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In this paper, we propose a resource-efficient system for real-time 3D terrain reconstruction and landing-spot detection for micro aerial vehicles. The system runs on an on-board smartphone processor and requires only the input of a single downlooking camera and an inertial measurement unit. We generate a two-dimensional elevation map that is probabilistic, of fixed size, and robot-centric, thus,...
In this paper, we use sliding mode control theory to design a 3D vision based controller that is robust to bounded parametric estimation errors. First, we give a model of an eye-in-hand 6 DOF robotic system, including the Pose Reconstruction Algorithm (PRA) used to estimate the position and orientation of the camera with respcet to the scene. In a second step, we propose a model for the uncertainties...
This paper reports that uncertainty of detected edges on a fish-eye image depends on the direction to observe the edges. In fish-eye cameras, dimensions of observation space corresponding to a pixel greatly change with the pixel location. This dimension is defined as “spatial uncertainty” in this paper and formulated with typical projection models of fish-eye cameras. Experimental results showed that...
To increase the autonomy of robots, it is necessary to have a precise and guaranteed localization. We propose a SLAM algorithm based on interval analysis and constraints propagation. The problem is casted into a constraint satisfaction which is solved in a guaranteed way via Interval Analysis. We define a new bounded landmark parameterization and an initialization method for monocular camera. Finally,...
This paper describes an extensible framework for real-time self-calibration of cameras in the simultaneous mapping and localization (SLAM) setting. The system is demonstrated to calibrate both pinhole and fish-eye camera models from unknown initial parameters while seamlessly solving the maximum likelihood online SLAM problem in real-time. Self-calibration is performed by tracking image features,...
Current charged-particle detectors are able to estimate the position and energy of a particle, but not its direction. This study is aimed at developing a detector capable of measuring the direction of a charged particle as well as its position. The detector uses an image intensifier and a lens-coupled CMOS (complementary metal-oxide-semiconductor) camera to capture the scintillation light excited...
In this paper, an optical camera communication system utilizing the under-sampled phase shift ON-OFF keying modulation is proposed to support non-flickering visible light communication. This system sends three types of light symbols through light emitting diode (LED) lamps, which are recorded by a camera. By employing a dual LED lamp with a designated mapping and framing method, the data rate can...
Researchers at Lawrence Livermore National Laboratory (LLNL) have started digitizing technical films spanning the above ground atmospheric nuclear testing operations conducted by the United States from 1950 through the 1960s. This technical film test data represents unique information that can be use as a primary validation data source for nuclear effects codes that are used by national researchers...
Visual servoing techniques are proven to be beneficial in unstructured workspaces. However, visual servoing is bounded by several constraints and is prone to the uncertainties of the system, leaving it of limited applicability. Several previous works have tackled these problems; yet, most of these works considered only a partial set of the aforementioned shortcomings. This work proposes a novel two-stage...
This paper reports on an active visual SLAM path planning algorithm that plans loop-closure paths in order to decrease visual navigation uncertainty. Loop-closing revisit actions bound the robot's uncertainty but also contribute to redundant area coverage and increased path length.We propose an opportunistic path planner that leverages sampling-based techniques and information filtering for planning...
Visual servoing methods have proven their usefulness for robot control in unstructured environments. However, the practicality of such methods highly depends on their robustness to system uncertainties and ability to handle the constraints of the system. Many of the previous works proposed effective remedies for constraint handling; yet, only a few of them considered the system uncertainties. This...
Requirement on accuracy of geometrical size of axis parts is very high. By adopting traditional contact measuring methods may scratch the work piece, and it has disadvantages like high cost and low efficiency. Axis part meter of light curtain style has adopted optics non-contact measurement, so it has perfectly solved problems like this. In the paper, in-depth analysis of image de-noising principle...
A comprehensive uncertainty, baseline, and noise analysis in computing 3D points using a recent L1-based triangulation algorithm is presented. This method is shown to be not only faster and more accurate than its main competitor, linear triangulation, but also more stable under noise and baseline changes. A Monte Carlo analysis of covariance and a confidence ellipsoid analysis were performed over...
On December 13, 2012, China's Chang'e 2 Spacecraft successfully flew past No.4179 Asteroid Toutatis, and acquired a series of clear optical images concerning Toutatis. The data obtained is very important for us to be able to establish feasible methods for deep-space optical navigation. However, as the fly-by process cannot be repeated and deep-space environments cannot be tested using physical platforms...
In this paper, we propose an effective approach for moving object detection based on modeling the ego-motion uncertainty and using a graph-cut based motion segmentation. First, the relative camera pose is estimated by minimizing the sum of reprojection errors and its covariance matrix is calculated using a first-order errors propagation method. Next, a motion likelihood for each pixel is obtained...
In planetary exploration space missions, motion measurement of a vehicle on the surface of a planet is a very important task. The main contribution of this work is an experimental comparison among visual odometry systems using lenses with three different focal lengths (an ultra wide angle, a medium wide angle and a telephoto lens). The comparison is performed with a rigorous uncertainty analysis....
Current light field (LF) cameras provide low spatial resolution and limited depth-of-field (DOF) control when compared to traditional digital SLR (DSLR) cameras. We show that a hybrid imaging system consisting of a standard LF camera and a high-resolution standard camera enables (a) achieve high-resolution digital refocusing, (b) better DOF control than LF cameras, and (c) render graceful high-resolution...
In this paper, we present an optimal sensor management technique for an Unmanned Aerial Vehicle (UAV) to autonomously geo-localize multiple mobile ground targets. The target states are continuously estimated using target locations asynchronously captured by a gimbaled camera with a limited field of view and processed with a set of Extended Kalman Filters (EKFs). The technique incorporates a Dynamic...
We build on recent fast and accurate 3-D reconstruction techniques to segment objects during scene reconstruction. We take object outline information from change detection to build 3-D models of rigid objects and represent the scene as static and dynamic components. Object models are updated online during mapping, and can integrate segmentation information from sources other than change detection.
The main contribution of this paper is to bridge the gap between passive monocular SLAM and autonomous robotic systems. While passive monocular SLAM strives to reconstruct the scene and determine the current camera pose for any given camera motion, not every camera motion is equally suited for these tasks. In this work we propose methods to evaluate the quality of camera motions with respect to the...
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