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;

}

}

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