Questions tagged [lidar]

Lidar (also written LIDAR, LiDAR or LADAR) is a surveying technology that measures distance by illuminating a target with a laser light. Lidar exists as an acronym of Light Detection And Ranging.

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VLP16 phase locking

I don't fully understand the phase locking of a VLP16. Will the motor track the PPS so each PPS X number of rotations will have occured? Suppose I want to synchronize an external trigger camera with a ...
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Is there regulation of LiDAR in the public space?

Are there any regulations (in the US or the EU), plans to regulate or initiatives that think about the "pollution" with or amounts of laser emission in urban spaces in general and the impact ...
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How to deal with inexact pointcloud matching?

When running ICP(for example with SLAM) it's possible your next position does not have a point cloud which matches up with the prior point cloud due to resolution limits. How is this dealt with it? ...
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Dynamic mapping without localization in ROS

I have a /scan topic coming from a 2D lidar scanner. The task is to receive a mapping of the dynamic environment. It is assumed that the position of the scanner is always known, so localization is not ...
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Loop closure in 3d lidar slam

I am currently working on 3d LIDAR SLAM and trying to apply LOAM, LIO-SAM etc. I have already read some of these papers to get a better idea of the way they work. However, i did not find anything ...
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Custom sensors and materials simulation in Gazebo: how to simulate specific sensors behaviors for heterogenous materials / buildings

We are currently working on a simulation for a drone that would evolve in an urban environment. It would flight in front of facades and thus must avoid collision into walls, balconies, windows, etc. ...
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A short-range alternative to LiDAR

LiDAR is a very popular choice for long distance applications such as autonomous vehicles. I'm looking for a device that can give me a 3-dimensional representation of a close proximity environment (e....
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Merging multiple LIDARs real time

Is there a standard practice for merging the pointclouds generated by several LIDARs when there is overlap? For example, if my vehicle has two LIDARS (front and back) I'd rather fuse and deal with a ...
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How to make a synchronized LiDAR/Camera rig for Autonomous Driving research?

I am just starting a research project at my university involving sensor fusion between a Camera and a LiDAR device to detect and localize cars around our vehicle (bounded boxes around cars in 3D point-...
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3D LiDAR synchronization with RGB Camera

There's a general procedure for estimating projection transformation between camera and 3d LiDAR but there's a secondary problem which is associating pixels with depths in a grid which isn't uniformly ...
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What is the most cost effective yet still reliable outdoor boundary system?

I am working on a robot that will operate outside in people's lawns in a predefined space. The issue that I am having right now is figuring out what kind of boundary system I should implement in order ...
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How do I identify the different wires on RPLidar?

I bought an RPLidar A1M8-R6 from the following site: https://www.dfrobot.com/product-1125.html?tracking=585c2ddea9c83 I am trying to connect RPLidar to Arduino so I could get information on the ...
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How does Lidar penetrate jungle canopy for archeological surveys?

I've read articles like these https://www.nationalgeographic.com/history/article/maya-laser-lidar-guatemala-pacunam and wanted to understand what's going on here. My understanding is the lidar would ...
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Using Google Cartographer library standalone

I am working on a project that requires the analysis of the results of different SLAM libraries with respect their accuracy on building a map. Right now, I am more interested in the development with ...
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Reflective surface

Have you encountered the problem of reflective surfaces for realsense camera (d435 or t265) and lidar (A1 or A2). I would like to know what are the ways to solve problems with reflective surfaces for ...
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Vulnerability of LiDAR systems for autonomous drones

I will soon be working on an autonomous drone project and we're planning to use LIDAR systems for localization & mapping. However, at the same time, we are looking into how to make drones safer ...
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What would I need to be able to calculate the LiDAR confidence score?

According to the definition, the LiDAR confidence score is given by the intensity of light reflection. For example, in one datasheet, they mentioned that white objects within 6m have typical ...
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How to perform map matching algo using lidar scan s

I have run a code to extract features from lidar scans like poles and facades, and I created the reference map just concatenating results from each scan (i.e local map) now my question is; How can I ...
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does lidar sensor output data have spatial locality?

i have a question about the output of lidar sendor (like velodyne vlp-16, etc) Is there any spatial or temporal locality for output data which is from lidar sensor? Does the produced output data from ...
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LiDAR rig that scans within a projection window

I had an idea for a LiDAR scanner but am having trouble locking in the feasibility of it. First of all - I know stereo matching would be way more efficient - this is more of a thought experiment at ...
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Extract laser scan from a map and known location

If we have the map of an environment (an occupancy grid for instance) and precisely know the pose of the robot within it. How can one reconstruct what the laser scan should look like at a given ...
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Fusing cross-correlated measurements for mobile robot's localization using unscented kalman filter (ukf)

I'm currently working on a mobile robot's indoor localization. On the perception side, I can only rely on a 2D lidar and wheel odometry. I have used these sources as input of different localization's ...
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Is Lidar SLAM with only lidar sensor and no loop closure detection just a odometry?

I'm a newbee to SLAM. I have a question that in Lidar SLAM(including 2D lidar and 3D lidar), if I only use a single lidar without any other sensors like IMU and no loop closure in the mapping process, ...
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How to keep a sensor pointed downward

I am using LIDAR to measure a robot's altitude. The robot's orientation relative to the ground is dynamic; i.e. the XY plane tilts relative to the Z axis. I would like the LIDAR to remain pointed ...
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Compute how well a laser scan matches or overlaps with its environment given a map of the environment and location of the robot is known

If I knew the exact location of my robot and have an accurate map (for eg. an occupancy grid map) of the environment beforehand, how can I compute a measure of how well the laser scan data agree with ...
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How to use data collect from lidar to generate a 2d map with

I'm new to robotics and I'm using ros noetic with the package rp_lidar. I want to use the data collected from my a1m8 slamteck lidar and generate a 2d map for my rover to navigate and avoid collision. ...
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Which scan matching algorithm can be used to extract the moving objects (in 2D lidar scanner)?

