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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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Why are there 3 conflicting OpenCV camera calibration formulas?

I'm having a problem with OpenCV's various parameterization of coordinates used for camera calibration purposes. The problem is that three different sources of information on image distortion formulae apparently give three non-equivalent description…
John
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Up to a scale factor

I am reading up on homographies and i have seen some places that it says that the homography is defined "up to a scale factor" what does this mean? Is there an upper limit for scaling the homography or what does it mean, and why?
user1823350
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How to plot the camera and image positions from camera calibration data?

I have the intrisic and extrinsic parameters of the camera. The extrinsic is a 4 x 4 matrix with rotation and translation. I have sample data as under, I have this one per camera image taken. 2.11e-001 -3.06e-001 -9.28e-001 7.89e-001 6.62e-001…
Kevin Boyd
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Properly rectifying stereo images for GPU (opencv)

I have been using cv::StereoBM for a while, and am trying to switch to cuda::StereoBM (uses the GPU) but have run into a problem where they look completely different, even with the same settings and input images. I read in this post that the inputs…
Zock77
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3D reconstruction from two calibrated cameras - where is the error in this pipeline?

There are many posts about 3D reconstruction from stereo views of known internal calibration, some of which are excellent. I have read a lot of them, and based on what I have read I am trying to compute my own 3D scene reconstruction with the below…
s-low
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OpenCV Stereo Matching/Calibration

I'd initially posted this on the OpenCV forums, but unfortunately, I didn't get too many views/replies so I'm posting here with the hopes that someone might have a direction to please suggest? I am using the Bumblebee XB3 Stereo Camera and it has 3…
BumblebeeUser89
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Fisheye/Wide-Angle lens Calibration in OpenCV

I know the default OpenCV Calibration systems model a Pinhole camera, but I'm working with a system using extremely wide FOV lens (187-degrees). If there any existing way to do this in OpenCV, or to work with just wide lenses? Or will I have to…
Yeraze
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iPhone/iPad front camera FOV

There are some measured results available for certain older ios devices but I'm not able to find FOV numbers for newer models, specifically, iPhone 5s ~ 6s Plus and iPad 4 ~ iPad Pro. Also, the numbers listed on the above link don't match with some…
Ziju Feng
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Image center in the calibration matrix

I have a camera and a 3D object, I have calculated the camera matrix as given in this. The image captured using the camera is having size 1600x1200. But in the camera matrix I am not getting the value of image centers properly. Instead of 800, 600…
Deepak
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Wide angle lenses calibration with Opencv

I'm using a wide-angle lens (178º Diagonal FOV ) and I'm trying to calibrate it properly using Opencv Calibration module. All the detection and calibration process are working fine, but the result is very poor. I have tried many different…
Josep Bosch
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create opencv camera matrix for iPhone 5 solvepnp

I am developing an application for the iPhone using opencv. I have to use the method solvePnPRansac: http://opencv.willowgarage.com/documentation/cpp/camera_calibration_and_3d_reconstruction.html For this method I need to provide a camera matrix: …
Isaac
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Find distorted rectangle in image (OpenCV)

I am looking for the right set of algorithms to solve this image processing problem: I have a distorted binary image containing a distorted rectangle I need to find a good approximation of the 4 corner points of this rectangle I can calculate the…
Dennis Kempin
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extrinsic matrix computation with opencv

I am using opencv to calibrate my webcam. So, what I have done is fixed my webcam to a rig, so that it stays static and I have used a chessboard calibration pattern and moved it in front of the camera and used the detected points to compute the…
Luca
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Calibration of images to obtain a top-view for points that lie on a same plane

Calibration: I have calibrated the camera using this vision toolbox in Matlab. I used checkerboard images to do so. After calibration I get the cameraParams which contains: Camera Extrinsics RotationMatrices: [3x3x18 double] TranslationVectors:…
Abhishek Bhatia
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image coordinate to world coordinate opencv

I calibrated my mono camera using opencv. Now I know the camera intrinsic matrix and distortion coefs [K1, K2, P1 ,P2,K3 ,K4, K5, K6] of my camera. Assuming that camera is place in [x, y, z] with [Roll, Pitch, Yaw] rotations. how can I get each…
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