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：