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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 does a 3D point appear to be behind the camera?

I wrote a simple script to project 3D points into an image bases on the camera intrinsics and extrintics. But when I have a camera at the origin pointing down the z-axis and a 3D points further down the z-axis it appears to be behind the camera…
nickponline
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Editing Camera Settings by using Opencv

Is there any way to set camera settings (iso, focus, etc.) by using OpenCV Python? We are using computer vision on robot, but everytime angle or light changes, camera reconfigures itself so using SVM from SciKit Learn is not possible. Is there any…
mkmeral
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bad Disparity map using opencv StereoBM

I am trying to use StereoBM to get disparity map of two images. I tried some sample code and images. They are working fine. However, when I try my own images, I got very bad map, very noisy. my StereoBM parameters sbm.state->SADWindowSize =…
fnhdx
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reverse UndistortRectifyMap

I'm making multicamera-stereo calibration program. My idea is to rectify each pair of cameras separately. For example: for given 3 cameras I compute undistortion and rectification maps (using stereoRectify() and initUndistortRectifyMap()) separately…
paws
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Extrinsic Calibration With cv::SolvePnP

I'm currently trying to implement an alternate method to webcam-based AR using an external tracking system. I have everything in my environment configured save for the extrinsic calibration. I decided to use cv::solvePnP() as it supposedly does…
SwarthyMantooth
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Camera Calibration: How to do it right

I am trying to calibrate a camera using a checkerboard by the well known Zhang's method followed by bundle adjustment, which is available in both Matlab and OpenCV. There are a lot of empirical guidelines but from my personal experience the accuracy…
user3667089
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How to draw 3D Coordinate Axes with OpenCV for face pose estimation?

Suppose I have got the face euler angles (pitch, yaw, roll). How can draw the 3D Coordinate Axes which show the face pose? Here is an example from here:
tidy
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Does the varying of aperture influence the camera calibration?

I am calibrating an industrial AVT camera. Is it ok, when I focus on the plane where I will do my measurements with the f/4 aperture then close the aperture to f/16, calibrate the internal parameters of the camera and then open the aperture to f/4 ?…
missZBH
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Bad results when undistorting points using OpenCV in Python

I'm having trouble undistorting points on an image taken with a calibrated camera using the Python bindings for OpenCV. The undistorted points have entirely different coordinates than the original points detected in the image. Here's the offending…
Daniel Lee
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Pose from Fundamental matrix and vice versa

I have computed the Fundamental Matrix between two cameras using opencv's findFundamentalMat. Then I plot the epipolar lines in the image. And I get something like: Now, I tried to get the pose from that fundamental matrix, computing first the…
Josep Bosch
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OpenCV Stereo rectification from manually created matrices

I am currently working on a 3d reconstruction of X-Ray images, and therefore I need to stereo-rectify images of two views before I can match some features with help of the epilines. I am using OpenCV 2.4 with C++. For this purpose I got a set of…
bumuckl
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OpenGL/VTK: setting camera intrinsic parameters

I am trying to render views of a 3D mesh in VTK, I am doing the following: vtkSmartPointer render_win = vtkSmartPointer::New(); vtkSmartPointer renderer =…
Aly
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OpenCV findChessboardCorners function is failing in a (apparently) simple scenario

I'm trying to find the corners of a chessboard using OpenCV. The image I'm using contains two chessboards, but I'm interested only in a sub-region of one of those. The following image shows the original image. Using GIMP, I've then selected the…
Muffo
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OpenCV: solvePnP tvec units and axes directions

I'm trying to find the relative position of the camera to the chessboard (or the other way around) - I feel OK with converting between different coordinate systems, e.g. as suggested here. I decided to use chessboard not only for calibration but…
Aleksander Lidtke
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Determine extrinsic camera with opencv to opengl with world space object

I'm using opencv and openframeworks (ie. opengl) to calculate a camera (world transform and projection matrixes) from an image (and later, several images for triangulation). For the purposes of opencv, the "floor plan" becomes the object (ie. the…
Soylent Graham
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