Questions tagged [pose]

Pose is a typical task is to identify specific objects in a space and to determine each object's position and orientation relative to some coordinate system.

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68 views

3D Rigid Body Pose Optimization in flat euclidean space

I am confused about what is the best way to optimize the 3D pose of an object and the best way to parametrize the translation and rotation for optimization in flat euclidean space. Assume I have a ...
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73 views

How do you handle angle discontinuities in estimation problems?

When one is implementing a state estimator in a system that involves kinematics, will inevitably face the problem of angle discontinuities, i.e., the fact that the angles have to be wrapped between ...
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46 views

given current position and Quaternion and target local rotations (α, β, γ, in radians), how to calculate the new Quaternion

Say we have an object (e.g., end-effector of a robot) that is defined in a general coordinate system by a Cartesian position and Quaternion. since the Quaternion is with respect to a general and fixed ...
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36 views

Number of diagonal elements in the pose covariance matrix

The control.yaml file inside the husky_gazebo package defines the value of the ...
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1answer
5k views

AprilTag vs Aruco markers [closed]

AprilTag and Aruco are both popular methods for vision-based fiducial marker pose estimation. What are the pros and cons of each fiducial marker pose estimation systems?
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130 views

Error in Pose(): All values are zero for turtlesim/Pose

Here is the program I have written. The function is to make the turtlesim complete one revolution, with a fixed angular velocity and speed. ...
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1answer
26 views

How to calculate extrinsic calibration of a non-overlapping multicamera rig?

thanks for taking the time to check my question. Firstly, let me describe the current configuration, I am using 4 cameras that produce non-overlapping images and the goal is to calculate their ...
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1answer
72 views

Reset coordinate system of robot while maintaining relationship to the previous

I am currently estimating a robot's pose (3d position and rotation matrix) with an IMU and I want to reset the localizer in the middle of the run while keeping the relationship to the pose it had when ...
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1answer
73 views

Calculate transform from different poses

My robot is at a starting pose $s_0 = (x_0, y_0, \theta_0)$ and, while moving, I receive a sequence of motion measurements $[\mu_1, \mu_2, \: ... \: \mu_n]$, where $\mu_i = (\Delta x_i, \Delta y_i, \...
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15 views

What's the difference between optimizing a pose graph only once as opposed to optimizing a pose graph whenever loop closures are found?

I am trying to optimize a pose-graph generated through visual odometry with loop closure constraints. I wanted to know if there are any particular situations where optimizing the graph only once is ...
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24 views

Cartographer: What determines how many nodes are added to a trajectory?

I'm testing cartographer using the Deutsches Museum public bag. I'm trying different Lua settings and checking how it affects the mapping process, etc. What I notice is that, no matter what ...
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84 views

What is the difference between a Bayes Net and a Factor Graph

I am just getting started on understanding Factor Graphs, by going through the excellent guide Factor Graph For Robot Perception by Dallaert and Kaess While I am familiar with the SLAM problem, and ...
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Orientation Movement Primitives for Imitation Learning

Can Movement Primitives be used to model the orientation (or pose) of a robotic arm end effector? In literature (see for instance this imitation learning review at pag.69) it's common to see DMP (...
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303 views

Is easier to detect a large or a small marker? (Aruco / Apriltags)

I need to detect Aruco/Apriltags markers and perform pose estimation, but I've no particular constraint on their physical size. I'm not talking about the number of square (e.g. 4x4, 6x6, etc.), but of ...
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0answers
12 views

Getting the new heading after a Transformation

Lets say I have 2d poses as such (angles in degrees): world_to_robot = {0, 4, 45} robot_to_object = {4, -4, -45} From a graph it would be easy to see that: world_to_object = {4, 8, theta}, what goes ...
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Self localization inside machine of interest

I have a type of flight sensor interfaced with Arduino Uno via I2C. The sensor is VL53L0X i am getting the 1D measurement value of distance in mm which i can monitor using serial monitor in Arduino ...
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105 views

How can I calibrate 3 cameras without knowing global pose of the object & camera locations? How can I find the pose of each camera wrt the first one?

