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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2answers
2k views

Understanding and correct drift when using BreezySLAM (aka tinySLAM / CoreSLAM)

I was looking for a Python implementation of SLAM and stumbled upon BreezySLAM which implements tinySLAM aka CoreSLAM. My robot is equipped with the hokuyo urg-04lx-ug01. I have odometry hence ...
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8answers
15k views

Absolute positioning without GPS

Using an IMU a robot can estimate its current position relative to its starting position, but this incurs error over time. GPS is especially useful for providing position information not biased by ...
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3answers
4k views

Difference between SLAM and “3D reconstruction”?

I'm reading this paper: http://arxiv.org/abs/1310.2053 (The role of RGB-D benchmark datasets: an overview) and see the following words: Thanks to accurate depth data, currently published papers ...
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2answers
387 views

Typical laser scanner noise values

I am building an application that executes graphSLAM using datasets recorded in a simulated environment. The dataset has been produced in MRPT using the GridMapNavSimul application. To simulate the ...
14
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3answers
584 views

How to determine quality of ICP matches?

In SLAM frontends which use the Iterative Closest Point (ICP) algorithm for identifying the association between two matching point clouds, how can you determine if the algorithm is stuck in a local ...
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0answers
312 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 ...
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1answer
367 views

Autonomous Indoor Positioning System Robot based on CV approach

I have some questions regarding an IPS autonomous robot system, Configuration: Mounting a camera to the ceiling of a room Assume the room is a cube of 5mx5mx5m (LxWxH) Assume the camera is ...
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0answers
585 views

SLAM - odometry motion model

I am making a project with a 4 wheeled differential robot to make visual SLAM using a stereo rig. I have some encoders to measure de displacement and the steering angle of the robot and I want to use ...
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3answers
943 views

Build a simple robot to learn ROS [closed]

I am a beginner to ROS and I wanted to know if I could build a simple robot to learn ROS. I currently have the following components available: Arduino Uno Simple two wheeled robot chassis Some ...
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1answer
1k views

Is there an algorithm using the Kinect depth image (not the point cloud) for registration?

I know given the intrinsics fx, fy, cx, cy (where fx, fy are the horizontal and vertical focal length, and ...
2
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0answers
120 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 ...
4
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1answer
946 views

Calculate the uncertainty of a 6-dof pose for graph-based SLAM

This question is strongly related to my other question over here. I am estimating 6-DOF poses $x_{i}$ of a trajectory using a graph-based SLAM approach. The estimation is based on 6-DOF ...
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1answer
265 views

Is there an alternative to manifolds when using quaternions for orientation representation in Pose Graph SLAM?

I want to implement my own pose graph SLAM following [1]. Since my vehicle is moving in 3D-space i represent my pose using a 3D-translation vector and a quaternion for orientation. [1] tells me that ...
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4answers
238 views

Single Touch Based Sensor and Odometry SLAM in Noisy Rectilinear Environment

A Co-worker said he remembered a 2011(ish) ICRA (ish) paper which used just a touch/bump sensor and odometry to do SLAM. I can't find it - I've paged thru the ICRA and IROS agendas and paper ...
4
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1answer
272 views

In order to integrate MCL and Occupancy Grid to implement Grid-based FastSLAM, do you have to record all data?

It's unclear as to how one goes about integrating Occupancy Grid mapping and Monte Carlo localization to implement SLAM. Assuming Mapping is one process, Localization is another process, and some ...
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1answer
2k views

Pose-Graph-SLAM: How to create edges if only IMU-odometry is given?

I want to estimate the poses of a vehicle at certain key frames. The only sensor information I can use is from an IMU which yields translational acceleration and orientation measurments. I obtain a 7D ...
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2answers
173 views

Slam Odometer Requirement

How accurate must my odometer reading be for SLAM ? I am writing this extra section because it says my question body does not meet the quality standard.
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3answers
251 views

In the SLAM for Dummies, why are there extra variables in the Jacobian Matricies?

