23，霍夫变换----圆检测

霍夫圆检测
函数原型

public static CircleSegment[] HoughCircles(InputArray image, 
                                           HoughMethods method, 
                                           double dp, 
                                           double minDist, 
                                           double param1 = 100, 
                                           double param2 = 100, 
                                           int minRadius = 0, 
                                           int maxRadius = 0);

返回值: CircleSegment[], 包含圆心,半径
image: 输入图像,单通道,灰度图像
method: 霍夫变换方法,HoughCirclesMethod.Gradient
dp: 用来检测圆心的累加器图像的分辨率与图像之比的倒数,且此参数允许创建一个比输入图像分辨率较低的累加器,如,dp=1累加器和输入图像具有相同的分辨率,dp=2累加器只有输入图像一半大的宽度和高度
minDist: 霍夫变换检测到圆的圆心之间的最小距离,用来分辨不同的圆
param1: 第一个方法特定的参数。[默认值是100]，边缘检测的低阈值
param2 : 第二个方法特定于参数。 [默认值是100]，中心点累加器阈值，候选圆心
minRadius : 最小半径
maxRadius : 最大半径

以下代码,有的是无用的

private static void HoughCircular()
{
    Mat src = new Mat(@"I:\OpenCvSharp学习\气泡.jpg", ImreadModes.AnyColor);
    Mat Gray = new Mat();
    Mat Canny = new Mat();
    Mat Threthold = new Mat(src.Size(), MatType.CV_8UC3, Scalar.White);
    Mat Result = new Mat(src.Size(), MatType.CV_8UC3, Scalar.White);
    //灰度化
    Cv2.CvtColor(src, Gray, ColorConversionCodes.RGB2GRAY);
    //二值化
    Cv2.Threshold(Gray, Threthold, 100, 255, ThresholdTypes.Binary);
    Cv2.Canny(Threthold, Canny, 60, 200, 3, false);
    CircleSegment[] circle;
    circle = Cv2.HoughCircles(Gray, HoughMethods.Gradient, 1, 30, 100, 30, 1, 100);
    Scalar Colar = new Scalar(0, 255, 0);
    Scalar Colar1 = new Scalar(0,0,255);
    for (int i = 0; i < circle.Length; i++)
    {
        int X = (int)circle[i].Center.X;
        int Y = (int)circle[i].Center.Y;
        int a = (int) circle[i].Radius;
        Cv2.Circle(src,X,Y,a,Colar,2,LineTypes.Link8);//圆
        Cv2.Circle(src, X, Y, 2, Colar1, 2, LineTypes.Link8);//圆心
    }
    Window Win1 = new Window("src", WindowMode.AutoSize, src);
    Window Win2 = new Window("Gray", WindowMode.AutoSize, Gray);
    Window Win4 = new Window("Canny", WindowMode.AutoSize, Canny);
    Window Win5 = new Window("Result", WindowMode.AutoSize, src);
    Cv2.WaitKey(0);
}