Thanks for explaining gamma as an exponent. For as many things that I've read
about gamma I've never seen that before.
Chuck Norcutt
> -------Original Message-------
> From: Jan Steinman <Jan@xxxxxxxxxxxxxx>
> Subject: [OM] Re: RAW Bit Depth
> Sent: Apr 09 '07 07:41
>
>
> > From: Moose <olymoose@xxxxxxxxx>
> >
> > I have no idea how JPEG compression works inside. For all I know, it
> > uses a nonlinear, base two, mapping and the quality levels are setting
> > the number of steps per stop.
>
> It's considerably more complicated than that. It does a discrete
> cosine transform on 8x8 blocks, re-quantizing the result.
>
> You're thinking of colour spaces, which map pixel values to
> luminosity, also known as gamma. Gamma is the exponent used to come up
> with the non-linear curve. The 2.2 gamma typically used by computer
> monitors results in packing about 11 stops into 8 bits.
==============================================
List usage info: http://www.zuikoholic.com
List nannies: olympusadmin@xxxxxxxxxx
==============================================
|