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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1answer
149 views

sparse matrix in EKF SLAM

I've successfully done with EKF Localization Algorithm with known and unknown correspondences that are stated in "Probabilistic Robotics". The results make perfect sense,so I can estimate the position ...
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1answer
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EKF SLAM and Mahalanobis distance?

So far I have done EKF Localization (known and unknown correspondences) and EKF SLAM for only known correspondences that are stated in Probabilistic Robotics. Now I moved to EKF SLAM with unknown ...
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EKF based Slam implementation with landmark identification in Global frame

I am working on mobile Robotics. I want to implement Slam. I have a very specific question about EKF Slam. To implement Slam I read the book "Probabilistic Robotics". I read its online version. There ...
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Which micro-controler/processor to be used for autonomous stereo vision robot system?

I am very new two robotics, however I have a working stereo algorithm which I want to combine with a SLAM algorithm. I am developing this system for an other application but I decided integrating it ...
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364 views

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 ...
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1answer
173 views

Does marginalization increase the number of edges in Graph SLAM?

I thought marginalization does not change the number of the edges but this material (page 11) describes that as a result of marginalization we will have more edges in graph. Why does it increase the ...
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2answers
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Why do we need a marginalization in Bundle Adjustment?

A common practice in Bundle Adjustment is to reduce the state dimension by marginalizing structure or pose states to improve the optimization speed. In case 3d points(structure) $\textbf{p}_i$ are ...
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1answer
817 views

GraphSLAM: why are constraints imposed twice in the information matrix?

I was watching Sebastian Thrun's video course on AI for robotics (freely available on udacity.com). In his final chapter on GraphSLAM, he illustrates how to setup the system of equations for the mean ...
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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. ...
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3answers
1k views

Which sensors will best suited for indoor/outdoor SLAM system with high accuracy of localization? [closed]

We need a SLAM system for mobile platform which will be used in on-site construction. We are to build a 3D map from clouds of points and need localization in it. We don’t need fast localization, but ...
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2k views

Calculating the covariance matrix of a measurement

I want to estimate the covariance matrix of a measurement for a robot evolving on plane and having the following state vector. $$ X = \begin{bmatrix} x\\ y\\ \theta \end{bmatrix} $$ $x$ and $y$ are ...
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4answers
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3D mapping using only a 2D Lidar

How can I map a 3D environment using only a 2D lidar? The lidar would be hand held and it would have 6 DoF. So if I move it in arbitrary motion in all 6DoF, I expect my algorithm to generate a 3D map ...
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4answers
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How to obtain dense point clouds from stereo cameras?

I am trying to use a stereo camera for scene reconstruction, but I can usually only obtain sparse point clouds (i.e. over half the image does not have any proper depth information). I realize that ...
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1answer
133 views

Once matching features are computed between a stereo pair, how can they be tracked?

I am currently working on a SLAM-like application using a variable baseline stereo rig. Assuming I'm trying to perform visual SLAM using a stereo camera, my initialization routine would involve ...
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2answers
621 views

Using an IMU to build an INS

What's needed to utilize an IMU such as the ArduIMU+ V3 to be used in an INS. Is there any other hardware needed?
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1answer
248 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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104 views

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) ...
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1answer
403 views

Questions about SLAM: bundle adjustment, covariance etc

I have been recently studying about the SLAM family of algorithms, with the idea of implementing some for a multi-robot framework I have. With regards to the concept, I have a couple of related ...
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114 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, ...
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1answer
50 views

In the SLAM for dummies what is z-h in updating X?

In SLAM for Dummies there is on page 40 this formula: $X = X+K(z-h)$ What is $z-h$ in updating $X$?
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730 views

How would i implement position and heading readings into my SLAM system?

I am trying to build a low-cost SLAM system with an MPU-6050 and GY-271 (magnetometer). Currently, i have a robot with an Arduino that collects the sensor data and a Raspberry Pi that (hopefully) will ...
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1answer
376 views

How can we estimate the likelihood field for a particular scan in probabilistic terms?

I am trying to implement a scan matcher using Scan based sensor model but I cant figure out how to estimate likelihood for a particular scan. Is there any implementation available ? Would be thankful ...
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2answers
928 views

ROS + SLAM + kinect. which platform to use?

I am doing a project where I've robot which will be using kinect + ROS for Simultaneous Localization and Mapping. Which board should I use? I've heard that Raspberry pi , beaglebone are not sufficient....
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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 ...
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1answer
95 views

Do i really need an AHRS for 2D maps?

I am currently making a 2 wheeled SLAM robot that will use an array of either ultrasonic or sharp IR sensors with a particle filter. I also have a MPU-6050 and GY-271 and i am looking to turn it into ...
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141 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 ...
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2answers
1k views

SLAM system for LIDAR and Stereo camera for cone detection for Autonomous driving

The purpose of the SLAM system is very specific, for detecting cones in an image and triangulate their position to create a map. The data input would be the camera data, odometry and the LIDAR data. I ...
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1answer
20 views

Can we specify the working zone for the robot using SLAM approach for navigation?

