Hot answers tagged

17 votes

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

A 3D laser range finder or LIDAR such as the one on the Google Car is far more expensive than a camera. The other reason is that while in case of a LIDAR the distance of every pixel is available, the ...
user avatar
5 votes
Accepted

Are there any advantages to using a LIDAR for SLAM vs a standard RGB camera?

My question: are there cases where you'd still need a LIDAR or can this expensive sensor be replaced with a standard camera? ... A each one of them has its advantages/disadvantages. Thus in some ...
user avatar
  • 309
4 votes

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

In addition to those points in Bence's answer, cameras can: Calculate many complex features that result in very robust matching between frames, and object recognition High angular resolution (typical ...
user avatar
  • 872
4 votes

How does 3D Lidar work?

Lidar, sonar, and radar all work generally the same: Emit a pulse. For radar, this means briefly energizing an antenna. For sonar, it means briefly energizing a sound transducer/speaker. For lider, ...
user avatar
  • 14.7k
4 votes

What is the definition of the contents of PointCloud2?

I totally agree that the documentation is poor and it took me quite some time to understand what is going on. I recorded a rosbag for "velodyne_points" topic using a Velodyne VLP-16. The recorded ...
user avatar
  • 41
3 votes

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

navigation in urban environments Depending on the laser, there might be legal constraints on where you can use it. Running around town throwing laser rays around might require special permission/...
user avatar
3 votes
Accepted

Simple way of 3d perception

The best answer is probably going to be an ultrasonic sensor on a servo, you can get them in a huge range of values, from very close to very far range depending on your application, and varying beam ...
user avatar
  • 1,909
3 votes

What are some low cost alternatives for lidar?

This representative sample of what's out there may give you some idea of what's out there at various price points: Unfortunately, you're talking several thousand dollars for an outdoor unit with 10's ...
user avatar
3 votes
Accepted

Iterative Closest Point for 2-D LIDAR Data

You can use 3D feature descriptors here to register two point clouds. I've personally used two most recent ones that performed well enough for a similar application. Following are the references to ...
user avatar
  • 133
3 votes

How to cope with an optical window limitation on 2D LiDAR?

The answer by @nathangeorge1 is valid for the case of not hitting the legs of the chair. However, you are faced with limited sensor input. This is the case for most robots, even people need to turn ...
user avatar
3 votes

How come LIDAR is not commonly used for indoor navigation?

I think LiDAR is common for indoor navigation. Definitely, LiDAR is the easiest and accurate solution for indoor navigation or SLAM. Many commercial robot vacuums are already in use of LiDAR for ...
user avatar
  • 1,375
3 votes

What is the definition of the contents of PointCloud2?

I get why you are confused. Looking at the definition of PointCloud2, you see that the field that holds the "actual" point cloud data is a 1-dimensional array. Now,...
user avatar
3 votes

Data collected from ROS

As Ben noticed, you may want to elaborate on your question, but in general data collection in ROS is performed using tools from the rosbag package. As you'll find when you read the documentation, ...
user avatar
  • 1,266
2 votes

What are some low cost alternatives for lidar?

Your cheapest option will probably be to use a ultrasonic sensor on a stepper, by advancing the server one step and reading the distance. The only downside to this will be the resolution you can get, ...
user avatar
2 votes

What are some low cost alternatives for lidar?

I don't have enough reputation to comment, but I'll add my 2cents in an answer. Basically you're limited to lidar mapping if you want any decent fidelity. Stereoscopic imaging via OpenCV in one ...
user avatar
2 votes

What kind of lidar is necessary for SLAM?

I know this is not a specific answer, but I have found that the more range and field-of-view the better. I have a gut feeling that if you can trade these off for accuracy and resolution, then you ...
user avatar
  • 5,215
2 votes

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

If cost is a factor, you can also do 3D reconstruction using stereo vision with a pair of commercial digital cameras. Many algorithms are available online to reconstruct 3D scenes from a pair of ...
user avatar
  • 146
2 votes

Lidar problems in a multi-robot setup

I wouldn't recommend using sensors with different laser frequencies either, because that likely means using an entirely different product, with different accuracy and other properties. don't tilt, ...
user avatar
2 votes

Determining position from a 2D map and LIDAR

I just wanted add on to both user12895 and AL-ROBOT's answers. Based on experience: What you need is an (Iterative Point Cloud) ICP algorithm. Do not worry, if the robot cannot detect the entire ...
user avatar
  • 141
2 votes

Determining position from a 2D map and LIDAR

1- Of course you don't have perfect matches 2- ICP is not used for localization, it is used to calculate the transformation the robot's pose has undergone (T+R) 3- To localize your robot, you would ...
user avatar
  • 309
2 votes
Accepted

Calculating acceleration and velocity

I noticed a weird thing in your code -- It looks like you are calculating a first derivative of something labeled altitude in LidarLitePwm::getAcceleration() (which ...
user avatar
  • 729
2 votes

Do multiple LIDAR systems in same area interfere?

Based on two different company's sensors for use in autonomous cars - yes they do interfere. And honestly, I am not sure what is going to happen when you have 30 cars in an intersection, the noise ...
user avatar
2 votes
Accepted

Do multiple LIDAR systems in same area interfere?

One could use lasers with slightly different wave length - just as different channels for Wi-Fi signal. Also there could be used some kind of wave modulation... but I don't think LIDARs use such ...
user avatar
  • 440
2 votes

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

Like other already answered. Cameras typically are much cheaper than Laser Range Finders. When you talk about camera you mean the 2D cameras isn't it? There are some 3D cameras like the ifm O3D3xx ...
user avatar
2 votes

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

I think you can divide your problem into two subproblems: 1) Partition your 2D scan into segments/clusters which represent single objects. A basic algorithm could be: Start at first laser reading ...
user avatar
2 votes
Accepted

Multiple Line Estimation

You can start by using split-and-merge segmentation algorithm. There are many algorithms available A Comparison of Line Extraction Algorithms using 2D Laser Rangefinder for Indoor Mobile Robotics. ...
user avatar
  • 384
2 votes

Is this SLAM performance typical or am I doing something wrong?

Your lidar has a minimum range for 12 cm, which means your maze corridors should probably be double that range (for either side of the sensor), plus the width of the sensor itself, which is 9.5 cm. ...
user avatar
  • 14.7k
2 votes

What wavelengths are most commonly used in laser-scanners and LIDAR systems?

You are correct. Most Velodyne LIDARs (very commonly used on autonomous vehicles), use 905 nm diode lasers, and so do many Hokuyo laser scanners and SICK LIDARs. A new company, Ouster, uses 850 nm ...
user avatar
  • 1,091

Only top scored, non community-wiki answers of a minimum length are eligible