OpenCV3.1.0鱼眼相机标定及畸变校正

       常用的相机模型为针孔模型，此模型在视场较小的情况下是适用的,随着视场的增加，模型误差越来越大。

       普通镜头和鱼眼镜头成像原理的差异是造成此现象的根本原因。具体原理可以参见：

[1] http://docs.opencv.org/master/db/d58/group__calib3d__fisheye.html#gsc.tab=0

[2] Juho Kannalaand Sami S. Brandt. A generic camera model and calibration method for conventional,wide-angle and fish-eye lenses. IEEE Transactions on Pattern Analysis andMachine Intelligence, vol. 28, no. 8, August 2006.

[3] Juho Kannala,Janne Heikkila and Sami S. Brandt. Geometric camera calibration. WileyEncyclopedia of Computer Science and Engineering, 2008.

            

      我的源程序：

      vector img_ptsTemp;
      vector> img_ptsVector;

      vector obj_ptsTemp;
      vector> obj_ptsVector;

       // 鱼眼镜头参数
         Mat intrinsic_mat;            //Matx33d intrinsic_mat亦可;           Mat intrinsic_mat(3, 3, CV_64FC1, Scalar(0))亦可，注意数据类型;      
         Mat distortion_coeffs;     //Vec4d distortion_coeffs亦可

 int flag = 0;
 flag |= cv::fisheye::CALIB_RECOMPUTE_EXTRINSIC;
 flag |= cv::fisheye::CALIB_CHECK_COND;
 flag |= cv::fisheye::CALIB_FIX_SKEW;  /*非常重要*/

           cv::fisheye::calibrate(
                                       obj_ptsVector,
img_ptsVector,
board_img_size,
intrinsic_mat, 
distortion_coeffs,
cv::noArray(),      
cv::noArray(),     
flag,
cv::TermCriteria(3, 20, 1e-6)
);

//畸变校正

void FishEyeImgUndistort()
{
Mat DistortImg = cv::imread("fore_1.jpg");


Mat UndistortImg;   
Mat new_intrinsic_mat;    //Mat new_intrinsic_mat(3, 3, CV_64FC1, Scalar(0))亦可，注意数据类型;


//fx,fy变大（小），视场变小（大），裁剪较多（少），但细节清晰（模糊）；很关键，new_intrinsic_mat决定输出的畸变校正图像的范围
intrinsic_mat.copyTo(new_intrinsic_mat);

//调整输出校正图的视场
new_intrinsic_mat.at(0, 0) *= 0.5;      //注意数据类型，非常重要
new_intrinsic_mat.at(1, 1) *= 0.4; 


//调整输出校正图的中心
new_intrinsic_mat.at(0, 2) += 0.0;   
new_intrinsic_mat.at(1, 2) += 0.0;


cv::fisheye::undistortImage(
DistortImg,
UndistortImg,
intrinsic_mat,
distortion_coeffs,
new_intrinsic_mat    //
);      //最后一个camera_matrix必须写上  Ref:http://answers.opencv.org/question/64614/fisheyeundistortimage-doesnt-work-what-wrong-with-my-code/


cv::imshow("DistortImg", DistortImg);
cv::imshow("UndistortImg", UndistortImg);
cv::imwrite("feModelUndistortFore.jpg", UndistortImg);
cv::waitKey(0);
}