Doug Cooper of the Center for Research in Computational Linguistics has presented a very interesting paper with this title on how to distinguish Thai letters in a variety of styles, chiefly printed. He has put it on the web as a zipped plain postscript file, but not all of us can easily read plain postscript. I have therefore put the file in PDF (zipped - 466kB) in my web space as a general service.
In March 2005 there was been much interest in this paper in the topic Why are Thai Letters So Hard to Read? at the Thai Visa forum.
Prepared by: Richard Wordingham