大家好，又见面了，我是你们的朋友全栈君。如果您正在找激活码,请点击查看最新教程,关注关注公众号 “全栈程序员社区” 获取激活教程,可能之前旧版本教程已经失效.最新Idea2022.1教程亲测有效,一键激活。
Jetbrains全家桶1年46，售后保障稳定
cv::fitLine用法
定义
在opencv官方文档定义如下：
void cv::fitLine(InputArray points,
OutputArray line,
int distType,
double param,
double reps,
double aeps
)
#include <opencv2/imgproc.hpp>
Fits a line to a 2D or 3D point set.
Parameters
points Input vector of 2D or 3D points, stored in std::vector<> or Mat.
line Output line parameters. In case of 2D fitting, it should be a vector of 4 elements (like Vec4f) - (vx, vy, x0, y0), where (vx, vy) is a normalized vector collinear to the line and (x0, y0) is a point on the line. In case of 3D fitting, it should be a vector of 6 elements (like Vec6f) - (vx, vy, vz, x0, y0, z0), where (vx, vy, vz) is a normalized vector collinear to the line and (x0, y0, z0) is a point on the line.
distType Distance used by the M-estimator, see DistanceTypes
param Numerical parameter ( C ) for some types of distances. If it is 0, an optimal value is chosen.
reps Sufficient accuracy for the radius (distance between the coordinate origin and the line).
aeps Sufficient accuracy for the angle. 0.01 would be a good default value for reps and aeps.
代码示例
简而言之，就是利用已有的点拟合直线，本篇只针对使用做简单示例，基于opencv3.4.5, C++；
主要介绍输出参数，
- OutputArray line：在二维下为四个元素，前两个为向量（x, y），后两个为拟合直线上的一个点
- distType，参考如下：
//! @see distanceTransform, fitLine enum DistanceTypes { DIST_USER = -1, //!< User defined distance DIST_L1 = 1, //!< distance = |x1-x2| + |y1-y2| DIST_L2 = 2, //!< the simple euclidean distance DIST_C = 3, //!< distance = max(|x1-x2|,|y1-y2|) DIST_L12 = 4, //!< L1-L2 metric: distance = 2(sqrt(1+x*x/2) - 1)) DIST_FAIR = 5, //!< distance = c^2(|x|/c-log(1+|x|/c)), c = 1.3998 DIST_WELSCH = 6, //!< distance = c^2/2(1-exp(-(x/c)^2)), c = 2.9846 DIST_HUBER = 7 //!< distance = |x|<c ? x^2/2 : c(|x|-c/2), c=1.345 }; - param： 默认0，opencv自动优化
- reps：0.01精度即可
- aeps：建议0.01，0.01 would be a good default value…
y = x + 1直线
向量（0.707107，0.707107）如图下
