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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.

31 questions with no upvoted or accepted answers
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32 views

### 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 ...
• 151
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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 ...
• 191
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### 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 ...
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### 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,...
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1 vote
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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 ...
1 vote
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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....
1 vote
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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 ...
• 563
1 vote
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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 ...
• 51
1 vote
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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?
• 137
1 vote
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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. ...
• 273
1 vote
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### 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 ...
• 273
1 vote
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### 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 ...
• 111
1 vote
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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 ...
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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 ...
• 101
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### ROS2_Iron - Camera calibration file (camera_info.yaml) not loaded by usb_cam camera driver

Running ROS2 Iron with the usb_cam driver. ...
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### 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 ...
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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 ...
• 151
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### 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 ...
• 359
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### 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 ...
• 121
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### 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 ...
• 151
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### 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 ...
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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### 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 ...
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 ...
• 359
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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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### 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 ...
• 1,577
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 ...