c# - High rms return by camera calibration using circlegrid,WHY

Question

i wonder why i obtain higher rms while using circle grid for calibration.

initialize the object list

for (int i = 0; i < 27; i++)
{
    for (int j = 0; j < 31; j++)//width
    {
        objectList.Add(new MCvPoint3D32f((j * squareSize)+(i*squareSize/2), (i * squareSize)/2, 0.0F));
    }

}
           found1 = CvInvoke.FindCirclesGrid(thresh, new Size(31,27), cornerPoints, CalibCgType.AsymmetricGrid |CalibCgType.Clustering ,blobDetector);
   double error = CvInvoke.CalibrateCamera(objectPoints, imgPoints.Select(a => a.ToArray()).ToArray(), thresh.Size,
             cameraMatrix, distortionCoeffs, CalibType.SameFocalLength, term, out rVecs, out tVecs);

double rms = CvInvoke.StereoCalibrate(objectPoints, imgPoints.Select(a => a.ToArray()).ToArray(), imgPoints2.Select(a => a.ToArray()).ToArray(), cameraMatrix, distortionCoeffs, cameraMatrix2, distortionCoeffs2, thresh.Size, R, T, E, F, CalibType.FixIntrinsic | CalibType.UseIntrinsicGuess | CalibType.RationalModel | CalibType.SameFocalLength, term);

i am able to detect all the circle grid(total 20 frames with different view and position at the photo frame) but the rms return by camera calibration and also stereo calibration are both high ( 10, 31 respectively) and the rms remain there even i add more frames.

one of the blob found image: https://pasteboard.co/JLRvQFc.png

one of the findcirclegridimage: https://pasteboard.co/JLRvkmt.png

please help

question from:https://stackoverflow.com/questions/65952007/high-rms-return-by-camera-calibration-using-circlegrid-why

Answer 1

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