I am reading SLAM for Dummies, which you can find on Google, or at this link: SLAM for Dummies - A Tutorial Approach to Simultaneous Localization and Mapping. They do some differentiation of matrices ...
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1answer
2k views

Understanding Drift in Simultaneous Localization and Mapping (SLAM)

I am trying to understand the effect of drift in Simultaneous Localization and Mapping (SLAM). My understanding is that drift occurs because the robot tracks its position relative to a set of ...
2
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1answer
130 views

EKF SLAM (prediction of new landmarks)

Prediction of new landmarks are commonly expressed as: Xm = Xr + r*cos(phi + theta_r), Ym = Yr + r*sin(phi + theta_r) However this is only true ...
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1answer
1k views

How to compute the error function in graph SLAM for 3D poses?

Given a pose $x_i = (t_i, q_i)$ with translation vector $t_i$ and rotation quaternion $q_i$ and a transform between poses $x_i$ and $x_j$ as $z_{ij} = (t_{ij}, q_{ij})$ I want to compute the error ...
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2answers
285 views

Ensemble Kalman Filter SLAM

I know that there is an extended kalman filter approach to simultaneous localization and mapping. I'm curious if there is a SLAM algorithm that exploits the ensemble kalman filter. A citation would ...
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2answers
2k views

Real-time camera localisation in known environment

I am young researcher/developer coming from different (non-robotic) background and I did some research on camera localisation and I came to the point, where I can say that I am lost and I would need ...
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1answer
2k views

Modelling Point Clouds for Collision Detection in Gazebo

I am currently applying path planning to my robotic arm (in Gazebo) and have chosen to use an RRT. In order to detect points of collision, I was thinking of getting a Point Cloud from a Kinect ...
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3answers
498 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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2answers
1k views

EKF-SLAM initialize new landmark in covariance matrix

I am trying to implement an EKF-SLAM using the algorithm for unknown correspondences proposed in the book "Probalistic Robotics" by Sebastian Thrun in Table 10.2 . By now I understand actually all ...
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2answers
557 views

how to plot $\pm 3 \sigma$ of a landmark in EKF-SLAM

I have implemented 2D-SLAM using EKF. The map is based-feature in which there is only one landmark for the sake of simplicity. I've read some papers regarding this matter. They plot the $\pm3\sigma$ ...
2
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2answers
1k views

Is it possible to do SLAM with few IR sensors like Buddy?

I saw Buddy's page and want to purchase for my SLAM research. However, I wonder is it possible to program Buddy for SLAM? According to Buddy's spec, they're only few IR's, sonars and a camera. As I ...
4
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1answer
194 views

EKF-SLAM: Shrink covariance matrix on one direction

I have implemented an EKF on a mobile robot (x,y,theta coordinates), but now I've a problem. When I detect a landmark, I would like to correct my estimate only on a defined direction. As an example, ...
2
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1answer
208 views

Using SLAM to create 2D topography

I have a small mobile robot with a LidarLite laser range finder attached to a servo. As of now I have the range finder side-sweeping in a 30 degree arc, taking continuous distance readings to the side ...
2
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1answer
1k views

Covariance and optimization

I am trying to build a map containing lamps as landmarks. I drive around with a robot and a monocular camera looking to the ceiling. The first step is detect the edges of each observed rectangular ...
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2answers
193 views

indoor positioning system: which is better? [closed]

Which method is better, in term of accuracy, for detection of indoor localization of a drone. Camera based system or wireless techniques like WLAN or Bluetooth?
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1answer
124 views

Optimal hardware for linear algebra operations

I've been working lately on SLAM algorithms implementing extended kalman filtering to brush up on some localisation techniques and I have been thinking forward to the hardware side of things. Are ...
4
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1answer
4k views

Graph optimization with G2O

I'm trying to do graph optimization with G2O, mainly in order to perform loop closure. However finding minimal working examples online is an issue (I've found this project, as well as this one. The ...
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1answer
366 views

