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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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

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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Is it common for 3D LiDARs to require thermal management?

My team had a 3D LiDAR sponsored to us and we were expecting to be able to use it with no issues, but in the datasheet it specifies that performance can suffer once the temperature rises above 50C. ...
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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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Google Cartographer: bag validation detects gaps in LIDAR messages

I'm using google cartographer to do SLAM, and I'm experiencing some accuracy issues, in particular my map rotates and gets distorted when the robot rotates. I run ...
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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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Working with .dat files using Veloview

I am using .dat file and I want to see its point cloud using veloview. The .dat file has been generating a Velodyne LiDAR but as far as I know, Veloview supports .pcap files. Is there a way to run ....
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How to 'fake' Lidar reflectivity

I have simulated Lidar data obtained from Unreal Engine with AirSim. The scans consist of X, Y and Z coordinates, and no reflectivity. I need to perform object classification with Lidar data, and most ...
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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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72 views

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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Trying to make a map with gmapping but Rviz shows nothing

I'm trying to visualize and create a map using a Lidar and Rviz. I have a Lidar that publishes the LaserScan data on /scan and that is visible in Rviz. That is working fine. I also have installed ...
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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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How does 3D Lidar work?

It is a beginner question for most of you, I had Googled this question but I didn't find any satisfying answer. What is the returned raw data from lidar, the difference between 2d and 3d lidar? How we ...
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590 views

how to implement autonomous navigation using lidar and hector?

I want to make an autonomous mobile robot, which can localise itself and navigate to the goal in an unknown environment. As sensor, i just have a RPLidar to get laser scan, that's it. I used Hector ...
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35 views

RpLIDAR unable to see black objects

I am working on a ROSBOT for a natural navigation project. While working with RpLIDAR A2 version, I found that it does not sense thin black surfaces like black pants/trousers while at close range (...
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ICP for LiDAR point cloud data in two frames

I am currently using the ICP to register Lidar point clouds in two frames. The problem is that the translation value calculated by the difference of average point values of utilized points in two ...
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242 views

How to convert PointCloud2 message to a grid?

I'm using a Velodyne sensor which publishes on /velodyne_points topic, and its class type is PointCloud2. Now I want to convert ...
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Do I need a camera along with LIDAR for SLAM?

Equipment: Pi 3 B Mega 2x Encoder Motor 12VDC 299RPM MPU 6050 12V bat 2000mAh LIDAR or Kinect ? I want to implement EKF SLAM. I have referred bot NOX ROS wandering robot, Hussarian CORE and Robotics ...
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SLAM from partly occluded LiDAR sensor

I am building my first project which will use 2D LIDAR for SLAM and the robotic platform is a small car. However the LIDAR is hidden inside and it's occluded by 4 cylinders which connect the roof with ...
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LiDAR Point cloud data reliability/quality

I'm trying to develop a quality measurement (kind of a metric) for the reliability / quality of given point cloud data (coming from a 3D LiDAR) at a given point or region. It should come into account ...
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Sensor model and Inverse sensor model using occupancy grid mapping with lidar for particle filter

I'm a bit confused about how one goes about calculating the sensor model $p(z_t|x_t, m) $ and inverse sensor model for position $p(x_t |z_t,m_{t-1})$. From this answer, it seems like one way for ...
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Likelihood Field Matching

I have LIDAR data of an environment in my hand and I want to apply likelihood field matching to this data. I found a source. But I don't understand what the variables of the algorithm mean and how it ...
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How to determine the rotation matrix and translation vector of a fixed LiDAR from the sensor frame to an aircraft's vehicle frame?

I am using a fixed 3D LiDAR sensor on a small aircraft. The vehicle has a GPS/INU to calculate its own position and orientation. I do not know the exact offset of the LIDAR from the center of the ...
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What wavelengths are most commonly used in laser-scanners and LIDAR systems?

In Photography SE I've just asked LIDAR burnout; ways to check for damaging infrared lasers before shooting besides looking for posted warnings? and discussed a camera that was damaged by a self-...
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3D mapping on spinning 2D unit, and Lidar Resources?

Very new to Lidar but I am seeking to use Lidar in a project and have a Spinning 2d unit I made with garmins v3HP but. Now I am caught up on mapping, I was wondering if it was possible to do things ...
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How to cope with an optical window limitation on 2D LiDAR?

I have a very small and cheap robot and I wanted to mount a 2D LiDAR on a bottom of it (3cm above the ground). It seems to be great as during the mapping the lidar will detect even small elevations ...
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Is this SLAM performance typical or am I doing something wrong?

I'm experimenting with SLAM for the first time. I am using ROS on a Turtlebot3, which has a Raspberry Pi and a single Lidar sensor, Robotis LDS-01. I am running a configuration with three computers, ...
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234 views

In practical terms, how close is the accuracy of camera-based visual odometry/SLAM methods to lidar-based methods for autonomous car navigation?

Benedict Evans, a general partner at Andreessen Horowitz, claims that “almost all autonomy” projects are using lidar for SLAM, and that not all of them use HD maps. An MIT group is testing self-...
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Using Lidar data to detect distance of nearest obstacle, and rate of change

What's the statistically and mathematically correct way to process lidar data so that I can find out a good current estimate of the closet obstacle and its rate change? Should I be learning about ...
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Appropriate distance sensing technology for specified conditions [closed]

I have been considering different distance sensing technologies for the following circumstance: Range needs to be about 2.5 meters The surface being measured is a wall that is painted black The ...
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ROS Gazebo Odometry Issue

I am setting up a Gazebo model for use with the navigation stack. I have been reading the Navigation Tuning Guide and am confused about the lidar data in the odom frame. I would think that the tuning ...
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225 views

Methods for odometry/IMU/Gyro free lidar pointcloud registration for pose estimation

I am currently trying to register a pointcloud in time to find my change in position and heading at each timestep (High speed application). So this is essentially an implementation of SLAM. I am ...
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Iterative Closest Point for 2-D LIDAR Data

I have two 2-D point clouds obtained from LIDAR (Light Detection And Ranging) scans at two different poses (positions and orientations) inside a circular structure, where a small object (vertical ...
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174 views

good laser scanner/ lidar for 4 wheel robot? [closed]

i was wondering what could be a good laser scanner can someone get for as much as 180$ ? i am planning to use it from SLAM to build a map, so this is why i wanted to ask here ? have anyone tried ...
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Multiple Line Estimation

Background: I am working on a design in which an autonomous RC car implements a LIDAR sensor to navigate a course. The primary LIDAR sensor returns a 270 array of points, scanning in a line like ...
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Interfacing multiple ethernet sensors on ROS system (single ethernet port) [closed]

My system consists of the following: A PC with a single ethernet port and other USB ports, a robot mobile base, a SICK LMS lidar with ethernet cable, a Velodyne sensor with Ethernet cable. The robot ...
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Waterproofing LiDAR?

I am interested in using a cheap LiDAR module for an outdoor robot I am building. The LiDAR modules that I am looking at are not waterproof and I was wondering how hard it would be to build a ...
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759 views

Scan an Auditorium, Count People, and Display Open Seats [closed]

I'm looking for any recommended approaches to be able to digitally process a room full people, like an auditorium or a movie theater and output the following information: How many people are in the ...
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275 views

Cannot see ground plane patterns with LiDAR

I mounted VLP-16 on the roof of my car while driving, I was expecting the lidar to detect the lanes on the ground since the white lines should have higher reflectivity. But in fact I cannot see any ...
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how to get h*w point cloud from laser scan not just planer

I am trying to convert a laser scan into point cloud so i can use its cartesian cordintes for computer vision purpose. But when i do it it seems like the width of point cloud converted is only 1. ...