Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [calibration]

Correlate the readings of a robot's instrument, sensor, etc. with those of a standard in order to check its accuracy. Adjust experimental results to take external factors into account or to allow comparison with other data.

0
votes
0answers
21 views

Extrinsic calibration of a multicamera-rig mounted rigidly on a mobile robot

We have a set of 8 cameras mounted rigidly on a mobile robot. The cameras are forming an arc, which allows a 360º vision. I want the extrinsic parameters of them referred to the robot. Is there any ...
1
vote
0answers
41 views

robot Hand Eye Calibration problem

I am trying to understand the implementations and the relative performance of various classical and new Hand-eye calibration approaches. Note: The following discussion assumes implementations are in ...
0
votes
0answers
11 views

Ready to use camera calibration in linux

I am looking for a ready-to-use implementation of "opencv" camera calibration in Ubuntu. I have mine but the code was implemented for the windows. I would like to convert it but simply the deadline is ...
1
vote
0answers
32 views

Stereo-Calibration with Variable focal cameras

Is it possible to perform stereo-calibration with cameras having variable focus? and if so, how is it done basically?
2
votes
0answers
20 views

Stereo Rectification when Extrinsics are known

Suppose I have two cameras $C_1$ and $C_2$ arranged in a stereo configuration. Let us assume that the camera is free of distortion with ideal intrinsics and that the camera extrinsics $R$ and $t$ are ...
1
vote
0answers
24 views

hand-eye calibration for wheeled mobile robots

I am new to robotics and working with a wheeled mobile robot with one Kinect mounted on top of it currently. The robot knows its position in the environment via some means. I encounter one problem. ...
1
vote
2answers
59 views

Hand eye calibration of robot arm using a 2D camera and marker of known size

If my understanding is correct, one flavor of hand eye calibration requires the following pairs of data for different robot arm positions: The transform from the robot base to the robot hand. The ...
0
votes
1answer
43 views

Transformation matrix between a 2D and a 3D coordinate system

I have 2 sensors : one has 2D coordinate system and the other has a 3D coordinate system (not same origin). Knowing the positions of some corresponding target points (used as fixed reference) in both ...
2
votes
0answers
86 views

Magnetometer Calibration

I'm looking at using a magnetometer in a project and I'm struggling to understand the proper procedure for calibration of the sensor. I understand that magnetometers need to be calibrated to ...
3
votes
2answers
70 views

Question about Lens distortion

Suppose I have a 240x180 camera with the following distortion co-efficients, $$k_1 = -0.138592767408$$ $$k_2=0.0933736664192$$ $$k_3=0.0$$ $$p_1=k_4=-0.000335586987532$$ $$p_2=k_5=0.000173720158228$$ ...
2
votes
1answer
217 views

Calibrating Logitic C920 HD 1080p using ros kinetic

I am trying to follow the ROS monocular camera calibration for a USB camera I have, but the calibration routine fails when I try to run it. I was expecting to see an image like the one below, but I ...
1
vote
1answer
45 views

measurement model of the accelerometers in IMU

I am new to IMU. About the measurements from IMU, different materials give different explanations. From the link: https://www.it.uu.se/edu/course/homepage/systemid/vt14/tokp2.pdf Here the b maybe ...
2
votes
2answers
66 views

Practicality of using magnetometer inside AUV

I have an AUV with a 12 inch diameter, 29 inch long capsule. Inside the capsule sits an Intel NUC computer, an NVIDIA Jetson GPU, an Arduino Mega, a Sparton IMU (9 DOF) as well as a custom voltage ...
1
vote
1answer
85 views

Why adding odometry data as control vectors to EKF-Monoslam algorithm fails?

I am working on EKF-MonoSlam (Davson) method for the mere input as a webcam, (it works "fine" if we calibrate and use reasonable sigmas) , and I am trying to add the odometry of some dataset (as ...
0
votes
1answer
69 views

Extrinsic Calibration Target Depth Camera

What's a good calibration object for the extrinsic calibration (rotation + translation) of a depth camera (no color sensor, only depth)? With RGB, people seem to typically use chessboard pattern or ...
1
vote
3answers
360 views

Zero-Point/Home Position/Origin of Absolute Encoder: What is the Proper Name?

