举个🌰
一个培养皿里有若干条鱼苗，需要将它全部区分识别出来，
像如下图所示的小蝌蚪就是（培养皿里三个黑点是热带鱼苗，做实验用的，一毫米长）
用的是海康威视的黑白工业相机拍摄。
先讲讲思路，图片是一组庞大的矩阵数据，每一个像素点有用数据为五个分别为RGB（三原色），以及XY坐标。也就是说我们能将整张图片每一个像素点的数据提取出来加以分析。那么就可以做到图片识别。
源代码会在最下方贴出。
首先整个流程思想是这杨
#region 6孔混合鱼苗
VisionHelper.Two_Level(@"C:\Users\Administrator\Desktop\右上角三只鱼的提取\小鱼图片2-单个.png", @"C:\Users\Administrator\Desktop\3.1\二级化.png");
VisionHelper.Outline(@"C:\Users\Administrator\Desktop\3.1\二级化.png", @"C:\Users\Administrator\Desktop\3.1\轮廓检测.png");
VisionHelper.CutCircle(@"C:\Users\Administrator\Desktop\3.1\轮廓检测.png", @"C:\Users\Administrator\Desktop\3.1\圆形剪切.bmp");
VisionHelper.ExtractCircle(@"C:\Users\Administrator\Desktop\3.1\圆形剪切.bmp", @"C:\Users\Administrator\Desktop\3.1\圆形提取.jpg");
var data = VisionHelper.GetImagePixel(@"C:\Users\Administrator\Desktop\3.1\圆形提取.jpg");
data = VisionHelper.FishExtract(data, @"C:\Users\Administrator\Desktop\3.1\圆形提取.jpg");
var fish = VisionHelper.FishGroup(data);
fish = VisionHelper.FishDistinct(fish);
data = VisionHelper.FishCenter(fish);
#endregion 先将抓取的图片二级化,效果如下所示 VisionHelper.Two_Level(@"C:\Users\Administrator\Desktop\右上角三只鱼的提取\小鱼图片2-单个.png", @"C:\Users\Administrator\Desktop\3.1\二级化.png"); 原图左，处理图右二级化以后，这张图片的数据就只剩黑色和白色，如果二级化时没有损坏到目标特征像素点，那么接下来提取目标特征像素点会很容易，因为只有黑白两色
接下来做轮廓监测，将整个培养皿扫描出来并且去除，这杨就只剩培养皿内的鱼苗和食物或者排泄物
VisionHelper.Outline(@"C:\Users\Administrator\Desktop\3.1\二级化.png", @"C:\Users\Administrator\Desktop\3.1\轮廓检测.png");效果如下所示在图片处理的算法中，我用红圈标注了培养皿内的区域，并且用蓝点打出了中心
接下来呢，可以将其他无用的图片区域全部剪切掉，就是图片内圆形切割
VisionHelper.CutCircle(@"C:\Users\Administrator\Desktop\3.1\轮廓检测.png", @"C:\Users\Administrator\Desktop\3.1\圆形剪切.bmp");切割效果如下图所示
因为当初代码里设定生成的图片是BMP,上传不了博客，所以这粗糙的截图一下。
可以看到圆形剪切.bmp里只剩培养皿内区域的图片了
之前轮廓处理和圆形剪切形成的红色,蓝色圆圈或者中心点代码里可以设置不写入
那么接下来就是对圆形剪切区域的有用像素进行提取和分析
var data = VisionHelper.GetImagePixel(@"C:\Users\Administrator\Desktop\3.1\圆形提取.jpg");
data = VisionHelper.FishExtract(data, @"C:\Users\Administrator\Desktop\3.1\圆形提取.jpg");
var fish = VisionHelper.FishGroup(data);
fish = VisionHelper.FishDistinct(fish);
data = VisionHelper.FishCenter(fish);我先展示下最终的结果
经过我进行数据处理后的图片内提取出了三条鱼的中心点位数据
我们校验一下答案
下图1是原图
三个小黑点是三条鱼数据正确，坐标是否正确？我用画图工具打开校验
如下三图所示，为了更直观的展示结果，用鼠标浮在指定坐标，手机拍摄的，不是很清楚但是看得清，大家可以双击图片放大
第一条数据151，77，在图内鼠标右上角指向的小鱼苗内
第二条数据22，88，在图内鼠标左侧指向的小鱼苗内
第三条数据137，148，88，在图内鼠标右下角指向的小鱼苗内
接下来贴出我手搓的核心算法
整个VisionHelper运用了OpenCvSharp和Emgu.CV这两个第三方图片处理框架的算法，所有的方法都可以灵活运用，方法体内的参数可以随着实际需要识别的物体做调整
（源代码里有那么多注释应该就不用在讲解基础框架和算法应用了吧，嘻嘻）
using Emgu.CV;
using Emgu.CV.CvEnum;
using Emgu.CV.Structure;
using OpenCvSharp;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using FishVision.Model;
namespace FishVision
{
public class VisionHelper
{
/// <summary>
/// 1.二级化
/// </summary>
/// <param name="oldpath"></param>
/// <param name="newPath"></param>
public static void Two_Level(string oldpath,string newPath)
{
Emgu.CV.Mat image = CvInvoke.Imread(oldpath, Emgu.CV.CvEnum.ImreadModes.Grayscale);
