226,422 research outputs found
Multiple-target tracking using spectropolarimetric imagery
Detection and tracking methods are two hot research topics in the field of multiple target tracking. Often change detection and motion tracking are used to detect and track moving vehicles, but in this thesis new approaches are provided to improve these two aspects. In the detection aspect, a combined detection method is presented to improve target detection techniques. The method of combining RX (Reed-Xiaoli) with change detection has demonstrated good performance in highly cluttered, dynamic ground-based scenes. In the tracking aspect, Kalman filter and Global Nearest Neighbor are applied in motion tracking to predict the location and implement data association respectively. Spectral features are extracted for each vehicle to solve the limitation of motion tracking through feature matching. The Bhattacharyya distance is used as a criterion in the feature matching procedure. Our algorithm has been tested using three sets data. One is a set of multispectral polarimetric imagery acquired by the Multispectral Aerial Passive Polarimeter System (MAPPS). Another two data sets are spectropolarimetric imagery generated by the Digital Imaging and Remote Sensing Image Generation tool. The tracking performance is analyzed by calculating performance metrics: track purity and (Multiple Object Tracking Accuracy ) MOTA. For MAPPS data, the average MOTA and track purity of feature-aided tracking increase 1 percent and 9 percent over those of motion-only tracking respectively. For DIRSIG data with trees, the average track purity of feature-aided tracking in without noise case increases 2 percent over that of motion-only tracking. In this work, we have demonstrated the capability of detection and tracking methods applied in a complex environment
Application of Machine Vision in UAVs for Autonomous Target Tracking
This research presents experimental results for the application of Machine Vision (MV) techniques to address the problem of target detection and tracking. The main objective is the design of a prototype UAV surveillance environment to emulate real-life conditions. The model environment for this experiment consists of a target simulated by a small electric train system, located at ground level, and a MV camera mounted on a motion-based apparatus located directly above the model setup. This system is meant to be a non-flying mockup of an aerial robot retrofitted with a MV sensor. Therefore, the final design is a two degree-of-freedom gantry simulating aircraft motions above the ground level at a constant altitude. On the ground level, the design of the landscape is an attempt to achieve a realistic natural landscape within a laboratory setting. Therefore, the scenery consists of small scale trees, bushes, a mountain, and a tunnel system within a 914 mm by 1066 mm boundary. To detect and track the moving train, MV algorithms are implemented in a Matlab/SimulinkRTM based simulation environment. Specifically, image pre-processing techniques and circle detection algorithms are implemented to detect and identify the chimney stack on the train engine. The circle detection algorithms analyzed in this research effort consists of a least squares based method and the Hough transform (HT) method for circle detection. The experimental results will show that the solution to the target detection problem could produce a positive detection rate of 90% during each simulation while utilizing only 56% of the input image. Tracking and timing data also shows that the least squares based target detection method performs substantially better then the HT method. This is evident from the result of using a 1--2 Hz frequency update rate for the SimulinkRTM scheme which is acceptable, in some cases, for use in navigation for a UAV performing scouting and reconnaissance missions. The development of vision-based control strategies, similar to the approach presented in this research, allows UAVs to participate in complex missions involving autonomous target tracking
Visual tracking of small animals in cluttered natural environments using a freely moving camera
Image-based tracking of animals in their natural habitats can provide rich behavioural data, but is very challenging due to complex and dynamic background and target appearances. We present an effective method to recover the positions of terrestrial animals in cluttered environments from video sequences filmed using a freely moving monocular camera. The method uses residual motion cues to detect the targets and is thus robust to different lighting conditions and requires no a-priori appearance model of the animal or environment. The detection is globally optimised based on an inference problem formulation using factor graphs. This handles ambiguities such as occlusions and intersections and provides automatic initialisation. Furthermore, this formulation allows a seamless integration of occasional user input for the most difficult situations, so that the effect of a few manual position estimates are smoothly distributed over long sequences. Testing our system against a benchmark dataset featuring small targets in natural scenes, we obtain 96% accuracy for fully automated tracking. We also demonstrate reliable tracking in a new data set that includes different targets (insects, vertebrates or artificial objects) in a variety of environments (desert, jungle, meadows, urban) using different imaging devices (day / night vision cameras, smart phones) and modalities (stationary, hand-held, drone operated)
Bayesian Programming Multi-Target Tracking: an Automotive Application
A prerequisite to the design of future Advanced
Driver Assistance Systems for cars is a sensing system
providing all the information required for high-level driving
assistance tasks. In particular, target tracking is still
challenging in urban trafc situations, because of the large
number of rapidly maneuvering targets. The goal of this
paper is to present an original way to perform target position
and velocity, based on the occupancy grid framework. The
main interest of this method is to avoid the decision problem
of classical multi-target tracking algorithms. Obtained
occupancy grids are combined with danger estimation to
perform an elementary task of obstacle avoidance with an
electric car
The Fundamentals of Radar with Applications to Autonomous Vehicles
Radar systems can be extremely useful for applications in autonomous vehicles. This paper seeks to show how radar systems function and how they can apply to improve autonomous vehicles. First, the basics of radar systems are presented to introduce the basic terminology involved with radar. Then, the topic of phased arrays is presented because of their application to autonomous vehicles. The topic of digital signal processing is also discussed because of its importance for all modern radar systems. Finally, examples of radar systems based on the presented knowledge are discussed to illustrate the effectiveness of radar systems in autonomous vehicles
DS-SLAM: A Semantic Visual SLAM towards Dynamic Environments
Simultaneous Localization and Mapping (SLAM) is considered to be a
fundamental capability for intelligent mobile robots. Over the past decades,
many impressed SLAM systems have been developed and achieved good performance
under certain circumstances. However, some problems are still not well solved,
for example, how to tackle the moving objects in the dynamic environments, how
to make the robots truly understand the surroundings and accomplish advanced
tasks. In this paper, a robust semantic visual SLAM towards dynamic
environments named DS-SLAM is proposed. Five threads run in parallel in
DS-SLAM: tracking, semantic segmentation, local mapping, loop closing, and
dense semantic map creation. DS-SLAM combines semantic segmentation network
with moving consistency check method to reduce the impact of dynamic objects,
and thus the localization accuracy is highly improved in dynamic environments.
Meanwhile, a dense semantic octo-tree map is produced, which could be employed
for high-level tasks. We conduct experiments both on TUM RGB-D dataset and in
the real-world environment. The results demonstrate the absolute trajectory
accuracy in DS-SLAM can be improved by one order of magnitude compared with
ORB-SLAM2. It is one of the state-of-the-art SLAM systems in high-dynamic
environments. Now the code is available at our github:
https://github.com/ivipsourcecode/DS-SLAMComment: 7 pages, accepted at the 2018 IEEE/RSJ International Conference on
Intelligent Robots and Systems (IROS 2018). Now the code is available at our
github: https://github.com/ivipsourcecode/DS-SLA
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