I'm writing an academic paper describing the calibration of a system. Part of that system is an absolute rotary encoder measuring the angle of a joint. However, the position at which the encoder gives ...
3
votes
1answer
193 views

How is gyroscope bias exposed and tracked?

For an accelerometer, the measurement is defined in the following way: $$a_m = R_w^b(a_{w} - g) + b_a + v_a$$ Where $R$ is a rotation matrix, $g$ is gravity, $v_a$ is noise, and $b_a$ is the bias. ...
3
votes
2answers
324 views

Robot Calibration using DH parameters

I'm new in robotics. My problem is the next one: I have a 6DOF robot manipulator and because the implementation was for real-time application my calculation time had to be really fast so that I used ...
3
votes
1answer
152 views

OpenCV get topdown view of planar pattern by using intrinsic and extrinsic from cameraCalibrate

Originally I have a image with a perfect circle grid, denoted as A I add some lens distortion and perspective transformation to it, and it becomes B In camera calibration, A would be my destination ...
2
votes
1answer
92 views

Hand eye calibration wrong result

I am trying to do hand eye calibration between the robotic arm end effector and Kinect V1. I am using handeye_calib_camodocal repository for calibration and trying to find $X$ by solving the equation: ...
3
votes
1answer
370 views

Poor accuracy of hand eye calibration when using vanilla Tsai's method

I’m working on the hand eye calibration for the robotic arm. I attached the camera near the tip of the robot (or end effector) and took around 40 pictures of an asymmetric circles pattern. I ...
1
vote
1answer
45 views

Can someone explain what is going on in this calibration video?

I am trying to understand this IMU calibration video. https://www.youtube.com/watch?v=xF7sLU0fX7k&feature=em-comments In the video the operator gets accelerometer data when pointing each axis in ...
0
votes
1answer
108 views

Tool calibration- orientation

I'm currently working on calibration of robot tool. I have found some simple methods to get the tool centre point. But I'm sure how to get the tool orientation wrt the robot's tip (the point where the ...
1
vote
0answers
25 views

Are homogeneous coordinates represented by appending image coordinates with a 1 in camera imaging

In camera imaging, there are several terms for point coordinates. World coordinates: [X, Y, Z] in physical unit Image coordinates: [u, v] in pixel. Do these coordinates become homogeneous ...
0
votes
1answer
2k views

normalized point coordinates in undistortPoints function

In undistortPoints function from OpenCV, the documentations says that http://docs.opencv.org/2.4/modules/imgproc/doc/geometric_transformations.html#undistortpoints where undistort() is an ...
2
votes
1answer
110 views

Calibrating a laser scanner to a line camera

We have a high-resolution Riegl laser scanner and mounted atop it a Resonon Pika L, which is a hyperspectral camera which records one spatial column at a time, using the second dimension of the sensor ...
2
votes
1answer
394 views

Correct Fish eye camera radial distortion and blurry stretch at the image edges

There are a lot of questions regarding this topic, but I am trying to get a more clear picture from these questions. I am trying to calibrate a fish eye camera and I am using OpenCV ...
1
vote
1answer
47 views

Correct calibration parameters of stereo system due to vibrations

In stereo vision, the camera is calibrated using the popular chessboard before use. During the course of use, the camera maybe be subject to environmental factors such as vibrations.This may cause ...
0
votes
1answer
205 views

setup requirement of stereo camera

In the stereo camera system, two cameras are needed and should be mounted side by side. I see someone just glues two cameras to a wooden board. However one mobile phone manufacture claimed that the ...
0
votes
1answer
254 views

Effect of camera misalignment errors in dual cameras

In the camera module assembly process, parameters of camera modules vary due to manufacturing tolerance. Camera calibration is performed to obtain actual parameters. In the paper Effects of camera ...
5
votes
2answers
2k views

Wheel Odometry Covariance Matrix for Custom Robot

I have been looking around in the forums, but could not find any answer for how to go about getting the wheel odometry covariance matrix for a custom built planar robot (I found some posts related to ...
5
votes
2answers
100 views

Why are two cameras mounted in paralle in stereo application?

For stereo cameras on the market, two cameras are always mounted side by side and with a displacement that is perpendicular to the cameras’ optical axes. I take this setup for granted. One idea came ...
1
vote
1answer
239 views

Gauss Newton Method for Accelerometer calibration

I am following the code obtained in matlab file exchange for the paper http://ieeexplore.ieee.org/document/4655611/ He calculates the Hessian matrix as follows using Jacobian Matrix J, ...
1
vote
0answers
185 views

Accelerometer, gyro, and magnetometer sensor fusion for material resource survey

As a hardware engineer, I have studied quite a lot on sensor spec such as Accel, Gyro and Magnetometer including custom made fluxgate. I have studied matrix and quadarion (complex number) and so on. I ...
2
votes
0answers
378 views

How to properly calibrate a magnetometer in IMU for precise yaw?

EDIT: Moved to ElectricalEngineering StackExchange Community I'm using Sparkfun Razor IMU 9DOF sensor which incorporates accelerometer, gyroscope, and magnetometer, for giving the Euler's angles (yaw,...
3
votes
2answers
200 views

Inverse kinematics after calibration

I am working on a 6DOF robot arm project and I have one big question. When I first derived the inverse kinematics (IK) algorithm after decoupling (spherical wrist), I could easily get the equations ...
1
vote
1answer
4k views

Making a car go straight [duplicate]

I'm trying to work a car that's being controlled by an Arduino. I'm using the following chassis: New 2WD car chassis DC gear motor, wheels easy assembly and expansion and an L298N motor driver. The ...
1
vote
0answers
24 views

Is the distortion introduced by a lens protector significant in practice?

I have a computer-vision application I made to localize a robot in a room; the software has been in use for a while and is working fine. When I calibrated the camera and got the intrinsics and lens ...
4
votes
3answers
224 views

Discontinuity in device orientation

Why is there a discontinuity in the quaternion representation of my device orientation? I'm using a SENtral+PNI RM3100+ST LSM330 to track orientation. I performed the following test: Place the ...
2
votes
2answers
86 views

Aligning datasets with drift

I have a dataset that contains position information from tracking a robot in the environment. The position data comes both from a very accurate optical tracking system (Vicon or similar) and an IMU. I ...
1
vote
3answers
813 views

Camera Calibration fails to run on ROS

I am running ROS Indigo on Ubuntu 14.04. I am doing a mono-camera calibration and trying to follow the camera calibration tutorial on the ROS Wiki. I give the following command: rosrun ...
6
votes
1answer
1k views

Hand Eye Calibration Solver [closed]

I have a rig for which I have a pretty good estimate of the static transformation between the camera and a joint based off of the CAD. It has some errors though and I was hoping to fix it by doing a ...
6
votes
2answers
2k views

Why do we generally prefer DH parameters over other kinematic representations of robot arms?

I am specifically interested in DH parameters versus other representations in terms of kinematic calibration. The best (clearest) source of information I could find on kinematic calibration is in the ...
1
vote
2answers
296 views

PTAM CameraCalibrator error

I am trying to run the cameracalibrator.launch using PTAM according to this Camera Calibration tutorial. However, when I do so, I get the following error: ...
3
votes
2answers
923 views

ROS Calibration Camera Problems

I am trying to calibrate a monocular camera using ROS with the help of this website: How to Calibrate a Monocular Camera. When I run rostopic list, I get: ...
4
votes
3answers
7k views

Hand Eye Calibration

I'm trying to use a dual quaternion Hand Eye Calibration Algorithm Header and Implementation, and I'm getting values that are way off. I'm using a robot arm and an optical tracker, aka camera, plus a ...
1
vote
1answer
147 views

FreeIMU External Magnetometer

I have been using the FreeIMU library successfully but now I want to add an external magnetometer that I can mount away from my motors. I've figured out how to modify the FreeIMU library to use an ...
0
votes
1answer
459 views

Mobile Camera Calibration and rectification frame rate

I've been searching the internet for an answer to this question, but I haven't come across anything that will help me. Basically, we have a Meka Humanoid Robot in our lab, which has a shell head in ...
1
vote
1answer
2k views

3D Magnetometer calibration algorithm

I want to calibrate my compass, which is installed on a board which inherits a GPS module. Because the GPS antenna is up-side-down the compass is 180° inverted. The easiest way to correct the problem ...
1
vote
1answer
992 views

Calculate object distance with camera

Firstly I'm unsure whether this question belongs here or on another SE site (but I'll wing it for now). I've recently been given the job of connecting up a 'smart camera' to a setup where a robotic ...