OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Fri, 26 Jul 2013 10:10:25 -0500NEWBIE calibrateCamera and calibrationMatrixValueshttp://answers.opencv.org/question/17590/newbie-calibratecamera-and-calibrationmatrixvalues/hi- i am a total newb to opencv- and to python as well. i'm trying to get a better understanding of the workings of the calibrateCamera and calibrationMatrixValues functions. i'm stepping through someone else's (working) python code. thanks in advance for your patience.
i am ultimately trying to use calibrationMatrixValues to extract the fovx and fovy from a previously (successfully) solved camera calibration using calibrateCamera. these are the settings used (where geoPoints, imgPoints, pWidth, and pHeight have been determined).
calibrateCamera((geoPoints,imgPoints),width=pWidth, height=pHeight, useIntrinsicGuess=True, fixAspectRatio=True, zeroTangentDist=True, fixPrincipalPoint=False)
calibrateCamera - the output camera matrix i get is indeed a 3x3 matrix, but it is a rotation matrix that is being used to calculate my camera's extrinsics. i think i am looking for output that is a projection matrix- so i can feed that into calibrationMatrixValues.
calibrationMatrixValues - where can i find the camera matrix to input? imageSize, is this an array of two values [x,y]? i know the image size, i'm not sure how to format it properly.
and finally- apertureWidth and apertureHeight. these i am stuck on. any guess as to how i would extract or calculate these values from calibrateCamera?
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in stepping through the source code for the calibrationMatrixValues function i find:
fovx = 2 * atan(imgWidth / (2 * alphax)) * 180.0 / CV_PI;
fovy = 2 * atan(imgHeight / (2 * alphay)) * 180.0 / CV_PI;
alphax and alphay are pulled directly from the input camera matrix. so, a big problem for me is the matrix i feed it looks like a rotation matrix, and this produces very unusable results.
thanks very muchgardyllFri, 26 Jul 2013 10:10:25 -0500http://answers.opencv.org/question/17590/