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.

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How to get transform between two fixed frames using a camera

In my task, I have two manipulators: one 6 dof robot (Manipulator 2 as shown in attached link picture), and one passive arm (Manipulator 1 as shown in attached link picture). Both the frames 1 and 2 ...
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IMU Senosr fusion algorithm of gyro and accelerometer during acceleration of vehicle

Hello so we have a car with 10 IMUs mounted at different locations of the car and the idea is the measure the centripetal force at each location of the car and compare it to each other. We also need ...
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Why would we solve AX=XB instead of just using the Kabsch algorithm?

I have a high precision stereo camera and a robot which are independent units (the camera is not mounted to the robot). I wish to compute a transformation from the camera frame to the robot base frame....
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How to calibrate an accelerometer?

I'm confused about a few points on how to best calibrate an accelerometer, whose data will be used in an orientation sensor fusion algorithm. As a summary, the most common approaches I've seen take ...
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Find a mistake in transformation between different coordinate frames in the WIP-calibration pipeline

I design the extrinsics calibration pipeline for the robotic agents, carrying onboard two sensors of different modalities. I aim to calibrate one of them (S) ...
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Do electromagnets affect magnetometer calibration?

I am designing a landing pad for a drone that will have electromagnets built into the pad. My drone has a pixhawk 2 with PX4. I'm worried that the electromagnets in the pad will throw off the drone's ...
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How to calibrate a magnetometer on a heavy robot

I am wondering how to calibrate a magnetometer on an IMU that is installed on a heavy robot. Normally, hard and soft iron calibration is done by spinning the IMU in all axis, but since it is installed ...
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Algorithm for Hand-eye Calibration with static camera brings wrong parameters

I tried a hand-eye-calibration with a static camera and the following alogorithm in Matlab. https://de.mathworks.com/matlabcentral/fileexchange/48696-camera-to-robotic-arm-calibration The algorithm is ...
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Focus calibration to infinity

Well, it sounds easy problem but can we do it without pointing the camera to a faraway place? How does the manufacturer do this during mass production? Is there any focusing machine?
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lens calibration with a circles grid

When we project a 3D circle onto image, its real center and the center of the ellipse fitted to the projected circle is different. To accurately estimate the true center from the projected image, a ...
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How to calibrate a lens with wide fov and low F number

To calibrate a wide fov lens either a calibration board should be large or bring the calibration board closer to the lens. As making a large calibration board is expensive, I usually prefer the second ...
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ROS Camera Calibration for Webcam - Not working

As a part of learning, I am trying to perform Camera calibration with my laptop's Webcam. I am really new to this process. I will explain everything about how far I have come so far, and where I have ...
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Unstable principal point estimation in zoom camera calibration

I have a camera with a 1/2.9" image sensor from FLIR and a 12-50mm motorized zoom lens from Theia. Because the lens is a motorized zoom lens, I tried to calibrate the camera for different zoom ...
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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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Closed-form solution of extrinsic in 2D to 3D projection problem

The title is pretty much it. Anyone have seen a closed-form solution of extrinsic on 2D to 3D projection problem? Seems like this should exist in old camera calibration literature but I can't really ...
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Depth camera pixel values to 3D coordinates

I have a robotic arm 6-DOF and an Intel RealSense depth camera. I want to go from pixel values to 3D world coordinates, is it possible with eye-in-hand calibration? If yes can you guide me on how to ...
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Trouble aligning/calibrating camera with laser scanner

I have a robot which has 2 multi-spectral cameras and 1 laser scanner attached. In the end I would like to have the images from the cameras aligned with the scanner so that I can have spectral ...
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Hand-Eye Calibration without Robot Arm Calibration

I'm trying to do Hand-Eye Robot-Camera calibration. And I'm using MZ12(NACHI robot) and D435(Intel camera). But accuracy of the calibration result is so low. Average error of translation moving is ...
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Understanding types of hand eye calibration

I have been reading about hand eye calibration for a couple days. Basically, I have 2 setups I want to execute hand eye calibration. Camera is fixed in a position and arm is moving (eye on base); ...
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how to calibrate gyroscope using raw gyro data?

I wrote a simple code for where I take 500 samples with stationary gyro and subtract those offset values to get calibrated gyro data. Question: Is this much calibration enough to implement this gyro ...
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How do I calibrate a rotating laser scanner pose from known global coordinates?

Assume the following scenario: A 2D LIDAR sensor is mounted with a vertical (not exactly known) scan plane at a height of 20m The scanner can be rotated about the vertical axis and the encoder values ...
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Robotic vision eye-in-hand research

I started researching Robotic Vision topics for a while but I found myself a bit stuck. My background is in the Computer Vision and Machine Learning fields but I lack the knowledge in robotics. My ...
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How to get transformation between a camera and a CNC plotter?

I have a question about robot and camera calibration. I have experience to calibrate btw 6DOF robot arm and hand-eye camera. But this time I should use a machine like CNC plotter. This machine can ...
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What is the baseline of a RGBD camera?

I'm looking at some ORB SLAM2 settings where there's a parameter for "IR projector baseline times fx". Could someone here explain what exactly is the baseline of an IR projector? Is it the distance ...
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solving for unknown 2d rotation + translation

This is a continuation of the question I asked here. I thought I'll ask a more concrete question. So far, this is what I have done to transform from a feature point detected by camera sensor in to a ...
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Robot Hand to Eye calibration without joint encoder

I have two degrees of freedom robot with a camera mounted on the tool center point where the system is modeled as $^wT_c = {^wT_z}(\theta_1){^zT_m}(\theta_2) {^mT_c}(\textbf{r})$, $\textbf{r} \in ...
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calibrating large scale manipulator

I'm facing the problem of model calibration for a large-scale manipulator (e.g. example image) with a half-spherical workspace of around 40m diameter. The typical approach would be computer vision, ...
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Is it possible to calculate a homography matrix for any 2 views?

I've been experimenting with opencv to estimate the homography matrix between 2 images captured with my computer's webcam. I have noticed that when the 2 views are not very far apart (that's when I ...
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Hand-Eye calibration of a 2D barcode scanner and a robot

I have a Keyence barcode scanner that can give me the coordinates of a detected barcode in pixels. I have a 6 DOF robot whose end effector pose I know at any given time. My ultimate goal is to place a ...
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RGBD Camera Eye in Hand Calibration

Hello I am new to robotics. So far I have a basic understanding of the camera calibration. One would need rotation and transformation matrices to convert a point from camera coordinate system to robot/...
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vision guided robotic arm always required 6d pose of object? [closed]

I have an object like attached in image. It is hanging vertical (its position may change but static object) and I want to grasp it using 6DOF Robotic arm. I am Using camera to detect object. I am ...
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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 ...
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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 ...
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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?
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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 ...
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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. ...
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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 ...
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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 ...
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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 ...
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Question about Lens distortion

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