[pm90]

A bit off-topic: a prof. at the Uni once told me that David Lowe (who invented SIFT) never got any money from the patent (which I think belongs jointly to him and UBC) because commercial implementations would make a few changes to the algo and just use it, without citation or license. If any HN'ers know more about this, I would be glad to hear it

[jjwiseman]

While it does seem to be regarded to be easy to avoid infringing on the SIFT patent by changing the algorithm in a minor way (e.g. using SURF features but doing SIFT-style search), I know there are companies that have licensed SIFT from Lowe, and I would expect he's been paid for those licenses.