// 定義灰度調色盤

System.Drawing.Imaging.ColorPalette GreyColorPalette = null;

// 定義新Bitmap影象

System.Drawing.Bitmap newBitmap = null;

// 讀取BitMap影象

System.Drawing.Bitmap curBitmap = new Bitmap("00.bmp");

// 定義處理區域

Rectangle rect = new Rectangle(0, 0, curBitmap.Width, curBitmap.Height);

// 獲取畫素資料

System.Drawing.Imaging.BitmapData bmpData = curBitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly, curBitmap.PixelFormat);

// 獲取畫素資料指標

IntPtr IntPtrPixelData = bmpData.Scan0;

// 定義Buffer

byte[] PixelDataBuffer = new byte[curBitmap.Width * curBitmap.Height];

// 拷貝Bitmap的畫素資料的到Buffer

System.Runtime.InteropServices.Marshal.Copy(IntPtrPixelData, PixelDataBuffer, 0, PixelDataBuffer.Length);



unsafe
{
    fixed (byte* pSrc = PixelDataBuffer)
{ 
newBitmap = new Bitmap(curBitmap.Width, curBitmap.Height, curBitmap.Width, System.Drawing.Imaging.PixelFormat.Format8bppIndexed, new IntPtr(pSrc));


GreyColorPalette = newBitmap.Palette;
for (int Index = 0; Index <= byte.MaxValue; Index++)
{
    GreyColorPalette.Entries[Index] = Color.FromArgb(byte.MaxValue, Index, Index, Index);
}
newBitmap.Palette = GreyColorPalette;
newBitmap.Save("newBitmap.bmp");
pictureBox1.Image = newBitmap;