Reply #58: Some links to the law on the matter

[dbmk]

http://www.publaw.com/photo.html
http://www.photosecrets.com/links.law.html
http://www.usatoday.com/tech/columnist/andrewkantor/2005-12-29-camera-laws_x.htm
http://en.wikipedia.org/wiki/Photography_and_the_law
http://www.rcfp.org/photoguide/stateindex.html

It may or may not apply in your individual case - and I have not idea of how correct they are - so if in doubt, seek more information locally.

But I am somewhat sure that you are in the clear as long as the picture is not published for commercial reasons and does not violate the privacy of the involuntarily depicted to an unreasonable degree. Otherwise street photography would be a problematic artistic outlet for photogs. But IANAL.

Edit:
From the wikipedia link
"In 2006, a New York trial court issued a ruling in a case involving Philip-Lorca diCorcia, who had set up elaborate strobe rigs on a New York City street corner and had photographed people walking down the street, including Emo Nussenzweig, an Orthodox Jew who objected on religious grounds to diCorcia's publishing in an artistic exhibition a photograph taken of him without his permission. The photo's subject argued that his privacy and religious rights had been violated by both the taking and publishing of the photograph of him. The judge dismissed the lawsuit, finding that the photograph taken of Nussenzweig on a street is art - not commerce - and therefore is protected by the First Amendment."

I would say that a project like this would clearly fall inside the protected use of pictures taken in public.