302 research outputs found
Keyframe-based monocular SLAM: design, survey, and future directions
Extensive research in the field of monocular SLAM for the past fifteen years
has yielded workable systems that found their way into various applications in
robotics and augmented reality. Although filter-based monocular SLAM systems
were common at some time, the more efficient keyframe-based solutions are
becoming the de facto methodology for building a monocular SLAM system. The
objective of this paper is threefold: first, the paper serves as a guideline
for people seeking to design their own monocular SLAM according to specific
environmental constraints. Second, it presents a survey that covers the various
keyframe-based monocular SLAM systems in the literature, detailing the
components of their implementation, and critically assessing the specific
strategies made in each proposed solution. Third, the paper provides insight
into the direction of future research in this field, to address the major
limitations still facing monocular SLAM; namely, in the issues of illumination
changes, initialization, highly dynamic motion, poorly textured scenes,
repetitive textures, map maintenance, and failure recovery
An Image-Based Real-Time Georeferencing Scheme for a UAV Based on a New Angular Parametrization
Simultaneous localization and mapping (SLAM) of a monocular projective camera installed on an unmanned aerial vehicle (UAV) is a challenging task in photogrammetry, computer vision, and robotics. This paper presents a novel real-time monocular SLAM solution for UAV applications. It is based on two steps: consecutive construction of the UAV path, and adjacent strip connection. Consecutive construction rapidly estimates the UAV path by sequentially connecting incoming images to a network of connected images. A multilevel pyramid matching is proposed for this step that contains a sub-window matching using high-resolution images. The sub-window matching increases the frequency of tie points by propagating locations of matched sub-windows that leads to a list of high-frequency tie points while keeping the execution time relatively low. A sparse bundle block adjustment (BBA) is employed to optimize the initial path by considering nuisance parameters. System calibration parameters with respect to global navigation satellite system (GNSS) and inertial navigation system (INS) are optionally considered in the BBA model for direct georeferencing. Ground control points and checkpoints are optionally included in the model for georeferencing and quality control. Adjacent strip connection is enabled by an overlap analysis to further improve connectivity of local networks. A novel angular parametrization based on spherical rotation coordinate system is presented to address the gimbal lock singularity of BBA. Our results suggest that the proposed scheme is a precise real-time monocular SLAM solution for a UAV.Peer reviewe
Recent advances in monocular model-based tracking: a systematic literature review
In this paper, we review the advances of monocular model-based tracking for
last ten years period until 2014. In 2005, Lepetit, et. al, [19] reviewed the status
of monocular model based rigid body tracking. Since then, direct 3D tracking has
become quite popular research area, but monocular model-based tracking should
still not be forgotten. We mainly focus on tracking, which could be applied to aug-
mented reality, but also some other applications are covered. Given the wide subject
area this paper tries to give a broad view on the research that has been conducted,
giving the reader an introduction to the different disciplines that are tightly related
to model-based tracking. The work has been conducted by searching through well
known academic search databases in a systematic manner, and by selecting certain
publications for closer examination. We analyze the results by dividing the found
papers into different categories by their way of implementation. The issues which
have not yet been solved are discussed. We also discuss on emerging model-based
methods such as fusing different types of features and region-based pose estimation
which could show the way for future research in this subject.Siirretty Doriast
Hybrid Visual SLAM for Underwater Vehicle Manipulator Systems
This paper presents a novel visual scene mapping method for underwater
vehicle manipulator systems (UVMSs), with specific emphasis on robust mapping
in natural seafloor environments. Prior methods for underwater scene mapping
typically process the data offline, while existing underwater SLAM methods that
run in real-time are generally focused on localization and not mapping. Our
method uses GPU accelerated SIFT features in a graph optimization framework to
build a feature map. The map scale is constrained by features from a vehicle
mounted stereo camera, and we exploit the dynamic positioning capability of the
manipulator system by fusing features from a wrist mounted fisheye camera into
the map to extend it beyond the limited viewpoint of the vehicle mounted
cameras. Our hybrid SLAM method is evaluated on challenging image sequences
collected with a UVMS in natural deep seafloor environments of the Costa Rican
continental shelf margin, and we also evaluate the stereo only mode on a
shallow reef survey dataset. Results on these datasets demonstrate the high
accuracy of our system and suitability for operating in diverse and natural
seafloor environments.Comment: This work has been submitted to the IEEE for possible publication.
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