Emgu.CV.Mat mid = new Emgu.CV.Mat();
CvInvoke.Threshold(image, mid, 125, 255, ThresholdType.Binary);//180 改
CvInvoke.Imwrite(newPath, mid);
}
/// <summary>
/// 2.轮廓检测
/// </summary>
public static void Outline(string oldpath, string newPath)
{
//读取图片
var img = Cv2.ImRead(oldpath);
//转换成灰度图
OpenCvSharp.Mat gray = img.CvtColor(ColorConversionCodes.BGR2GRAY);
//阈值操作 阈值参数可以用一些可视化工具来调试得到
OpenCvSharp.Mat ThresholdImg = gray.Threshold(135, 255, ThresholdTypes.Binary);
//Cv2.ImShow("Threshold", ThresholdImg);
//降噪 高斯变化
//Mat gaussImg= ThresholdImg.GaussianBlur(new Size(5, 5), 0.8);
//Cv2.ImShow("GaussianBlur", gaussImg);
//中值滤波降噪
//Mat medianImg = ThresholdImg.MedianBlur(5);
//Cv2.ImShow("MedianBlur", medianImg);
//膨胀+腐蚀
//Mat kernel = new Mat(15, 15, MatType.CV_8UC1);
//Mat DilateImg = ThresholdImg.Dilate(kernel);
////腐蚀处理
//Mat binary = DilateImg.Erode(kernel);
OpenCvSharp.Mat element = Cv2.GetStructuringElement(MorphShapes.Ellipse, new OpenCvSharp.Size(3, 3));
OpenCvSharp.Mat openImg = ThresholdImg.MorphologyEx(MorphTypes.Open, element);
//Cv2.ImShow("Dilate & Erode", openImg);
//设置感兴趣的区域
int x = 0, y = 0, w = img.Width, h = img.Height;
Rect roi = new Rect(x, y, w, h);
OpenCvSharp.Mat ROIimg = new OpenCvSharp.Mat(openImg, roi);
//Cv2.ImShow("ROI Image", ROIimg);
//寻找图像轮廓
OpenCvSharp.Point[][] contours;
HierarchyIndex[] hierachy;
Cv2.FindContours(ROIimg, out contours, out hierachy, RetrievalModes.List, ContourApproximationModes.ApproxTC89KCOS);
//根据找到的轮廓点，拟合椭圆
for (int i = 0; i < contours.Length; i++)
{
//拟合函数必须至少5个点，少于则不拟合
if (contours[i].Length < 150 || contours[i].Length > 200) continue;
//椭圆拟合
var rrt = Cv2.FitEllipse(contours[i]);
//ROI复原
rrt.Center.X += x;
rrt.Center.Y += y;
//画椭圆
Cv2.Ellipse(img, rrt, new Scalar(0, 0, 255), 2, LineTypes.AntiAlias);
//画圆心
Cv2.Circle(img, (int)(rrt.Center.X), (int)(rrt.Center.Y), 4, new Scalar(255, 0, 0), -1, LineTypes.Link8, 0);
}
//Cv2.ImShow("Fit Circle", img);
Cv2.ImWrite(newPath, img);
}
/// <summary>
/// 3.圆形剪切
/// </summary>
/// <param name="oldpath"></param>
/// <param name="newPath"></param>
public static void CutCircle(string oldpath, string newPath)
{
Image<Bgr, Byte> src = new Image<Bgr, byte>(oldpath);
int scale = 1;
if (src.Width > 500)
{
scale = 2;
}
if (src.Width > 1000)
{
scale = 10;
}
if (src.Width > 10000)
{
scale = 100;
}
var size = new System.Drawing.Size(src.Width / scale, src.Height / scale);
Image<Bgr, Byte> srcNewSize = new Image<Bgr, byte>(size);
CvInvoke.Resize(src, srcNewSize, size);
//将图像转换为灰度
Emgu.CV.UMat grayImage = new Emgu.CV.UMat();
CvInvoke.CvtColor(srcNewSize, grayImage, ColorConversion.Bgr2Gray);
//使用高斯滤波去除噪声
CvInvoke.GaussianBlur(grayImage, grayImage, new System.Drawing.Size(3, 3), 3);
//霍夫圆检测
CircleF[] circles = CvInvoke.HoughCircles(grayImage, Emgu.CV.CvEnum.HoughModes.Gradient, 2.0, 200.0, 100.0, 180.0, 5);