I have camera feed (in the form of RGB images) from 3 cameras with partially overlapping Field-of-view i.e. for the time stamp 0 to 100, I have total 300 frames or say synchronized 100 RGB frames for ...
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42 views

IMU Vision Fusion using EKF

I am trying to track an object indoors using an IMU (only accel and gyroscope) and a visual marker. This is similar to IMU+GPS fusion, where GPS is effectively replaced by the position that my vision ...
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2answers
63 views

For pose estimation, what is the typical range of the rotation values that are estimated? Is it from -180 to 180 degrees?

I am currently working with the Rutgers APC 2015 data set for pose estimation, and see that the pose estimates, specifically the rotation estimates, have seemingly been rescaled to range between -1 ...
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325 views

How to properly initialize every new pose in a Visual SLAM algorithm (namely DSO)?

My question is a bit specific, because it is linked to a certain algorithm. Therefore I didn't find any other solutions on how to go about this problem. If you could refer me to research papers, ...
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1answer
44 views

Dual constraint non-linear optimization for SLAM

I am trying to achieve a nonlinear optimization for SLAM on a function that contains two different constraints, like this : $$ T_{opt} = \underset{T}{\arg\min} \sum_i(\left\lVert T.X_i - x_i \right\...
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219 views

two wheel mobile robot odometry

I am using an encoder to calculate the position and orientation of a mobile robot. The robot has two-wheel and each wheel is attached with an encoder, the result I am getting for my position x,y and ...
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2answers
152 views

Is pose estimation using images necessary in visual-inertial SLAM

In visual SLAM, pose estimation is performed between two adjacent frames or keyframes using feature detection and pose estitmation from corresponding features. However in visual-inertial SLAM, pose ...
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2answers
79 views

What's the difference between Pose Measurement and Position Measurement?

I have read a robotic related paper called Estimating SE(3) elements using a dual quaternion based linear Kalman filter, and the author proposed that the equation of position measurement is denoted as:...
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27 views

Two Link Manipulator End Effector Position

My professor described the end effector position as $q_{e} = \begin{bmatrix} x_e \\y_e\end{bmatrix} = \begin{bmatrix} l_1 cos(\alpha_1) + l_2cos(\alpha_1 + \alpha_2) \\ l_1 sin(\alpha_1) + l_2sin(\...
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What's the difference between the term "pose estimation" and "visual odometry"?

I'm reading a paper: Choi C, Trevor A J B, Christensen H I. RGB-D edge detection and edge-based registration[C]//Intelligent Robots and Systems (IROS), 2013 IEEE/RSJ International Conference on....
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1answer
159 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: ...
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3answers
469 views

State of a Robot

I saw the expression "robot state" in many articles and resources, but I could not understand what that exactly mean. What does state of a robot exactly refers to ?
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816 views

Position vs Image based visual servoing?

Can anyone explain Image based visual servoing for robotic arm through example? I can understand Position based based visual servoing like this, .... there is an object and estimating it 6D Pose ...
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131 views

How to get RPY(Roll, Pitch, Yaw) from directional cosines from a single vector?

I'm trying to find the pose of an 3D vector in terms of RPY. Let's say the two end points of the vector is P0(x0, y0, z0) and P1(x1, y1, z1). So the centered vector I get is V(Vx, Vy, Vz) = P1 - P0 = (...
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262 views

smooth robot 3D trajectory using graph optimization

I want to solve a trajectory smoothing problem using graph optimization. I have asked questions on how to solve this problem in a previous post and got directed towards using graph optimization. I ...
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227 views

smoothing the robot poses inbetween two known poses

I have a set of N robot poses between point A and B. I use a global localization technique to estimate poses at point A and B. As a result, I have a new corrected pose B'. Please see the figure below. ...
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2k views

Integrating GPS into Graph SLAM (how orientation fixed?)

