Question

我正在尝试比较每个SolvePnP可能性之间的精度和时间：CV_ITERATIVE，CV_EPNP和CV_P3P

我还将我的结果与Matlab EPNP进行了比较。

看起来像EPNP和P3P失败了：

std::vector<cv::Point2f> imgPoints;
imgPoints.push_back(cv::Point2f(400,188));
imgPoints.push_back(cv::Point2f(400,300));
imgPoints.push_back(cv::Point2f(512,300));
imgPoints.push_back(cv::Point2f(512,188));

double size = 80.0;
std::vector<cv::Point3f> objPoints;
objPoints.push_back(cv::Point3f(0,0,0));
objPoints.push_back(cv::Point3f(0,size,0));
objPoints.push_back(cv::Point3f(size,size,0));
objPoints.push_back(cv::Point3f(size,0,0));

cv::Mat rvec0 = cv::Mat::zeros(3, 1, CV_64FC1);
cv::Mat tvec0 = cv::Mat::zeros(3, 1, CV_64FC1);

cv::Mat rvec1 = cv::Mat::zeros(3, 1, CV_64FC1);
cv::Mat tvec1 = cv::Mat::zeros(3, 1, CV_64FC1);

cv::Mat rvec2 = cv::Mat::zeros(3, 1, CV_64FC1);
cv::Mat tvec2 = cv::Mat::zeros(3, 1, CV_64FC1);

cv::Mat cam, coeff;
cam = (cv::Mat_<double>(3,3) << 700,0,300,0,700,400,0,0,1);
cv::solvePnP(objPoints,imgPoints,cam,coeff,rvec0,tvec0,CV_ITERATIVE);
cv::solvePnP(objPoints,imgPoints,cam,coeff,rvec1,tvec1,CV_P3P);
cv::solvePnP(objPoints,imgPoints,cam,coeff,rvec2,tvec2,CV_EPNP);

cv::Mat rmat0,rmat1,rmat2;
cv::Rodrigues(rvec0,rmat0);
cv::Rodrigues(rvec1,rmat1);
cv::Rodrigues(rvec2,rmat2);

std::cout << "ITERATIVE : Rotation matrix : " << std::endl << rmat0 << std::endl;
std::cout << "ITERATIVE : Tranlation vector : " << std::endl << tvec0 << std::endl << std::endl;

std::cout << "P3P : Rotation matrix : " << std::endl << rmat1 << std::endl;
std::cout << "P3P : Tranlation vector : " << std::endl << tvec1 << std::endl << std::endl;

std::cout << "EPNP : Rotation matrix : " << std::endl << rmat2 << std::endl;
std::cout << "EPNP : Tranlation vector : " << std::endl << tvec2  << std::endl << std::endl;

给我：

ITERATIVE：旋转矩阵：[1，-2.196885546074445e-016,9.692430825310778e-016; 2.196885546074445e-016,1,11012059558506939e-015; -9.692430825310778e-016，-1.012059558506939e-015,1]

ITERATIVE：Tranlation vector：[71.42857142857143; -151.4285714285714; 500]

P3P：旋转矩阵：[1,0,0; 0,1,0; 0,0,1]

P3P：Tranlation载体：[ - 3.97771428571427e-015; -4.022285714285698e-015; 9.989999999999962e-017]

EPNP：旋转矩阵：[1,0,0; 0,1,0; 0,0,1]

EPNP：Tranlation vector：[ - 3.97771428571427e-015; -4.022285714285698e-015; 9.989999999999962e-017]

有什么建议吗？

Alexandre Kornmann

Answer 1

我有你的提示，有些事情对我来说很奇怪：

您在凸轮矩阵中给出（300,400）中心点，因此您的图像是600 * 800（垂直）？
对于2D点的投影位置，请确保以OpenCV方式放置它们：图像中的（0,0）点位于左上角。
你的分数是共面的（平面z = 0），也许solvePnP对此很敏感。

Answer 2

P3P'不是一个好方法，它的精度非常差.EPNP似乎是精度的最佳选择。但是你不应该只使用EPNP，Ransac算法会更好。

Opencv：解决PNP错误，EPNP和P3P失败

2 个答案: