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Questions tagged [slam]

SLAM (Simultaneous Localization And Mapping) refers to a robot building a map of its environment through it's sensor data (mapping) and keeping track of its own position in that map (localization) at the same time.

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How does marginalization of variables effect least squares SLAM energy function?

Consider a simple example of Bundle Adjustment where I have robot and landmark poses $x = \left[ x_p \text{ } x_m\right]^T$ and measurements given by $z$, such that a simple factor graph can be ...
quartzfun's user avatar
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3 votes
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How to calibrate IMU for large scale deployments possibly using deep neural network

We were testing our visual SLAM algorithm on robots. We were getting poor performance. Then we calculated wite noise and random walk parameters (using kalibr) for the IMU and used it in our algorithm ...
Mahesha999's user avatar
3 votes
1 answer
118 views

Covariance of Gaussian after sequence of homogeneous transformations

Assume we have a robot that moves and observes landmarks on his path. The path is composed of $k$ poses $s_1 \: ... s_k$ where $s_i = [x,\ y,\ \theta]$. From the sensors, we read the motion ...
Federico Taschin's user avatar
3 votes
2 answers
316 views

EKF SLAM : Missing older landmarks in new observation

I am a beginner to SLAM and robotics in general and I have been trying to implement SLAM on my GoPiGo3 robot car kit using primarily Chapter 10 from Probabilistic Robotics by Sebastian Thrun as ...
Ananda Kumar's user avatar
3 votes
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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 ...
oswinso's user avatar
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3 votes
1 answer
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SEIF ,online version of Graph slam create doubt in Motion Update state

I have a thesis work about Graph Slam The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures I try to implement it with the help of this paper but during the ...
Encipher's user avatar
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3 votes
1 answer
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Camera ego-motion estimation via dense optical flow

Help me please resolve some questions in the article 1) "A Robust Method for Computing Vehicle Ego-motion", Gideon P. Stein et al. According to this paper we can find three components of motion (...
Roman Dosaev's user avatar
3 votes
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392 views

Triangulation from calibrated stereo rig

I am using a stereo rig to do SLAM, calibrated using the MATLAB Calibration Tool. I need to compute the 2D coordinates of a landmark using the observation model obtained from triangulation (the images ...
osuarez's user avatar
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2 votes
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How does marginalization work in fixed lag smoothing?

I have read in SLAM papers talk about marginalization. I am confused about how this process works, why you do it and how it differs from global smoothing. In particular if you're interested in ...
FourierFlux's user avatar
2 votes
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2k views

How to use Nav2, slam_toolbox with odom data, gps and imu sensors?

Setup details: ROS2 foxy on amd64 architecture CPU with nav2 and slam_toolbox installed Robot is Clearpath husky with Velodyne VLP-16 lidar, IMU and GPS sensor in gazebo. Can see data on every topic ...
you_know_who's user avatar
2 votes
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Monocular SLAM position estimation

I have been reading about mono SLAM and I have a couple questions which are not so clear: When doing pose estimation, I have seen people both reference homography transformation and also reference 5\...
FourierFlux's user avatar
2 votes
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How does loop closure backpropagate the robots states into prior times?

I have read some about loop closure and I am somewhat confused. Suppose we implement something like EKF slam using LIDAR and suppose loop closure is aided by computer vision based features so that if ...
FourierFlux's user avatar
2 votes
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283 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 ...
David Lee's user avatar
2 votes
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Lost on SEIF Slam repeated update landmark

I am working on Sparse Extended Information Slam. I take the reference from Probabilistic Robotics, by Dr.Sebastian Thrun (Chapter 12,page 303). I have some doubt about the implementation of the ...
Encipher's user avatar
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Monocular SLAM depth reconstruction

I am trying to derive the inverse depth equation used in monocular SLAM algorithms. Specifically the equation 8 of the ORB SLAM paper I am very close, except I do not understand where the (u_j-c) ...
Marc HPunkt's user avatar
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263 views

Visual SLAM for wheeled robot

I would appreciate your help for choosing the appropriate real-time SLAM algorithm. I am interested in having autonomous robot, thus a SLAM component is needed for autonomous navigation. The ...
user3294823's user avatar
2 votes
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126 views

Need help in implementing EKF based SLAM

I just started learning about slam and I have been trying to simulate a robot moving around a set of landmarks for the past 3 days. The landmarks have known correspondences. My problem is, if I add ...
harish satishchandra's user avatar
2 votes
1 answer
336 views

Camera pose to world coordinate transformation

I have managed to receive camera_pose for ORB-SLAM by following their code. If I run $ echo /world /camera_pose I receive something like this: ...
Gabriele's user avatar
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Local Costmap is not receiving map in "Odom global frame" while using AMCL and GMapping in SLAM

