c# - 不使用Aforge或OpenCv进行圆检测

Question

我想在没有库的位图中检测圆。首先，我使用大津脱粒机进行二值化。二值化后，我使用了拉普拉斯边缘检测。现在我的位图中有一个圆圈。我如何检测到这个圈子。

注意:我试图绘制一个圆并 float x和y坐标。但是这种方法太慢了，而且存在半径问题。因为，如果我的tempCircle的半径为10，而真实圆的半径为9，则我的算法找不到该圆。

    BitmapProcess bmpPro = new BitmapProcess((Bitmap)(pictureBox1.Image));
    bmpPro.LockBits();
    int black = 0, temp = 0,fixX=0,fixY=0;

    Bitmap bmp = (Bitmap)pictureBox1.Image;
    Graphics g = this.pictureBox1.CreateGraphics();
    Pen pen = new Pen(Color.Red, 10);
    int x = 0, y = 0;
    for (int a = 0; a < pictureBox1.Image.Width - 1; a += 1)
    {
        for (int b = 0; b < pictureBox1.Image.Height - 1; b++)
        {
            double radius = 10;

            temp = 0;
            for (double i = 0.0; i < 360.0; i += 1)
            {
                double angle = i * System.Math.PI / 180;
                x = (int)(a + radius * System.Math.Cos(angle));
                y = (int)(b + radius * System.Math.Sin(angle));
                Color aa = bmpPro.GetPixel(Math.Abs(x), Math.Abs(y));

                if (bmpPro.GetPixel(Math.Abs(x), Math.Abs(y))!=Color.Black) temp++;

            }
            if (temp > black)
            {
                black = temp;
                fixX = a;
                fixY = b;

            }

        }

    }
    g.DrawEllipse(pen,fixX,fixY,50,50);



using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace LockBitBitmap
{
    class BitmapProcess
    {
        public int b = 0;
        int TotalPixelLocked; 
        Bitmap source = null; //kaynak bmp
        IntPtr Iptr = IntPtr.Zero; //baslangıc adresi
        BitmapData bitmapData = null;

        public byte[] Pixels { get; set; }
        public int Depth { get; set; }
        public int Width { get; set; }
        public int Height { get; set; }

        public BitmapProcess(Bitmap source)
        {
            this.source = source;  //bitmapı dısardan al
        }

        public void LockBits()
        {
            //resmin en ve boyunu al
            Width = source.Width;
            Height = source.Height;

            //kilit için rectangle olustur
            Rectangle rect = new Rectangle(0,0,Width,Height);

            //kaynak bitmap ın pixel formatını al
            Depth = System.Drawing.Bitmap.GetPixelFormatSize(source.PixelFormat);

            //pixel basına bit sayısını bul(Bpp)
            if (Depth != 8 && Depth != 24 && Depth != 32)
            {
                return; //bit türü desteklenmiyor...
            }

            //bitmapı kilitle ve veriyi döndür...          
            bitmapData = source.LockBits(rect, ImageLockMode.ReadWrite, source.PixelFormat);

            //kilitlenecek pixel sayısını al
            TotalPixelLocked = Math.Abs(bitmapData.Stride) * source.Height;

            //pixel verilerini tutmak için byte dizisi olustur
            int step = Depth / 8;
            Pixels = new byte[TotalPixelLocked * step];
            Iptr = bitmapData.Scan0;

            //verileri pointerden diziye aktar
            Marshal.Copy(Iptr, Pixels, 0, TotalPixelLocked);

        }

        public Color GetPixel(int x, int y)
        {
            Color clr = Color.Empty; //boş renk

            //renkli nesne sayısını al
            int cCount = Depth / 8;

            //istenen pixelin baslangıc adresini bul
            int i = y * bitmapData.Stride + x * cCount;
            if (i > (Pixels.Length - cCount))
            {
                throw new IndexOutOfRangeException("index out of range ( dizi adresi geçersiz)");
            }
            if (Depth == 32) //r g b a
            {
                byte b = Pixels[i];
                byte g = Pixels[i + 1];
                byte r = Pixels[i + 2];
                byte a = Pixels[i + 3];
                clr = Color.FromArgb(a,r,g,b);
            }

            if (Depth == 24) //r g b 
            {
                byte b = Pixels[i];
                byte g = Pixels[i + 1];
                byte r = Pixels[i + 2];
                clr = Color.FromArgb(r, g, b);
            }

            if (Depth == 8) // r g b hepsi aynı
            {
                byte c = Pixels[i];
                clr = Color.FromArgb(c,c,c);
            }


            return clr;

        }

        public void SetPixel(int x, int y, Color color)
        {
            // renkli nesne sayısı
            int cCount = Depth / 8;

            // baslangıc indexini bul
            //int i = ((y * Width) + x) * cCount;
            int i = y * bitmapData.Stride + x * cCount;
            if (i > (Pixels.Length - cCount))
            {
                throw new IndexOutOfRangeException("index out of range ( dizi adresi geçersiz)");
            }
            if (Depth == 32) // r,g,b, (alpha)
            {
                Pixels[i] = color.B;
                Pixels[i + 1] = color.G;
                Pixels[i + 2] = color.R;
                Pixels[i + 3] = color.A;
            }
            if (Depth == 24) // r,g,b
            {
                Pixels[i] = color.B;
                Pixels[i + 1] = color.G;
                Pixels[i + 2] = color.R;
                b++;
            }
            if (Depth == 8)//r g b hepsi aynı
            {
                Pixels[i] = color.B;
            }
        }

        public Bitmap giveBitmap()
        {
            System.Runtime.InteropServices.Marshal.Copy(Pixels, 0, Iptr, TotalPixelLocked);
            source.UnlockBits(bitmapData);
            return source;
        }





    }
}

Answer 1

如果图像中只有几个圆圈，建议您使用RANSAC。

简要说明:从您的边缘像素中随机选择3个点，并选择适合这些点的find the equation of the circle。在所有剩余边缘点上使用此方程式，可以查看圆上有多少边缘点，即有多少满足该方程式。重复此过程N次(可以根据各种因素来确定N，包括边缘点的数量，圆的数量等)，并记录具有最高内线数(位于圆上的点)的迭代。与此最大迭代相对应的方程是您的最佳拟合圆。

如果图像中有多个圆圈，请在删除或掩盖所有先前找到的圆圈后再重复上述步骤。