Rectangle rectangle = new Rectangle();
float maxRadius = 0;
foreach (CircleF circle in circles)
{
var center = circle.Center;//圆心
var radius = circle.Radius;//半径
if (radius > maxRadius)
{
maxRadius = radius;
rectangle = new Rectangle((int)(center.X - radius) * scale,
(int)(center.Y - radius) * scale,
(int)radius * 2 * scale + scale,
(int)radius * 2 * scale + scale);
}
srcNewSize.Draw(circle, new Bgr(System.Drawing.Color.Blue), 4);
}
//CvInvoke.Imwrite("原始图片.bmp", srcNewSize); //保存原始图片
if (maxRadius == 0)
{
//MessageBox.Show("没有圆形");
}
CvInvoke.cvSetImageROI(srcNewSize.Ptr, rectangle);//设置兴趣点---ROI（region of interest ）
var clone = srcNewSize.Clone();
CvInvoke.Imwrite(newPath, clone); //保存结果图
src.Dispose();
srcNewSize.Dispose();
grayImage.Dispose();
}
/// <summary>
/// 4.圆形提取
/// </summary>
public static void ExtractCircle(string oldpath, string newPath)
{
// 加载原始图片
Bitmap originalImage = new Bitmap(oldpath);
int diameter = Math.Min(originalImage.Width, originalImage.Height); // 获取最小边长作为直径
int x = (originalImage.Width - diameter) / 2; // 计算起始x坐标
int y = (originalImage.Height - diameter) / 2; // 计算起始y坐标
// 创建与圆形大小相等的bitmap
Bitmap croppedImage = new Bitmap(diameter, diameter);
using (Graphics g = Graphics.FromImage(croppedImage))
{
g.Clear(Color.LightBlue); // 设置圆圈外的颜色
// 设置高质量插值法
g.InterpolationMode = InterpolationMode.HighQualityBicubic;
// 设置高质量,低速度呈现平滑程度
g.SmoothingMode = SmoothingMode.HighQuality;
g.PixelOffsetMode = PixelOffsetMode.HighQuality;
g.CompositingQuality = CompositingQuality.HighQuality;
// 创建一个圆形路径
using (GraphicsPath path = new GraphicsPath())
{
path.AddEllipse(0, 0, diameter, diameter);
// 设置裁剪区域为圆形路径
g.SetClip(path);
// 从原始图片中绘制圆形区域到新图片
g.DrawImage(originalImage, new Rectangle(0, 0, diameter, diameter), x, y, diameter, diameter, GraphicsUnit.Pixel);
}
}
// 保存剪切后的图片
croppedImage.Save(newPath, ImageFormat.Jpeg);
}
/// <summary>
/// 5.像素提取（默认黑像素）
/// </summary>
/// <param name="img"></param>
/// <returns></returns>
public static List<string> GetImagePixel(string oldpath)//过滤
{
// 加载原始图片
Bitmap img = new Bitmap(oldpath);
//0 黑色
//95 深灰
//240 浅灰
//255 白
List<int> R = new List<int>();
List<int> G = new List<int>();
List<int> B = new List<int>();
List<string> xyList = new List<string>();
for (int y = 0; y < img.Height; y++)
{
for (int x = 0; x < img.Width; x++)
{
var a = img.GetPixel(x, y);
if (a.R == 0 && a.G == 0 && a.B == 0)
{
R.Add(img.GetPixel(x, y).R);
G.Add(img.GetPixel(x, y).G);
B.Add(img.GetPixel(x, y).B);
xyList.Add(x + "|" + y);
}
}
}
return xyList;
}
/// <summary>
/// 6.鱼像素提取
/// </summary>
/// <returns></returns>
public static List<string> FishExtract(List<string> data ,string circleImg)
{
for (int i = 0; i < data.Count; i++)
{
var str = data[i].Split("|");
if (!string.IsNullOrWhiteSpace(data[i]))
{