I am implementing SLAM using the AMCL (Adaptive Monte Carlo Localization) and GMapping packages in ROS. While the map is successfully displayed on the Global Costmap, it does not appear on the Local ...
Muhammad Wasiq Saleem's user avatar
1 vote
0 answers
19 views

SLAM Toolbox map size too small

I am working out of a simple 4 walled gazebo world with a 2 wheel differential drive robot similar in size to the turtlebot3. I am using the nav2_bringup package to launch the nav2 nodes and the slam ...
Abhi's user avatar
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Conversion from body frame to NED frame

I have following Python code: ...
RajS's user avatar
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[Slam Toolbox]Map is overlapping and doesn't make loop_closure

Required Info: Operating System: Ubuntu 22.04 Installation type: binaries ROS Version : ROS2 Humble Version or commit hash: release version Laser unit: RP Lidar We mapped it on the map above and ...
zarqu0n's user avatar
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1 vote
1 answer
34 views

sensor fusion with many sensors and different update rates

It seems like there is no shortage of sensor fusion libraries that can fuse basic common odometric sensors like IMUs and GPS, but none that can fuse from an arbitrary number of sources, especially ...
TheDarkSaint's user avatar
1 vote
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112 views

slam_toolbox - Failed to compute odom pose (No map received in rviz)

I'm trying to do mapping using slam toolbox and it's on a real robot. I don't have ros2 control since the supplier already provided the hardware interface with the robot launching file without a URDF. ...
Ahmed greynoon's user avatar
1 vote
0 answers
35 views

Running SLAM without encoders

I am new to the concept of SLAM and mapping, however I ordered a robot vehicle platform which I bought here so that I can explore and practice it on the platform. I also got a 2d liDAR, depth camera ...
Daniel Abayomi's user avatar
1 vote
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134 views

Does ORB-Slam3 perform better than ORB-Slam2?

I was trying to compare ORB-Slam2 performace with ORB-Slam3 performance. Consider following comparison from ORB-Slam3 paper (columns with numbers correspond to different sequences from EuRoC dataset): ...
Mahesha999's user avatar
1 vote
0 answers
33 views

slam map edit or view tools

I'm a newer ros2 and slam engineer. Recently, we use the imu and 2D lidar run the Cartographer. However, it alwayes break in different place everytime. And I found that a company use the Karto and a ...
user21493099's user avatar
1 vote
0 answers
58 views

No map received | rvis | le potato aml-s905X-cc | rp lidar a1

I currently have a SLAMTEC RPlidar a1 hooked up to a le potato (rasp pi copy). I'm trying to run turtlebot3 cartographer (and eventually nav2). When I run the command ...
kyle brockman's user avatar
1 vote
2 answers
104 views

SLAM but without actually driving the Robot?

I am just starting with SLAM and have to implement SLAM to get a dimensions (map) of an indoor space. I have looked at the turtlebot3 slam and slam_toolboox packages with algorithms like gmapping and ...
Rushabh's user avatar
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How should a small robotics startup go about building a data platform?

We're a small company making ROS based robots that rely heavily on SLAM and perception. We're looking for a data platform solution, something like Foxglove or formant.io as a base data management tool,...
user36880's user avatar
1 vote
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Observability of Gravity in SLAM

A number of SLAM systems only optimize over 4 variables(location and yaw) as they argue gravity is observable which constrains roll and pitch. I don't understand this argument since in theory you ...
FourierFlux's user avatar
1 vote
0 answers
35 views

Alternative Landmark Observation Model for Fast SLAM using 3D Point Clouds

I am in the process of implementing a Fast-SLAM Algorithm as it is described in Chapter 13 of Probabilistic Robotics by Thrun, Burgard and Fox or this publication by Thrun, Koller and Wegbreit however,...
Roman Stadlhuber's user avatar
1 vote
0 answers
421 views

How does IMU pre-integration work and how is it different from EKF?

My understanding is that IMU pre-integration is to get away from having to re-integrate the the IMU between key-frame intervals when doing bundle adjustment. The formulations I ave seen involve a ...
FourierFlux's user avatar
1 vote
0 answers
163 views

Cheap global shutter cameras with external synchronization

Please recommend cameras for multi-camera setup satisfying the following conditions: Relatively cheap (up to 100$ per camera). Global shutter. No filters on lenses or pixels. Resolution of 1 MP or ...
user3234005's user avatar
1 vote
0 answers
58 views

SLAM - Angle calculation failure ?-EKF

i am currently building up a EKF SLAM. I dont know where my mistake is but i think it has something to do with the angle my robot is driving towards but im not completly sure. First i thought it could ...
muller135's user avatar
1 vote
0 answers
78 views

How to correctly use [VertexSE3Expmap] as two connecting Vertex in Edge_V_V_GICP?

