Scanning docs

[Magnus Danielson]

From: Jeroen Proveniers <J.Proveniers at orga.nl>
Subject: RE: Scanning docs
Date: Fri, 25 Aug 2000 08:19:08 +0200

> > > Unh...  How many colors deep was the GIF file - if you are scanning
> > > schematics, there should only be two colors and with this, 
> > GIF will far far
> > > outshine JPG.
> > > 
> > is the LZW
> > section of TIFF not commonly used.
> 
> I've to correct you. TIFF compression is used everyday, all over the world.
> Namely fax documents are encoded this way, before being sent. And it not
> LZW, it's Huffman coding. The code table is fixed, while LZW makes a new one
> for each job.
> I know this because I'm current working on a fax project. (Argh, 8051 doing
> Huffman compression)

Faxes don't use TIFF. They use Run-Length Encoding followed by a fixed Huffman
scheme. This is NOT TIFF. TIFF is a file format and group 3 faxes predates TIFF
with margin. TIFF does support RLE compression, but that is another thing.

TIFF compression could only mean using one of the many image compression
schemes to be found in the TIFF file format spec. There is also a JPEG
compression method in TIFF which supports a more complete JPEG than out
everyday JFIF does. Nobody seems to be using it alot thought.

Cheers,
Magnus