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Re: pixels, bis

<x-charset iso-8859-1>Your mutual fund data and pictures are both binary (on or off) data.  No
difference there.  To define one pixel takes from one to a bunch of bits.
Strictly black and white (no shades of gray) images need one bit per pixel.
Realistic color requires many bits.

The program that uses that data is written with expectations about the data
it will be given, and organizes the data according to that format.  The
format it expects determines where it thinks the data for one pixel starts
and stops in the stream of bits.

Some picture formats specify the original image size.  That's additional
data included along with the other 1's and 0's that specify the data for the
actual image pixels.  That dimensional info is provided for the image as a
whole rather than with each individual pixel.

Of course, as image representation becomes more sophisticated, like using
fractal geometry, all the above will probably be wrong.

It just happens that it's convenient to use "on" and "off" to represent data
in computers.  It works well with the hardware.  Rather than two states, a
"bit" could have three.  Except, since "bit" came from "binary digit", I
suppose it would be a "trit".

Bruce Roorda
Possum Hill Farm

Robert Bollini wrote:

> Now apparently pixels are data like other data: electrical pulses that
> turn switches off and on. But I'm getting the impression that pixel data
> is bounded data, something like what Dan Margulis calls the "spots" that
> make up half-tone dots. If that ain't so, how do pixels differ from the
> stream of shut-it-offs and turn-it-ons that makes up, say, the mutual
> fund information coming to me every night via an old DOS financial
> program?

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