Bitmap image2 = new Bitmap(circleImg);
//周边检测 6
var list = GetSurroundingPixels(image2, Convert.ToInt32(str[0]), Convert.ToInt32(str[1]));
if (list.Where(a => a.R == 0 && a.G == 0 && a.B == 0).Count() >= 2)//这是鱼像素特征
{
}
else
{
data[i] = string.Empty;
//非鱼
}
}
}
return data;
}
//像素周边检测
public static List<FishVision.Model.Pixel> GetSurroundingPixels(Bitmap bitmap, int x, int y)
{
var result = new List<FishVision.Model.Pixel>();
int width = bitmap.Width;
int height = bitmap.Height;
Color[,] surroundingPixels = new Color[3, 3]; // 3x3 grid including the center pixel
for (int i = -1; i <= 1; i++) // Loop through the 3x3 grid around the center pixel
{
for (int j = -1; j <= 1; j++)
{
int newX = x + i;
int newY = y + j;
// Check if the new coordinates are within the bounds of the image
if (newX >= 0 && newX < width && newY >= 0 && newY < height)
{
surroundingPixels[i + 1, j + 1] = bitmap.GetPixel(newX, newY);
}
else
{
// Optionally, set out-of-bounds pixels to a default color or handle them as needed
surroundingPixels[i + 1, j + 1] = Color.Transparent; // or any other color you prefer
}
}
}
// Use surroundingPixels as needed (e.g., print colors)
for (int i = 0; i < 3; i++) // Printing the surrounding pixels for demonstration purposes
{
for (int j = 0; j < 3; j++)
{
var model = new FishVision.Model.Pixel();
model.X = x + i - 1;
model.Y = y + j - 1;
model.R = surroundingPixels[i, j].R;
model.G = surroundingPixels[i, j].G;
model.B = surroundingPixels[i, j].B;
result.Add(model);
//Console.WriteLine($"Pixel ({x + i - 1}, {y + j - 1}): {surroundingPixels[i, j]}");
}
}
return result;
}
/// <summary>
/// 7.鱼像素去重
/// </summary>
/// <param name="listFish"></param>
/// <returns></returns>
public static List<FishModel> FishDistinct(List<FishModel> listFish)
{
if (listFish != null && listFish.Count() > 0)
{
for (int i = 0; i < listFish.Count; i++)
{
listFish[i].FishIndex = listFish[i].FishIndex.Distinct().ToList();
}
}
return listFish;
}
/// <summary>
/// 8.鱼像素分组
/// </summary>
public static List<FishModel> FishGroup(List<string> data)
{
var fish = new List<FishModel>();
//鱼像素分组
for (int i = 0; i < data.Count; i++)
{
for (int b = 0; b < data.Count; b++)
{
if (!string.IsNullOrWhiteSpace(data[i]) && !string.IsNullOrWhiteSpace(data[b]))
{
var data_i_xy = data[i].Split("|");
var data_b_xy = data[b].Split("|");
if (AreAdjacent(Convert.ToInt32(data_i_xy[0]), Convert.ToInt32(data_i_xy[1]), Convert.ToInt32(data_b_xy[0]), Convert.ToInt32(data_b_xy[1])))//相邻的鱼像素合并一组
{
var entity = fish.Where(a => a.FishIndex.Contains(data[i]) || a.FishIndex.Contains(data[b])).FirstOrDefault();
if (entity != null)
{
entity.FishIndex.Add(data[i]);
entity.FishIndex.Add(data[b]);
}
else
{
FishModel model = new FishModel();
model.FishIndex = new List<string>();
model.FishIndex.Add(data[i]);
model.FishIndex.Add(data[b]);
