Dilate膨胀

函数说明：用特定的结构元素膨胀图像。膨胀可以看成是最大值滤波，即用最大值替换中心像素点。该函数就地模式，可以指定迭代次数，多通道图像的话，每个通道分开处理。

用3x3矩形结构元素膨胀

//函数原型
void Dilate(InputArray src,OutputArray dst,InputArray? element,Point? anchor = null,int iterations = 1,BorderTypes borderType = BorderTypes.Constant,Scalar? borderValue = null)

GetStructuringElement获取形态操作的结构元素

函数说明：返回一个指定大小、形状的结构元素，用于膨胀、腐蚀或其它形态操作。

//函数原型1
Mat GetStructuringElement(MorphShapes shape,Size ksize)//函数原型2
Mat GetStructuringElement(MorphShapes shape, Size ksize, Point anchor)

Erode腐蚀

函数说明：用特定的结构元素腐蚀图像。腐蚀可以看成是最小值滤波，即用最小值替换中心像素点。

该函数就地模式，可以指定迭代次数，多通道图像的话，每个通道分开处理。

用3x3矩形结构元素腐蚀

//函数原型
void Erode(InputArray src,OutputArray dst,InputArray? element,Point? anchor = null,int iterations = 1,BorderTypes borderType = BorderTypes.Constant,Scalar? borderValue = null)

图像示例

原图

膨胀与腐蚀

定位下划线位置

源码示例

public void Run() {TestDilateAndErode();MorphologyDemo();LocateGapFilling();
}/// <summary>
/// 定位下划线
/// </summary>
/// <exception cref="Exception"></exception>
private void LocateGapFilling() {using (var src = Cv2.ImRead(ImagePath.GapFilling, ImreadModes.Grayscale)) {if (src.Empty()) throw new Exception($"图像打开有误：{ImagePath.GapFilling}");Cv2.Threshold(src, src, 0, 255, ThresholdTypes.Otsu | ThresholdTypes.BinaryInv);Cv2.ImShow("GapFilling", src);using var dst = new Mat();var element = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(15, 1));//可消除部分垂直线Cv2.Erode(src, dst, element);ShowMat("Location", element, dst);Cv2.WaitKey();Cv2.DestroyAllWindows();}
}/// <summary>
/// 膨胀、腐蚀
/// </summary>
/// <exception cref="Exception"></exception>
private void MorphologyDemo() {using (var src = Cv2.ImRead(ImagePath.Morphology, ImreadModes.Grayscale)) {if (src.Empty()) throw new Exception($"图像打开有误：{ImagePath.Morphology}");Cv2.Threshold(src, src, 0, 255, ThresholdTypes.Otsu | ThresholdTypes.Binary);Cv2.ImShow("gray", src);using var dst = new Mat();var element = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(15, 15));//膨胀Cv2.Dilate(src, dst, element);ShowMat("Dilate Rect", element, dst);//腐蚀Cv2.Erode(src, dst, element);ShowMat("Erode Rect", element, dst);Cv2.WaitKey();Cv2.DestroyAllWindows();}
}private void ShowMat(string winNameFix, Mat element, Mat dst) {Cv2.ImShow($"{winNameFix},{element.Size()}", dst);
}/// <summary>
/// 演示Dilate与Erode，细看其中的不同。
/// 注意：一幅图像膨胀后再腐蚀的图像，不一定与原图一样。
/// </summary>
private void TestDilateAndErode() {using (var mat = new Mat(11, 15, MatType.CV_8UC1, new byte[] { 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,1,1,1,0,0,0,0,1,1,1,0,0,0,0,0,1,1,1,0,0,0,0,1,1,1,0,0,0,0,0,1,1,1,0,0,0,0,0,1,1,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,0,0,0,1,1,1,1,1,0,0,0,0,0,0,0,0,0,1,1,1,1,1,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0})) {Helper.Dump(mat);var element = Cv2.GetStructuringElement(MorphShapes.Rect, new Size(3, 3));//膨胀Cv2.Dilate(mat, mat, null, iterations: 2);Console.WriteLine("Dilate X 2");Dump(mat);using var dst = new Mat();//加上空白边缘Cv2.CopyMakeBorder(mat, dst, 1, 1, 1, 1, BorderTypes.Constant, new Scalar(0, 0, 0));Cv2.Erode(mat, mat, null);Console.WriteLine("The first time of Erode");Dump(mat);Cv2.Erode(mat, mat, null);//可连接腐蚀多次//Cv2.Erode(mat,mat,null,iterations: 2);Console.WriteLine("The second time of Erode");Dump(mat);//加了空白边缘的图像Console.WriteLine("dst");Dump(dst);//对比前面的腐蚀结果//腐蚀Cv2.Erode(dst, dst, null);Console.WriteLine("ErodeX1");Dump(dst);Cv2.Erode(dst, dst, null);Console.WriteLine("ErodeX2");Dump(dst);}
}#region Dump
/// <summary>
/// 控制台显示矩阵
/// </summary>
/// <param name="mat">待显示的矩阵</param>
/// <param name="dumpChannel">要显示通道</param>
public static void Dump(Mat mat, FormatType formatType = FormatType.Default) {Dump(mat, new OpenCvSharp.Range(0, mat.Channels() - 1), formatType);
}
/// <summary>
/// 控制台显示矩阵
/// </summary>
/// <param name="mat">等显示的矩阵</param>
/// <param name="channelRange">要显示的通道范围</param>
public static void Dump(Mat mat, OpenCvSharp.Range channelRange, FormatType formatType = FormatType.Default) {var nChannels = mat.Channels();if (nChannels == 1) {Console.WriteLine(mat.Dump(formatType));return;}var splits = mat.Split();for (int c = channelRange.Start; c <= channelRange.End; c++) {if (c < nChannels) {Console.WriteLine(splits[c].Dump(formatType));}else {Console.WriteLine($"通道值{c}必须小于{nChannels}");}}
}
#endregion

OpenCvSharp函数示例(目录)

参考

https://docs.opencv.org/

https://edu.csdn.net/learn/38286/608282