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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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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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rgbd_calibration YAML Parsing Exception: Bad Conversion Error

This work is a recurrence of Basso's work: https://github.com/iaslab-unipd/rgbd_calibration, but I have encountered the following problems: ...
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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 ...
trycatch22's user avatar
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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 ...
user22120's user avatar
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272 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 ...
sararht's user avatar
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Obtaining Camera Pose via TF

I have the calibration board fixed on the work station, and I have its world coordinates, entered them in URDF, all good. I used OpenCV's pose estimation module to find the board's pose (rvecs and ...
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159 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 ...
ihti's user avatar
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Determine tool frame (aka measuring tool center point)

I've been (unsuccessfully) looking for a package that could work out the tool center point point of a tool attached to the flange of an industrial robot. Some controllers (e.g. ABB's IRC5) contain an ...
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58 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?
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129 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 ...
Ashish Rao M's user avatar
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camera calibration algorithm

Hello everyone ! I wanted to calibrate my camera ( Bus 001 Device 002: ID 058f:3881 Alcor Micro Corp.) screen I did everything that was written in this article and tried with this video But nothing ...
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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. ...
Jogging Song's user avatar
2 votes
2 answers
805 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 ...
Mr. Fegur's user avatar
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camera calibration with different chess board size

Hi, I want to perform monocular camera calibration using a chessboard that has 6X6 squares in it where each square has side length as 0.054 m. The number of squares in the chessboard and side of ...
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135 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 ...
Mohamed Benmahdjoub's user avatar
2 votes
1 answer
179 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 ...
Mark's user avatar
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2 answers
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Question about Lens distortion

Suppose I have a 240x180 camera with the following distortion co-efficients, $$k_1 = -0.138592767408$$ $$k_2=0.0933736664192$$ $$k_3=0.0$$ $$p_1=k_4=-0.000335586987532$$ $$p_2=k_5=0.000173720158228$$ ...
Ashish Rao M's user avatar
2 votes
1 answer
2k 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 ...
Mona Jalal's user avatar
2 votes
1 answer
542 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 ...
Jogging Song's user avatar
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1 answer
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Identification of kinematics of industrial robots

Hi, I am looking for a way to identify (or calibrate) the kinematic information (Joint angle and robot frame offsets) of my 6-DOF industrial robot. I am aware of the packages robot_calibration and ...
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2 votes
2 answers
195 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 ...
koverman47's user avatar
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Remove a single ROS package

I'm still trying to solve this problem in another question. I decided to uninstall camera_calibration and install it again, see if that helps. However if I try to remove the package with apt-get it ...
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2 answers
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camera_calibration opens gui window but freezes

I'm trying to run the camera_calibration node. I run this command: ...
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1 vote
1 answer
148 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 ...
Yasin Yousif's user avatar
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1 answer
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How to find the pose of a pattern

Hi, I a currently working an a project and i need to find the pose of a pattern this one for example :link text i know that some calibration package use the pose to calibrate the camera but i don't ...
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1 answer
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Using camera calibration results in OpenCV

I've calibrated Kinect intrinsics (both depth and rgb) using camera_calibration module and saved a bunch of rgb images afterwards (calibration file was detected successfully; subscription to kinect1/...
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1 answer
157 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 ...
Armin Meisterhirn's user avatar
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1 answer
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Calibrating AR-Drone after flight

Hi all, I am using ROS to fly a real AR-Drone. My problem is that after a takeoff-flight-land sequence if I try to takeoff again the drone can't stabilize properly and will not fly well. If I take out ...
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1 answer
3 views

Using a larger chessboard for ROS stereo calibration?

Hi, I have been trying to calibrate (using chessboard pattern) a pair of stereo cameras using the ROS camera_calibration tool. However, when I move the stereo cameras far apart (eg:- baseline > 30-...
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1 answer
8 views

How to get raw stereo camera calibration from left and right camera_info messages

Hi guys, I am trying to obtain the stereo un-rectified calibration (that is un-rectified extrinsics R and t; and calibration matrix K for each camera) from the left_camera_info.yaml and the ...
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0 votes
1 answer
34 views

Left and Right camera according to ROS/OpenCV

HI, I am currently trying to calibrate 2 cameras (stereo calibration) and tried using this tutorial. Question: What is the Translation (and Rotation) vector in the output of the calibration ? Is it ...
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0 votes
1 answer
16 views

The right way to use CameraInfo to correct barrel distortion

Environment: Kinetic, on Ubuntu 16, kernel 4.13.0-31-generic OpenCV: 3.3.0 C++ code base I have a USB camera which is easily publishing the raw images and the default camera_info topics, as generated ...
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1 vote
3 answers
2k 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 ...
JMikes's user avatar
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3 votes
1 answer
855 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. ...
Martin Deegan's user avatar
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1 answer
298 views

How to use camera_info_manager to publish camera_info

I am trying to calibrate my ov7251 camera using the camera_calibration package. I adapted a sample camera driver that I found which use the UV4L API so that I can try to publish images to the ROS ...
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3 votes
2 answers
1k 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 ...
Paul Tumbaco's user avatar
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1 answer
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how to check calibration of a single camera?

Hi, What's the best way to check the calibration of a single camera? Is there a way to load the calibration into the camera_calibration package and check it using ...
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0 votes
1 answer
20 views

Export matlab monocular camera calibration parameters to ROS

I have calibrated my camera using matlab's calibration toolbox and saved it as a .mat file. Is there a way to convert this file into yaml? Also once I have the yaml file, how can this file be accepted ...
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0 votes
1 answer
2 views

Unable to view image using image_view in ROS Indigo with rosberrypi_cam

I have succesfully installed the rosberrypi_cam package following this page. After that when I execute the command rosrun rosberrypi_cam rosberrypi_cam_node the ...
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3 votes
1 answer
1k 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 ...
ricecakebear's user avatar
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1 answer
146 views

Can't find camera calibration file

Hi, I'm trying to use a USB Camera, HP HD 4310, with ROS. The thing is, i'm reallu new at ROS, so i must be missing something really basic. First, I installed uvc_camera. I confirmed that my camera is ...
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0 votes
1 answer
1 view

Camera Pose Calibration Valid_Pattern_Ratio_Threshold and Circle Spacing

Hi, I started working with the Camera Pose Calibration Package by Delft Robotics (https://github.com/delftrobotics/camera_pose_calibration) to find extrinsic calibration parameters for a Realsense ...
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0 votes
1 answer
1 view

Does robot_localization pakcage requires inter-sensor extrinisic parameteres to be known?

Hi Just two short question Does this package requires inter-sensor extrinisic parameteres to be known? Does it requires synchronous sensors? My camera works at 20fps but my IMU works at 100 ...
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3 votes
2 answers
394 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: ...
MIRMIX's user avatar
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6 votes
1 answer
2k 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 ...
kangaroo's user avatar
  • 193
1 vote
1 answer
54 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 ...
rielt12's user avatar
  • 191
2 votes
2 answers
449 views

Tool calibration- orientation

I'm currently working calibrating a robot's tool. I have found some simple methods to get the tool centre point. But I'm unsure about how to get the tool's orientation relative to the robot's tip (the ...
vinjk's user avatar
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1 vote
0 answers
37 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 ...
Jogging Song's user avatar
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1 answer
5k 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 ...
Jogging Song's user avatar

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