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。