There are different types of scan matching algorithms to match consecutive 2D lidar scans, see https://youtu.be/nvFcN2-NqRc?t=421 (ICP, correlative matching, RANSAC). Most of the algorithms return the ...
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Res-Scaling method beats PID controller. How?

Scenario: I have a robotic arm that has a (1D) lidar on its end, to orient itself with respect to the slant table in front of it. The lidar returns pretty accurate distance values in mm. The motor ...
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Is Kalman filter really desired here?

I am trying to use Kalman Filter in my project to eliminate outliers that go beyond certain limit. I am use 1D lidar to get the distance between the robot and an object. I get pretty accurate values ...
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Not getting expected performance from kalman filter+mahalanobis distance

I am using a 1D lidar in one of my projects and it returns the distance it measures, in millimeters (mm). At some point in time, it gives garbage values that go as high as 10,000 or higher, when the ...
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What is the state-of-the-art approach to detect moving objects from mobile robot with 2D Lidar only?

Having a setup of a mobile robot with a 360° 2D lidar (1 plane). What is the current easiest approach to detect moving object with a high reliability from a moving robot? To make it simple, we ...
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2D point cloud registration success probability

I am trying to implement localisation by storing images from a camera and their accompanying point clouds from a 2D lidar during mapping. During localisation I then use image matching to suggest the ...
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LiDAR Feature Extraction

I'd like to extract "features" of an environment scanned with a 2D LiDAR. I tried to create a temporary occupancy map to extract "corners" with the Harris Corner Detector. However ...
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ROS Laser Scan rotates with the robot in RVIZ

I am currently working on developing a ROS application for autonomous navigation using AMCl. I am first trying to get move_base to work before continuing with AMCL. ...
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Applying Rotation & Translation Matrix Obtained from Iterative Closest Point

Suppose I have M lidar contour points from t = k and N lidar contour points from t = k+1. (Some of you might question why I have differing number of contour points, and the reason is that these lidar ...
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Assistance in finding correct LIDAR for short-range object detection task [closed]

I am working on a task that involves finding a distance of a moving object going a static linear object, e.g a long pole. After trying some approaches (mostly involving stereo vision), I have come up ...
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ICP(Iterative Closest Point) with Partially Overlapping Conditions & Changing Point Numbers

I am currently working on fixing vehicle odometry data using lidar contour points. Since I am receiving lidar data in the form of countour points, I thought I'd use ICP to correct the odometry error ...
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Vehicle Odometry Correction Using Lidar Contour Points (Localization)

I am currently working on a project where... Vehicle travels from point A to B GPS trajectory is used as a reference Vehicle odometry (bicycle model without slip angle beta) was used to estimate a ...
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Applying initial guessing to LiDAR point cloud for ICP processing in Graph SLAM

I am currently in the process of implementing Graph SLAM using ICP and g2o in python 2.7 The data I have are pose data (4 x 4 transformation matrix) and lidar data ( in the format of [x y z 1] with ...
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Data collected from ROS

How can we collect the flight data after a ROS simulation and what kind of dataset do we obtain? Can we get the sensor and video dataset with timestamps to be used in analysis?
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Use Realsense camera to get the camera image

I have to use LIDAR in my project. I was searching for some LIDARs with a camera and came across the Intel RealSense d400 series. I know it has a camera but please suggest a way to use that camera ...
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How do I calibrate a rotating laser scanner pose from known global coordinates?

Assume the following scenario: A 2D LIDAR sensor is mounted with a vertical (not exactly known) scan plane at a height of 20m The scanner can be rotated about the vertical axis and the encoder values ...
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How does scan matching find overlapping regions in two scans?

I have been reading about scan matching and so far I have gathered that scan matching tries to find the transformation (rotation and translation) which leads to the best match between overlapping ...
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How to obtain live vertical height values using LIDAR

I plan to control the flying height of my drone using a LIDAR (in real-time). Therefore, I would be attaching the LIDAR to my UAV, pointing vertically downwards. However, after looking at some of the ...
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Usage of Falkolib(OpenSLAM) for 2D lidar landmark extraction

I am using Falkolib for landmark extraction in a 2D environment. Currently I am using the testKeypointOC executable from the bin directory. I have changed the testKeypointOC.cpp file and the ...
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How to get unix/posix time stamp in header of ROS msg?

I am using two sensors each connected to different machine (each machine separately runs Ubuntu 16.04 and ROS Kinetic). When I echo topic on these two machines, I ...
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Fusing Multiple Lidars Into 1 Point Cloud

I have a car with 8 lidars, each with a field of view of 60 degrees. My car looks like this How can I merge all the lidar readings into 1 point cloud?
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Fusion multiple LaserScans to PointCloud

I am currently trying to do 3D SLAM with two 2D Lidars and possibly additional IMU in ROS. However, there seems to be no ROS package available to meet my needs. The closest one would be laser_pipeline ...
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What is the definition of the contents of PointCloud2?

What does the contents of PointCloud2 means in ROS? fields.offset? fields.datatype? ...
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How come LIDAR is not commonly used for indoor navigation?

I'm reading this survey on the state-of-the-art techniques for indoor positioning and navigation. I noticed that LIDAR isn't mentioned at all in the paper. Is LIDAR not meant to be a common method for ...
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