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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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Linear predictor from predict.coxph from coefficients only

I need to calculate the linear predictor of a Cox PH model manually. I can get continuous and binary variables to match the output of predict.coxph (specifying 'lp') but I can't seem to figure out how to calculate it for categorical variables with…
Michelle
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OpenCV Stereo Camera Calibration Error: Assertion failed

I know this question was asked a few Times, but the answers doesn't solve my problem. I want to calibrate a pair of Cameras to use as Stereo Input. But when I run the code I get the error Message : OpenCV(3.4.1) Error: Assertion failed (nimages >…
Chris
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rectifyStereoImages (Image rectification) output looks distorted

I have implemented rectifyStereoImages, but the result looks weird. Please look at the images attached. Both cameras are the same model (Logitech C920). left = webcam(3); right = webcam(1); I1 = snapshot(left); figure(1); imshow(I1); I2 =…
SSS
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How the checkerboard size affect an accurate Camera Calibration?

Right now, I am calibrating a monocular camera so afterwards I can calculate distance of planar objects in the image (Z=0). However, I'd like to know how much it is important to know the structure size. The board's squares sizes change a lot in…
Hesham.K
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For loop and apply to do math on a nested list in R (finding mean of calibrated ages from Bchron)

First off, I'm new to both R and Stack Overflow, so I apologize in advance for the inevitable faux pas or silly mistakes I make in this question and will do what I can to remedy them. In the meantime, please excuse my naïveté. I'm using the R…
m.s.bolton
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OpenCV 3.4 camera calibration yields strange principal point

I'm doing camera calibration using the calibration.cpp sample provided in the OpenCV 3.4 release. I'm using a simple 9x6 chessboard, with square length = 3.45 mm. Command to run the code: Calib.exe -w=9 -h=6 -s=3.45 -o=camera.yml -oe…
Remus Pop
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Simple neural network "calibration" (python)

I'm getting started with neural networks and this kind of stuff, I understood how a perceptron works and the logic behind feed-forward and backpropagation mechanisms and I am now trying to write a simple multi-layer network with 3 neurons (2 in a…
Davide Della Giustina
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How to use opencv.omnidir module for dewarping fisheye images

I am trying to use omnidirectional module for dewarping fisheye images in Python. I am trying to adapt this C++ tutorial in Python but running into issues. Here is my code: import numpy as np import cv2 import glob nx = 9 ny = 6 # termination…
Kunal Lad
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How to alter one weibull curve to approximate another weibull curve?

I have one data set that I wish to calibrate to another. What makes this tricky is I do not have the full distribution, I have count data. I know that the distribution is supposed to be Weibull, so I created 2 Weibull curves, but I am then uncertain…
Danielle Watts
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Bug with CalibratedClassifierCV when using a Pipeline with TF-IDF?

First of all thanks in advance, I don't really know if I should open an issue so I wanted to check if someone had faced this before. So I'm having the following problem when using a CalibratedClassifierCV for text classification. I have an estimator…
Iñigo Cortajarena Sauca
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Efficiently removing calibration rolls and replacing them with NaN's

Here is an image that represents Magnetic Field Data that, near the y=0 axis, the data varies as it should. However, there are clear occurrences in which the varied data transitions into oscillations that easily stand out. These large and…
M. Cuesta
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Auto calibration of internal RTC

In my Application I want to make a kind of auto-calibration of the internal RTC. I want avoid (if possible) to use external equipment for the calibration. My idea is to use the Smooth calibration with 32 second calibration window. I want to check…
Lorenzo
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OpenCV - Project image plane point to 3d

I've used OpenCV to calibrate my camera from different views and I obtained intrinsics, rvec and tvec with a reprojection error of .03 px (I thus think the calibration is fine). Now, given one view of my scene, I want to be able to click on a point…
Jérémy Riviere
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Polar 2D Interpolation

Say we are creating a calibration lookup table for a device, shown in the plot below. The theta represents different phase values, and the r represents different magnitude values. The calibration setpoints are shown in blue circles, and are taken at…
Vivek Sharma
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RTC Clock Calibration

I am looking for a Cost x Performance method to calibrate microcontrollers RTC clock reference (usually 32.678kHz). I need a way to find the reference clock drift and inform it to the microcontroller, so that it can calculate and aplly the…
Wagner Silveira
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