sobel边缘检测java_C#图像处理之边缘检测（Sobel）的方法
//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;
}
}