image processing

Question

hi for all,

i want to apply correlation method between two images; so i have to make some mathematical calculations on them.

after reading images from a file like this:

Image b = Image.FromFile( "c:\\standard\\test1.bmp" );

Bitmap bb = (Bitmap)b;

the problem is how can i deal with images using operators like -, /, XOR.....
I try to convert them to byte at first like this:

MemoryStream ms = new MemoryStream();

bb.Save(ms, ImageFormat .Bmp);

byte[] s = ms.GetBuffer();

But that does not work!!!
So what is the form images have to be before applying calculations; and how can i do it?

thanx