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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11
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7answers
6k views

Why people use camera instead of laser sensor for robot navigation?

I am working on Robot localization and navigation in urban environments. I want to use Camera. But I am a little bit confused about LRF data or other laser data. Why people want to use camera? why ...
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1answer
228 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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7answers
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What are some low cost alternatives for lidar? [closed]

It need not be as effective as lidar or it may have some disadvantages when compared with lidar. What are the probable alternatives? Edit: I'm intending to use it outdoors for navigation of ...
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1answer
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Are there any advantages to using a LIDAR for SLAM vs a standard RGB camera?

I've been thinking about building a small UAV with an onboard LIDAR, just for fun. I'm interested in SLAM and autonomous flight indoors and thought that I would need a lidar to get a 3D map of the ...
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2answers
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Do multiple LIDAR systems in same area interfere?

LIDARs use a pulse of light to measure distance, usually from the time of flight to reflection and back. With a collection of these measurements they can determine their surroundings in two or three ...
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1answer
887 views

LIDAR Points as Landmarks

I am currently trying to implement a GraphSLAM/SAM algorithm for LIDAR. From papers I've read, you generate a directed graph from expected LIDAR measurements to landmarks similar to the image below (...
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3answers
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Determining position from a 2D map and LIDAR

We need to determine the 2D position of my robot. To do so, we have a LIDAR at a known high, with an horizontal plane, which gives us the distance to the nearest point for each angular degree (so 360 ...
4
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1answer
150 views

Simple way of 3d perception

I wonder is there any simple (can be computed in microcontroller level) option which is suitable for 3d object perception (depth, position, pose or coordinate estimation) of flying robots except LIDAR,...
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1answer
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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 ...
4
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1answer
3k views

LIDAR solutions [closed]

I am surprised by the price range of Lidar applications considering the simplicity of the design. I try to make a simple project that requires lidar for object recognitions etc. I wouldn't like to use ...
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3answers
789 views

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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2answers
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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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1answer
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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 ...
3
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2answers
301 views

Lidar problems in a multi-robot setup

Consider multiple mobile bases driving around in some area. In order to get meaningful data from the lidar of each base, the sensors should be mounted as horizontal as possible. Due to safety ...
3
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1answer
96 views

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 ...
3
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1answer
115 views

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 ...
3
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2answers
270 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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2answers
1k views

How to move a robot to a point while avoiding obstacles?

I am trying to move a robot in a straight line from point A, to point B. The robot's primary sensor is a Hokuyo URG-04LX-UG01 LIDAR that gives me the magnitude and direction of each point it detects ...
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1answer
82 views

What different sensing approaches are used in the current batch of indoor 3D cameras?

I'm aware of the PrimeSense camera powering the Kinect. Are more advanced sensor types available now in the < $500 range? For example, has there been any sort of game-changer in structured light ...
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2answers
54 views

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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2answers
206 views

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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2answers
306 views

What kind of lidar is necessary for SLAM?

I've read about various robots using a 2D lidar system for SLAM ( such as at IGCV, http://www.igvc.org/ ) but I'm wondering how good exactly does the sensor have to be? Specifically: What accuracy ...
2
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1answer
347 views

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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1answer
2k views

Calculating acceleration and velocity

I'm writing some Quad Copter software and beginning to implement an altitude hold mode. To enable me to do this I need to get an accurate reading for vertical velocity. I plan to use a Kalman filter ...
2
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1answer
68 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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1answer
428 views

Regarding Pose Graph Slam using Lidar

So I'm trying to incorporate pose graph optimization into a mapping framework using a Lidar. So I basically have all the relative transformations between the pointclouds and I have pairs of ...
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1answer
1k views

Inexpensive lidar/radar rangefinder good up to 100m? [closed]

I've been looking around for a lidar/radar rangefinder for a few months now and can't seem to find anything reasonable for my application. My requirements are pretty straightforward: 100m range I2C ...
2
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1answer
112 views

Directly observing lidar laser rays

I am working with SICK lidars and have to mount/unmount them quite often on my robot. The mounting process is very tedious especially when it comes to making sure that the lidars are horizontal. I ...
2
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3answers
482 views

What are the approaches for indoor robot positioning? [closed]

I understand that most of the self-driving cars solutions are based on Lidar and video SLAM. But what about robots reserved for indoor usage? Like robot vacuums and industrial AGVs? I see that Lidar ...
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0answers
36 views

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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1answer
381 views

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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1answer
148 views

Will Lidar see a fence?

I am looking at the possibility of using LIDAR to do obstacle avoidance for a robotics project I am working on but the project involves avoiding a chain link fence. Has anyone used LIDAR to detect ...
2
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1answer
143 views

What sensors can track small objects (5 cm - 25 cm) in bright sunlight? [closed]

ToF (time-of-flight) cameras seem susceptible to bright outdoor conditions. Are there any sensors made for bright outdoor conditions and could be embeddable in a robot that could detect and/or track ...
2
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1answer
965 views

Landmark extraction algorithm

The landmarks are often used in SLAM. What are the algorithms used to extract them, and how can a robot differentiate the landmarks, if they detect one in point A at Xt and another in Xt+1? How can ...
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1answer
45 views

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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2answers
210 views

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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2answers
358 views

How can I achieve long distance, high quality 3D Scans on a mobile robot?

Am going to be competing in Robocup Rescue in Thailand next year - I was too busy to pull off a campaign for Brazil this year :( Will be using CUDA powered GPUs, Kinect/Xtions, and ROS as the primary ...
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1answer
36 views

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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1answer
36 views

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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1answer
218 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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2answers
745 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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0answers
77 views

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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1answer
166 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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0answers
522 views

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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1answer
91 views

How do visual obstructions impact the ability to localize using LIDAR?

If a street is extremely crowded to an extent that the terrain is not visible from the point of view of the LIDAR (e.g. in google's self driving car), can it still manage to localize itself and ...
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2answers
424 views

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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1answer
40 views

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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1answer
59 views

How does 3D Lidar work

It is a beginner question for most of you, I had Google this question but I didn't reach any satisfied answer . What is the returned raw data from lidar,difference between 2d and 3d lidar ? How we map ...
0
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1answer
2k views

Resources for object detection with 2D Laser Scanner (planar only)

Would you happen to know some good books, tutorials or articles on how to detect objects and their poses, using 2D laser scanners? My goal is to equip a mobile robot with a laser scanner for object ...
0
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1answer
18 views

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 ...