Filmscanners mailing list archive (filmscanners@halftone.co.uk)
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: filmscanners: Vuescan - A few technical questions
In a message dated 3/5/2001 1:52:06 PM EST, michael@shaffer.net writes:
> > What on earth is a 3X3 matrix?
>
> 3 by 3 is the small matrix (or "kernal") around the pixel to be
> filtered ... i.e., its nearest neighbors. Other common filter kernals
> are 5x5 (a pixel beyond nearest neighbor), and 7x7 ... and even
> larger.
Yes, this is one type of 3x3 matrix. The type I use in the
restore colors algorithm is actually 9 numbers that are
used to convert from one set of rgb numbers to another:
Rnew = M11*R + M12*G + M13*B
Gnew = M21*R + M22*G + M23*B
Bnew = M31*R + M32*G + M33*B
The Mxy numbers form a 3x3 matrix. This matrix multiplication
is at the heart of color space conversions as well.
Regards,
Ed Hamrick
|
