OpenCV's Pinhole calibration model reduces FOV, should i use Fisheye?

Question

I have a wide angle camera, the specifications say it is around 150°, but to me seems more ~100° horizontal and ~80° vertical. Anyway, once calibrated these fields of view are reduced by ~20 degrees each.

This is true for both the values returned by cv::calibrationMatrixValues function and the rectified frames, in which relatively big external portions are cropped.

Is this behavior normal? If it is, can I avoid this problem using the newer Fisheye camera model? With Fisheye is it possible to know the measured FOVs? I cannot find something like fisheye::calibrationMatrixValues.

Answer 1

cv :: getOptimalNewCameraMatrix可以完成这项工作。

Answer 2

对于您的情况，我认为最好的解决方案是使用Open CV 3.4.X中的cv :: fisheye模块。 （C ++，MS Windows）。未失真的图像会比初始图像大得多，但会具有一定的大小。

在我的情况下，我使用cv :: fisheye :: calibrate制作了K和D（相机矩阵和径向失真系数矩阵）。然后，我使用cv :: fisheye :: initUndistortRectifyMap生成X和Y坐标的地图。最后，我使用cv :: remap通过initUndistortRectifyMap中的地图使鱼眼镜头的图像不失真。