I am working on a pose estimation problem solved by Levenberg-Marquardt with g2o. I want to build 3D rigid constraint between two pose, so I choose Edge_V_V_GICP and test the g2o/examples/icp/...
Jerry123's user avatar
1 vote
0 answers
2k views

What does the normalized image coordinates imply?

In VSLAM or visual odometry, we use a camera matrix P to transform 3D scene points to 2D image points. When using homogeneous representation, we may choose the image coordinates as the normalized ...
lzx071021's user avatar
1 vote
0 answers
61 views

Intel Realsense Cameras for Object Avoidance and SLAM to go to destination

My goal is to make a UAV which can search an area while avoiding obstacles. I figured I would navigate using the SLAM and Intel Realsense D435i (a stereoscopic camera with an IMU built in), but all of ...
figbar's user avatar
  • 111
1 vote
1 answer
67 views

Are there any Algorithms/Papers about 3D Mapping the Interior of Buildings using Computer Vision and IMU Data?

I was wondering if it would be possible to do something like this: Vision-based Autonomous Navigation and Mapping with a Small Quadrotor without using lidar/lasers. I have tried ORB-SLAM, but the ...
Brian Nguyen's user avatar
1 vote
0 answers
359 views

How to calculate observation matrix Jacobians in EFK based mono slam? What are projection Jacobians?

I have been trying to understand an implementation of monoSLAM 1. But my question is generic to EKF based single camera SLAM. My Jacobian calculation leads to complex and lengthy expressions while ...
Vinmean's user avatar
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1 vote
0 answers
89 views

Map initialization problem in Mono SLAM

I'm reading and trying to implement the paper Monofusion(V. Pradeep, C. Rhemann, S. Izadi, C. Zach, M. Bleyer and S. Bathiche, "MonoFusion: Real-time 3D reconstruction of small scenes with a single ...
kju's user avatar
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1 vote
0 answers
197 views

How to calculate a covariance of trajectory?

I have a drifted LiDAR odometry $^w \textbf{T}_{1:k}\in SE(3)$ and a drift corrected LiDAR odometry $^w \textbf{T}'_{1:k}\in SE(3)$ by a loop closure where w represents the reference world frame. ...
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1 vote
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104 views

How to update a new pose in iterative pose optimization problem?

There are multiple ways to update new pose in iterative pose optimization problem. The easiest one we often find in papers in robotics is as SO3 + translation Update on right \begin{equation} \...
Chanoh Park's user avatar
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1 vote
1 answer
1k views

ROS: joint_state_publisher dies when used in remote launch file

I've been trying to run robot_state_publisher and joint_state_publisher on a remote TX1 running Ubuntu 16.04 and ROS Kinetic. When running the node from a local launch file (manually ssh into the ...
Kemal Ficici's user avatar
1 vote
0 answers
64 views

How to penalize blurred images in Bundle Adjustment?

We know that when rotational and linear velocity of the camera is high it is highly likely to get blurred images. The blurred image affects the quality of the accuracy in the feature tracking problem. ...
Chanoh Park's user avatar
  • 1,577
1 vote
0 answers
151 views

Camera calibration sequence with ground truth data

I'm looking for a SLAM dataset (monocular or stereo) specifically with a checkerboard, meaning the camera always has a checkerboard in frame. Most popular datasets provide calibration sequences, ...
Sepehr's user avatar
  • 111
1 vote
0 answers
266 views

EKF based SLAM, marginalization and key-frames

I have a couple of tightly related questions regarding EKF-based visual SLAM. It is common in the Kalman based VSLAM litterature to marginalize 3d points and past poses. Condsidering the EKF as a ...
Ash's user avatar
  • 420
1 vote
0 answers
149 views

Kalman filter localisation equations

I am doing mobile robot localisation as a project. Now I stuck in obtaining the equations of EKF localisation. My robot moves straight for 10 seconds parallel to x-axis and robot equipped with 2 ...
Nekromant's user avatar
1 vote
0 answers
216 views

Scaling monocular SLAM with another source?

I have implemented a stable monocular slam tracking system, based on ORBSLAM2. I am trying to find a way to add real-world distance/scale to this. At the same time, I am running a (less stable) ...
anti's user avatar
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1 vote
0 answers
725 views

Calculate input parameters of CTRV model

I am using Constant Turn Rate and Veloctity (CTRV) model to predict the position of the vehicle.The CTRV model assumes a circular path between two consecutive time steps of the car as depicted in the ...
Beginner_In_Image_Processing's user avatar