Spec of the ALTifier project


  Here is finally the promised draft of the pager of my ALTifier project.
You can download it from http://www.vorburger.ch/project/alt/ in Word, PDF
or PS format. Sorry for no time for an HTML version of this draft. The
abstract is given below. Notice that this is a draft, and one should
frequently substitute "is" by "will be" ... ;-)

  All comment is welcome! Any pointers to libraries that might be usefull
are of interest; especially a proxy server, a GIF & PNG comment extracting
stuff, and a simple OCR API.


ABSTRACT of "ALTifier - Web Accessibility Enhancement Tool"
full report at http://www.vorburger.ch/project/alt/

The goal of this project («ALTifier - Web Accessibility Enhancement Tool»)
was to research and implement tools to generate textual alternatives such as
the ALT attribute in IMG and other graphical HTML elements.

Often image and some other HTML tags lack a textual alternative. This makes
them inaccessible to screen readers, non-visual/text-only browsers and
braille readers. Adding alternate descriptions can make such pages more

On one hand, the project focuses on HTML authors with an "author mode" tool
to set ALT texts on a site-wide per-image basis, instead per each occurrence
in HTML documents. The idea of this tool is motivate HTML authors to set ALT
on all images by facilitating this job.

On the other hand, for users surfing on existing sites with lack of ALT, a
"user mode" tool tries to guess ALT text by heuristics. This tool is a proxy
server which filters/transforms HTML and reads pages from the original Web
server, inserts ALT, and sends them on to the Web client.

The heuristics used to guess alternate text range from looking at an image's
height & width, following links to extract a description from a document
title, apply OCR to find text on buttons, to some simple natural language

The project report gives a detailed description of the implementation and
explains design choices.

Michael Vorburger <mike@vorburger.ch> & <michael.vorburger@epfl.ch>
QUOTE: "Everything that does not kill you, makes you stronger."
HOMEPAGE: http://www.vorburger.ch

Received on Thursday, 3 December 1998 00:47:33 UTC