用到的算法是robert算子，這是一種比較簡單的算法：
f(x,y)=sqrt((g(x,y)-g(x+1,y+1))^2+(g(x+1,y)-g(x,y+1))^2)
博主一共寫了三段代碼，第一段是邊緣提取，第二段是線條加粗，第三段是原圖和邊緣圖重合，三段代碼可以放在一起，但為了看得清晰我就把他們分開了。
簡單粗暴直接上代碼！
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); //原圖
BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb); //新圖即邊緣圖
unsafe
{
//首先第一段代碼是提取邊緣，邊緣置為黑色，其他部分置為白色
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;//博主一直在糾結要不要除以3，感覺沒差，選阈值的時候調整一下就好了- -
if (bgr > 80) //阈值，超過阈值判定為邊緣（選取適當的阈值）
{
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;
}
//這裡博主加粗了一下線條- -，不喜歡的同學可以刪了這段代碼
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; //邊緣點的前一個像素點置為黑色（注意一定要是遍歷過的像素點）
}
pin_5 += 3;
}
pin_5 += newData.Stride - newData.Width * 3;
}
//這段代碼是把原圖和邊緣圖重合
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：