C#图像处理之边缘检测（Sobel）的方法

本文实例讲述了C#图像处理之边缘检测（Sobel）的方法。分享给大家供大家参考。具体如下：

//定义sobel算子函数
private static Bitmap sobel(Bitmap a)
{
int w = a.Width;
int h = a.Height;
try
{
 Bitmap dstBitmap = new Bitmap(w, h, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
 System.Drawing.Imaging.BitmapData srcData = a.LockBits(new Rectangle
  (0, 0, w, h), System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
 System.Drawing.Imaging.BitmapData dstData = dstBitmap.LockBits(new Rectangle
  (0, 0, w, h), System.Drawing.Imaging.ImageLockMode.WriteOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb);
 unsafe
 {
  byte* pIn = (byte*)srcData.Scan0.ToPointer();
  byte* pOut = (byte*)dstData.Scan0.ToPointer();
  byte* p;
  int stride = srcData.Stride;
  for (int y = 0; y < h; y++)
  {
  for (int x = 0; x < w; x++)
  {
   //边缘八个点像素不变
   if (x == 0 || x == w - 1 || y == 0 || y == h - 1)
   {
   pOut[0] = pIn[0];
   pOut[1] = pIn[1];
   pOut[2] = pIn[2];
   }
   else
   {
   int r0, r1, r2, r3, r4, r5, r6, r7, r8;
   int g1, g2, g3, g4, g5, g6, g7, g8, g0;
   int b1, b2, b3, b4, b5, b6, b7, b8, b0;
   double vR, vG, vB;
   //左上
   p = pIn - stride - 3;
   r1 = p[2];
   g1 = p[1];
   b1 = p[0];
   //正上
   p = pIn - stride;
   r2 = p[2];
   g2 = p[1];
   b2 = p[0];
   //右上
   p = pIn - stride + 3;
   r3 = p[2];
   g3 = p[1];
   b3 = p[0];
   //左
   p = pIn - 3;
   r4 = p[2];
   g4 = p[1];
   b4 = p[0];
   //右
   p = pIn + 3;
   r5 = p[2];
   g5 = p[1];
   b5 = p[0];
   //左下
   p = pIn + stride - 3;
   r6 = p[2];
   g6 = p[1];
   b6 = p[0];
   //正下
   p = pIn + stride;
   r7 = p[2];
   g7 = p[1];
   b7 = p[0];
   // 右下
   p = pIn + stride + 3;
   r8 = p[2];
   g8 = p[1];
   b8 = p[0];
   //中心点
   p = pIn;
   r0 = p[2];
   g0 = p[1];
   b0 = p[0];
   //使用模板
   vR = (double)(Math .Abs (r1+2*r4+r6-r3-2*r5-r8)+Math .Abs (r1+2*r2+r3-r6-2*r7-r8));
   vG = (double)(Math .Abs (g1+2*g4+g6-g3-2*g5-g8)+Math .Abs (g1+2*g2+g3-g6-2*g7-g8));
   vB = (double)(Math .Abs (b1+2*b4+b6-b3-2*b5-b8)+Math .Abs (b1+2*b2+b3-b6-2*b7-b8));
   if (vR > 0)
   {
    vR = Math.Min(255, vR);
   }
   else
   {
    vR = Math.Max(0, vR);
   }
   if (vG > 0)
   {
    vG = Math.Min(255, vG);
   }
   else
   {
    vG = Math.Max(0, vG);
   }
   if (vB > 0)
   {
    vB = Math.Min(255, vB);
   }
   else
   {
    vB = Math.Max(0, vB);
   }
   pOut[0] = (byte)vB;
   pOut[1] = (byte)vG;
   pOut[2] = (byte)vR;
   }
   pIn += 3;
   pOut += 3;
  }
  pIn += srcData.Stride - w * 3;
  pOut += srcData.Stride - w * 3;
  }
 }
 a.UnlockBits(srcData);
 dstBitmap.UnlockBits(dstData);
 return dstBitmap;
}
catch
{
 return null;
}
}

希望本文所述对大家的C#程序设计有所帮助。