C#图像伪彩色处理方法

//灰度图转伪彩色图像函数public Bitmap PGrayToColor(Bitmap src){  try  {   Bitmap a = new Bitmap(src);   Rectangle rect = new Rectangle(0, 0, a.Width, a.Height);   System.Drawing.Imaging.BitmapData bmpData = a.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format24bppRgb);   int stride = bmpData.Stride;   unsafe   {     byte* pIn = (byte*)bmpData.Scan0.ToPointer();     byte* P;     int R, G, B;     int temp = 0;     for (int y = 0; y < a.Height; y++)     {     for (int x = 0; x < a.Width; x++)     {       P = pIn;       B = P[0];       G = P[1];       R = P[2];       temp = (byte)(B * 0.114 + G * 0.587 + R * 0.299);       if (temp >= 0 && temp <= 63)       {        P[2] = 0;        P[1] = (byte)(254 - 4 * temp);        P[0] = (byte)255;       }       if (temp >= 64 && temp <= 127)       {        P[2] = 0;        P[1] = (byte)(4 * temp - 254);        P[0] = (byte)(510 - 4 * temp);       }       if (temp >= 128 && temp <= 191)       {        P[2] = (byte)(4 * temp - 510);        P[1] = (byte)(255);        P[0] = (byte)0;       }       if (temp >= 192 && temp <= 255)       {        P[2] = (byte)255;        P[1] = (byte)(1022 - 4 * temp);        P[0] = (byte)0;       }       pIn += 3;     }     pIn += stride - a.Width * 3;     }   }   a.UnlockBits(bmpData);   return a;  }  catch (Exception e)  {   MessageBox.Show(e.Message.ToString());   return null;  }}