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Questions tagged [calibration]

Use this tag for questions related to the process of adjusting the output or indication on a measurement instrument.

443 questions
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Trying to calibrate accelerometer

I am writing an app that will use the accelerometer to calculate the average geforce exerted on the phone. Thinking about the problem, I came to the conclusion that when the phone is in rest, adding all of the axis values together will give me an…
Ian
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Overfitting and Brier score

I have a classification problem where i want to see if a client is defaulter or non defaulter. What is important to me is the probability of default, and how well calibrated the model is so i am doing a grid search with brier score as my scoring…
Maths12
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RedLaser driver's license scanner - calibrating for each state (iOS)

I'm using RedLaser's PDF214 scanner to pull data off the 2D barcode on the back of driver's licenses (iOS). Issue: for each new state (or at least most), I have to recalibrate to work with that specific state's barcode. Examples of differing…
dmt2989
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Automatic camera calibration

From Wikipedia, camera resectioning is the process of finding the true parameters of the camera that produced a given photograph or video. Camera resectioning is also known as geometric camera calibration. Currently I am using Camera Calibration…
worbel
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Software to Tune/Calibrate Properties for Heuristic Algorithms

Today I read that there is a software called WinCalibra (scroll a bit down) which can take a text file with properties as input. This program can then optimize the input properties based on the output values of your algorithm. See this paper or the…
Karussell
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stereoCalibrate for different cameras (rgb and infrared)

I have problems with calibrating two cameras: first is rgb and second is infrared. They have different resolution (I resized and croped bigger image), focal length, etc... Examples: RGB 1920x1080 Infrared 512x424 How to calibrate them to each…
DmT021
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Multi-Kinect Calibration using opencv chessboard

I'm using opencv2.4.6, and kinect sdk to do multi kinect calibration. After I get image data from kinects, I turn them into opencv images, and follow some tutorials, e.g. RGBDemo, and use the following pipeline: //find the…
user2695996
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Android: How does one deal with inaccurate baromters?

I have been using a Samsung Galaxy S3 to work on an app that uses the barometer estimate the user's altitude. I use SensorManager.getAltitude(p0, p), and set p0 equal to the sea-level pressure reported at the nearest airport. I set p equal to the…
Probity
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Use calibration matrix to know CCD sensor size

How can we know the camera sensor size from the calibration matrix? I already have the calibration matrix. But the focal length is in pixels form.
kenneth
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Using the same validation set for model and for CalibratedClassifierCV

In the documentation of CalibratedClassifierCV it's stated The samples that are used to train the calibrator should not be used to train the target classifier. As far as I would understand; it is that if we use X_train to train our model then we…
CutePoison
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Couldn't find Chessboard corners

My aim is to obtain the recognition of colour and position of pawns in Chessgame. The recognition was pretty easy because of many tutorials on github. With opencv functions cv2.findChessboardCorners and cv2.drawChessboardCorners (clear Chessboard) I…
piotr24n
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camera calibration. difference between april tags and chess pattern calibration?

Why April tags are better than chess pattern for camera calibration? Why it gives different camera matrix? I have already used calibration via chess pattern and made it another time with April tags and both gave me two different camera matrix. The…
Timon
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What is the correct way to undistort points captured using fisheye camera in OpenCV in Python?

INFO: I've calibrated my camera and have found the camera's intrinsics matrix (K) and its distortion coefficients (d) to be the following: import numpy as np K =…
Angelo
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Multiclass classification: probabilities and calibration

I'm working on a multiclass classification problem with different classifiers, working with Python and scikit-learn. I want to use the predicted probabilities, basically to compare the predicted probabilities of the different classifiers for a…
Vera O
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OpenCV + photogrammetry

i have a stereopair, photo 1: http://savepic.org/1671682.jpg photo 2: http://savepic.org/1667586.jpg there is coordinate system in each image. How can I find coordinates of point A in this system using OpenCV library. It would be nice to see sample…
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