The image has been recovered twice, once by professionals and then more recently (and much more quickly) by Amelia Carolina Sparavigna using freely downloadable software from the internet. You can read the story and see the results of her efforts on MIT's 'Technology Review'.The self portrait shows Leonardo as a young man, the only other existing self-portrait is one he made when he was old (this is the image shown here).
It's fascinating how the text can be removed and at every point automatically replaced by an average of the surrounding area. That's what Amelia Carolina Sparavigna did using the packages she downloaded. She used The Gimp (image processing software) to superimpose the young face on the old face to check whether the eyes, nose and mouth showed the same relative spacings. They did! This helps to confirm that both portraits are of the same person - we may get wrinkles as we age but the proportions of our face remain the same.
Kudos to Amelia, but also to the science journalist who first noticed the presence of a portrait underlying da Vinci's text on bird flight.
