLAM para cámaras monoculares, estéreo y RGB-D, siendo la primera solución de código libre capaz de funcionar con estos tres tipos de cámara. Bibliografía:R. Mur-Artal and J. D. Tardós.Fast Relocalisation and Loop Closing in Keyframe-Based SLAM.IEEE International Conference on Robotics and Automation (ICRA). Hong Kong, China, June 2014.R. Mur-Artal and J. D. Tardós.ORB-SLAM: Tracking and Mapping Recognizable Features.RSS Workshop on Multi VIew Geometry in RObotics (MVIGRO). Berkeley, USA, July 2014. R. Mur-Artal and J. D. Tardós.Probabilistic Semi-Dense Mapping from Highly Accurate Feature-Based Monocular SLAM.Robotics: Science and Systems (RSS). Rome, Italy, July 2015.R. Mur-Artal, J. M. M. Montiel and J. D. Tardós.ORB-SLAM: A Versatile and Accurate Monocular SLAM System.IEEE Transactions on Robotics, vol. 31, no. 5, pp. 1147-1163, October 2015.(2015 IEEE Transactions on Robotics Best Paper Award).R. Mur-Artal, and J. D. Tardós.Visual-Inertial Monocular SLAM with Map Reuse.IEEE Robotics and Automation Letters, vol. 2, no. 2, pp. 796-803, April 2017. (to be presented at ICRA 17).R.Mur-Artal, and J. D. Tardós. ORB-SLAM2: an Open-Source SLAM System for Monocular, Stereo and RGB-D Cameras.ArXiv preprint arXiv:1610.06475, 2016. (under Review).<br /
RIDI: Robust IMU Double Integration
This paper proposes a novel data-driven approach for inertial navigation,
which learns to estimate trajectories of natural human motions just from an
inertial measurement unit (IMU) in every smartphone. The key observation is
that human motions are repetitive and consist of a few major modes (e.g.,
standing, walking, or turning). Our algorithm regresses a velocity vector from
the history of linear accelerations and angular velocities, then corrects
low-frequency bias in the linear accelerations, which are integrated twice to
estimate positions. We have acquired training data with ground-truth motions
across multiple human subjects and multiple phone placements (e.g., in a bag or
a hand). The qualitatively and quantitatively evaluations have demonstrated
that our algorithm has surprisingly shown comparable results to full Visual
Inertial navigation. To our knowledge, this paper is the first to integrate
sophisticated machine learning techniques with inertial navigation, potentially
opening up a new line of research in the domain of data-driven inertial
navigation. We will publicly share our code and data to facilitate further
research
Integrating Simulink, OpenVX, and ROS for Model-Based Design of Embedded Vision Applications
OpenVX is increasingly gaining consensus as standard platform to develop portable, optimized and power-efficient embedded vision applications. Nevertheless, adopting OpenVX for rapid prototyping, early algorithm parametrization and validation of complex embedded applications is a very challenging task. This paper presents a comprehensive framework that integrates Simulink, OpenVX, and ROS for model-based design of embedded vision applications. The framework allows applying Matlab-Simulink for the model-based design, parametrization, and validation of computer vision applications. Then, it allows for the automatic synthesis of the application model into an OpenVX description for the hardware and constraints-aware application tuning. Finally, the methodology allows integrating the OpenVX application with Robot Operating System (ROS), which is the de-facto reference standard for developing robotic software applications. The OpenVX-ROS interface allows co-simulating and parametrizing the application by considering the actual robotic environment and the application reuse in any ROS-compliant system. Experimental results have been conducted with two real case studies: An application for digital image stabilization and the ORB descriptor for simultaneous localization and mapping (SLAM), which have been developed through Simulink and, then, automatically synthesized into OpenVX-VisionWorks code for an NVIDIA Jetson TX2 boar
A scalable FPGA-based architecture for depth estimation in SLAM
The current state of the art of Simultaneous Localisation and Mapping, or SLAM, on low power embedded systems is about sparse localisation and mapping with low resolution results in the name of efficiency. Meanwhile, research in this field has provided many advances for information rich processing and semantic understanding, combined with high computational requirements for real-time processing. This work provides a solution to bridging this gap, in the form of a scalable SLAM-specific architecture for depth estimation for direct semi-dense SLAM. Targeting an off-the-shelf FPGA-SoC this accelerator architecture achieves a rate of more than 60 mapped frames/sec at a resolution of 640×480 achieving performance on par to a highly-optimised parallel implementation on a high-end desktop CPU with an order of magnitude improved power consumption. Furthermore, the developed architecture is combined with our previous work for the task of tracking, to form the first complete accelerator for semi-dense SLAM on FPGAs, establishing the state of the art in the area of embedded low-power systems
Stereo Vision-based Semantic 3D Object and Ego-motion Tracking for Autonomous Driving
We propose a stereo vision-based approach for tracking the camera ego-motion
and 3D semantic objects in dynamic autonomous driving scenarios. Instead of
directly regressing the 3D bounding box using end-to-end approaches, we propose
to use the easy-to-labeled 2D detection and discrete viewpoint classification
together with a light-weight semantic inference method to obtain rough 3D
object measurements. Based on the object-aware-aided camera pose tracking which
is robust in dynamic environments, in combination with our novel dynamic object
bundle adjustment (BA) approach to fuse temporal sparse feature correspondences
and the semantic 3D measurement model, we obtain 3D object pose, velocity and
anchored dynamic point cloud estimation with instance accuracy and temporal
consistency. The performance of our proposed method is demonstrated in diverse
scenarios. Both the ego-motion estimation and object localization are compared
with the state-of-of-the-art solutions.Comment: 14 pages, 9 figures, eccv201
Fast, Autonomous Flight in GPS-Denied and Cluttered Environments
One of the most challenging tasks for a flying robot is to autonomously
navigate between target locations quickly and reliably while avoiding obstacles
in its path, and with little to no a-priori knowledge of the operating
environment. This challenge is addressed in the present paper. We describe the
system design and software architecture of our proposed solution, and showcase
how all the distinct components can be integrated to enable smooth robot
operation. We provide critical insight on hardware and software component
selection and development, and present results from extensive experimental
testing in real-world warehouse environments. Experimental testing reveals that
our proposed solution can deliver fast and robust aerial robot autonomous
navigation in cluttered, GPS-denied environments.Comment: Pre-peer reviewed version of the article accepted in Journal of Field
Robotic
Direct Sparse Odometry with Rolling Shutter
Neglecting the effects of rolling-shutter cameras for visual odometry (VO)
severely degrades accuracy and robustness. In this paper, we propose a novel
direct monocular VO method that incorporates a rolling-shutter model. Our
approach extends direct sparse odometry which performs direct bundle adjustment
of a set of recent keyframe poses and the depths of a sparse set of image
points. We estimate the velocity at each keyframe and impose a
constant-velocity prior for the optimization. In this way, we obtain a near
real-time, accurate direct VO method. Our approach achieves improved results on
challenging rolling-shutter sequences over state-of-the-art global-shutter VO
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