如何从点中找到平均线?

我使用OpenCV检测了轮廓,我想从轮廓中找出线条。

我找到了一个示例代码,用于从散点图中查找直线。

// Construct line from points
bool ShapeDetection::FitPoints(const std::vector<cv::Point> &pts) {
  int nPoints = pts.size();
  if( nPoints < 2 ) {
    // Fail: infinitely many lines passing through this single point
    _slope = 0;
    _yInt = 0;
    return false;
  }
  double sumX=0, sumY=0, sumXY=0, sumX2=0;
  for(int i=0; i<nPoints; i++) {
    sumX += pts[i].x;
    sumY += pts[i].y;
    sumXY += pts[i].x * pts[i].y;
    sumX2 += pts[i].x * pts[i].x;
  }
  double xMean = sumX / nPoints;
  double yMean = sumY / nPoints;
  double denominator = sumX2 - sumX * xMean;
  // You can tune the eps (1e-7) below for your specific task
  if( std::fabs(denominator) < 1e-7 ) {
    // Fail: it seems a vertical line
    _slope = 0;
    _yInt = xMean;

    return false;
  }
  _slope = (sumXY - sumX * yMean) / denominator;
  _yInt = yMean - _slope * xMean;

  return true;
}

找到像上面这样的水平线非常有效。但是,它没有找到垂直线,就像这样:

我在这个网站上做过类似的测试: https://www.rapidtables.com/tools/scatter-plot.html

它必须在h轴上显示一条接近3的垂直线,但不是。

我应该用什么方法来解决这个问题?