325 research outputs found

    Real-time automated road, lane and car detection for autonomous driving

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    In this paper, we discuss a vision based system for autonomous guidance of vehicles. An autonomous intelligent vehicle has to perform a number of functionalities. Segmentation of the road, determining the boundaries to drive in and recognizing the vehicles and obstacles around are the main tasks for vision guided vehicle navigation. In this article we propose a set of algorithms which lead to the solution of road and vehicle segmentation using data from a color camera. The algorithms described here combine gray value difference and texture analysis techniques to segment the road from the image, several geometric transformations and contour processing algorithms are used to segment lanes, and moving cars are extracted with the help of background modeling and estimation. The techniques developed have been tested in real road images and the results are presented

    3D Point Capsule Networks

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    In this paper, we propose 3D point-capsule networks, an auto-encoder designed to process sparse 3D point clouds while preserving spatial arrangements of the input data. 3D capsule networks arise as a direct consequence of our novel unified 3D auto-encoder formulation. Their dynamic routing scheme and the peculiar 2D latent space deployed by our approach bring in improvements for several common point cloud-related tasks, such as object classification, object reconstruction and part segmentation as substantiated by our extensive evaluations. Moreover, it enables new applications such as part interpolation and replacement

    3D Point Capsule Networks

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    In this paper, we propose 3D point-capsule networks, an auto-encoder designed to process sparse 3D point clouds while preserving spatial arrangements of the input data. 3D capsule networks arise as a direct consequence of our novel unified 3D auto-encoder formulation. Their dynamic routing scheme and the peculiar 2D latent space deployed by our approach bring in improvements for several common point cloud-related tasks, such as object classification, object reconstruction and part segmentation as substantiated by our extensive evaluations. Moreover, it enables new applications such as part interpolation and replacement.Comment: As published in CVPR 2019 (camera ready version), with supplementary materia

    Bayesian Pose Graph Optimization via Bingham Distributions and Tempered Geodesic MCMC

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    We introduce Tempered Geodesic Markov Chain Monte Carlo (TG-MCMC) algorithm for initializing pose graph optimization problems, arising in various scenarios such as SFM (structure from motion) or SLAM (simultaneous localization and mapping). TG-MCMC is first of its kind as it unites asymptotically global non-convex optimization on the spherical manifold of quaternions with posterior sampling, in order to provide both reliable initial poses and uncertainty estimates that are informative about the quality of individual solutions. We devise rigorous theoretical convergence guarantees for our method and extensively evaluate it on synthetic and real benchmark datasets. Besides its elegance in formulation and theory, we show that our method is robust to missing data, noise and the estimated uncertainties capture intuitive properties of the data.Comment: Published at NeurIPS 2018, 25 pages with supplement

    A Minimalist Approach to Type-Agnostic Detection of Quadrics in Point Clouds

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    This paper proposes a segmentation-free, automatic and efficient procedure to detect general geometric quadric forms in point clouds, where clutter and occlusions are inevitable. Our everyday world is dominated by man-made objects which are designed using 3D primitives (such as planes, cones, spheres, cylinders, etc.). These objects are also omnipresent in industrial environments. This gives rise to the possibility of abstracting 3D scenes through primitives, thereby positions these geometric forms as an integral part of perception and high level 3D scene understanding. As opposed to state-of-the-art, where a tailored algorithm treats each primitive type separately, we propose to encapsulate all types in a single robust detection procedure. At the center of our approach lies a closed form 3D quadric fit, operating in both primal & dual spaces and requiring as low as 4 oriented-points. Around this fit, we design a novel, local null-space voting strategy to reduce the 4-point case to 3. Voting is coupled with the famous RANSAC and makes our algorithm orders of magnitude faster than its conventional counterparts. This is the first method capable of performing a generic cross-type multi-object primitive detection in difficult scenes. Results on synthetic and real datasets support the validity of our method.Comment: Accepted for publication at CVPR 201

    Analytically Investigation of FRP Ductility Effect on Retrofitted RC Columns

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    Retrofitting of currently used buildings has come into question with the determination of buildings’ performance levels due to earthquake force effect. In this sense, lots of retrofitting techniques have been applied for the retrofitting of current buildings. Columns, beams, joints and slab can be reinforced on the basis of member, with the retrofitting techniques. By this way, building safety is provided by increasing the performance level of the buildings. Within the scope of this study, force-deformation relationship of a single column reinforced with FRP (Fiber Reinforced Polymer) compared with not reinforced column was analysed with regard to finite element method. In the analyses, a column in 300x300 mm in size, 2000 mm in height was modelled. Load was applied step by step as lateral load from 50 nodes which are on 1/7 top of column. After the force-displacement relationship of not retrofitted column was revealed, analysis was repeated by modelling FRP material through plastic hinge area of not damaged column. In conclusion, it is found out that FRP material increases energy consumption capacity of a single column up to 30%

    Monte Carlo Comparison of the Parameter Estimation Methods for the Two-Parameter Gumbel Distribution

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    The performances of the seven different parameter estimation methods for the Gumbel distribution are compared with numerical simulations. Estimation methods used in this study are the method of moments (ME), the method of maximum likelihood (ML), the method of modified maximum likelihood (MML), the method of least squares (LS), the method of weighted least squares (WLS), the method of percentile (PE) and the method of probability weighted moments (PWM). Performance of the estimators is compared with respect to their biases, MSE and deficiency (Def) values via Monte-Carlo simulation. A Monte Carlo Simulation study showed that the method of PWM was the best performance the other methods of bias criterion and the method of ML outperforms the other methods in terms of Def criterion. A real life example taken from the hydrology literature is given at the end of the paper

    A Monte Carlo Comparison of Regression Estimators When the Error Distribution is Long-Tailed Symmetric

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    The performances of the ordinary least squares (OLS), modified maximum likelihood (MML), least absolute deviations (LAD), Winsorized least squares (WIN), trimmed least squares (TLS), Theil’s (Theil) and weighted Theil’s (Weighted Theil) estimators are compared under the simple linear regression model in terms of their bias and efficiency when the distribution of error terms is long-tailed symmetric

    Inference for the jones and faddy's skewed t-distribution based on progressively type-II censored samples

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    In this paper, the location and the scale parameters of Jones and Faddy’s skewed t (JFST) distribution are estimated based on progressively Type-II censored samples. We obtain maximum likelihood (ML) and modified maximum likelihood (MML) estimators of unknown parameters. Then, confidence intervals for the estimators of μ and σ are obtained. The performances of proposed methodologies are compared via Monte-Carlo simulation study. It is concluded that the ML and MML estimators are close, especially for moderate and large sample sizes. At the end of the study, real life data is analyzed for illustrative proposes
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