Path: utzoo!mnetor!uunet!husc6!cmcl2!brl-adm!umd5!rutgers!bellcore!faline!thumper!mike From: mike@thumperbellcore.com (Michael Caplinger) Newsgroups: comp.sys.mac Subject: Re: 3-D Graphics Question Message-ID: <883@thumperbellcore.com> Date: 10 Dec 87 21:26:46 GMT Organization: Bell Communications Research Lines: 18 Keywords: geometric transform, photoclinometry If all you want to do is rotate the image such that you get a straight-down view of it, a simple geometric transformation with some kind of bilinear interpolation will do what you want -- a little guesswork about slant angles is all that's needed. Try looking in an elementary image processing book. I don't know of any commercial software that'll do this, but it's easily within the processing power of a Mac, if you don't mind waiting a few tens of minutes per transformation. Getting elevation data from a single image can also be done, given a knowledge of lighting angle and surface reflectivity characteristics; it's like doing image synthesis backwards, and the process is usually called photoclinometry. Such techniques have been used on data from the Voyager mission since stereo pairs typically weren't available. I'm a little bemused by peoples' reactions to this problem; it just isn't as hard as y'all thought... Mike Caplinger, mike@bellcore.com