Need help regarding EKF in MonoSLAM

I am trying to understand the implementation of Extended Kalman Filter for SLAM using a single, agile RGB camera. The vector describing the camera pose is $$ \begin{pmatrix} r^W \\ q^W \\ V^W \\ \...
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1answer
2k views

What is the difference between Positioning and Localization Systems

I would like to know what are the differences between Positioning and Localization Systems. In most review papers they are used interchangeably. Are they the same? For example: GPS(Global Positioning ...
12
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1answer
394 views

What is the difference between SAM and SLAM?

What is the difference between Smoothing and Mapping (SAM) and Simultaneous Localization and Mapping (SLAM)? These general approaches seem closely related. Can someone describe the differences?
0
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1answer
109 views

EKF over-correcting?

I've been implementing an extended kalman filter, following Thrun's Probabilistic Robotics implementation. I believe my correct step may be wrong, as the state appears to be corrected far too much. ...
4
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2answers
2k views

the uncertainty of initializing new landmark in EKF-SLAM

In EKF-SLAM (based-feature map) once the robot senses a new landmark, it is augmented to state vector. As a result, the size of the state vector and the covariance matrix are expanded. My question is ...
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1answer
962 views

EKF-SLAM Computing the jacobians for landmark updates

I've been working through this informative guide on EKF-SLAM but I'm having difficulty understanding the jacobians required for the 'landmark update', on page 35. What exactly is Jxr and Jz taking as ...
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1answer
656 views

EKF-SLAM, how best to manage the 'P' covariance matrix, programatically

I've recently been learning about SLAM and EKF-SLAM. I've began my implementation in python, but have had trouble managing the updating of P, especially when it comes to adding new landmarks. ...
0
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1answer
439 views

SLAM noob here, a few questions regarding EKF-SLAM

I've recently been learning about SLAM and have been attempting to implement EKF-SLAM in python. I've been using this great article as a guide. Some progress has been made, but I'm still confused by ...
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1answer
121 views

Robotics SLAM datasets - scaling factor

There are several robotics datasets for SLAM, like this one. In this webpage you can see that the depth image is scaled by a factor of 5000, so that float depth images can be stored in 16 bit png ...
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1answer
119 views

Finding changes in environment using 2d laser

I have known map of the environment (2d occupancy grid map). I am trying to find if anything changed in environment using 2d laser while navigating by using maximum likelihood of laser with known map. ...
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1answer
2k views

joint compatibility branch and bound (JCBB) data association implementation

I would like to implement the joint compatibility branch and bound technique in this link as a method to carry out data association. I've read the paper but still confused about this function $f_{H_{i}...
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3answers
115 views

The uncertainty is big while the sensor is rather accurate at measuring a landmark in EKF-SLAM

I've a 2D sensor which provides a range $r$ and a bearing $\phi$ to a landmark. In my 2D EKF-SLAM simulation, the sensor has the following specifications $$ \sigma_{r} = 0.01 \text{m} \ \ ,\sigma_{\...
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3answers
2k views

SLAM without landmarks?

First, is it possible to build map without landmarks for a robot in 2D? Let's say we have an aisle surrounded by two walls. The robot moves in this environment. Now is it feasible to build such a ...
5
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1answer
1k views

role of chi2 in SLAM back-end optimization

All-most all SLAM back-end implementation compute chi2 estimates. Chi2 computation is usually used to compute the best-fitness score of model to the data. How it is related to optimization framework ...
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0answers
55 views

SLAM Goal Babbling

I am struggling to find good links to the use of goal babbling in SLAM applications. Has this technique been used as a method for optimizing movement in a SLAM environment?
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3answers
370 views

Is the accuracy of estimated position in localization better than estimated position in SLAM?

We estimate position of robot in localization and SLAM. My intuition says we get better position estimation in localisation than in SLAM because we have better sensor model likelihoods in localization ...

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