fish.Add(model);
}
}
}
}
}
return fish;
}
/// <summary>
/// 像素是否相邻
/// </summary>
/// <param name="x1"></param>
/// <param name="y1"></param>
/// <param name="x2"></param>
/// <param name="y2"></param>
/// <returns></returns>
public static bool AreAdjacent(int x1, int y1, int x2, int y2)
{
// 检查x和y坐标之差是否为1，这样可以确保像素是直接相邻的
return (Math.Abs(x1 - x2) <= 1 && Math.Abs(y1 - y2) <= 1) && !(x1 == x2 && y1 == y2);
}
/// <summary>
/// 9.每条鱼的像素群寻找中位值作为轨迹坐标
/// </summary>
/// <param name="listFish"></param>
/// <returns></returns>
public static List<string> FishCenter(List<FishModel> listFish)
{
var result = new List<string>();
if (listFish != null && listFish.Count() > 0)
{
for (int i = 0; i < listFish.Count; i++)
{
//取中位值
var index = -1;
if (listFish[i].FishIndex.Count() % 2 == 0) // 偶数长度
{
index = listFish[i].FishIndex.Count() / 2;
}
else // 奇数长度
{
index = (listFish[i].FishIndex.Count() + 1) / 2;
}
//这条鱼中心坐标
var center = listFish[i].FishIndex[index];
result.Add(center);
}
}
return result;
}
/// <summary>
/// 反向二级化
/// </summary>
/// <param name="oldpath"></param>
/// <param name="newPath"></param>
public static void Two_LevelReversal(string oldpath, string newPath)
{
OpenCvSharp.Mat src = Cv2.ImRead(oldpath, OpenCvSharp.ImreadModes.Grayscale);
OpenCvSharp.Mat dst = new OpenCvSharp.Mat();
// 反向二值化：大于 127 的像素设为 0，其他设为 255
Cv2.Threshold(src, dst, 135, 255, ThresholdTypes.BinaryInv);
Cv2.ImWrite(newPath, dst);
}
/// <summary>
/// 96孔鱼苗高光二级化处理
/// </summary>
/// <param name="oldpath"></param>
/// <param name="newPath"></param>
public static void Two_LevelHeight(string oldpath, string newPath)
{
Emgu.CV.Mat image = CvInvoke.Imread(oldpath, Emgu.CV.CvEnum.ImreadModes.Grayscale);
Emgu.CV.Mat mid2 = new Emgu.CV.Mat();
CvInvoke.Threshold(image, mid2, 180, 255, ThresholdType.Binary);
CvInvoke.Imwrite(newPath, mid2);
}
/// <summary>
/// 斑点检测(用不着)
/// </summary>
/// <param name="mat">图片</param>
/// <param name="resultMat">结果图片</param>
/// <returns>斑点中心点数据</returns>
public static KeyPoint[] SimpleblobDetector(OpenCvSharp.Mat mat, out OpenCvSharp.Mat resultMat)
{
// 转化为灰度图
OpenCvSharp.Mat gray = new OpenCvSharp.Mat();
Cv2.CvtColor(mat, gray, ColorConversionCodes.BGR2GRAY);
// 创建SimpleBlobDetector并设置参数
OpenCvSharp.SimpleBlobDetector.Params parameters = new OpenCvSharp.SimpleBlobDetector.Params();
parameters.BlobColor = 0;//斑点的亮度值，取值为0或255，默认为0，表示只检测黑色斑点。
parameters.FilterByArea = true; // 是否根据斑点的面积进行过滤，默认为true
parameters.MinArea = 10; // 最小的斑点面积，默认为25
parameters.MaxArea = 6000; // 最大的斑点面积，默认为5000
// 创建SimpleBlobDetector
OpenCvSharp.SimpleBlobDetector detector = OpenCvSharp.SimpleBlobDetector.Create(parameters);
// 检测斑点
KeyPoint[] keypoints = detector.Detect(gray);
// 在图像上绘制斑点
resultMat = new OpenCvSharp.Mat();
Cv2.DrawKeypoints(mat, keypoints, resultMat, Scalar.All(-1));
return keypoints;
}
}
}