C# 简单的图像边缘提取

博主做的很简单，大家看一看就好了......

用到的算法是robert算子，这是一种比较简单的算法：

                                  f(x,y)=sqrt((g(x,y)-g(x+1,y+1))^2+(g(x+1,y)-g(x,y+1))^2)

博主一共写了三段代码，第一段是边缘提取，第二段是线条加粗，第三段是原图和边缘图重合，三段代码可以放在一起，但为了看得清晰我就把他们分开了。

简单粗暴直接上代码！

private void Image_Test()
        {
            if (this.pBox.Image != null)
            {
               
                int Height = this.pBox.Image.Height;
                int Width = this.pBox.Image.Width;
                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bppRgb);
                Bitmap MyBitmap = (Bitmap)this.pBox.Image;
                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb); //原图
                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);  //新图即边缘图
                unsafe
                {   
                    //首先第一段代码是提取边缘，边缘置为黑色，其他部分置为白色
                    byte* pin_1 = (byte*)(oldData.Scan0.ToPointer());
                    byte* pin_2 = pin_1 + (oldData.Stride);                 
                    byte* pout = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height - 1; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {
                            //使用robert算子
                            double b = System.Math.Sqrt(((double)pin_1[0] - (double)(pin_2[0] + 3)) * ((double)pin_1[0] - (double)(pin_2[0] + 3)) + ((double)(pin_1[0] + 3) - (double)pin_2[0]) * ((double)(pin_1[0] + 3) - (double)pin_2[0]));
                            double g = System.Math.Sqrt(((double)pin_1[1] - (double)(pin_2[1] + 3)) * ((double)pin_1[1] - (double)(pin_2[1] + 3)) + ((double)(pin_1[1] + 3) - (double)pin_2[1]) * ((double)(pin_1[1] + 3) - (double)pin_2[1]));
                            double r = System.Math.Sqrt(((double)pin_1[2] - (double)(pin_2[2] + 3)) * ((double)pin_1[2] - (double)(pin_2[2] + 3)) + ((double)(pin_1[2] + 3) - (double)pin_2[2]) * ((double)(pin_1[2] + 3) - (double)pin_2[2]));
                            double bgr = b + g + r;//博主一直在纠结要不要除以3，感觉没差，选阈值的时候调整一下就好了- -
                            
                            if (bgr > 80) //阈值，超过阈值判定为边缘（选取适当的阈值）
                            {
                                b = 0;
                                g = 0;
                                r = 0;
                            }
                            else
                            {
                                b = 255;
                                g = 255;
                                r = 255;
                            }
                            pout[0] = (byte)(b);
                            pout[1] = (byte)(g);
                            pout[2] = (byte)(r);
                            pin_1 = pin_1 + 3;
                            pin_2 = pin_2 + 3;
                            pout = pout + 3;

                        }
                        pin_1 += oldData.Stride - oldData.Width * 3;
                        pin_2 += oldData.Stride - oldData.Width * 3;
                        pout += newData.Stride - newData.Width * 3;
                    }

                    //这里博主加粗了一下线条- -，不喜欢的同学可以删了这段代码
                    byte* pin_5 = (byte*)(newData.Scan0.ToPointer());                    
                    for (int y = 0; y < oldData.Height - 1; y++)
                    {
                        for (int x = 3; x < oldData.Width; x++)
                        {
                            if(pin_5[0]==0&&pin_5[1]==0&&pin_5[2]==0)
                            {
                                pin_5[-3] = 0;
                                pin_5[-2] = 0;
                                pin_5[-1] = 0;      //边缘点的前一个像素点置为黑色（注意一定要是遍历过的像素点）                                                    
                            }
                            pin_5 += 3;
                            
                        }
                        pin_5 += newData.Stride - newData.Width * 3;                     
                    }
                    
                    //这段代码是把原图和边缘图重合
                    byte* pin_3= (byte*)(oldData.Scan0.ToPointer());
                    byte* pin_4 = (byte*)(newData.Scan0.ToPointer());
                    for (int y = 0; y < oldData.Height - 1; y++)
                    {
                        for (int x = 0; x < oldData.Width; x++)
                        {
                            if (pin_4[0] == 255 && pin_4[1]==255 && pin_4[2]==255) 
                            {
                                pin_4[0] = pin_3[0];
                                pin_4[1] = pin_3[1];
                                pin_4[2] = pin_3[2];
                            }
                            pin_3 += 3;
                            pin_4 += 3;
                        }
                        pin_3 += oldData.Stride - oldData.Width * 3;
                        pin_4 += newData.Stride - newData.Width * 3;
                    }
                    //......
                    bitmap.UnlockBits(newData);
                    MyBitmap.UnlockBits(oldData);
                    this.pBox.Image = bitmap;
                }

            }
            
        }

例子1：

例子2：