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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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How to calibrate IMU for large scale deployments possibly using deep neural network

We were testing our visual SLAM algorithm on robots. We were getting poor performance. Then we calculated wite noise and random walk parameters (using kalibr) for the IMU and used it in our algorithm ...
Mahesha999's user avatar
3 votes
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96 views

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 ...
S.E.K.'s user avatar
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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 ...
Chanoh Park's user avatar
  • 1,577
2 votes
0 answers
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
2 votes
2 answers
448 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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2 votes
0 answers
573 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,...
yode's user avatar
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1 vote
1 answer
126 views

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 ...
prince salasi's user avatar
1 vote
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197 views

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....
Alexander Soare's user avatar
1 vote
0 answers
240 views

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 ...
John M.'s user avatar
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1 vote
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158 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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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?
Iron Fist's user avatar
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50 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. ...
Jogging Song's user avatar
1 vote
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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
1 vote
0 answers
217 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 ...
Riscy's user avatar
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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 ...
Gouda's user avatar
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How to estimate the parameters in this accelerometer calibration model?

I'm using the xioTechnologies Fusion AHRS library to estimate orientation from readings from a 6-axis IMU. The library provides functions to apply calibration parameters according to this calibration ...
avs's user avatar
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100 views

ROS2_Iron - Camera calibration file (camera_info.yaml) not loaded by usb_cam camera driver

Running ROS2 Iron with the usb_cam driver. ...
Gotvm's user avatar
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16 views

Why multiply noise and random walk values by some constant value

I was exploring calculation of IMU intrinsics (random walk and noise values) for IMU using kalibr tool using this video. At timestamp 25:48, Patrick says, "typically we dont use values generated ...
Mahesha999's user avatar
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Why different noise terms are read at specific sampling interval in Allan Variance plot?

I was trying to identify Quantization Noise, Angle Random Walk, Bias Instability, and Rate Random Walk from Allan Variance plot which as Allan deviation on y axis and Sampling Time Interval ...
Mahesha999's user avatar
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17 views

How to transform frames so axis align

I have the location of two sensors, S_1 and S_2 with frames attached to each and I have the frame Transformation that gives S_2 location and orientation with respect to S_1. Additionally I have a ...
FourierFlux's user avatar
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57 views

Calculating IMU random walk using allan variance

I am trying to calculate accel and gyro noise and random walk for Intel realsense using allan variance. I quickly generated imu csv in the format specified here using custom CPP script for just 3 ...
RajS's user avatar
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23 views

How to scale projection matrix?

I was going through the camera calibration lecture by professor Shree Nayar. At 4:49, he is : Scaling the projection matrix implies simultaneously scalign the world and the camera, which does not ...
Mahesha999's user avatar
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0 answers
32 views

Cartesian Planning Issue

I recently performed camera and robot-robot calibration and, I wanted to validate the results with the touch test method. So I retrieved a particular point on the ChArUco board and wrote a node that ...
sam-opt's user avatar
0 votes
2 answers
19 views

completely black rectified images (Kind of solve....?)

Hello, I just got a couple of cameras for stereo vision. I calibrated them with camera_calibration. I got the ost.txt file which looks like this: ...
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0 votes
1 answer
83 views

Cannot solve extrinsic matrix between camera and robot

I am triying to calibrate a RGB-D Realsense camera , with an eye in hand configuration. I have the following set-up: I know the transformation matrix between base/ef and cam/obj. I want to solve ...
Unai Granados Ormaetxea's user avatar
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0 answers
35 views

Synchronize GPS orientation with cameras

I'm interested in using GPS system to generate ground truth for evaluation of some SLAM systems I am testing. I'm confused on how I can initialize the location and orientation of the GPS unit to be ...
FourierFlux's user avatar
0 votes
0 answers
12 views

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?
Chanoh Park's user avatar
  • 1,577
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23 views

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 ...
Chanoh Park's user avatar
  • 1,577
0 votes
0 answers
146 views

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 ...
Diwakar Manickavelu's user avatar
0 votes
0 answers
27 views

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 ...
Chanoh Park's user avatar
  • 1,577
0 votes
0 answers
56 views

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 ...
Soonmyun Jang's user avatar