//定義圖像線性運算函數（y=kx+v）private static Bitmap LinearOP(Bitmap a, double k, double v){  Rectangle rect = new Rectangle(0, 0, a.Width, a.Height);  System.Drawing.Imaging.BitmapData srcData = a.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, a.PixelFormat);  IntPtr ptr = srcData.Scan0;  int bytes = 0;  bytes = srcData.Stride * a.Height;  byte[] grayValues = new byte[bytes];  System.Runtime.InteropServices.Marshal.Copy(ptr, grayValues, 0, bytes);  int temp = 0;  for (int i = 0; i < bytes; i++)  {   temp = (int)(k * grayValues[i] + v + 0.5);   temp = (temp > 255) ? 255 : temp < 0 ? 0 : temp;   grayValues[i] = (byte)temp;  }  System.Runtime.InteropServices.Marshal.Copy(grayValues, 0, ptr, bytes);  a.UnlockBits(srcData);  return a;}