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Questions tagged [camera-calibration]

In Computer Vision, camera-calibration is the process of finding the true parameters of the camera that produced a given photograph or video. Usually, the camera parameters are represented in a 3 × 4 matrix called the camera matrix.

Usually we say a camera is calibrated when we know the Intrinsic Parameters.

Source: Wikipedia

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Finding distance from camera using SolvePnp

I am trying to find distance of a person from the camera in a video using landmarks and cv2.solvePnp function. Ideally I want to get distance in some real world unit like metres/cm/mm I have used Mediapipe pose detector to find 2d and 3d landmarks…
Anon231312
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How can I retrieve the camera intrinsic parameters and distortion coefficients of a smartphone using a mobile app?

How to get intrinsic parameters of a smartphone camera using a mobile app? I want to access camera parameters like camera matrix intrinsic parameters and distortion coefficients using a mobile app or using a browser of a smartphone iOS or Android
Ayo
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On the uniqueness of stereo camera calibration results

I'm currently in the process of trying to calibrate a stereo endoscope using the openCV framework and have some trouble interpreting the results I'm getting. I collected a clean dataset of 70 chessboard target images (size: 7x6), which are…
hey0
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How to convert the radius from meter to pixel?

I have a camera with these specs: full resolution 1280x1024 pixel size 0.0048mm focal length 8 mm I need to detect a ball in this image. It is 4 meters away and its radius is 0.0373 meter. How to convert the radius to from meter to pixel in this…
S.EB
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Questions about the parameters T and t in the stereoCalibrate function and recoverPose function in Opnecv

I want to verify the rotation matrix and translation vector of the intrinsic matrix factorization calculated by SFM with the rotation matrix and translation vector calculated in the binocular calibration with two cameras. ` …
JunWen Si
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Undistort image containing planar object of known dimensions using openCV python

I have the following image extracted from a video: It is a field hockey pitch with standard dimensions (91.4m x 55m). I can even map all lines intersections if necessary. The image is distorded. I'd like to undistord it using openCV. I thought…
Adrien Kinart
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Opencv Charuco Calibration board

I have an issue with the Charuco calibration. I have a large pre-printed board lying around that i would like to use, but my calibration results are useless. When generating my own board, I found out that it is using the correct markers but that the…
Phil333
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Rigid body transformation between 4 views

I have 4 cameras placed in the corners of a room and would like to estimate the rotation and translation of the cameras to one of those 4 cameras with the help of opencv. I was going to estimate R and t based on the essential matrix between camera 1…
b_stan
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Strange results with OpenCV camera calibration in C++

I’m making a camera calibration toolkit with OpenCV in C++. I’m using "calibrateCamera” and “undistort” functions from opencv2/calib3d. I get good results for two image set but I get terrible result for 5 image set. All image sets are good and has…
newww
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Undistortion fail in OpenCV

I'm making a camera calibration toolkit. I'm using cv::calibrateCamera(...) funtion from opencv2/calib3d.hpp and this works fine for images which taken by fish-eye camera, at least undistorted image looks correct. However when I try this with images…
newww
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How openCV estimates focal length using object points and image points

I'm trying to display 3D chessboard image(involved rotation, translation) like matlab's camera calibration tool box, using openCV, openGL. To make this, I'm studying camera calibration, homogeneous, etc.. My question is the function…
alcoholic
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How can I remove the bottom part distortion of a undistort panaroma image from scaramuzza omnidirectional camera calibration toolbox?

Original Image Undistorted image Scaramuzza omnidirectional camera calibration toolbox has been used to calibrate and save the camera parameters. Then these parameters are used to get the panaromic view from the 180 degree FOV fisheye camera. I have…
Tutul
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camera position relative to World coordinate

I am taking the Computer Vision course, and I had some problems while doing some exercise: I have the intrinsic matrix K, and extrinsic matrix [R|t] of a camera as followings, K = 478.989 2.67423 405.437 0 476.472 306.35 0 0 1 [R|t] =…
cptsai
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Why do all the coordinates from the QueryVertices are zero?

For the following code: Reads the depth data from the sensor and fills in the matrix ***/ void SR300Camera::fillInZCoords() { Image::ImageData depthImage; Image *depthMap = sample->depth; depthMap->AcquireAccess(Image::ACCESS_READ,…
Mona Jalal
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Assembly explanation about stereoCalibrate error with OutputArray::Create assertion error

I came across an error during execute stereoCalibrate in Opencv 2.4.11, which is says : OpenCV Error: Assertion failed (!fixedSize() || ((Mat*)obj)->size.operator()() == Size(cols, rows)) in cv::_OutputArray::create, I think this must be some size…
EdwinDebuger
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