我在KeypointBasedMotionEstimator类的OpenCV中有一个仿射变换矩阵。
它的形式如下:
[1.0008478, -0.0017408683, -10.667297;
0.0011812132, 1.0009096, -3.3626099;
0, 0, 1]
我现在想将变换应用于矢量< Pointf&gt ;,这样它就可以转换每个点,就像它们在图像中一样。
OpenCV似乎不允许转换点,函数:
void cv::warpAffine ( InputArray src,
OutputArray dst,
InputArray M,
Size dsize,
int flags = INTER_LINEAR,
int borderMode = BORDER_CONSTANT,
const Scalar & borderValue = Scalar()
)
似乎只将图像作为输入和输出。
有没有办法可以在OpenCV中对单点应用仿射变换?
答案 0 :(得分:3)
你可以使用
void cv::perspectiveTransform(InputArray src, OutputArray dst, InputArray m)
e.g。
cv::Mat yourAffineMatrix(3,3,CV_64FC1);
[...] // fill your transformation matrix
std::vector<cv::Point2f> yourPoints;
yourPoints.push_back(cv::Point2f(4,4));
yourPoints.push_back(cv::Point2f(0,0));
std::vector<cv::Point2f> transformedPoints;
cv::perspectiveTransform(yourPoints, transformedPoints, yourAffineMatrix);
不确定Point数据类型,但转换必须具有double
类型,例如CV_64FC1
另见http://docs.opencv.org/modules/core/doc/operations_on_arrays.html#perspectivetransform
答案 1 :(得分:2)
它有点笨拙,但你可以手动矩阵乘以你的点数:
// the transformation matrix
Mat_<float> M(3,3);
M << 1.0008478, -0.0017408683, -10.667297,
0.0011812132, 1.0009096, -3.3626099,
0, 0, 1;
// a point
Point2f p(4,4);
// make a Mat for multiplication,
// must have same type as transformation mat !
Mat_<float> pm(3,1);
pm << p.x,p.y,1.0;
// now , just multiply:
Mat_<float> pr = M * pm;
// retrieve point:
Point2f pt(pr(0), pr(1));
cerr << pt << endl;
[-6.67087, 0.645753]