Optar – OPTical ARchiver – a codec for encoding data on paper

ronja.twibright.com

14 points·pmoriarty··3 comments

This is awesome. I remember finding this a while back for some project.

> Optar fits 200kB on an A4 page, then you print it with a laser printer.

I'm kind of surprised newer programs haven't come out since Optar (which is pretty old) that could store even more data on a page.

There must be research in the compression, optical recognition, or error correction fields that could improve on Optar's efficiency and/or reliability.

Optar itself is pretty bare-bones from a feature perspective, unpolished, and hasn't been maintained in ages. It has no official GitHub repo (or any other kind of source code repo) that I could find. The released tarball doesn't even have a version number. It only works with the obscure PGM image format (for which you need ImageMagick or GraphicsMagick to convert to/from) instead of something common like PNG.

It does actually work (or did when I tried it a decade or more ago), so by that measure it could be considered good enough, but it's sad that there's been no more modern open source alternative in the many years since it's been released.

I'd guess the limits of information theory have been just about reached. The only real improvement I can think of would be either the ability to scan and resolve smaller individual squares (and that is dependent on how much the printer ink bleeds), or printing in color.

It would be cool to update optar, and make it a little more flexible. It would be fun to make a python package that can output arbitrary data as a printable image.

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