圆形识别方案

识别流程

• 判断是否为封闭图形；
• 根据圆的方程，取输入点集中的1/6、3/6、5/6处的三个点，求得圆的方程，获取圆心及半径；
• 取点集中的部分点，计算点到圆心的距离与半径的比例，与设定的阈值比较，得出结果。~~~~
  

实现

public static bool IsCircle(List<Point> points, out Point center, out double radius){ int len = points.Count; center = new Point(); radius = 0; // 判断是否为封闭图形 if (!IsClosedFigure(points)) return false; int judgePointNum = len * 50 / 100; if (len < judgePointNum) return false; // 取链表上三个点作为判断圆的根据 Point p1 = points[len / 6]; Point p2 = points[len / 2]; Point p3 = points[len * 5 / 6]; if ((Math.Abs(p1.X - p2.X) < 100 && Math.Abs(p1.Y - p2.Y) < 100) || (Math.Abs(p1.X - p3.X) < 100 && Math.Abs(p1.Y - p3.Y) < 100) || (Math.Abs(p2.X - p3.X) < 100 && Math.Abs(p2.Y - p3.Y) < 100)) return false; // 三个点确定圆的方程，获取圆心坐标及半径 GetCircle(p1, p2, p3, out center, out radius); // 获取圆上平均分部的多个点，判断其到圆心的距离与半径之差是否在精度内 for (int i = 0; i < judgePointNum; ++i) { // 获取圆上点 Point p = points[len * i / judgePointNum]; double deviation = Math.Abs(GetDistance(center, p) - radius); // 点在圆上的偏移量与半径的比值若大于固定值，则不为圆 if (deviation/radius > MaxRatio) return false; } return true;}

直线识别方案

步骤

1.使用最小二乘法回归直线：

2.得到直线方程y=kx+b后，计算所有点到直线的距离，若在阈值范围内，认为是直线。

实现

/// <summary>/// 最小二乘法求回归直线方程/// </summary>/// <param name="points">输入数据</param>/// <param name="k">直线斜率</param>/// <param name="b">直线截距</param>/// <param name="type">直线类型 1：水平线 2：垂直线 3：一般直线</param>/// <returns></returns>public static bool IsLine(List<Point> points, out double k, out double b, out int type){ k = 0; b = 0; type = 0; if (points.Count < 2) return false; double averageX = 0, averageY = 0, n = 0; n = points.Count; foreach (Point p in points) { averageX += p.X; averageY += p.Y; } averageX /= n; averageY /= n; double numerator = 0, denominator = 0; foreach (Point p in points) { numerator += (p.X - averageX) * (p.Y - averageY); denominator += (p.X - averageX) * (p.X - averageX); } if (numerator == 0) //平行于X轴为水平线，返回纵坐标平均值 { b = averageY; type = 1; } else if (denominator == 0)//平行于Y轴为垂直线，返回横坐标平均值 { b = averageX; type = 2; } else { type = 3; } k = numerator / denominator; b = averageY - k * averageX; foreach (Point p in points) { dis = GetPoint2LineDistance(p, k, b, type); if (dis > MAX_POINT_LINE_DIS) return false; //点到拟合直线距离过大 } return true;}/// <summary>/// 计算点到直线的距离/// </summary>/// <param name="p">待计算点</param>/// <param name="k">直线斜率</param>/// <param name="b">直线截距</param>/// <param name="type">直线类型 1：水平线 2：垂直线 3：一般直线</param>/// <returns>距离</returns>private static double GetPoint2LineDistance(Point p, double k, double b, int type){ if (type == 1) { return Math.Abs(p.Y - b); } else if (type == 2) { return Math.Abs(p.X - b); } else { double numerator = 0, denominator = 0; numerator = Math.Abs(k * p.X - p.Y + b); denominator = Math.Sqrt(k * k + 1); return numerator / denominator; }}

以上就是c# 圆形识别方案和直线识别方案的实现示例的详细内容，更多关于c# 圆形识别方案和直线识别方案的资料请关注其它相关文章！