I am using SLAM for the autonomous vehicle navigation. I want to the specify the working zone for the vehicle before the start of navigation, or can we restrict the working zone of the vehicle using ...
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1answer
351 views

Why the IMU measurements only accumulate drift in 4DOF

I'm studying the Technical Report of VINS-Mono: A Robust and Versatile Monocular Visual-Inertial State Estimator available at: https://github.com/HKUST-Aerial-Robotics/VINS-Mono/blob/master/...
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1answer
284 views

What is the intuitive explanation of using Jacobian of observation model while calculating Kalman gain in EKF SLAM?

The idea of using Kalman gain in EKF SLAM is to figure out how much we trust our motion model and sensor/observation model. As explained in The Extended Kalman Filter: An Interactive Tutorial for Non-...
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1answer
128 views

Why EKF-SLAM uses EKF instead of linear Kalman Filter?

I am writing a bachelor's diploma on vSLAM. I learned and programmed EKF-SLAM like it's written in MonoSLAM paper, and I was going to write, that I can't use KF and have to use EKF because of non-...
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3answers
948 views

How can I implement tremaux algo in arduino line follower to navigate and create map?

The Map1 The task is divided into 2 runs, In first run, We have to navigate through whole map and reach the end mark taking all checkpoints. In second run, using the mapping from first run we have to ...
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2answers
7k views

Difference between Rao-Blackwellized particle filters and regular ones

From what I've read so far, it seems that a Rao-Blackwellized particle filter is just a normal particle filter used after marginalizing a variable from: $$p(r_t,s_t | y^t)$$ I'm not really sure ...
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1answer
1k 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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2answers
1k views

using range-only sensors for mapping in SLAM

SLAM noob here but trying to implement an algorithm that fuses odometry data and mapping based on wifi signal strengths for a 2D robot. 1) After various readings of different resources, I came across ...
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1answer
523 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
381 views

Pose-graph-slam:using only a camera

I'd like to know how to form my pose graph if the only information I have available is that from a camera, (1) What are my poses? Are they just the accumulated transformations from pairwise matching? ...
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2answers
371 views

Can i use a predictive kalman filter to 'increase' my sample rate?

I have a slam algorithm that outputs at around 30Hz, an implementation of ORBSLAM2. https://github.com/raulmur/ORB_SLAM2 I am reading this into a renderer that expects 60+ Hz. Because my sample ...
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0answers
199 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) ...
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1answer
2k views

SLAM: Why use two cameras (stereo) if SLAM can be done using single camera (monocular)?

I am aware that algorithm for monocular SLAM is complex compared to stereo SLAM. But my question is if by any means it is possible to do SLAM using one camera why one should use two cameras to do the ...
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0answers
254 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 ...
2
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1answer
311 views

SLAM without data association?

I would like to build 2D EKF-SLAM in openGL. I've implemented the entire virtual environment in which there is a robot that moves in 2D and there are some landmarks(feature-based map). I have the ...
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2answers
418 views

SLAM for Autonomous car

I am working on SLAM for autonomous car like vehicles with 2D lasers and IMU (deriving odometry). I would like to know how efficient is using the existing SLAM algorithms (for example: gmapping in ...
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2answers
3k views

How to use SLAM with simple sensors

What 2D SLAM implementations (preferably included in ROS) can be used with simple distance sensors like IR or ultrasonic rangefinders? I have a small mobile platform equipped with three forward ...
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2answers
283 views

Having a hard time understanding this equation in monocular EKF SLAM

Reading this paper on visual odometry, where they have used a bearing vector to parameterize the features. I am having a hard time understanding what the state propagation equation for the bearing ...
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1answer
248 views

Covariance Check?

I have a localization data estimated and GPS_truth and generated [3x3] covariance matrix along with them. What i would like to do is to see if the covariance is correct or not? Can we check it by ...
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1answer
56 views

Orthogonal projection of laserscanner data

I recently discovered this ROS-package: http://wiki.ros.org/laser_ortho_projector . Which is basically exactly what I need. However I am not using ROS, so I need to do what is been done in this ...
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1answer
871 views

How to implement a particle filter when sensors can't identify landmarks?

I'm attempting to build a robot that leverages a particle filter to identify where it is relative to a map that is known. The robot only has IR sensors, so while it is able to determine its distance ...
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2answers
103 views

Hi i am working on this project regarding localization of a mobile robot using laser scanner and odometry ( encoder sensors) using labview [closed]

I have a Sick laser scanner LMS 100 attached with my robot which scans the environment. Data acquistion is already done for the laser scanner and now Encoder sensor attached on the wheel gives the ...
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1answer
106 views

In vision based localization, is it possible to make multiple vehicles cooperate to improve the estimation of each other?

I am currently working on a project that involves structure from motion using multiple cameras on multiple aerial vehicles (each vehicle has a monocular camera: think of it as a distributed stereo), ...

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