I'm working on Graph SLAM to estimate robot poses (x, y, z, roll, pitch, yaw). Now I want to integrate GPS measurement (x, y, z, of course no angles). I implemented GPS as pose's prior. But I have a ...
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0answers
69 views

How to apply Kalman filter in this case?

I have some straight and curve pieces with numbers, they are used to build tracks (of $5$ lanes) for my cars (figure $1$), I can send commands to the cars using an SDK on the Raspberry (set the speed ...
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3answers
84 views

How to detect writing on a chalkboard? [closed]

I've got an idea for a simple robot (with an Arduino or something similar) that will play noughts-and-crosses (aka tic-tac-toe) on a chalkboard, so that kids can play against it. It will use a couple ...
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1answer
154 views

Perspective N point solution: Position drifting linearly with rotation angles?

I am using a PNP algorithm to compute the rotation and translation of a camera given pre-mapped 3D points, and their corresponding projections on the 2D plane. The algorithm I am using is the one ...
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1answer
1k views

How many AR markers should I use to get the object pose?

I'd like to get the object pose based on the attached AR marker to the object. I believe I only need one tag to get the 6D pose. However, I sometimes see more than one AR markers are used in the ...
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1answer
2k views

Which is the best visual fiducial marker (2D barcode)?

Which is the best visual fiducial marker (2D barcode) for detection and robust and accurate pose estimation? Im not looking for a fiducial marker which can store lot of information. The main goal is ...
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366 views

What is the difference between object pose estimation and object tracking?

In papers the terms object pose estimation and object tracking are used side by side with different meanings. Can somebody explain me the difference?
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845 views

Full 3D Pose (Scale, Rotation and Translation) Estimation using Gyro and Acceleromter sensors fusion

I am implementing a 3D pose estimation algoriothm on mobile device (Android) which has Gyro, Accelerometer and Magnetometer sensors. I have already develeoped a Visual SLAM algoirthm to estimate full ...
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0answers
124 views

Help with fusing multiple measurements with known covariances

I am working on an estimation application for multiple robots, each of which uses measurements from various sources to calculate position and orientation data. For now, I am looking at about three ...
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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 ...
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6k views

Determining pose from ar_track_alvar message in ROS

I am using the ar_track_alvar package in Indigo to detect AR Tags and determine their respective poses. I am able to run the tracker successfully as I can visualize the markers in RViz. I give the ...
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1answer
272 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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1answer
53 views

Step size in numerical differentiation

I get position information and a corresponding timestamp from a motion tracking system (for a rigid body) at 120 Hz. The position is in sub-millimeter precision, but I'm not too sure about the time ...
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1answer
269 views

Choosing the state vector for an EKF

Could someone help me understand the logic behind choosing a particular state space vector for an EKF? Context: Say there is a 4 wheeled robot that operates only in 2D. It is equipped with an ...
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1answer
4k views

How do I go about implementing a Kalman Filter for a pose estimation algorithm?

I am currently in the process of writing a pose estimation algorithm using image data. I receive images at 30 fps, and for every image, my program computes the x,y,z and roll, pitch, yaw of the camera ...
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1answer
369 views

Kalman filter for estimating position with “direction” measurements

I am currently working on a pose estimation problem for which I would like to use filtering. To explain the system briefly, it consists of two cameras and each has its own GPS/IMU module. The main ...
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1answer
300 views

Pose estimation, how to populate set of known edges and points?

I am building an estimator that solves for the camera pose relative to a reference frame which contains a known set of features and edges. Currently, the system works with an unscented kalman filter ...
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1answer
3k views

Open source implementations of EKF for 6D pose esimation

I am looking for open source implementations of an EKF for 6D pose estimation (Inertial Navigation System) using at minimum an IMU (accelerometer, gyroscope) + absolute position (or pose) sensor. ...