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Accurate 3D object detection with LiDAR is critical for autonomous driving. Existing research is all based on the flat-world assumption. However, the actual road can be complex with steep sections, which breaks the premise. Current methods…

Computer Vision and Pattern Recognition · Computer Science 2022-07-20 Junyuan Ouyang , Haoyao Chen

We tackle the problem of exploiting Radar for perception in the context of self-driving as Radar provides complementary information to other sensors such as LiDAR or cameras in the form of Doppler velocity. The main challenges of using…

Computer Vision and Pattern Recognition · Computer Science 2020-07-29 Bin Yang , Runsheng Guo , Ming Liang , Sergio Casas , Raquel Urtasun

Ground-based direct imaging of exoplanets at high contrast requires precise correction of atmospheric turbulence using adaptive optics (AO). The planet-to-star contrast ratio at small angular separations from the host star is often limited…

In this paper I investigate what factors -- both observational and physical -- can change the measured slope of the observed 21cm HI power spectrum. The following effects can make the observed turbulence appear two dimensional rather than…

Astrophysics · Physics 2007-05-23 A. H. Minter

Observations of the Sun in the visible spectral range belong to standard measurements obtained by instruments both on the ground and in the space. Nowadays, both nearly continuous full-disc observations with medium resolution and dedicated…

Solar and Stellar Astrophysics · Physics 2020-06-30 Michal Švanda , Jan Jurčák , David Korda , Jana Kašparová

Aerodynamic prediction of glaze ice accretion on airfoils and wing is studied using the Reynolds-averaged Navier-Stokes method. Two separation fixed turbulence models are developed considering the nonequilibrium characteristics of…

Fluid Dynamics · Physics 2021-05-27 Haoran Li , Yufei Zhang , Haixin Chen

Turbulent fluctuations of the atmospheric refraction index, so-called optical turbulence, can significantly distort propagating laser beams. Therefore, modeling the strength of these fluctuations ($C_n^2$) is highly relevant for the…

Atmospheric and Oceanic Physics · Physics 2023-08-11 Maximilian Pierzyna , Rudolf Saathof , Sukanta Basu

Adaptive optics will almost completely remove the effects of atmospheric turbulence at 10 microns on the Extremely Large Telescope (ELT) generation of telescopes. In this paper, we observationally confirm that the next most important…

Instrumentation and Methods for Astrophysics · Physics 2010-03-26 Andrew Skemer , Philip Hinz , William Hoffmann , Laird Close , Sarah Kendrew , Richard Mathar , Remko Stuik , Thomas Greene , Charles Woodward , Michael Kelley

The optical turbulence above Dome C in winter is mainly concentrated in the first tens of meters above the ground. Properties of this so-called surface layer (SL) were investigated during the period 2007-2012 by a set of sonics anemometers…

Small and cluttered objects are common in real-world which are challenging for detection. The difficulty is further pronounced when the objects are rotated, as traditional detectors often routinely locate the objects in horizontal bounding…

Computer Vision and Pattern Recognition · Computer Science 2022-04-29 Xue Yang , Junchi Yan , Wenlong Liao , Xiaokang Yang , Jin Tang , Tao He

We present some statistics of turbulence monitoring at the Plateau de Calern (France), with the Generalised Differential Image Motion Monitor (GDIMM). This instrument allows to measure integrated parameters of the atmospheric turbulence,…

Instrumentation and Methods for Astrophysics · Physics 2018-11-20 Eric Aristidi , Yan Fantei-Caujolle , Julien Chabé , Catherine Renaud , Aziz Ziad , Malak Ben Rahhal

Terrain surface roughness, often described abstractly, poses challenges in quantitative characterisation with various descriptors found in the literature. This study compares five commonly used roughness descriptors, exploring correlations…

Computer Vision and Pattern Recognition · Computer Science 2024-03-15 Lei Fan , Yang Zhao

Ocean turbulence dissipation rate is estimated either by means of microstructure shear measurements, or by adiabatically reordering vertical profiles of density. The latter technique leads to the estimate of the Thorpe scale, which in turn…

Fluid Dynamics · Physics 2014-12-16 Andrea Cimatoribus , Hans van Haren , Louis Gostiaux

In a context of 3D mapping, it is very important to get accurate measurements from sensors. In particular, Light Detection And Ranging (LIDAR) measurements are typically treated as a zero-mean Gaussian distribution. We show that this…

Robotics · Computer Science 2019-08-29 Johann Laconte , Simon-Pierre Deschênes , Mathieu Labussière , François Pomerleau

Lidar point cloud distortion from moving object is an important problem in autonomous driving, and recently becomes even more demanding with the emerging of newer lidars, which feature back-and-forth scanning patterns. Accurately estimating…

Robotics · Computer Science 2022-07-05 Wen Yang , Zheng Gong , Baifu Huang , Xiaoping Hong

Spatial resolution of depth sensors is often significantly lower compared to that of conventional optical cameras. Recent work has explored the idea of improving the resolution of depth using higher resolution intensity as a side…

Computer Vision and Pattern Recognition · Computer Science 2016-03-08 Ulugbek S. Kamilov , Petros T. Boufounos

In optical metrology, grating-like structures are used as tools to evaluate the performance of lithographic techniques. In particular, several shape parameters characterize those structures. One of them, termed side-wall angle, suffers from…

Optics · Physics 2015-10-21 Luca Cisotto , Paul H. Urbach

The 4D Millimeter wave (mmWave) radar is a promising technology for vehicle sensing due to its cost-effectiveness and operability in adverse weather conditions. However, the adoption of this technology has been hindered by sparsity and…

Computer Vision and Pattern Recognition · Computer Science 2023-10-06 Jianan Liu , Qiuchi Zhao , Weiyi Xiong , Tao Huang , Qing-Long Han , Bing Zhu

Expressions of the correlation between the log-amplitude and the phase of a wavefront propagating through the atmospheric turbulence are presented. These expressions are useful to evaluate the feasibility of proposed methods to increase the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Guillaume Molodij

Highly-multiplexed, robotic, fiber-fed spectroscopic surveys are observing tens of millions of stars and galaxies. For many systems, accurate positioning relies on imaging the fibers in the focal plane and feeding that information back to…