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[ASP.net教程]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)=sqtr((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: