本文测试环境:
win10 64位
vistual studio 2019
Emgu CV 4.6.0
环境配置准备:
1 新增控制台项目,.net framework为4.7.2
2 把win-x64目录的native目录下的文件全部拷贝到项目的运行目录Debug目录下
3 项目选择x64
4 添加项目引用Emgu.CV.dll、Emgu.CV.Platform.NetFramework.dll、System.Drawing.dll和System.Runtime.InteropServices.RuntimeInformation.dll
具体配置参考:
Emgu CV4图像处理之环境搭建1(C#)_zxy2847225301的博客-CSDN博客
下面的内容参考自:21-22轮廓绘制(EmguCV学习)_牛客博客
查找轮廓API函数原型:
其中轮廓contours可以使用VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint()进行存储;hierarchy可以使用VectorOfRect hierarchy = new VectorOfRect()进行存储
参考例子:
stopSign.png原图如下:
代码如下:
- using Emgu.CV;
- using Emgu.CV.Structure;
- using Emgu.CV.Util;
- using System;
- using System.Collections.Generic;
- using System.Drawing;
- using System.IO;
- using System.Linq;
- using System.Text;
- using System.Threading.Tasks;
-
- namespace EmguCVDemo2
- {
- class Program
- {
- static void Main(string[] args)
- {
-
- Image
srcPic = new Image("stopSign.png"); - ImgFindContoursAndDraw1(srcPic);
- CvInvoke.WaitKey(0);
- Console.ReadLine();
- }
-
- ///
- /// 查找轮廓并绘制轮廓(方式1)
- ///
- ///
- private static void ImgFindContoursAndDraw1(Image
srcPic ) - {
- CvInvoke.Imshow("srcPic_before", srcPic);
- Mat gray_srvPic = new Mat();
- //转灰度图
- CvInvoke.CvtColor(srcPic, gray_srvPic, Emgu.CV.CvEnum.ColorConversion.Bgr2Gray);
- VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
- VectorOfRect hierarchy = new VectorOfRect();
- //二值化
- CvInvoke.Threshold(gray_srvPic, gray_srvPic, 100, 255, Emgu.CV.CvEnum.ThresholdType.Binary);
-
- //查找轮廓
- CvInvoke.FindContours(gray_srvPic, contours, hierarchy, Emgu.CV.CvEnum.RetrType.Tree, Emgu.CV.CvEnum.ChainApproxMethod.ChainApproxSimple);
-
-
- //绘制轮廓
- Mat countours_Pic = new Mat(srcPic.Size, Emgu.CV.CvEnum.DepthType.Cv8U, 3);
- for (int i = 0; i < contours.Size; i++)
- {
- VectorOfPoint vectorOfPoint = contours[i]; //轮廓是由点组成的,这是一个轮廓向量点的集合
- for (int j = 0; j< vectorOfPoint.Size-1; j++) //这里绘制的轮廓就差最后一条线还没有闭合
- {
- CvInvoke.Line(countours_Pic, vectorOfPoint[j], vectorOfPoint[j + 1], new MCvScalar(0, 255, 0), 3);
- CvInvoke.Line(srcPic, vectorOfPoint[j], vectorOfPoint[j+1], new MCvScalar(0, 255, 0),3);
- }
- //最后一个点要起点相连,才能算全部闭合
- CvInvoke.Line(countours_Pic, vectorOfPoint[vectorOfPoint.Size - 1], vectorOfPoint[0], new MCvScalar(0, 255, 0), 3);
- CvInvoke.Line(srcPic, vectorOfPoint[vectorOfPoint.Size-1], vectorOfPoint[0], new MCvScalar(0, 255, 0), 3);
- }
- CvInvoke.Imshow("countours_Pic", countours_Pic);
- CvInvoke.Imshow("srcPic_after", srcPic);
- CvInvoke.WaitKey(0);
- }
-
-
-
- }
- }
运行结果如下:
其中srcPic_before是原图,countours_Pic是轮廓,srcPic_after是在原图中绘制轮廓
上面的例子是找到轮廓后,遍历轮廓的点,然后把点与点直接通过直线连接起来组成轮廓,其实不用那么麻烦,EmguCV已经提供绘制轮廓的Api了,函数原型如下:
image:要绘制轮廓的图像
contours:通过查找轮廓函数查找到的轮廓信息
contourIds:要绘制contours中的那一条,一般遍历contours获取到,如contours[0]
color:线条的颜色,如new McvScalar(0,255,0)
thickness[可选]:线条的粗细
例子代码如下:
- using Emgu.CV;
- using Emgu.CV.Structure;
- using Emgu.CV.Util;
- using System;
- using System.Collections.Generic;
- using System.Drawing;
- using System.IO;
- using System.Linq;
- using System.Text;
- using System.Threading.Tasks;
-
- namespace EmguCVDemo2
- {
- class Program
- {
- static void Main(string[] args)
- {
-
- Image
srcPic = new Image("stopSign.png"); - ImgFindContoursAndDraw2(srcPic);
- CvInvoke.WaitKey(0);
- Console.ReadLine();
- }
-
-
-
- ///
- /// 查找轮廓并绘制轮廓(方式2)
- ///
- ///
- private static void ImgFindContoursAndDraw2(Image
srcPic ) - {
- CvInvoke.Imshow("srcPic_before", srcPic);
- Mat gray_srvPic = new Mat();
- //转灰度图
- CvInvoke.CvtColor(srcPic, gray_srvPic, Emgu.CV.CvEnum.ColorConversion.Bgr2Gray);
- VectorOfVectorOfPoint contours = new VectorOfVectorOfPoint();
- VectorOfRect hierarchy = new VectorOfRect();
- //二值化
- CvInvoke.Threshold(gray_srvPic, gray_srvPic, 100, 255, Emgu.CV.CvEnum.ThresholdType.Binary);
-
- //查找轮廓
- CvInvoke.FindContours(gray_srvPic, contours, hierarchy, Emgu.CV.CvEnum.RetrType.Tree, Emgu.CV.CvEnum.ChainApproxMethod.ChainApproxSimple);
-
-
- //绘制轮廓
- Mat countours_Pic = new Mat(srcPic.Size, Emgu.CV.CvEnum.DepthType.Cv8U, 3);
- for (int i = 0; i < contours.Size; i++) //遍历轮廓
- {
- CvInvoke.DrawContours(countours_Pic, contours, i, new MCvScalar(0, 255, 0), 3);
- CvInvoke.DrawContours(srcPic, contours, i, new MCvScalar(0, 255, 0), 3);
- }
- CvInvoke.Imshow("countours_Pic", countours_Pic);
- CvInvoke.Imshow("srcPic_after", srcPic);
- CvInvoke.WaitKey(0);
- }
-
-
- }
- }
运行结果如下: